19th European Symposium on Radiopharmacy and Radiopharmaceuticals (ESRR’18)

OP01 Novel Acyclic Chelators for Zr and Ga S. Ait-Mohand, A. Alnahwi, V. Dumulon-Perreault and B. Guérin Department of nuclear medicine and radiobiology, Faculty of medicine and health sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada J1H 5N4; Centre d’Imagerie Moléculaire de Sherbrooke (CIMS), CR-CHUS, Sherbrooke, QC, Canada J1H5N4 Correspondence: B. Guérin EJNMMI Radiopharmacy and Chemistry 2018, 3(Suppl 1):OP01

. Scheme of the synthesizer including the self-constructed unit for the formulation of the second tracer Aim: Nowadays copper-mediated radiofluorination of arylboronic acids pinacol esters (ArylBPin) found ample application for 18 F-labeling of various electron-rich arenes. 1 The improvement of this methodology, in particular, 18 F-recovery step, has been in focus of the recent researches. 2,3 The suggested use of aqueous solutions of non-ionic bases for 18 F-elution was efficient, however in non-aqueous solutions these weak bases cannot reach sufficient degree of protonation for 18 F-recovery. Non-aqueous solutions of 4-dimethylaminopyridinium sulfonates may constitute an amenable alternative. These salts may serve both as a source of co-ligand for Cu(OTf) 2 py 4 catalyst, increasing its efficiency, 4 and as appropriate PTC agents. Methods: Following earlier suggested procedure 2 an aqueous [ 18 F]fluoride was loaded onto an anion exchange cartridge from the male side (OASIS WAX 1cc, 30 mg, preconditioned with 0.5 M NaHCO 3 and water). The cartridge was rinsed with 1 ml of i-PrOH in the same direction and dried by compressed air. [ 18 F]Fluoride was eluted from female side with 25 μmol of 4-dimethylaminopyridinium tosylate (4-DMPTs) or 4-dimethylaminopyridinium triflate  in 0.5 mL of DMA into the vial containing 5.3 μmol of Cu(OTf) 2 py 4 and 17.9 μmol of ArylBPin precursor in 0.5 ml of DMA. The mixture was heated (110°C, 20 min) in a sealed vial under air. After cooling radiochemical conversion (RCC) was determined by radioTLC. Results: Both sulfonates provided similar 18 F-elution efficiency (EE), however higher RCC were achieved using triflate salt. Notably, with this protocol relatively small amount of precursor and catalyst was required. Its feasibility was confirmed for a series of model aromatic substrates. Conclusion: Easily accessible 4-dimethylaminopyridinium triflate has shown to be suitable 18 F-eluting agent for alcohol-enhanced Cumediated radiofluorination. The developed procedure is very simple, avoids any solvents evaporation steps and easy adaptable to automation. Work is now in progress to adapt this procedure to the preparation of clinically relevant radiotracers. Research support: RFBR grant № 16-54-12062\16.

OP09
Development of biocompatible and functionalised polymer nanoparticles for the specific vectorisation of an imaging agent N. Lepareur  Aim: Nanomedicine, the application of nanotechnologies to the medical domain, is a fast-growing research field, especially the production of nanoparticles enabling encapsulation then controlled and targeted release of molecules of interest, such as a cytotoxic drug. Diagnostic could also benefit from the use of such nanovectors containing one or more imaging agent(s) (fluorescent dye, contrast agent, radionuclide) to image a tumour. Methods: Benzyl polymalate and its derivatives (pegylated and biotinylated) were prepared according to the method previously described. (1) Different techniques have been used to formulate the nanoparticules and to incorporate an imaging agent (DiD-Oil, fluorescein amine and a 99m Tc-based radiotracer). The resulting nanoparticles were characterised using various techniques (DLS, zetametry, AF4, TEM, EDS). Preliminary in vitro studies have also been done.
Results: Prepared nanoparticles were monodisperse and stable. To encapsulate fluorescent DiD-Oil and lipophilic 99m Tc-SSS radiotracer, nanoprecipitation method was not suitable and had to be modified. (2) The resulting nanoparticles were also monodisperse and stable, with a slightly higher diameter. Electron-dispersive spectroscopy coupled to TEM demonstrated the presence of sulphur in the nanoparticles, thus confirming the encapsulation of the radiotracer. Various peptides have been grafted through streptavidin and their affinity to different hepatoma cell lines was tested. Conclusion: We have developed a family of nanoparticles based on degradable, biocompatible and functionalisable polymers, enabling the binding of specific targeting agents (eg. peptides) and incorporating an imaging agent, either for optical or scintigraphic imaging. These objects deserve further investigation to gain a deeper understanding on their properties and in vivo behaviour. Direct grafting of the most promising peptides is underway. Encapsulation of a therapeutic radiotracer is also planned. Aim: Monoclonal antibodies have been widely exploited for both diagnostic and therapeutic purposes. For antibody radiolabeling with Cu-64, a bifunctional chelator is required which can seize the radio metal quite robustly into its cavity. Thus development of crossbridged chelator is in need. Unlike the other biomolecules (e.g., peptide, aptamer), antibody radiolabeling condition is tricky and needs sophisticated and mild labelling conditions which limits the application of cross-bridged chelator in immuoPET. We report a new kind of cross-bridged macrocyclic chelator (PCB-TE2A-alkyne), which can be converted to any copper free clickable moiety or any functional group for antibody conjugation (Fig. 1). It thus enables a general platform for antibody tagging with Cu-64. Methods: The propylene cross-bridged chelator was modified to different clickable moieties and various functional groups in a single step prior to radiolabeling. To confirm its applicability radiolabeled chelator was then conjugated to trastuzumab and biodistribution and microPET imaging was done in NIH3T6.7 tumor-bearing BALB/c nude mice. Results: Starting from cyclam the PCB-TE2A-alkyne was synthesized in five consecutive steps with 32% overall yield. It was then modified to different functional groups, viz., tetrazine, NHS-ester, maleimide, in a single step in excellent yield. Modifications to different functional groups did not require any HPLC purification. In further, the tetrazine modified chelator was radiolabeled with Cu-64 in high yield and conjugated to trastuzumab within 10 minutes at room temperature. Conclusion: A versatile propylene cross-bridged macrocyclic chelator for radiolabeling of heat-sensitive antibody with Cu-64 was demonstrated.
Aim: Pseudomonas aeruginosa (P.a.) is an increasingly prevalent opportunistic pathogen that causes a variety of life-threatening nosocomial infections, especially in immunocompromised hosts. The diagnosis of infections caused by P.a. can be challenging due to inconvenient diagnostic methods, which are often slow, invasive or lack sensitivity and/or specificity. Novel diagnostic tools are urgently needed. One of the novel diagnostic strategies for the specific detection of P.a. infections could be utilization of radiolabelled siderophores. Siderophores are small molecules produced by many microorganisms to scavenge essential iron. Replacing iron in siderophores by suitable radiometal could open approaches for targeted imaging of infection. Here we report on the preclinical evaluation of Ga-68 labelled pyoverdine, siderophore produced by P.a., for specific diagnosis of P.a. infections. Methods: Radiolabelling of pyoverdine isolated from P.a. with Ga-68 was performed using acetate buffer. Radiochemical purity was analyzed by RP-HPLC and ITLC-SG. Protein binding, partition coefficient and stability values of 68 Ga-pyoverdine in human serum and in the excess of competing chelator and metal were determined. In vitro uptake was tested in various microbial cultures. Ex vivo biodistribution was studied in normal Balb/c mice. Uptake of 68 Ga-pyoverdine by P.a. in vivo was studied in respiratory and muscle infection animal models using PET/CT imaging. In vivo specificity of 68 Ga-pyoverdine for P.a. was compared with other radiopharmaceuticals. Results: Pyoverdine was labelled with 68 Ga with high (>95%) radiochemical purity. The resulting complex showed hydrophilic properties (log P = -3.07±0.08), low protein binding (<3% up to 120 min incubation) and~95% stability in human serum. In vitro uptake of 68 Ga-pyoverdine was highly dependent on iron load and type of microbial culture. In P.a. cultures high uptake under iron-deficient conditions was observed that could be blocked. Furthermore in all other tested microbial cultures the uptake of 68 Ga-pyoverdine was significantly lower. In normal mice 68 Ga-siderophore showed rapid renal excretion and low blood values (0.09±0.01 %ID/g) even at a short time period (90 min) after application. PET/CT imaging in infected animals displayed specific accumulation of 68 Ga-pyoverdine in infected tissues and better distribution than other, clinically used radiopharmaceuticals. Conclusion: We have shown that pyoverdine can be labelled with Ga-68 with high affinity and radiochemical purity. 68 Ga-poverdine displayed suitable in vitro characteristics and excellent pharmacokinetics. The high and specific uptake of 68 Ga-pyoverdine by P.a. was confirmed both in vitro and in vivo, proving its potential for specific imaging of Pseudomonas infections.
Aim: Invasive pulmonary aspergillosis (IPA) mainly caused by Aspergillus fumigatus (AFU) is a major cause of mortality in immunosuppressed patients mainly due to the lack of sensitive and specific diagnostic procedures. AFU secrets the siderophore triacetylfusarinine C (TAFC) to sequester iron for acquisition and uptake via the MirB transporter. This system is essential for AFU virulence and is highly upregulated during infection. We have shown that TAFC can be radiolabeled with 68 Ga thereby exhibiting excellent targeting properties in an AFU infection model [1]. Here we aimed to modify TAFC and investigate the influence of introduced substituents on preservation of AFU-targeting characteristics in vitro and in vivo by μPET/CT imaging. Methods: TAFC derivatives with various substituents (different carbon chain lengths, charges, fluorescent dye) were synthesized starting from the deacetylated forms of TAFC, characterized by HPLC and MS and radiolabeled with 68 Ga. Stability, protein binding and logP values were determined. In vitro uptake by AFU was performed in iron-depleted and iron-replete cultures. Selected compounds with highest, lowest and comparable uptake ratio to TAFC were studied regarding their biodistribution behaviors in normal BALB/c mice as well as via μPET/CT imaging in healthy and AFU-infected Lewis rats. Results: 15 different TAFC derivatives with varying substitutions were synthetized in high yields and could be labeled with 68 Ga at high specific activity. Lipophilicities as expressed in logP were -0.38 to -3.80 ([ 68 Ga]TAFC -2.1). In vitro uptake studies revealed retained recognition by the MirB transporter with reduced uptake efficiency with increasing number of substitutions (mono-, >di, > tri). Introduction of fluorescent dye (FITC) allowed imaging of uptake and processing of TAFC analogs. Three selected compounds, [ 3 , displayed no signal in μPET/CT image of infected Lewis rats.
Conclusion: This study shows the possibility of TAFC modification without losing its in vitro and in vivo properties to target AFU via specific recognition of the MirB transporter. Substitution of one acetyl group of TAFC by functionalities such as fluorescent dyes opens alternative strategies for theranostics of infectious diseases.  Aim: The current "gold standard" chelator to label antibodies with 89 Zr for immunoPET is desferrioxamine (DFO). Preclinical studies have shown that the 89 Zr-DFO complex is partly unstable in vivo, resulting in release of 89 Zr and subsequent accumulation in mineral bone tissue. This bone uptake may prevent the detection of bone metastases, and hampers accurate estimation of the radiation dose to the bone marrow in dose planning for radioimmunotherapy. Therefore, there is a need for a more stable 89 Zr chelator. Here we report DFOcyclo*, a preorganized extended DFO derivative introducing an octacoordination, and investigate the stability of its 89 Zr complex over the unsaturated hexacoordinated 89 Zr-DFO complex in vitro and in vivo.
The mechanism of cell labeling is based on the lipophilic complex formed upon reconstitution, which can freely cross the cell membrane and once in the cytoplasm, is transformed into a secondary complex. However, some efflux from cell has been reported, causing errors of interpretation in the scintigraphic studies, since the activity detected does not always correspond with true cellular uptake. In this sense, it is postulated by some authors that the conversion to secondary complex is reversible, and over the time, a percentage of the primary complex tends to appear and elute from cells. Methods: Leukocytes (≈10 8 ) from healthy human volunteers (n = 5) were labelled following guideline, splitted into two aliquots of 0.5 cc in plasma and saline and incubated under stirring at 37°C, for 2h and 4h. After incubation, samples were centrifuged at 2000xg and the supernatant was analyzed by HPLC in a C18 (4 μm, 3.9x150 mm) column with a gradient mobile phase of 0.05M sodium acetate/tetrahydrofuran at a flow rate of 1.5 ml/min. The percentages of primary and secondary complex and free 99m Tc pertechnetate were determined by their retention time (tr). 99m Tc-HMPAO-human leukocytes (n = 3) were mechanically lysed and extracted in 0.5 ml of water for injection, centrifuged at 2000xg and analyzed as described. Conclusion: While secondary complex was detected inside and outside the cells, primary complex was absent in extracts and effluxes at any time of study. The percentage of 99m Tc pertechnetate is probably due to oxidation during the incubation period. According to our results, the activity detected in cell effluxes is related to the exit of secondary complex, rather than the exit of primary complex after reversibility of the original conversion inside the cell.

OP15
In vivo imaging of mGluR1 neuroreceptor kinetics in mouse brain with [ 11 C]ITDM microPET Š. Aim: P-glycoprotein transporters (P-gp) at the Blood-Brain barrier (BBB) are efflux pumps that play an important role in protecting the brain against harmful substances. The expression and function of these proteins is of great interest in neurodegenerative diseases and drug resistance. Its function can be measured in vivo with positron emission tomography (PET) using the novel tracer 5-(1-(2-[18F]fluoroethoxy))-[3-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-propyl]-5,6,7,8-tetrahydronaphthalen, [ 18 F]MC225. Preclinical PET scans are performed under anesthesia, and in most longitudinal studies the animals are repeatedly anesthetized. However, the potential effect of anesthesia on P-gp function has not been explored yet using this tracer. Therefore, the aim of this study is to assess the effect of a preexposure to anesthesia on P-gp function in rats with [ 18 F]MC225. Methods: Six rats were anesthetized with isoflurane for 90 minutes. Five other rats were not subjected to anesthesia. One week later, all rats underwent a dynamic PET scan (60 min) with arterial blood sampling.
[18F]MC225 with a dose of 32±6 MBq and a molar activity higher than 29000 GBq/mmol was injected into a tail vein as a bolus of 1ml/min. After tracer injection, blood samples (0.15 ml) were collected to measure radioactivity in whole blood and plasma, besides the parent fraction of the tracer and its radioactive metabolites. The images were processed with PMOD software, and registered to a tracer-specific brain template. A total of 16 regions inside the brain were selected from a Wistar brain rat atlas. The volume of distribution (VT) which reflects Pgp function was calculated by Logan analysis using plasma activity corrected for metabolites as input function. Results Significant differences in V T of the whole brain were observed (p=0.002) between the 2 groups. In control animals, V T of the whole brain was 11.04±1.25, whereas in animals pretreated with anesthesia it was 7.89±1.25, a decrease of 29%. Moreover, significant decreases in V T were found between groups in all the brain regions analyzed such as amygdala, hippocampus, hypothalamus, midbrain.
Tracer concentration in whole-blood and plasma, and the rate of metabolism were not significantly different between the groups. Conclusion: Our results suggest that anesthesia has a prolonged effect on P-gp function at the BBB, lasting at least one week. The group with additional anesthesia displayed a significant decrease of tracer uptake in brain indicating an up-regulation of P-gp.
Results Substitution of the aromatic ring of R-baclofen with the fluoro 4-pyridyl ether moiety resulted in an increase (>10 times) of the GABA B agonistic properties. The baclofen analog [ 18 F]1 was radiolabeled via the corresponding bromo-precursor with a radiochemical yield of 12-18%, specific radioactivity in the range of 330-515 GBq/μmol and radiochemical purity greater than 97%. In the animal experiments [ 18 F]1 entered the mouse brain (1% ID/g tissue) followed by washout. The accumulation of [ 18 F]1 in the mouse brain was inhibited (35%) by pre-injection of a selective GABA B agonist, suggesting that the radiotracer binding is partially mediated by GABA B receptors. Conclusion: New GABA B agonists, fluoropyridylmethoxy analogues of R-baclofen, were synthesized and radiolabeled with 18 F. The mouse experiments with the most potent compound of the series, [ 18 F]1, demonstrated the feasibility of ex vivo quantification of GABA B receptors in the animal brain; however, its specific binding was insufficient for translation to human subjects. Our future research on GABA B PET imaging will target radiotracers with improved specific binding and greater blood-brain barrier permeability.

OP18
Measurement of blood brain barrier transport using radiolabeled antibodies G.Charest 1 , S. Aim Antibodies targeting transporters can function as carriers for the delivery of drugs in the brain for detecting and treating diseases of the central nervous system at the molecular level. Presently there is a need to develop efficient non-invasive method to validate the transport of these antibodies across the blood brain barrier (BBB). In this study, we investigated the potential of novel radiolabeled antibodies for measuring their engagement at the BBB. We compared different modes of delivery (Intravenous (IV), intra-arterial (IA)) to estimate their brain uptake and assess their biodistribution profiles. Methods: The antibodies were conjugated to NOTA chelator for 64 Cu-radiolabeling. The new [ 64 Cu]NOTA-antibody conjugates were tested in normal rats using both IA and IV modes of administration with or without pre-injection of unlabeled material and were compared to a control [ 64 Cu]NOTA-antibody.
Results We showed that the injection in the right carotid artery of our new 64 Cu-NOTA-antibody conjugates resulted in a brief but important radioactivity exposure in the right brain hemisphere, which persisted after exsanguination. The right to left hemisphere ratios remained constant across the different concentrations of unlabeled conjugates and exceed that obtained with the control 64 Cu-NOTAantibody.
Conclusion: This study demonstrates that our new [ 64 Cu]NOTA-antibodies allow for a transitory and specific brain uptake. These successful results are promising for the use of bi-specific radiolabeled antibody that can engage a target within the brain. Aim: Cyclic nucleotide phosphodiesterases (PDEs) are a class of intracellular enzymes that inactivate the secondary messenger molecules cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). Thus, PDEs regulate the signaling cascades mediated by these cyclic nucleotides and affect fundamental cellular processes, such as proliferation, differentiation, migration, survival, and apoptosis. Accordingly, they are promising therapeutic targets. Since PDE2A was found to be related to a variety of tumors, it is our aim to synthesize novel PDE2A inhibitors based on the benzoimidazotriazine (BIT) moiety that might be a prospective lead compound for the development of an F-18 labelled ligand for PDE2A imaging with PET. Methods: Based on BIT key intermediates (Fig. 1a), a small series of novel fluorinated BIT derivatives was successfully prepared (overall in 7-10 steps) and the affinities towards PDE2A and other PDE subtypes were estimated. The most promising compound, BIT1, was radiolabelled by using the corresponding nitro precursor. The reaction was optimized by choosing different solvents, amounts of precursor, modes of heating (conventional or microwave), temperatures, and reaction times. Afterwards, best conditions ( Fig. 1b)  Aim: MiRNA are single stranded RNAs of 18-22 nucleotides and they have been found to be promising diagnostic and prognostic markers for several pathologies, such as tumors, neurodegenerative, cardiovascular and autoimmune disease. In the present work the development and characterization of the first anti-miRNA 64 Cu-radiolabeled probes based on peptide nucleic acids for a potential non-invasive molecular imaging in vivo of giant cell arteritis are described. Methods: MiR-146a and miR-146b-5p were selected as targets because they have been found up-regulated in this disease. Anti-miR-PNA and scramble-PNA probes were synthesized and linked to carboxyfluorescein or DOTA. The affinity of the probes for the targets was assessed by circular dichroism and melting temperature. Differential uptake and functional activity of fluoresceinated anti-miRNA probes were tested on BCPAP and A549 cell lines, expressing different levels of miR-146a and -146b-5p. DOTA anti-miRNA probes were then labelled with copper-64 to function as non-invasive molecular imaging tools and their stability and uptake were assessed in the same cell lines. Results From circular dichroism studies it was possible to note that both PNA sequences (anti-miR-146a and -146b-5p) were able to recognize both miRNA sequences. The scrambled PNA sequence did not show any ability instead. Fluorescence of both BCPAP and A549 cells treated with anti-miR PNAs was higher than that of cells treated with the negative control scrambled-PNA. 64 Cu-DOTA-anti-miR-146a PNA showed an almost doubled uptake in BCPAP cells with respect to the A549 cells after 42 hours. Conversely, the uptake of the 64 Cu-DOTA-anti-miR-146b-5p PNA was comparable in the two cell lines. The uptake of the 64 Cu-DOTA-scramble PNA was really low in both the cell lines and can be assigned to unspecific binding. Conclusion: The experiments confirmed that anti-miR-146a PNA can selectively bound the miRNA target and its uptake is higher in miRNA overexpressing cells in vitro. 64 Cu-anti-miR-146a PNA might be further investigated for non-invasive PET imaging of miR-146a and miR-146b-5p overexpressing diseases. Results Clonogenic assays demonstrated a significantly higher cytotoxicity of T-DM1 on HER2 positive tumour cell lines sensitive or resistant to trastuzumab. Resistant cell lines, such as TrR1 (breast cancer) and SK-OV3 (ovarian cancer) showed significantly higher cytotoxicity with T-DM1 at 10 μg/mL and 0.01 μg/mL, respectively. There was a strong correlation between HER2 density measured by flow cytometry and in vivo uptake of 89 Zr-DFO-T-DM1 (incorporated into a therapeutic dose) with r 2 = 0.9892. A strong and direct correlation between in vivo response (doubling time) and uptake of 89 Zr-DFO-T-DM1 obtained with r 2 = 0.8202. A strong indirect correlation was established between in vivo response (doubling time) and in vitro % survival, r 2 = 0.9208. Conclusion: We conclude that there was a strong correlation between tumour uptake of 89 Zr-DFO-T-DM1, in vitro cytotoxicity, and in vivo response. 89 Zr-DFO-T-DM1 has application for PET imaging of the delivery of T-DM1 to tumours in patients with HER2-positive BC. Imaging may inform on which patients are likely to benefit from T-DM1 treatment.

OP22
Physicochemical and in vitro evaluation of a 99m Tc labelled NPY1 short analogue as potential breast cancer imaging agent M.E. Cardoso, E. Tejería, M. Terán, A. Rey Área de Radioquímica, Facultad de Química, Universidad de la República (UdelaR), Uruguay Correspondence: A. Rey EJNMMI Radiopharmacy and Chemistry 2018, 3(Suppl 1):OP22 Aim: Neuropeptide Y receptors subtype Y1 (NPY1) are overexpressed in primary breast carcinomas and metastases and consequently radiolabelled agonists for these receptors would allow in vivo targeting of tumours for diagnostic and therapeutic purposes. With the aim to develop a potential 99m Tc breast cancer imaging agent based on the NPY1 structure we developed a short analogue (MA-Cys-Tyr-Arg-Leu-Arg-BPA-Nle-Pro-Asn-Ile-OH) containing the active sequence of the peptide with the addition at the amino-terminal end of a cysteine- mercaptoacetic acid moiety to coordinate the radiometal through the formation of a 3+1 nitrido complex. Methods: Labelling was performed in two steps, namely: the preparation of a Tc(V)N precursor by reduction of pertechnetate (2,5-12,5mCi) with SnCl 2 (0,1mg) in the presence of succinic dihydrazide (1mg) for 20 minutes followed by incubation (1 hour,80°C) of the nitrido precursor (in 1mL) with the peptide (100μg), tris(2-cyanoethyl) phosphine (0,5mg) and hydroxypropyl-gamma cyclodextrin (2mg). Radiochemical Purity (RP) of the final product was assessed by RP-HPLC using CH 3 CN/0,1%TFA and H 2 O/0,1%TFA as mobile phases. Lipophilicity was determined with n-octanol and phosphate buffer (0.1M, pH=7.4). Plasmatic protein binding (PPB) was measured by size exclusion chromatography. Stability in plasma and in labelling milieu was assessed by HPLC at 2 and 4 hours after labelling, respectively. Cysteine challenge (100 fold molar excess) was also performed. Cellular uptake, internalization and membrane binding studies were performed using t MCF-7(ATCC® HTB-22TM) cells.
Results Labelling of the peptide yielded a single species with a retention time of 11.4 min and a RP>90%. The complex was stable in reaction milieu and human plasma. Challenge with cysteine revealed no ligand exchange for up to 2 hours. Physicochemical evaluation showed a log P of -0.4+0.1 and a PPB of 16+2%. A cellular uptake of 3.1±0.2 (at 4 hours) was obtained. Internalization and membrane binding studies showed that 15.2% of the activity is bound to the membrane and 84.8% is internalised. Conclusion: A 99m Tc-with agonist was obtained high RP, good stability and adequate physicochemical properties. In vitro characterization showed a promising uptake in MCF-7 cells. To establish whether it is a good diagnostic agent for breast cancer, it is necessary to deepen biological studies in tumour-bearing animals.  Aim: The theranostic use of mingastrin (MG)-based radioligands targeting cholecystokinin-2 receptor (CCK2R) expression in tumours is restricted by high kidney uptake or low enzymatic stability. Recently we have reported on the possibility to stabilise MG analogues against degradation by introducing specific amino acid modifications in the C-terminal receptor binding sequence (Trp-Met-Asp-Phe-NH 2 ). In this study we have further refined our approach leading to a highly promising new targeting probe. Methods: The new MG analogue DOTA-MGS5 was designed based on a combination of the substitutions applied in peptide derivatives previously developed by our group (1). The in vitro and in vivo characterisation after radiolabelling with In-111 and Lu-177 included stability analyses of the radioligands incubated in rat tissue homogenates and after injection into BALB/c mice. Receptor interaction in terms of receptor affinity and cell uptake was analysed using A431 human epidermoid carcinoma cells transfected with human CCK2R (A431-CCK2R) and mock-transfected cells (A431-mock). The targeting potential was evaluated by small animal dual modality single photon emission computed tomography (NanoSPECT/CT) as well as ex vivo biodistribution studies in tumour bearing BALB/c nude mice up to 4 h after injection. Results DOTA-MGS5 and the complexes with different natural isotopes showed a high CCK2R affinity in the low nanomolar range. Interestingly, 111 In-DOTA-MGS5 showed a particularly high internalisation (>40% and >80% after 1 h and 4 h respectively) into A431-CCK2R cells. The somewhat lower resistance against enzymatic degradation observed in rat tissue homogenates did not translate into a similar effect in vivo. Even though the stability in blood of 111 In-DOTA-MGS5 was comparable to other radioligands previously studied (>80% intact peptide after 10 min), the tumour uptake with values of 23.5±1.3% IA/g at 4 h p.i. was incredibly high, leading to extraordinary performance in NanoSPECT/CT. Also for 177 Lu-DOTA-MGS5 a similar stability in blood (>80% after 10 min) and tumour uptake (24.5±3.1% IA/g at 4 h p.i.) was found combined with favourable tumour-to-organ ratios of >3 for stomach and >6 for kidneys. Conclusion: The combination of substitutions from earlier investigations allowed us to further improve our concept of stabilising MG analogues in the receptor-specific C-terminal sequence. 177 Lu-DOTA-MGS5 with its extremely high tumour uptake seems to be the long-awaited theranostic probe for targeting CCK2R expression in tumours. Tc was performed at high yields without purification (> 95 %). Incubation of both radiolabeled preparations in saline and serum showed that the bisphosphonate-iron oxide bonding was very stable with only 10 and 15 % of 99m Tc detaching from the iron oxide after 24 h, respectively. The highest uptake was observed at 1 h p.i. in the liver followed by the spleen (Fig. 1). Ga therapy has been neglected due to lack of suitable chelators and targeting molecules. With the advent of 68 Ga-PET, excellent new chelators allow us to re-evaluate 67 Ga for therapy. Previously, we showed that 67 Ga causes DNA damage in cell-free systems and and cell kill in non-targeted cell studies. Here, we expand this work by targeting 67 Ga to breast cancer cells using trastuzumab and comparing toxicity to well-described Auger electron emitter, 111 In. Methods: Trastuzumab, dialysed against 50 mM EDTA, washed and recovered in metal-free HEPES buffer, was conjugated with tripodal tris(hydroxypyridinone) (THP) (3.23 mg trastuzumab, 0.8 mM H 3 THP-Ph-SCN; 260 μL) and purified by size exclusion chromatography (SEC). DOTA-trastuzumab was also prepared similarly. DOTAtrastuzumab was labelled with 111 In chloride at 40°C, pH 5.5 for two hours whereas THP-trastuzumab was labelling with 67 Ga chloride at room temperature, pH 6.5, for 15 minutes. SEC purification was performed when labelling efficiencies were <95%. Radiopharmaceuticals (0.19 MBq/μg) were tested for their internalisation and effects on viability (dye exclusion) and clonogenicity of Her-2-positive (HCC1954) and -negative (MDA-MB-231) cell lines. Microautoradiography of cells in 18% gelatine was also performed. Results Labelling efficiencies for 67 Ga-THP-trastuzumab and 111 In-DOTA-trastuzumab were 90% and 98%, respectively, giving 0.26±0.08 and 0.61±0.11 MBq/μg. At 4nM, 67 Ga-THP-trastuzumab showed significantly higher cell binding uptake (10.69±1.32%) than 111 In-DOTAtrastuzumab (6.15±1.64%; p=0.01) although the proportions internalised were equal; 62.08±1.43% and 60.78±15.45%, respectively. At 100nM however, cell binding percentages were equal: 1.15±0.98% 67 Ga-THP-trastuzumab and 0.83±0.85% 111 In-DOTA-trastuzumab. Controls 67 Ga-THP-Ac and 111 In-DOTA did not bind HCC1954 cells and binding of 67 Ga-THP-trastuzumab and 111 In-DOTA-trastuzumab in MDA-MB-231 cells was minimal (<0.2%). Microautoradiography showed that radioactivity bound to individual cells within the population varied considerably (from <10 to >90 silver grains per cell). Viability and clonogenicity decreased with increasing radiolabeled trastuzumab concentration, bound per cell. Radiopharmaceutical treatment of MDA-MB-231 cells or non-internalised activity in HCC1954 cells did not affect cell viability or clonogenicity. In HCC1954 cells, the surviving fraction after treatment at approximately 0.1 Bq/cell 67 Ga-THP-trastuzumab, reduced to 0.38±0.13, more than for 111 In-DOTA-trastuzumab (0.55 ± 0.16; p=0.03). Conclusion: 67 Ga-THP-trastuzumab and 111 In-DOTA-trastuzumab both bind specifically HER2-positive cells and reduce their viability and clonogenicity. This shows 67 Ga holds promise as a therapeutic radionuclide as a targeted radiopharmaceutical however nonhomogeneous uptake amongst cells needs further investigation.

Acknowledgments
The project was in part supported by the Academy of Medical Sciences and Malaysian Ministry of Education. Aim: Magnetic nanoparticles (MNPs) have been intensively used for a wide variety of biomedical applications. Only few reports on the in vivo biodistribution of functionalized MNPs with potential uses in magnetic hyperthermia (MHT) therapy are available [1,2]. Radiolabeled MNPs coated with hydrophilic phosphate ligands, i.e., imidodiphosphate (IDP) and inositol hexaphosphate (IHP), were developed as multifunctional agents to localize both radioactivity and magnetic energy at a tumor site. Methods: MNPs were synthesized by co-precipitation of ferric and ferrous salts in a basic solution [3,4]. The heating ability of MNPs was quantified through the specific power absorption (SPA) measurements. The MNPs were labeled with 37 MBq 90 YCl 3 , at room temperature for 1 h and were used in in vitro stability studies in saline and human serum and in vivo biodistribution studies in normal Wistar rats.

Results
The SPA values obtained for synthesized MNPs (46-81 W g -1 ) in different physiological media indicated their possible application in hyperthermia treatment (Fig. 1). Both types of coated MNPs were 90 Y-labeled in a reproducible high yield (>98 %) and exhibited high in vitro stability in saline and human serum. The results of  biodistribution, showed high uptake in the liver and spleen as well as in vivo stability up to 72 h. (Fig. 2). Conclusion: 90 Y-coated MNPs were radiolabeled for two purposes: to use the radiotracer to obtain an accurate biodistribution profile of the MNPs and to produce potential radiotherapeutical agents. Both 90 Y-labeled phosphate-coated MNPs exhibited favorable properties that justify further investigations toward their potential use in combined radiotherapy-hyperthermia cancer treatment.

OP27
Automation of FDG QC on Tracer-QC system R. Nair, A. Lebedev, A. Elizarov Trace-Ability, Inc., 6160 Bristol Pkwy., Suite 200, Culver City, CA 90230, Canada Correspondence: A. Elizarov EJNMMI Radiopharmacy and Chemistry 2018, 3(Suppl 1):OP27 Aim: Quality Control (QC) of PET tracers is the most labor-intensive part of clinical tracer production. Tracer-QC system is being used in the US for complete automation of QC for FDG production meeting the requirements set by United States Pharmacopeia. Here we present the technology developed to address European Pharmacopeia requirements for radiochemical and chemical purity.
Methods: A QC automation system has been developed that consists of Tracer-QC device integrated with an HPLC. The HPLC includes a quaternary pump, UV-Vis detector and a radioactivity detector. Notably, no electrochemical detector is included. An innovative coupling was developed that provides for automated HPLC injection of the radioactive sample by a pipette from the deck of Tracer-QC robot. The above described system is enabled by a consumable cartridge that incorporates all reagents needed for analysis of color, clarity, residual kryptofix, ethanol, acetonitrile, bacterial endotoxin, radioactivity concentration, radiochemical purity (including 18 F-fluoride and 18 F-FDM), half-life, residual concentration of Cl-DG. Pre-column derivatization of sugars with PMP reagent was utilized to quantify Cl-DG content. Robotic component of Tracer-QC system allows for precise and fast mixing of the liquids.

Results
The system presented here allowed for quantification of all impurities commonly analyzed in the production of FDG in Europe, while keeping the analysis time under 45 minutes. The derivatization and separation method was optimized to separate derivatized Cl-DG, Glucose, FDM and FDG with resolution exceeding Pharmacopeia requirements ( Fig. 1). Limit of quantification of Cl-DG was determined to be 15 ppm, Limit for detection for 19 F-FDG is~1 ppm. 18 F-FDG was fully converted to 18 F-FDG -PMP derivative which was detected on the radiation detector. TLC analysis confirmed that 18 F-FDG -PMP is the only radioactive product of the derivatization, with no competing decomposition. Conclusion: These developments enabled an automated QC platform that contains all hardware needed for analysis of FDG as well as other 18 F-based tracers. On this platform all analyses and sample manipulations are performed automatically, providing for maximum walk-away timethe user sets up a consumable cartridge and adds one sample. Then they only need to come back to collect the complete report. It is expected that such systems will have a dramatic impact in both routine production and development of new PET tracers.  Aim: The implementation of recently introduced metal-mediated "late-stage" approaches for nucleophilic n.c.a. 18 F-labelling of nonactivated aromatics into routine production of the radiotracers is currently on-going. These new strategies employed or copper (II) 1 catalysts that combined with stannyl-or Ni-based 2,3 precursors.   Moreover, classical kryptofix is often replaced by tetraethylammonium hydrogen carbonate (TEAHC) 2,3 . Therefore there is an urgent need in the development of simple analytical methods to control the removal of these toxic impurities from the final preparations until the allowable limits. Here we suggest the application of capillary electrophoresis (CE) for simultaneous determination of Cu, Ni, Sn and TEAHC in the analytical sample. Methods: CE analysis was performed using «Capel-105M» system that equipped with UV spectrophotometric detector. The sample was loaded via electrokinetic injection (10 s, 25 kV) under following conditions: column 60 cm × 75 μm; background electrolyte: benzimidazole 20 mmol/L + acetic acid 40 mmol/L; UV 230 nm, separation voltage 25 kV, 20°C. Stock solutions of Ni 2+ , TEAHC, Cu 2+ and Me 3 SnCl in normal saline at a concentration of 10, 1000, 100 and 200 ppm respectively were prepared. Calibration standards were than prepared by serial dilution of the stock solutions. Before analysis the samples were fourfold diluted by deionized water. Under these conditions the retention times (RT) for Ni 2+ , TEAHC, Cu 2+ and Me 3 SnCl were 4.4, 5.0, 5.6 and 7.8 min. All the peaks were well distinguished from that of sodium (3.9 min). Results The conditions for simultaneous determination of toxic impurities in the buffer solution by CE technique CE analytical procedure have been developed. Our data ( Fig. 1) show that the suggested method had a high sensitivity with detection limit for impurities according to ICH Guideline of Elemental Impurities Q3D. Conclusion: New analytical CE method was proposed for routine quality control of the radiotracers, synthesized via metal-mediated reactions. The method is fast, simple, reliable and can be easy adapted to any CE equipment. This research was supported by RFBR grant № 16-54-12062\16. Methods: Elution records of 7 generators, used between January 2013 and July 2017 were reviewed. The first 5 generators were eluted with 1 M HCl, and the last 2 generators with 0.6 M HCl. Ge-68 breakthrough was measured after decay of eluted Ga-68. The age of the generator and the time interval between elutions were calculated and plotted against breakthrough and yield. Results The number of elutions per generator ranged between 28 and 151, and the generators were used for periods ranging from 166 to 372 days. Yield within the first month were between 119 % and 133 % of the nominal Ge-68 activity on the column for generators eluted with 1 M HCl, and 107 to 110 % for those eluted with 0.6 M HCl. By 160 days the yields had decreased to 106 % to 110 % with 1 M HCl elutions and 80 % to 99 % with 0.6 M HCl eluant. Three generators, including those eluted with 0.6 M, showed Ge-68 breakthrough within the first 10 days of use. By 160 days age, the Ge-68 breakthrough varied between 0.02 % and 1.0 %, with the lower acidity eluant giving the second highest value. There were no correlation between interval between elutions and Ge-68 breakthrough and Ga-68 yield. Conclusion: Due to irregular intervals between elutions, it is difficult to compare elution yield at various ages of generators. All generators however clearly functioned poorer with increased use. The increasing Ge-68 breakthrough, and especially breakthrough early in the lifespan of the 2016 and 2017 generators is worrying, as it creates longliving radioactive waste. Elution with a less acidic eluant seems to provide a slightly lower yield but also lower Ge-68 breakthrough. Aim: Development of 68 Ga radiophamaceuticals (RPs) requires a lot of tests to be made during labeling conditions optimization, stability evaluation, etc. It is critically important not only to evaluate radiochemical purity (RCP) value, but to know exact value of every radiochemical impurity content. There's no doubt that TLC analysis is the most convenient method for the determination of all the radiochemical species content, given that the TLC system is adequate. Previously new method for determination of RCP of 68 Ga-RPs was developed [1]. The method is handy, fast and informative with a good correlation with pharmacopoeial and other frequently used methods. The method allows to determine 68 Ga-colloid, unbounded 68 Ga and labeled molecule content with a single strip. The method can be routinely used with 68 Ga-PSMA-617, 68 Ga-DOTA/NODAGA-RGD/TOC/-TATE, etc. However the method has a drawback: sometimes adequate chromatographic separation is not available with acyclic chelators (DATA/HBED-CC/DTPA, etc.). Also molecular weight has an impact on Rf of the complexes (main peak shift can be about ±0.3 Rf). The aim of this study is to develop a new method allowing to overcome these drawbacks. Methods: 68 Ge/ 68 Ga generator (Cyclotron Ltd, Obninsk, Russian Federation) was used. All chemicals and solvents were of high-purity or pharmaceutical grade and were purchased from Sigma-Aldrich or Panreac. Radiopharmaceutical precursors (PSMA-617, DOTA/ NODAGA-RGD/TOC/-TATE, etc.) were purchased from ABX. iTLC-SG strips of different manufacture periods were used (Pall/Varian/ Thermo). PET-MiniGita (Raytest) radio-TLC scanner was used for analysis of radioactivity distribution. Results The decision was made to develop a method, which allows to obtain retention factors as follows: Rf=0.0-0.1 for 68 Ga-colloid, Rf=0.5-0.6 for unbounded 68 Ga and for labeled molecules Rf=0.9-1.0. This separation pattern was obtained for labeled compounds listed above using mixtures with w:o = 1:1 or 1:3 (wwater, saline; oacetonitrile/ethanol/methanol). The presence of small amount of acid (TFA/HCl/HNO 3 , ect.) is essential. This amount should be kept very precise to provide pH 1.6±0.4. The most informative peak separation can be obtained with saline:acetonitrile mixture (1:1 ÷1:3) containing 0.06-0.08% TFA. Experiment details and critical features will be presented. This system is applicable for the most of 68 Ga-RPs under  Aim: Over the past years, many different PET agents have been developed to investigating on Prostate Cancer (PC) to make the non invasive approach a reality, in order to replace the biopsy and the related complications. The PC is the more common cancer that affect the male population. Due to the high incidence of this pathology are mandatory to investigate on a fluorine-18 tracer that give the possibility to overcame the gallium-68 tracers limitations. [1] The aim of this study is to optimize an automatic synthesis for [ 18 F]FPSMA1007 on Ge FASTLab® module, in a stable high yield with a wide range of inlet activity, and setting up a faster, efficient and EU Pharmacopoeia compliant quality control to shorten the time of product realize. [2] Methods: The synthesis method is based on one step synthesis using a new precursor commercialized by ABX and is tuned on Ge FAS-TLab® synthesizer. All the reagents are included on a single use cassette. The [ 18 F]Fluorine was trapped on QMA and eluted with a mixture of TBAHCO 3 /ACN or K222/ACN/K 2 CO 3 and after drying at 125°C on synthesis reactor, the ABX precursor dissolved in DMSO was added to proceed with the nucleophilic [ 18 F]-Fluorination. The reaction mixture was heated up at 95°C for 10 min after the reaction step the mixture was cooled at 35°C to starting the purification step followed by formulation. The total process takes place on 37 minutes. HPLC analysis was performed on an Agilent 1260 Infinity HPLC equipped with an Agilent 1260 UV detector and a Raytest gammaray detector, controlled with Gina Star software V.5.9. The analysis was performed on a 4,6x100 Eclipse Plus C18 3.5μm (Agilent) in isocratic conditions using CH 3 CN and 0.1 % TFA (70/30, run time 15 min). TLC analysis was performed on Merk Silica Gel 60 on PET (10x5 cm, developed over 2/3 of the plate), mobile phase MeOH/NaCl 0.9% a Perkin Elmer Cyclone. Other analysis were performed according to European Pharmacopoeia "Radiopharmaceutical Preparations".
Results Two different elution solution was used to compare the final process yields, at the same time, high activity runs were performed, in different inlet activity range, to evaluating the yield and product stability in final formulation. For stability study a range of 1-2.5 GBq/ ml radioactive concentration was evaluated at room and at 40°C for up to 12h. According to final product formula specification the synthesis yield was stable on range 30-50 % at the inlet activity range (55-170 GBq) with a very high A m ( 800-3500 GBq/ 훍mol) at EOS. The radiochemical purity for all the runs was > 96 % and chemical impurities were < 0.1 mg/V. The new HPLC/TLC method allow to make the quality control in terms of general indications of European Pharmacopoeia Monographs. Conclusion: All the synthesis performed by using the K222 elution solution shows slightly lower yield compared to TBA, at the same time any difference, in quality control profile and stability were found, all the products collected were stable and in high chemical/ radiochemical purity. The HPLC and TLC methods setup allow to perform a complete purity evaluation on less than 15 min. Aim: Radioiodine and astatine are increasingly studied for therapeutic or diagnostic purposes in nuclear medicine [1]. Particularly, 211 At (t 1/2 = 7.2 h, α-emitter) is a promising radioisotope for targeted α-particle therapy. To associate these radiohalogens to cancer targeting biomolecules (peptides, antibodies), the conventional approach consists in performing the radiohalogenation of a precursor bearing a N-Hydroxysuccinimidyl (NHS) ester function for conjugation to the biomolecule [2]. However this approach requires basic aqueous conditions leading to competitive hydrolysis of the NHS ester, resulting in sub-optimal conjugation yields (<50%). To overcome this issue, we have initiated the investigation of click chemistry based bioorthogonal conjugation approaches aiming at increasing the coupling yields and improving the radiolabelling procedure.
Methods: A series of bifunctional precursors bearing clickable functionalities (tetrazine, azide or alkyne) were specifically designed for radiolabelling with radioiodine and 211 At. Bioorthogonal ligation kinetics of the labelled prosthetic groups were evaluated on model peptides bearing the complementary clickable functions (transcyclooctene (TCO), bicyclononyne (BCN), alkyne) for identification of the best system, and transferred to antibody radiolabelling. Results All ligation reactions tested on model peptides produced quantitative yields from less than 1 minute to 9 hours with the following reactivity order:  Aim: The 5-year survival for PnCa patients is only 6% due to latestage diagnosis and inadequate treatment options. There is an urgent need for new treatment strategies. Human epidermal growth factor receptor (EGFR) is overexpressed on up to 90% of PnCa tumours. Panitumumab is an antibody against EGFR that can be modified with a NOTA chelator for radiolabeling with 177 Lu to treat PnCa cells as a radioimmunotherapy agent ( 177 Lu-RIT). This study aims to determine the RBE of 177 Lu-RIT compared to γ-radiation and examine EGFR positivity as a predictor of PnCa response to 177 Lu-RIT. Methods: Flow cytometry: EGFR density was measured on AsPC-1, PANC-1, MiaPACA-2, and Capan-1 cell lines. Cells were incubated with panitumumab for 60 min, then with Alexa Fluor 647 anti-human IgG immunoconjugates for 30 min at 4°C, then run on a flow cytometer. Clonogenic survival assays: Cells were treated with γ-radiation (0-8Gy) or 177 Lu-RIT (0-3MBq/72nM) then seeded in into 6-well plates and allowed to grow at 37°C, 5% CO 2 , for 14 days. Then colonies were fixed/stained and counted. Subcellular fractionation: Cells were treated with 177 Lu-RIT (1MBq/72nM) for 1, 3, 4, and 24 hours. Radioactivity associated with cell surface, cytoplasm, and nucleus was separated then measured in a γ-counter.
Results EGFR density was +++, +++, +, and ++, for AsPC-1, PANC-1, MIAPaca-2, and Capan-1 cells, respectively. Clonogenic survival after γ-radiation was reduced to 10% (D 10 ) for AsPC-1, PANC-1, MIAPaca-2, and Capan-1 cells at 3.2 Gy, 5.0 Gy, 4.0 Gy, and 2.5 Gy. 177 Lu-RIT caused D 10 at 3.1MBq, 1.1MBq, 6.0MBq, and 1MBq for AsPc-1, PANC-1, MIAPaca-2, and Capan-1 cells, respectively. Subcellular fractionation studies showed that PANC-1 had the highest nuclear localization of 177 Lu-RIT and results from these studies allowed microdosimetry to be performed to convert MBq to Gy. The D 10 after 177 Lu-RIT was 16.9 Gy, 5.7 Gy, 23.3 Gy, and 8.2 Gy for AsPc-1, PANC-1, MIAPaca-2, and Capan-1, respectively, resulting in RBE of 0.2, 1.0, 0.2, and 0.3. Conclusion: RBE of 177 Lu-RIT is less than γ-radiation and varies significantly between PnCa cell lines with no correlation to EGFR density. EGFR positivity is not an adequate predictor of response to RIT with 177 Lu-RIT. Aim: Breast cancer (BC) remains the most common invasive cancer diagnosed among women and the second most frequent cause of cancer-related death in women worldwide. The majority of BC cases are hormone-responsive and approximately 75% express the estrogen receptor (ER), a well-established biomarker for prognosis and guiding treatment of patients. ER has also been used as a target for BC imaging. In spite of the improved BC survival rate due to endocrine therapies that modulate ER action, resistance to treatment is a major clinical concern. Thus, new molecular imaging agents and more effective therapies are needed to improve BC management. Theranostics is particularly suitable for that purpose as the ER status profiling acquired by imaging can be used to targeted treatment. Peptides containing the LXXLL sequence have demonstrated high ER affinity and could be of potential value to develop targeted radiopharmaceuticals. Thus, our goal was to assess the potential value of a radiolabelled LXXLL peptide as theranostic agent for BC. For that purpose, we have selected from the literature a peptide with recognized ER affinity and have radiolabelled it with two different radionuclides, 111 In and 125 I. Methods: A LXXLL-peptide was synthesized and conjugated to the bifunctional chelator DOTA by microwave-assisted solid phase synthesis. The peptide conjugate was radiolabelled with 111 In. 125 I-labelling was performed by direct radioiodination in the histidyl residue using the oxidative method of chloramine-T. ER binding affinities were evaluated by a fluorescent polarization assay with the corresponding inactive In(III) complex or iodinated peptide. Cellular uptake was assessed in MCF-7 (ER+) and MDA-MB-231 (ER-) human breast cancer cells. Biodistribution was assessed in tumor-bearing Balb/c mice induced with MCF-7 cells and microSPECT imaging studies are underway. Results: The LXXLL peptide was successfully radiolabelled with both radionuclides with high radiochemical yield and purity at high specific activity. Chemical identity was ascertained by comparing its HPLC profile with that of the inactive congeners. Inactive LXXLLpeptide derivatives retained ER binding affinity. Both radiolabelled peptides have showed rapid and high uptake in MCF-7 cells (ER+). Biodistribution studies in tumor-bearing mice indicated high in vivo stability, fast blood clearance and high uptake in ER rich organs and MCF-7 xenografts. Conclusion: The favourable biological performance of radiolabelled LXXLL peptides in cellular and tumor-bearing mice models suggests their potential as theranostic agents.  Methods: The endotoxin limit(EL) for RCPs was fixed at 5EU/mL, based on the volume used for radiosynthesis and alert limit. BET assays were performed by gel-clot method. Maximum valid dilution (MVD) was calculated considering the sensitivity of lysate and EL. Sterility testing was validated by direct inoculation method using FTM and SCD media. Positive controls for S.aureus, P.aeruginosa, B.subtilis, C.albicans were set up at bacterial concentration <100 CFU (serial dilution-spread plate method) and corresponding negative controls were set up with and without RCPs. Positive and negative controls of RCPs were set up considering single patient dose (125-150 and 50-100 mCi of RP in a volume of 0.5 and 2.0mL meant for therapeutic and diagnostic radiopharmaceutical formulations respectively). Results In BET assay, 177 LuCl 3 and CH 3 COO 90 Y exhibited inhibition due to extreme pH conditions. Inhibition could be resolved by neutralizing with endotoxin negative (<0.25EU/mL) 0.25N Tris-base at first dilution. 68 GaCl 3 exhibited enhancement due to presence of excess Na + and inhibition because of extreme pH. The enhancement in BET test was resolved using endotoxin negative PBS as diluting agent instead of LRW and inhibition was taken care of by neutralization with 0.25N Tris-base. BET assay of Na 99m TcO 4 , Na 188 ReO 4 and H 18 F, did not demonstrate any inhibition. In sterility testing, luxuriant growth was observed for positive control culture in the presence of 1-2 mL (50-100 mCi) of Na 99m TcO 4 , Na 188 ReO 4 and H 18 F following incubation for 48 hours. Growth of all these microorganisms was inhibited (<100 CFU) in 0.5-1.0 mL 68 GaCl 3, 177 LuCl 3 and CH 3 COO 90 Y. However, inhibition was reversed on neutralization with sterile Tris-buffer (0.2/0.4/2N). This was also confirmed by counting CFU by spread plate method. No growth was seen in any of these RCPs in negative controls. Conclusion: The procedures for quantification of endotoxin limit and sterility tests of various RCPs used in radiopharmaceuticals formulations was standardized and validated. Aim: The GE-PET trace 800, a medical cyclotron facility in RMC provides proton beam of 16.5 MeV, with varying beam current from 1μA to 75 μA. This cyclotron has liquid and gaseous irradiation target cavities for production of non-metallic radioisotopes viz 18 F, 11 C, 13 N etc. In order to extend the utility of the cyclotron for producing medically useful isotopes viz 64 Cu, 111 In etc using the solid targets, a prototype semi-automated solid target assembly has been designed and fabricated indigenously. In this study the feasibility of this target for irradiation, to produce 64 Cu was tested. Materials: Natural Ni powder < 150 μm, 99.999% trace metal basis purchased from Aldrich, ORION gamma-ray spectrometer coupled with a high purity Ge-detector Methods: A proton beam of 2 μA was irradiated for 30 min on natural Ni (electroplated in-house with thickness 120 μm). The parameter such as the vacuum, He pressure, γ field and neutron flux was observed at regular time intervals during irradiation. After irradiation, target disc was transferred into a lead capsule. The γ spectrum of irradiated sample was recorded with HPGe detector. Quantity of 64 Cu produced was calculated by analysing the spectrum using InterWinner 7.0 software. Results The vacuum was found to be stable indicating proper sealing of the solid target assembly with cyclotron port. The He gas pressure was constant showing no leak of coolant from the target assembly. The γ field and neutron flux measured was found to be 38 mR/h and 236 n/cm 2 /s respectively during the irradiation. The HPGe spectrum showed a peak at 1.34 MeV corresponding to 64 Cu along with other peaks. The quantity of 64 Cu produced was estimated to be 29 μCi at the EOB. Conclusion: The indigenously developed solid target assembly was found to be compatible with GE-PET trace 800 cyclotron, having only liquid and gaseous target cavities. The target was successfully tested for irradiation at 2μA current for 30 m time duration with natural Ni target. This indigenous target can be used for production of higher amount of 64 Cu while using enriched 64 Ni with high current.   (1) Aim: Increasing patient demand for 68Ga-peptides in our facility has created the need for higher number of doses per batch produced. We have investigated several options for dual generator elution for the synthesis of 68Ga-DOTATATE on an iPHASE MultiSyn Synthesizer, using two ITG 68Ge/68Ga generators. Methods: The efficiency of three double elution methods of ITG generators using HCl 0.05M were compared: (i) Fractionated elution: The elution profile of one ITG generator was first determined. The most concentrated fractions from two generators were then collected and measured. (ii) "In series" elution: Two generators were connected in series and the elution profile determined. The optimum fraction and rate of elution were established. (ii) Pre-concentration (1) : the individual eluates from both generators were passed through a Strata SCX cartridge, and the trapped 68Ga eluted with acidified 5 M NaCl. The synthesis of 68Ga-DOTATATE was then optimised for elution methods (i) and (iii). TLC of the crude reaction mixture was performed before purification. After synthesis, activity of all the synthesis components were measured and decay corrected to EOS.

Results:
The % recovery for the three methods was determined as follows: double elution recovered activity/sum of activity recovered from 4 mL single elution of each generator (1-3 days prior) x 100. (i) Fractionated elution: 87% of 68Ga was recovered in 4.5 min from the collection of the 2-5 mL fractions from both generators. (ii) "In series" elution: the 2-8mL fraction was collected in 6.5 min, yielding 80% of recovered activity. (iii) The pre-concentration/elution method took 5.5 min and recovered 91% of the activity. 68Ga-DOTATATE synthesis: Using method (i) the precursor (25μg) in 1.5 mL 0.25M Na-acetate buffer was reacted with the 6 mL eluate (pH reaction 3.5-4) for 7 min at 90-95°C. The RCP of 68Ga-DOTATATE before purification was 98.4% (TLC). 68Ga-DOTATATE was obtained in 83% yield (n.d.c), 13% activity was found in the waste and was mostly accounted for the discarded fractions. Using method (iii), the precursor in 1 mL buffer + 3 mL Trace Select water was reacted with 0.8 mL eluate (pH reaction 3.5-4 Aim: In the last decades the Silk Fibroin Nanoparticles (SFNs) have received considerable attention for drug delivery due their high binding capacity for various drugs and controlled drug release properties. Up to date, multiple formulations of SFNs with different encapsulation methods and drugs have been described but it is still unknown their biodistribution in vivo after intravenous administration or tissue injection. Our aim in this work is to label the SFNs with a radioisotope to allow the visualization of the SFNs distribution in vivo. Postlabelling approach is proposed, nanoparticles are first functionalized with DTPA and then incubated with 111 InCl 3 . Methods: SFNs were prepared by a nanoprecipitation in MeOH [1]. The DTPA-functionalized silk fibroin nanoparticles (DTPA-SFNs) were prepared by amide coupling reaction between the amine groups of SFNs and one of the carboxylic groups of DTPA by using the EDC/ NHS activating system [2]. Suspensions of DTPA-SFNs (Zaverage = 191.1 ± 0.7 nm, PdI 0.115 and ζ= -32.1 ± 0.6 mV; pH 7.5) at concentration of 7 mg/mL were labelled with activities ranging from 22 to 79 MBq of 111 InCl 3 (Mallinckrodt Radiopharmaceuticals Spain, S.L.U) at room temperature up to 3 hours under stirring. After incubation, suspensions were washed twice with deionized water. Labelling yield was calculated as radioactivity in SFNs divided by total radioactivity (SFNs and supernatant).
Conclusion: The coupling of DTPA followed by incubation with 111 In chloride could be a promising method for SFNs radiolabelling. Further studies are needed in order to optimize the radiolabelling procedure, including stability tests, cytotoxicity in cell cultures and biocompatibility in vivo.  [1]. In vivo tracking of these nanoparticles is an actual challenge for researchers and labelling with radioisotopes would be an attractive alternative to other invasive biodistribution studies [2]. This work describes how silk fibroin nanoparticles (SFNs) are capable of adsorbing 99m Tc compounds by using different strategies. Radioisotope labelling of SFNs was optimized in terms of radioisotope/SFNs ratio (MBq/mg SFN), time and temperature of incubation. Methods: SFNs were prepared by a previously described nanoprecipitation method [3]. Aqueous suspensions of SFNs (Zave=168.1±2.5 nm, PdI = 0.095, ζ= -21.2±0.7 mV; pH 7.5) at two concentrations (5 and 12.5 mg/ml) were radiolabeled with activities ranging from 250 to 1050 MBq of 99m Tc-DTPA (Technescan DTPA, Mallinckrodt Radiopharmaceuticals Spain, S.L.U.) and 99m Tc-HMPAO (Exametazima, Radiopharmacy Laboratory Ltd), either at room temperature or 4°C, up to 3 hours under constant stirring and recovered by centrifugation and washed twice with deionized water in order to remove weakly bounded radioisotopes. Labelling yield was calculated as radioactivity in SFNs divided by total radioactivity (SFNs and supernatant). Radioisotope-labelled silk fibroin nanoparticles were further characterized in diameter (Z-Average) and Z-potential (ζ) by DLS.
Results Results of labeling yield in the assayed conditions are summarized in the following figure.
Higher concentration of nanoparticles shows higher isotope retention. Temperature of incubation does not significantly affect labelling yields. On one hand, DLS measurements showed that 99m Tc-HMPAO-SFNs are slightly bigger in diameter and negatively charged than the unloaded SNFs. On the other hand 99m Tc-DTPA-SFNs are significantly bigger in diameter but are less negatively charged than the unloaded SNFs. These are very preliminary outcomes and further studies are needed to optimize the radiolabelling procedure.

PP07
Investigation of radiopharmaceutic potential of a new radiolabelled graft polymer for using in the therapy and in the molecular imaging on albino wistar rats Aim: The main reason to use the nanoparticles is to make active substrate not to decay at the injection site, to target impact zones, to provide continuous active substrate oscillation and to improve the bioeffect of administration of drug. To assist intravenously applied anticancer drugs in overcoming barriers (such as Chemical, Biological, Physical, and Clinical Barriers) and to improve the balance between their efficiency and their toxicity, a large number of drug delivery systems have been developed over the years, ranging in nature from 'simple' liposomes, polymers [1] and micelles, to bacterially derived 'Minicells' and temporally targeted 'Nanocells' [2].
Methods: This study deals with grafted lysine aminoacid (Lys), metacryl derivate of a hydrophobic side chained aminoacid containing poly(2hydroxyethylmethacrylate) based magnetic graft-Lys-poly(HEMA) nanoparticles, and the attempts to radiolabel this compound with a appropriate radionuclide (such as 99m Tc) and evaluate the usefulness of the resultant radiopharmaceutical for the diagnosis and management of malignant tumors using nuclear methods. Hydrophobic nature of the nanoparticle, possibly increases the uptake of nanoparticle in different organs and tissues.
Results Magnetic graft-Lys-poly(HEMA) was labeled with 99m Tc and radiopharmaceutical potential was investigated using animal models in this study. Quality control procedures were carried out using thin layer radiochromatography (TLRC). The labeling yield of radiolabeled polymer, 99m Tc-m-graft-Lys-poly(HEMA), was found to be about 100%. Then, stability and lipophility studies were done for this radiolabeled polymer. The noctanol/water partition coefficient (lipophilicity) of 99m Tc-m-graft-Lys-poly(-HEMA) was determined. The lipophilicity was found to be 0.17. The results of the serum stability experiments demonstrated that approximately 100% of 99m Tc-m-graft-Lys-poly(HEMA) existed as an intact complex in the human serum within 240 min. Biological activity of 99m Tc-m-graft-Lyspoly(HEMA) was determined on female Albino Wistar rats by scintigraphy and biodistribution studies. The biodistribution study showed high uptake in the stomach, the pancreas, brain, ovarian, intestines and the breast. Conclusion: In conclusion, 99m Tc-m-graft-Lys-poly(HEMA), which has diagnostic and therapeutic application potentials in nuclear medicine, was first radiolabeled using the SnCl 2 method and investigated to evaluate its biodistribution. Radiolabeled m-graft-Lys-poly(HEMA) proved a useful tool for assessing the in vivo behavior of the drug in rats.  Radiochemical purity as well as radiochemical stability of the product was determined by radio-TLC and radio-HPLC methods. Results 177 Lu-DOTATATE was prepared in yield 86.7% ± 0.2% (n = 3) with a radiochemical purity greater than 99%. The final product passed all recommended quality control specifications (pH, sterility, pyrogen test & bubble test). The synthesis of 177 Lu-DOTATATE was completed in~45 min. A similar approach for the 177 Lu-PSMA is in progress. Conclusion: High activities of 177 Lu-DOTATATE were successfully prepared in good yields using a MultiSyn radiosynthesizer, passing all QC requirements. The automated synthesis was performed in a dedicated hotcell for proper radiation protection. This optimised method will be used to provide 177 Lu-labelled PSMA and DOTATATE for clinical use at Sir Charles Gairdner Hospital in 2018. Herein we introduce the synthesis of protected [ 18 F]NS12137 by a copper-mediated 18 F-labelling starting from a stannylated NS12137 precursor (Fig. 1). Methods: Radiolabelling was performed with a partly automated synthesis device, by applying a previously reported 18 F-labelling procedure [2]. Dry [ 18 F]KF/K 222 complex was formed by azeotropic drying of the cyclotron produced [ 18 F]fluoride at 120°C. Cu(OTf) 2 (py) 4 was added to the reaction vessel in anhydrous MeCN at room temperature and the reaction mixture was stirred for 10 minutes. The stannylated precursor was added to the reaction vessel in dimethylacetamide (DMA) or MeCN. When using DMA as a solvent, MeCN was first evaporated at 120°C. The reaction vessel was then heated at 120°C and samples for analytical radio-HPLC were collected during 30 minutes every 5 minutes. When using MeCN as a solvent, the reaction vessel was heated at 80°C and samples for analytical radio-HPLC were collected during 75 minutes every 15 minutes. Deprotection has been performed by changing the solvent (DMA to THF), evaporating THF to dryness and then treating with 48 % HBr. Results Protected [ 18 F]NS12137 was successfully prepared from the stannylated precursor via copper-mediated nucleophilic [ 18 F]fluorination. The radiochemical yield (RCY, non-decay corrected, based on radio-HPLC analysis of the crude reaction mixture) was up to 94% when using DMA as a reaction solvent after 5 minutes reaction. When MeCN was used, the RCY was up to 0.5% after 30 minutes reaction. Conclusion: Protected [ 18 F]NS12137 was produced with a high RCY by the copper-mediated synthesis. The RCY obtained is higher than with electrophilic 18 F-fluorination. Future work will include deprotection and isolation of the product.   Aim: Epidermal growth factor (EGFR) receptor is over-expressed in several solid tumors. EGFR tyrosine kinase inhibitors (EGFR-TKI) bind to the intracellular TK domain and compete with adenosine triphosphate (ATP), preventing thus tumor cell proliferation, angiogenesis, and protection from apoptosis. In the present study, we aimed towards the synthesis of potential 68 Ga labeled monomers and dimers of the EGFR-TKI pharmacophore (3-bromophenyl)quinazoline-4,6-diamine pharmacophore [1,2]. 1, bearing the complexing agent HBED-CC (N,N′-bis[2-hydroxy-5-(carboxyethyl)benzyl]ethylenediamine-N,N′-diacetic acid). Lead structure 1 was also linked to a 4-aminobutanoic acid 2. HBED-CC was conjugated to the aforementioned pharmacophores (1 and 2) via its functionalized propionic acid moieties, resulting in monomers 3 and 4 or dimers 5 and 6, respectively. Ligands 3-6 were tested in vitro for TK inhibition, radiolabeled with 68   Aim: Camelid single-domain antibodies (sdAb), also called VHHs, constitute a promising "new" class of imaging agent for nuclear medicine. When using the tricarbonyl method for radiolabelling VHH with Tc-99m, the optimal conditions must be specifically determined 1) by determining the parameters such as temperature and heating times to obtain the maximum of complexation with 99mTc but also 2) by evaluating the effects of temperature on their secondary structure. Methods: Five VHH (VHH-r1, VHH-r2, VHH-r3, VHH-r4 and VHH-r5) were radiolabeled with technetium-99m using tricarbonyl method at their C-terminal hexahistidine-tag (His-Tag). For each compound, various parameters such as specific activity, time and temperature of incubation were evaluated to determine the ones allowing for obtaining the most elevated complexation with 99mTc. The radiochemical purity (RCP) was determined by HPLC before and after purification step with a NAP-5 size exclusion column. Circular dichroism (CD) spectra were achieved from 205 to 260 nm at temperatures ranging from 25°C to 85°C.

Results
The conditions enabling to acquire the highest complexation with Tc-99m were found to depend on the evaluated VHH. For instance, they were of 45 min at 75°C for VHH-r1, VHH-r4 and VHH-r5, of 60 min at 60°C for VHH-r2, and of 90 min at only 40°C for VHH-r3. Similarly, conformational changes observed by CD were found to vary between the evaluated VHHs, with maximal thermal stabilities ranging from 40°C to 75°C. As a result, for 3 VHHs out of 5, the incubation temperature had to be reduced to achieve the maximum of complexation in order to preserve their 3D conformation (50°C for 90min for VHH-r2 and 60°C for 60min for VHH-r4 and VHH-r5). Once successfully radiolabeled and purified (PRC>95°C), we showed that all 99mTc-VHHs had preserved affinity for their target, except for 99mTc-VHH-r2.
Conclusion: This study underlines the fact that despite their structural similarities, each VHH responds differently to the conditions of radiolabeling with Tc-99m. Therefore, to radiolabel a VHH using 99mTc-tricarbonyl method it is very important to define optimal conditions of incubation in agreement with the maximum of complexation without affecting its 3D conformation. Aim: Dose calibrators are medical devices used in nuclear medicine to determine the amount of radioactivity to be administered to patients. According to Dutch Nuclear Medicine Guidelines, dose calibrators should be validated for all radionuclides and geometries with a maximum deviation of 5% with respect to the true radioactivity. This validation requires the use of well calibrated radioactive standards or measurements with calibrated equipment. Because this is expensive and time consuming, validation is often limited to a comparison to other dose calibrators. It is questionable if this limitation is justified, especially when looking at the effect of the (type of) isotope, the dose calibrator type/manufacturer and the geometry of the radioactive sample. Methods: In this study, we used and compared four different dose calibrators (ISOMED 2000, ISOMED 2010, Capintec CRC-25R, Veenstra VIK-202). In these, we measured activity from four commonly used isotopes ( 18 F, 68 Ga, 99m Tc and 111 In) using different volumes in both syringes and vials. Additionally, we analyzed the effect of using different geometries (3 different brands of syringes and 4 different brands of vials) on the measurements in more detail on one system. All measurements were compared to a fully calibrated gamma spectroscopy semi-conductor system (GR1018, Canberra) to determine the deviation from the true radioactivity. In are not conform legal regulations and require on-site modifications of the dose calibrator settings. Although the effect of sample geometry was generally limited (compared to the differences between isotopes), it frequently still exceeded the 5% limit as posed in the guidelines. We therefore advise to validate dose calibrators (at least one per type) for every isotope and for every geometry, using a well-calibrated standard. As this may affect the 'medical device' status of the system, discussion with the manufacturer is required. Aim: Neolignan 4'-O-methylhonokiol (MH) isolated from Magnolia grandiflora is known to have several biological activities, including anti-cancer, anti-inflammatory and anti-neurodegenerative effects [1]. MH has recently been shown to inhibit cyclooxygenase (COX) activity with a higher selectivity for COX-2 (IC 50 =0.062 μM) over COX-1 (IC 50 =2.4 μM) [2]. The development of COX-2 inhibitor radiolabeled analogs is of special interest for PET visualization of inflammation and tumors. Therefore we suggested a MH analog labeled with carbon-11 (4'-[ 11 C]methoxy-5-propyl-1,1'-biphenyl-2-ol or [ 11 C]MPbP) as a potential PET radiotracer. Unlabeled MPbP has demonstrated a high anti-inflammatory activity comparable to that of specific COX-2 inhibitor celecoxib in the preliminary tests on mice with a carrageenan-induced inflammation. The present study describes the radiolabeling procedure of [ 11 C]MPbP. Methods: The synthesis of [ 11 C]MPbP was performed by two-step procedure starting from precursor with Boc-protecting group and operated with home-made fully automated module. The radionuclide carbon-11 (T 1/2 = 20.4 min) in the form of [ 11 C]CO 2 was produced by a nuclear reaction 14 N(p, α) 11 C in a PETtrace cyclotron (GE Healthcare). [ 11 C]CH 3 I was produced using 'wet' method (LiAlH 4 /HI) and transferred under nitrogen flow (~10 ml/min) into reaction vessel with the precursor solution (2 mg in 1.2 ml of acetone and 0.7 М NaOH in water-ethanol solution (1:1, v/v) as a base). [ 11 C]-methylation reaction was performed at room temperature in 5 min. The hydrolysis step was accomplished at 60°C with 12 M HCl in 5 min. The efficiency of O-11 C-methylation as well as yield of [ 11 C]MPbP were determined in crude reaction mixture using radio-TLC on Silicagel 60 F 254 UV-plates with hexane/ethyl acetate (4/1) as a mobile phase and radio-HPLC (Waters X-Bridge column 4,6x150 mm, MeCN/H 2 O (60/40) as eluent with flow-1.3 ml/min). The radiochemical identity of [ 11 C]MPbP was evaluated by comparison with the reference compound. Results For the first time, [ 11 C]MPbP, a novel potential COX-2 inhibitor was produced. The 11 C-methylation yield was about 60% and [ 11 C]MPbP was resulted in 45% yield based on [ 11 C]CH 3 I. Work is now in progress to further optimize synthesis and purification of [ 11 C]MPbP and to investigate its biochemical characteristics (plasma stability, lipophilicity, BBB permeability, binding affinity to COX-2). This study was funded by RFBR according to the research project 17-04-02119 A. Aim: Binding of the urokinase-type plasminogen activator (uPA) to the membrane anchored receptor uPAR is defined by its amino terminal fragment (ATF) consisting of a kringle and a growth factorlike domain (GFD). The latter is buried deep in the binding cavity and harbours the majority of the high-affinity interactions. A cyclic peptide (WX-360: cyclo 21,29 [D-Cys 21 ]-uPA 21-30 [S21C;H29C]) was derived from this original structure demonstrating a capability to inhibit tumour growth and spread [1,2]. As the uPA system is frequently associated with the process of invasion/metastasis and a more aggressive phenotype in a great variety of cancers, there is a great interest in PET imaging using uPAR-directed tracers to visualise the tumour's potential for metastasis formation. Hence, this study uses the cyclic peptide WX-360 as a starting point for the development of new PET tracers. Methods: Ligands were synthesised on solid phase. A competitive bioassay based on immobilised rhuPAR was developed to assess their binding affinities. Briefly, increasing concentrations of ligand (0-1000 μM) were incubated in the presence of a 0.1 nM solution of a monoclonal mouse IgG 1 antibody (clone #62022, R&D Systems) directed against the uPA-binding pocket of uPAR. Binding of a horseradish peroxidase conjugated secondary goat anti-mouse IgG 1 antibody and subsequent conversion of a chromogenic substrate generated the signal which was read at 450 nm. A competitive cellbased binding assay to re-evaluate the initial results is currently being developed. Results Saturation and competitive binding studies employing the natural ligand uPA revealed specific binding of the primary mAb (K d = 1.0 ± 0.1 nM). Assay specific IC 50 values of the peptidebased, literature-known structures DOTA-AE105 and WX-360 were in the low micromolar range while no binding was detected for DOTA-AE105M (non-binding mutant) [3,4]. Studies on the optimisation of the binding motif were promising for methylation of the central lysine residue and exchange of the disulphide bridge for a peptide bond. Conjugation of a DOTA chelator for radiometal complexation was accomplished by insertion of various linkers at the C-terminus of WX-360, the resulting compounds displaying similar inhibitory potentials as compared to the original structure. Placing the chelator at the N-terminus, however, slightly reduced the binding affinity. Conclusion: With initial positive results, this study presents the potential of deriving uPAR-binding PET tracers from the peptide WX-360. The platform for compound characterisation is currently expanded to re-evaluation of IC 50 values in a cell-based assay as well as determination of logP values and serum stabilities. The reaction mixture was diluted with 2 mL (×2) of water and passed through an activated Alumina cartridge to the HPLC-injection vial. Solution was then loaded onto the HPLC-loop for purification in a semipreparative C18 reverse phase column (250/10 mm, Nucleosil 100-7 C18, Macherey-Nagel). Purification was performed under isocratic elution using two mobile phases at a flow rate of 3 mL/ min: first with 100% water for 10 min then switching to 40% MeCN in water. The collected product-fraction was diluted with water (1:5) and loaded onto a preconditioned C18 cartridge. After rinsing with 3 mL of water, [ 18 F]FFMZ was eluted with 1 mL of 70% EtOH, diluted with 10 mL of physiological saline, and sterilized by filtration (0.22 μm Millex-FG). Results: [ 18 F]FFMZ was eluted at 20 min after injection as shown in Fig. 1. Synthesis was satisfactorily accomplished yielding the final product in radiochemical yields of 20-25% decay corrected at the end of bombardment after a synthesis time of 60 min (n = 5), with a radiochemical purity >99% as determined by analytical HPLC. Conclusion: A convenient and reliable synthesis of [ 18 F]FFMZ was successfully adapted in an automated module by using two successive isocratic elutions instead of gradient HPLC. Final product showed no radioactive or non-radioactive impurities obtaining [ 18 F]-FFMZ in enough quantity and quality for clinical applications.  Aim: The radioiodinated products are used as diagnostic or therapeutic agents. The diversity of the labelling methodologies that used to introduce the radioactive iodine into the target molecule are wide enough to make the selection of a specific route is of great interest. Several oxidant agents were used in labelling biomolecules. Three famous ones are Chloramine-T, Iodogen and Iodo-beads (the solid state of the Ch-T). However, the mentioned agents are producing varies radiochemical yields and more importantly stabilities of the produced labelling product always questioned. The current report is detailing the findings out of a study that was aimed in investigating several reaction factors on the above labelling agents when used with small molecules and short peptides. Methods: The direct electrophilic method via Chloramine-T or similar oxidant was used. Following the end of the reaction the purification step was done using Sep-Pak C-18 Classic cartages that should be activated with 3 ml water prior the purification. Then the Sep-Pak was then washed with 1 ml water, then collect the product (labeled peptide) in the second wash which done by eluting with 0.5 ml MeCN and 1.5 ml mix of the HPLC system. The radioiodinated product was isolated by Sep-Pak and confirmed with the TLC and HPLC analysis methods. Results Chloramine-T gives constant RCY most of the time under all conditions except at basic PH (8.5) in which heat is required. Iodogen gives better RCY when heated and higher PH 7.4 and 8.5 were used. The effect of the heat was clear at PH 6.5 as the RCY was nine times higher at 60°C. Also Iodo-beads gives higher RCY than the other two labeling agents except at PH 8.5 and 60°C, it was about 25 % (±5) less. Conclusion: We can conclude that RCY and purity are very dependent on the right choice of the labeling agent and reaction conditions. However Iodo-beads give higher RCY than the other two labeling agents which make it the targeted intermediate oxidant reagents. Aim: Radiosynthesis an imaging radiotracer for a carefully selected biological process and choosing the right imaging modality become the top aims for all biomedical researchers. Positron Emission Tomography (PET) is the first on the list used for such investigations as it fulfils all informations required for imaging of biological process. On the other hand human cancer cells over express many peptide receptors which can be used as molecular targets. Therefore, radiolabeled receptorbinding peptides have emerged as an important class of radiopharmaceuticals for tumor diagnosis and therapy. As small peptides for receptor imaging and targeted radiotherapy have advantages over proteins, antibodies and antibody fragments as they are small and show rapid diffusion in target tissue and they have low molecular weight which will result in rapid clearance from blood and non-target tissues and that in turn will result in high tumor-to-background ratios. Methods: In a routine process a 0.1mg of nanoparticles that been attached to a biological molecule (peptide) dissolved in 50μl H 2 O. 68 GaCl 3 eluent from a 68 Ge/ 68 Ga generator is used as the generator is fractionally eluted beginning with 5.0 ml of sterile 0.1N HCl. For fractional elution, the first 1.6 ml of eluate always discarded, the next 2.0 ml is collected for use and the final 1.4 ml also discarded. 200 μl of the fractionated Ga-68 eluate (approximately 1 mCi/37 MBq) is added to nanoparticle solution then 100μl of sodium acetate buffer (1.25M) or ammonium acetate buffer (0.25M) is added and allowed to react at (85-90°C) for 30 minutes, the pH of the reaction mixture should be kept at 5.5. Following incubation, the labeled nanoparticle is then tested for radiochemical yield and purity using Radio-TLC and HPLC. Results: The labelled nanopatical attached to the biological molecule is monitered by both TLC and HPLC. Radio-TLC example of labelling reaction mixture; 68 Ga-anoparticle remains at the origin with retention factor of 0.00, the purity approximately 85%, and the free 68 Ga migrating to the solvent front with retention factor of 0.96. Conclusion: New efficient methodology to label nanoparticles with Ga-68 was developed in order to promote the development of PETnanoradiopharmaceuticals that in the future will overcome the limitation of the regular PET-radiopharmaceuticals in use nowadays. Fig. 1 (abstract PP19). See text for description Fig. 1 (abstract PP20). See text for description Aim: Melanoma is a tumor of constantly accumulative occurrence for which novel methods of imaging and targeted therapy are generally pursued. Developing a newly laminin class peptide that been labeled with position emitter Ga-68 or I -124 and with SPECT emitter I-131 will be discuss. In order to evaluate the potential relevance of positron emitter labeled a laminin class short peptide with enhanced melanoma targeting capacity, the uptake of 68 Ga/ 124 I-peptide were investigated in SK-MEL 28 melanoma cell line. Also the same peptide was labelled with 131 I to be tested as therapeutic approach.
Methods: High performance liquid chromatography (HPLC) system and Thin Layer Chromatography (TLC) were used for quality control purposes. The radiochemical purity were > 99.00% (n = 5). The stability was persistent over 6 h and amounted to > 98.55% ±0.35% (n = 15) for the 68 Ga-peptide. In vitro receptor binding was performed on the mentioed cell line and biological evaluation was done in normal and mice bearing SK-MEL28 cell xenograft. Animal PET/CT using 68 Ga-peptide and 124 IGa-peptide were performed in murine models of melanoma. Results: As determined by HPLC, the 68 Ga-short peptide efficiency was >70% and radiochemical purities always > 99% in short reaction time. These synthetic approaches hold substantial promise as a rapid and efficient method amenable for automation for the labelled of peptides with high radiochemical yield and short synthesis time. For radioiodination direct electrophilic method were used with High RCY. Conclusion: The uptake of 68 Ga-peptide was high by pheomelanotic SK-MEL-28 human melanoma cells. In vivo characterization in normal mice revealed rapid blood clearance of 68 Ga-peptide with excretion by both urinary and hepatobiliary pathways. In vivo imaging using animal PET/CT is confirming the later findings yielded a high tumorto-background ratio at 1 h and at 2 h. In vitro tests have shown that significant amount of the 68 Ga-peptide associated with melanoma cell fractions. Due to its easy handling and quite high uptake by melanoma cells, we expect that this peptide could be successfully used in routine application for melanoma imaging or eventual radiotherapy suggesting great potential for noninvasive clinical evaluation of suspected metastatic melanoma. Aim: Sodium Iodide (131 I) is a radiopharmaceutical available as oral capsule or solution, and is largely used in nuclear medicine for tyroid scintigraphy imaging and in radioiodine therapy. Radiochemical purity (% RqP) is defined as the percent of total radioactivity in the desired chemical form. The main methods to determine % RqP is paper chromatography (PC), thin-layer chromatography (TLC) and high perfomance liquid chromatography (HPLC). Some compendial methods also establish procedures for retardation factor (R f ) determination 1-2 . The objective of this work was to evaluate the mobile phase effect on the R f of iodide (I -) and iodate (IO 3 -) in the % RqP analysis of Sodium Iodide (131 I).
Methods: Whatman 3MM PC (1.5 × 12.5 cm), methanol and glacial acetic acid were from Merck Millipore. Methanol and purified water in the proportion of 50%, 70%, 75% and 85% (v/v) were the mobile phases. Diluent solution containing 0.1 mg/mL KIO 3 , 0.2 mg/mL KI and 1.0 g/mL Na 2 CO 3 , and standard solutions of 0.2 g/mL KI and 0.4 g/mL KIO 3 were prepared. In the origin position of a 10 cm paper strip, 5 μL of the diluent solution were applied. After chromatographic separation in each mobile phase, the suitable standard solution was dripped on the iodate and iodide expected positions followed by drops of glacial acetic acid to reveal the R f of the species with formation of a brown spot 3 . Results: The American and Argentine pharmacopoeial methods present iodate-131 as the main radiochemical impurity but differ in the mobile phase composition and in the color development method for iodide and/or iodate 1-2 . The systems advocate the use of 30 and 20 cm long stationary phases which require several hours for separation of the species, and methanol 70% and 75% (v/v), respectively. In a 10 cm strip and 70% (v/v) methanol, the R f for iodate was 0.5-0.7 and for iodide was 0.7-0.9; with 85% (v/v) methanol, the R f were 0.3-0.5 for iodate and 0.7-1.0 for iodide, respectively, taking an hour and a half for the chromatografic run. The resolution obtained with 85% (v/v) methanol was better when compared to methanol 70% (v/v). Conclusion: By the use of the staining test for iodate and iodide proposed by the Argentine pharmacopoeia, it was possible to improve the % RqP analysis of Sodium Iodide (131 I), decreasing the analysis time of more than 4 hours to an hour and a half. Aim: Internal contamination with plutonium (Pu), either in the context of accidental occupational exposure or as a result of possible terrorist use, continues nowadays to be a potential hazard. The practical way to reduce Pu body burden and the associated radiation risks is decorporation by chelation therapy by injection of marketed Na 3 -Ca-DTPA solution. This study aimed at assessing the efficacy of 110nm-sized liposomes encapsulating the DTPA in plutonium-exposed rats. The comparative effects of liposomal and free DTPA at similar doses were examined in terms of limitation of alpha activity burden in rats receiving various treatment regimens. Methods: Unilamellar liposomes (DSPC/Cholesterol/DSPE 69:30:1) were used to encapsulate DTPA (25mM). For decorporation experiments, rats were first contaminated by intravenous administration of the soluble citrate form of 238 Pu (4 to 10.3 kBq), before injection of DTPA, marketed free form or encapsulated in liposomes (2.25 at 6.74 μmol/kg). Treatment schedules started at one hour (prompt treatment) or at seven days (delayed treatment) after contamination and were given as a single injection or repeated injections. A prophylactic single treatment was also tested given at three days before contamination. Organs of interest (liver, bone and spleen mainly) and excreta were collected at different times for measurement of Pu alpha activity. Results Liposomal DTPA given at 1h post-contamination reduced significantly Pu retention by 2.5-, 1.6-and 3-fold in liver, bone and spleen respectively, compared with free DTPA. For delayed administration, liposome-entrapped DTPA decreased hepatic, skeletal and splenic Pu levels by, respectively 68, 39 and 74% of the levels in untreated control rats (only 19, 12 and 24% with a similar dose of free DTPA). In addition, repeated injections of liposomal DTPA improved the removal of Pu compared to single injection and the efficacy of the prophylactic treatment was also observed. Conclusion: The advantage of liposomal DTPA was undoubtedly directly and indirectly due to the better cell penetration of DTPA when loaded within liposomes, mainly in the tissues of the mononuclear phagocytic system. The decorporation induced by liposomal DTPA may result firstly from intracellular chelation of Pu deposited in soft tissues, predominantly in the liver. Afterwards, the slow release of free DTPA molecules from these tissues may enable a sustained action of DTPA, probably mainly by extracellular chelation of Pu available on bone surfaces. To conclude, Pu decorporation can be significantly improved by liposomal encapsulation of DTPA regardless of the treatment regimen applied. Aim: According the EU GMP Guide the radiopharmaceuticals should be manufactured in controlled areas and the premises maintained so that the level of particles and microbiological contamination are low. At Turku PET Centre (TPC) the production of radiopharmaceuticals is performed in EU GMP class C clean room. Thus validation of the clean room shall ensure that the area fulfills all EU GMP requirements for this classification. Methods: In order to grade our production premises, we have compiled a validation plan which was accepted by the quality assurance person of TPC. The validation process according the accepted validation plan was performed by an outside contractor according to valid standards (methods, calibrations of the measurement equipment and documentation). The tests include measurements of HEPA filter integrity, air volume flow, room differential pressure, airflow visualization, air change rate, airborne particle levels and viable microbial particles. The microbiological testing and measurement of airborne particles were performed both at rest and in operation. For microbiological testing, active and passive air samples using settle plates and surface samples using contact plates were taken from spots specified in the validation plan. Results: The contractor compiled a validation report including all measurement records. All the requirements were fulfilled, the report was checked and accepted by the responsible person at TPC. Conclusion: To maintain the classification, following measurements are performed annually: HEPA filter integrity test, air volume flow, room differential pressure, room air change rate and airborne particle levels. In addition, the room differential pressures are monitored automatically all the time giving alarm when out of specification. Microbiological sampling and measurement of airborne particles are performed regularly according to a standard operation procedure. Microbiological sampling is done at least once a month. Airborne particles are measured at least once a week during end product sterile filtration. While doing aseptic work, microbiological sampling and the measurement of particles are always performed. Aim: 177Lu-DOTATATE (Lutathera®) indicated in endocrine tumors PRRT should be administered according to its SPC by a slow intravenous infusion (7.4GBq whitin 30min-or-50mL/h) with either the "2pump" or the "gravity" methods. This latter method consists in using a saline solution placed in height and connected to the Lutathera® vial by an infusion line, which flows the vial causing volume expansion and overpressure, pushing the diluted product into a second infusion line that goes to the patient. The first trials we made with this technique showed that it was as imprecise as difficult to control. The aim of this work was to optimize exprimentally this technique and compare to the other ones. Methods: A saline bag(250mLw) as placed at 2m height, connected to an infusion line (set at 16drops/min -or-50mL/h) ending with a 22G/30mm-needle. The needle was inserted into the Lutethera vial placed at 1,5m height. A second long 19G/88mm-needle deeply inserted into the vial septum until touching its bottom -was connected to the venous perfusion line going to the patient. For radiation safety reasons, 177Lu-DOTATATE was substituted by a cold saline solution stained by Red Ponceau and placed a Lutathera empty vial sealed with a new rubber stopper and an alumunium ring. The evaluation of photometric absorption replaced the radioactive measurments. Once the assembly of this system set up, the infusion was started, 150 mL the colored solution was graudally collected at the line outlet in 5mL fractions which content was assessed by UVvisible-spectrophotometry at 550nm. Measurments permitted to evaluate 3 parameters: volumic activity of the perfusate (VAp), (in %, AT) and residual activity in the bottle (in %, AR). Results are expressed as mean±SD (n = 3). Results: Collected perfusate shohwed a volumic activity wich decreased gradually in exponential way [Vap=A0.e(-0,062. Perfused-Volume);R2=0.99]. Similar evolution was found in the residual activity of the vial, which disappeared according to the same mode. Symmetrically, the total perfused activity gradually increased in an exponential mode. After 30 minutes of infusion (infusion time requested in the SPC), a significant amount of the product (21.0±1.1%) remained in the vial. We calculated that to administer 99% the total delivered activity, it was necessary to infuse a a total volume between 81mL and 86 mL. After 100mL of infusion, only 0.45±0.26% remained in the vial. Conclusion: While the pump infusion techniques produce uniform and homogeneous perfusates, gravity technique was found to deliver a variable content perfusate making difficult the control of cumulative perfused activity, and perilous the planning administration of partial activities following dose adjustments. The infusion of the entire content requires at least 81mL of aline, significantly higher than the SPC requirements. Aim: 177Lu-DOTATATE is indicated in neuroendocine tumor PRRT. Its therapeutic efficiency and safety are tightly related the maintenance during all the treatment cycle of the chelate stucture integrity until its internalisation in tumour cells. Any alteration on its structure may lead to the complex destruction or unmettalation. These reactions may be suspected during co-infusion of other pharmaceuticals impacting pH, such as alkaline vehicles, or in patient freshly pretreated with cold somatostatin analogues which may be compettive to the bound peptide. The aim of this work is to study chemical interactions of 177Lu-DOTATATE in co-infusion conditions with various pharmaceutical vehicles and non-radioactive somatostatin analogues. Methods: 177Lu-DOTATATE (Lutathera ® ) was diluted to 1/5th in saline, 5% Glucose, Bicarbonate 8.4% solution, Ringer-Lactate, octreotide solution, octreotide LAR or incubated at 37°C in plasma or plasma enriched with 10% de octreotide. Radiochemical purity (RPC) was determined by ITLC-SG in 0.1mol/L sodium citrate pH=3. The labelled peptide had retention factor (Rf) of 0.1 (0.2 in plasma) and the free radionuclide migrates at Rf=1.0. RPC was also determined using C18 Sep-Pack-Plus cartridge (Waters, USA). The free radionuclide was eluted with 5mL of 0.1mol/L acetate buffer pH=3 and the labelled peptide with 5mL of methanol, and hydroxylated Lu-177 remained inside the cartridge. Mixtures were then analyzed immediately, 30min and 24h after dilution. Results were expressed as mean±SD (n = 3-4) and RPC was considered as compliant when it was >95%. Binary comparisons to the undiluted product were made by a Mann-and-Whitney U test and stability over time checked by a 1-way ANOVA (p < 5%). Results: 177Lu-DOTATATE diluted in saline or glucose or with cold peptides showed compliant RPC levels during the 24hours study duration. In Bicarbonate and Ringer Lactate, significant amounts of unbound Lutetium were found during Sep-Pack extraction, respectively 10.5±3.3% and 8.9±4.2%. In plasma mixtures, significant amounts of either hydroxylated Lutetium and or unbound lutetium were found only within 24h incubation: respectively 4.9%±1.3% and 4.2%±0.6% in plasma and respectively 6.3%±1.8% 4.8%±0.8% in plasma enriched with octreotide. Conclusion: Hydroxylated Lutetium and unbound lutetium found in plasma 24 hours post-incubation may be due to the catalytic activity of plasma which slowly deteriorates the lutated complex. This is unlikely to occur in vivo: Lutatate is rapidly cleared from the bloodstream within few hours post-infusion. According to our results, the co-infusion of 177Lu-DOTATATE with alkaline pharmaceutical vehicles should be avoided: it affects the complex stability and induces Lu-177 release. Aim: The positron-emitting 89 Zr (T 1/2 =78.42h) is widely studied for PET. Monoclonal antibodies labeling is the main focus of these studies. But should we disregard the diagnostic potential of simple 89 Zr compounds?! The possibility of effective diagnosis of inflammation, skeletal disorders and even tumors using 89 Zr-oxalate and other complexes was previously demonstrated [1,2]. The aim of this study is to develop handy procedure for production of 89 Zr-oxalate in physiologically acceptable form and evaluate its potential for PET diagnosis. Methods: All chemicals and solvents were of high-purity or pharmaceutical grade and were purchased from Sigma-Aldrich or Panreac. Quality control was carried out with TLC chromatography (iTLC-SG -50 mM DTPA solution and other eluents; PET-MiniGita radio-TLC scanner). Dowex 1, Chelex-100 (Sigma-Aldridge), ZR (Triskem), Chromafix HCO 3 (Macherey-Nagel) resins were used. 89 ZrCl 4 in 5 M HCl was purchased from Cyclotron Ltd, Obninsk, Russian Federation. In vivo experiments were carried out in BALB/C mice models with different pathologies. Wizard 2480 gamma-counter and G4 microPET (Sofie) were used for biological evaluation. Results: It was found that ZR resin allows to obtain 89 Zr-oxalate solution with highest yield and lowest metal impurities content. Chromafix HCO 3 and Chelex-100 resins allow to obtain high purity as well. However, 89 Zr-oxalate solution purified with ZR resin does not meet all the requirement for the PET radiopharmaceutical under development. Its virtues and shortcomings will be presented in detail. Using Chelex-100 resin allowed to develop the procedure for production of pH-neutral isotonic 89 Zr-oxalate solution with high purity and specific activity. Radiochemical yield of the preparation and purification procedure is ≥90%. Radiopharmaceutical radiochemical purity remains ≥95% for at least 2 weeks. 89 Zr complexes with other carboxylic acids were studied as well. Biological data indicate that 89 Zr complexes with carboxylic acids are promising visualizing agents for infection and inflammation foci and musculoskeletal injuries. Toxicity tests were carried out as well. Experimental results will be presented in detail. Conclusion: Handy procedure of production of 89 Zr-oxalate physiologically acceptable solution was developed. Its potential for PET diagnosis was evaluated. Ethics approval: Animal experiments were carried out according to European Convention for the Protection of Vertebrate Animals used for Experimental and Other Scientific Purposes. The work was financially supported by Ministry of Education and Science of the Russian Federation -State Contract № 14.N08.11.0162. with rinses of 10 ml between concentrations. Rinses were done using the eluent intended for the subsequent elution. A period of at least 5 hours was allowed between elutions. The generator was eluted with 0.5 ml fractions up to a volume of 10 ml to construct elution profiles for each eluent. Elution yield was calculated as percentage of nominal 68 Ge activity in the generator. 68 Ge breakthrough was determined in each sample. Metal contaminants (Zn, Fe, Cu, Ga) in eluates were determined by ICP-OES. Results Elution yield of the generator increased from 18% with 0.2 M HCl to 126% with 1.0 M HCl. 68 Ge breakthrough increased from 0.004% with 0.2 M HCl to 0.62% with 1.0 M HCl. Fe content was fairly consistent around 0.32 ppm; Zn increased with increasing acidity; and Ga content remained fairly constant up to 0.6 M HCl and then increased consistently. Cu was only detected in 1.0 M HCl eluates. Conclusion: An increase in the HCl concentration of the eluent resulted in increasing generator elution yields but also higher 68 Ge breakthrough and Zn content. 68 Ge breakthrough could be problematic with regards to radiation safety and radioactive waste control. In order to compromise optimal elution yield with minimal 68 Ge breakthrough, 0.6 M HCl should therefore be the eluent of choice for a SnO 2 -based generator.
Aim: Radiolabeled peptides have become very important in nuclear medicine and oncology in recent years mainly because they represent the molecular basis for in vivo imaging and radiopharmaceutical therapy with high specificity and affinity for overexpressed receptors in tumors. The objective was to evaluate the radiolabeling efficiency of the 131 I-peptides, as well as their interaction with overexpressed receptors on tumor cells related to glioblastoma. Methods: The EEEEYFELV peptide and its analogue DEDEYFELV both with affinity for EGFR receptor and the fragment GRGDYV with high affinity for the integrin receptor were synthesized accordingly to the Fmoc protocol and purified by preparative HPLC. All the peptides were radiolabeled with the radioisotope 131 I-Na. The radioiodination was evaluated and optimized using the methodology of Chloramine-T. Radiochemical yield analyses of 131 I-EEEEYFELV and 131 I-DEDEY-FELV peptides were performed by Whatmann 3MM using MeOH 95% and by thin layer chromatography on silica gel TLC-SG (Al) in ACN 95% for 131 I-GRGDYV peptide. The stability studies in vitro were realized at 2, 24, 48 and 72 hours in room temperature and refrigerate and in human serum at 37°C up to 24 hours. Partition coefficient and binding to plasma proteins were determinate for all radiopeptides. The interaction of radiolabeled peptides with tumorigenic cells was assessed by using culture cells (C6) and brain homogenate of the glioblastoma animal models (n = 6). Results: The peptides EEEEYFELV, DEDEYFELV and GRGDYV were efficiently synthesized, radiolabeled and showed radiochemical yield of 90.32% ± 0.30, 94.67% ± 0.27 and 97.95% ± 0.05 (n = 7), respectively. The stability studies showed that all the peptides were stable within 72 hours when stored in the refrigerator and up to 24 hours in human serum showing an average of radiochemical purity of 91.65% ± 1.33 (n = 3) for all peptides. All 131 I-peptides have hydrophilic features and showed a binding percentage to plasma proteins of 59.47% ± 0.74, 57.68% ± 1.29 and 34.92% ± 2.53 (n = 3). Furthermore, the peptides presented an interaction affinity with the tumorigenic cells of 4.48% ± 0.22; 4.40% ± 0.30 and 1.73% ± 0.38, respectively and a internalization of approximately 45% for all fragments. Conclusion: The peptides were efficiently synthesized and the tested radiolabeling strategies showed successful results. Moreover, all the peptides demonstrated affinity for the tumor cells evaluated. These results obtained in this study are consistent to adapt in the clinical application.  Aim: Ubiquicidine (UBI) 29-41 is currently being investigated as a potential infection imaging agent. All published methods for radiolabelling of this tracer to date describe manual processes. The current manual method for labelling UBI 29-41 with Ga-68 has several disadvantages, including unnecessary radiation exposure to operators, and difficulty to meet GMP requirements. The aim of this study was to develop an automated synthesis method for the labelling of Ga-68 UBI. Methods: Ga-68 for radiolabelling was freshly eluted from an iThemba Labs Ge-68/Ga-68 generator, using fractional elution with 0.6M HCl. NOTA-UBI was provided by BL Biochem (Shanghai, China). The approach to developing an automated method was to first duplicate the manual method developed by Ebenhan et al* using the generator, eluant and consumables available at our PET Centre. Next, the manual method was adapted to suit a Scintomics protocol, e.g. adapting volumes for the synthesis unit. The radiolabelling yield and radiochemical purity were determined after each labelling experiment. Results Initial manual labelling attempts indicated that the volume (± 0.55 ml) of sodium acetate required to adjust the pH of the labelling mixture was too small for use in an automated synthesis process. It was decided to use a 1.5 M HEPES buffer to adjust the eluate to an acceptable pH. Eluate volumes ranging from 1.0 to 2.0 ml were used to which 1.2 to 1.6 ml of HEPES buffer was added and the pH measured in order to find the most suitable combination of eluate volume and buffer volume to render a mixture with a pH between 3.5 and 4.0. Results indicated that 1.4 ml to 2.0 ml eluate and 1.2 ml HEPES buffer was suitable for use in the development of an automated synthesis method. Four successful automated labellings were performed using the HEPES buffer with an average decaycorrected radio-yield of 88.97% and a radiochemical purity of 99.49%. Conclusion: An automated synthesis protocol using a Scintomics GRP Module has been successfully developed and tested. This protocol can be utilised for the routine synthesis of Ga-68 UBI under GMP conditions. Aim: The current treatment methods such as chemotherapy have limited effects on cancer or other cells because of using conventional cytotoxic drugs. For this reason, using multifunctional nanoparticles in drug delivery systems become more important. [1,2] Some drug molecules are encapsulated nanoparticles as drug delivery systems. [3] Ampicillin is a one of effective antibiotics against Grampositive and Gram-negative bacteria. The present study aims to label ampicillin loaded graphene oxide nanoflake (AMP-GO) with 99m Tc and evaluate of its in vitro binding to S. aureus and E. coli. Methods: Graphene oxide nanoflakes were prepared according to Hummers' method. [4] Ampicillin was loaded onto graphene oxide nanoflake prepared. AMP-GO was characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM) techniques, and the amount of loaded ampicillin onto GO was determined by UV-Vis absorption spectroscopy. AMP and AMP-GO were labeled with 99m Tc using stannous chloride reducing agent. The stability of 99m Tc-AMP and 99m Tc-AMP-GO were determined in phosphate buffered saline (pH=7.2). The in vitro bacterial binding studies were performed by using both radiolabeled AMP and AMP-GO to S. aureus and E. coli. Results Labeling efficiency of 99m Tc-AMP was 92.6±5.94 % while labeling efficiency of 99m Tc-AMP-GO was found to be 97.66±2.06%. The stability results of radiolabeled compounds in phosphate buffered saline are summarized in Fig. 1. In vitro binding results of 99m Tc-AMP/ 99m Tc-AMP-GO to S. aureus are seen in Fig. 2. In vitro binding results of 99m Tc-AMP/ 99m Tc-AMP-GO to E. Coli are seen in Fig. 3. Conclusion: AMP and AMP-GO were labeled with 99m Tc with high yield. According to in vitro binding results, the binding efficiency of 99m Tc-AMP-GO was higher to S. aureus and E. coli than 99m Tc-AMP. 99m Tc-AMP-GO could be promising candidate as agent infection nuclear imaging. Furthermore, in vivo studies of 99m Tc-AMP-GO with infected rats are planned to be done. Aim: 18 F is the most commonly used radionuclide for PET imaging. Its half-life of approximately 110 min is suited for same-day imaging of many compounds that clear quickly from the body to allow visualization of uptake in the intended target. Recently, 18 F-labeling method using Al−F complex in aqueous solution was devised and offered a straightforward 18 F-labeling procedure. The radiolabeling of various chelates with Al-18 F at high temperature (~100-110 o C) is well documented in literature 1 . But high temperature radiolabeling is unsuitable for heat sensitive biomolecules. So facile method for radiolabeling at lower temperature is highly needed. We examine the efficiency of Al-18 F chelation by a variety of available macrocyclic chelators at low temperature (Fig. 1). Methods: 18 F − aqueous solution was first treated using a Sep-Pak cartridge equilibrated with 0.4 M KHCO 3 . The sample was then loaded, washed with water and eluted with 200-μL fractions . The radiolabeling was performed by adding 10 μL of the 2 mM Al 3+ stock solution, 10 μL of the chelator stock solution, and~500 μCi Na 18 F to a vial containing 100 μL 0.1 M ammonium acetate buffer (pH 5.5) solution and 100 μL ethanol at different temperature. Results: It was found that, chelators with TACN backbones bearing two acetate pendant arms and one benzyl-NCS moiety (NODA-MP-NCS) resulted quantitative labeling in a temperature as low as 30°C within 2 min. Conclusion: These results represent an important step toward rapid and efficient radiofluorination of biomolecules at room temperature.  Aim: Apoptosis, a genetically determined process of programmed cell death, has a crucial role in various processes including normal cell turnover, tissue homeostasis, and development. Moreover, apoptosis occurs in many medical disorders and hence the development of non-invasive evaluation method is highly demanded. We have reported high potential of the radiolabeled apoptosis-targeting peptide (ApoPep-1) for apoptosis detection, however in vivo stability of radiolabeled peptide was not acceptable to monitor apoptosis for a long time [1]. In this study, we prepared cyclic ApoPep-1 peptides (Fig. 1) to compare the stability with original linear ApoPep-1. A targeting ability of cyclic ApoPep-1 peptide for apoptosis was also investigated in acute myocardial infarct model. Methods: Linear and cyclic ApoPep-1 peptides were synthesized by a standard Fmoc method and an extra tyrosine residue was added for labeling with radio-iodine. The in vitro stability of the radiolabeled peptides was determined in FBS, and the in vivo stability test was performed by blood analysis. To evaluate its targeting efficacy of radiolabeled cyclic ApoPep-1, autoradiography was done in isoprenaline-induced acute myocardial infarct model. Results: All linear and cyclic peptide was synthesized and radiolabeled with I-131 in good yield. The radiolabeled peptides showed significant difference in vitro stability at 24 h (linear ApoPep-1: 72%, cyclic ApoPep-1:~95%). In vivo stability of radiolabeled linear and cyclic peptides at 1 h showed drastic difference between linear and cyclic peptides (linear ApoPep-1: 60%, cyclic ApoPep-1: 87%). Apoptosis induced in heart by myocardial infarction was clearly detected by the radiolabeled cyclic ApoPep-1. Conclusion: Effect of structural forms on the stability of linear and cyclic ApoPep-1 was demonstrated.
Results: In summary, radiochemical yield of the conversion of the arylboronic ester-derived precursor reached~80% when using 60 to 15 μmol (lower amounts brought significant losses in yield). Final [ 18 F]fluorinated compound was obtained with radiochemical purity ≥95% in an overall yield of 11% (d.c., non-automated synthesis). The radiotracer showed stability in solution up to 4 h and an experimental log D of -0.67±0.05. Conclusion: The [ 18 F]fluorinated arginase inhibitor was efficiently labeled with fluorine-18 in good yield. Preliminary in vitro studies using R22v1 cell lines, which express Arg2, revealed a cellular uptake of the radiotracer susceptible of being blocked after treatment with arginase inhibitors. Further studies are currently being performed in different cell lines which either overexpress Arg1 or Arg2 to evaluate the potential of the developed radiotracer towards arginase mapping. However, clinical applications of 6-[ 18 F]FMT have been limited by the paucity of practical production methods. Cu-mediated radiofluorination of pinacol arylboronates (aryl-Bpin) 2 enables the preparation of radiolabeled aromatics regardless of their electronic properties using nucleophilic [ 18 F]fluoride. We have applied our procedure for alcohol-enhanced Cu-mediated 18 F-fluorination 3,4 to prepare 6-[ 18 F]FMT using an easily accessible Bpin-substituted Ni-BPB-AA complex as a dual-protecting framework. Methods: Radiolabeling precursor was synthesized by alkylation of (S)-Ni-BPB-Gly with 6-Bpin-3-MOMO-benzyl bromide prepared via radical bromination of the corresponding toluene. Aqueous [ 18 F]fluoride was loaded onto a QMA vac 1cc cartidge from the male side, the cartridge was rinsed by 1.5 mL of i-PrOH and dried with helium. 18 F was eluted in the opposite direction using a solution of 12.5 μmol of TBAOTf in 0.6 mL i-PrOH directly to a solution of 7.5 μmol of Cu(OTf) 2 Py 4 , 15 μmol of I in 0.3 mL DMA. The mixture was heated in a sealed vial at 110°C for 20 min under air. 1.0 mL of 12 M HCl was added and the reaction mixture was heated (100 o C, 10 min) furnishing the crude 6-[ 18 F]FMT which was purified by HPLC using 2% EtOH in 0.1% AcOH as eluent. The product fraction was additionally purified using a SepPak Alumina N light cartridge. Results: Precursor for radiolabeling was prepared in 45% yield over two steps. The developed radiolabeling protocol provides a high 18 F-elution efficiency of 86-94% and 18 F-incorporation rate of > 90% (determined by TLC). Deprotection afforded the desired tracer in a RCC of 60%. 6-[ 18 F]FMT was produced in a RCY of 32%, RCP of 97% and enantiomeric purity > 99% within 70 min (EOB). Conclusion: Boronated Ni-BPB-AA complexes are valuable substrates for the preparation of labeled aromatic amino acids using alcohol-enhanced Cu-mediated radiofluorination. The novel protocol enables the simple and efficient production of 6-[ 18 F]FMT without time consuming solvent evaporation and intermediate SPE purification steps. Research support: RFBR grant № 16-54-12062\16 and DFG grant ZL 65/1-1.
IgG1 structures principally composed of β-sheets. Characteristic amide I band at~1670 cm -1 and amide III band (1230-1300 cm -1 ) were detected in Raman spectra. IR spectra also contain the amide I (1700-1600 cm -1 ), amide II (1480-1575 cm -1 ) and amide III bands (1255-1244 cm -1 ) specific for secondary structure of the proteins. Conclusion: The promising results from electrophoresis and vibrational spectroscopy are good basis for further radiolabeling of immunoconjugates with 177 Lu and 90 Y for treatment and imaging of HER2 positive lesions. Aim: Apoptosis represents the most abundant type of regulated cell death, and plays a key role in disease treatment. Many therapies targeted at promoting tumor apoptosis are currently in use for the treatment of cancer patients. Therefore, assessment of response to anticancer therapies can be achieved by readout of apoptosis in tumors. Non-invasive molecular imaging of therapy-induced apoptosis can be achieved by using positron emission tomography (PET) radiotracers that specifically target hallmarks of the apoptosis process such as the activation of caspase-3. We therefore aimed to develop 18 F-labeled activity-based probes (ABPs) to selectively monitor caspase-3 activity by PET imaging. Methods: Our concept is based on turning selective and potent peptide-based inhibitors into ABPs. For this Hyx-(Ahx) 2 -DW3-KE was developed bearing an optimized peptide sequence (DW3) for the selective detection and inhibition of caspase-3 in cells, and an electrophilic center (warhead, KE) for covalent binding to the enzyme active site. Radiolabeling of Hyx-Ahx 2 -DW3-KE with 18 F was performed using the copper-catalyzed azide-alkyne cycloaddition reaction. The binding efficiency of the 18 F-labeled ABP, [ 18 F]MICA-304, to human caspases will be evaluated using SDS-PAGE analysis. Radiotracer metabolic stability will be evaluated in vitro. The in vitro affinity and selectivity of the non-radioactive ABP will be profiled against a panel of human caspases.
Results "Click radiolabeling" was used to obtain [ 18 F]MICA-304 from [ 18 F]fluoroethylazide in a radiochemical yield ranging from 55 to 81% (based on HPLC analysis of the crude product, Table 1). Conclusion: Optimal radiochemical reaction conditions were defined to be 10 minutes at room temperature. In vitro and preliminary in vivo data will be reported. [ 18 F]MICA-304 is a candidate ABP for selective detection of caspase-3 activity, and will be modified for in vivo PET imaging in mouse models of apoptosis.  68 Ga liquid target/FASTlab system were submitted for ICP-MS analysis (ALS Scandinavia). Samples were either irradiated (but not chemically processed), or, samples were chemically isolated as~2.8 mL [ 68 Ga]GaCl 3 . For the analysis of Zn, it is critical to note that the m/z = 68 channel was used, along with appropriate scaling to account for the non-natural abundance of 68 Zn. Natural isotopic composition was assumed for the analysis of~70 additional elements. It is also imperative to note that samples were taken during the development phase, and may include sub-optimal chemistry processing and in some cases, ACS grade reagents. This wide range of samples was nevertheless included to provide insight to the process variability and robustness. Results: Data is tabulated below for both Zn and Fe (in μg/mL), as well as 8 other impurities (in ng/mL). These additional impurities were identified to be of interest due to known target contact materials, noted chemical variation between 68 Zn lots, potential concern for DOTA chelation competition with Ga, etc. Data is reported as the average and standard deviation for the noted number of samples. It should also be noted that current levels of 68 Zn are routinely below 1 μg/mL, with further reduction demonstrated with additional column rinsing. and BsAb were monitored by UPLC and electrophoresis for chemical purity, and after 125 I radiolabeling for antigen recognition.
Results Immunoreactivity was verified after each step described above. For BsAb, the antibody tested had the best final yield (20%) and the lowest aggregates percentage correscponding to a presaturation with 100 eq NEM and addition of 20 eq of DBCO and 20 eq of N3 for bioorthogonal chemistry.
The results are summarized in the following Table 1.
Conclusion: We demonstrated that click chemistry can be used to generate BsAb and that cysteine pre-saturation by NEM limits the formation of aggregates during the antibody functionalization. The yields obtained are comparable to those described in the literature with phenylenebismaleimide (3) . The immunoreactivity decrease is probably due to the large spacing between the Fab' fragments provided by the PEG chains. This problem can be solved by the use of new click modifiers presenting a minimal distance between the fragment and the click function.
Aim: Radiopharmaceutical preparations for human purpose may contain residual solvents. Headspace Gas Chromatography (HS-GC) remains the standard method for the analysis of volatile solvents, according to the European Pharmacopeia. Dimethylsulfoxide (DMSO), dimethylformamide (DMF) and dimethylacetamide (DMA) are less volatile solvents that are widely used in carbon-11 and fluorine-18 labeling. However, in that case, HS-GC quantification takes too much time for the release of short half-lives radiopharmaceuticals. Therefore, we developed a fast and robust Ultra High Pressure Liquid Chromatography (UHPLC) method for the simultaneous quantification of those 3 solvents. Methods: Analyses were carried out on an UHPLC (Waters) using a BEH C18 column (Waters). Validation was performed within the requirements of ICH validation guidelines (Q2A, Q2B and Q3C) and based on Good Laboratory Practices (GLP). It consisted in the evaluation of linearity, limit of quantification (LOQ), limit of detection (LOD), selectivity, specificity, carry-over, accuracy, precision and matrix effect.
Results The raw data were collected on six different days with a minimum of five days of exploitable data for each solvent. Separation of the three solvents can be achieved within 4 minutes with high resolutions. Solvents in samples can be quantified with good inter or intraday accuracy and precision. LOQ is far below the permitted daily exposure of each solvent. Selectivity and specifity were satisfactory. No matrix effect was observed.
Conclusion: This fast UHPLC method is routinely used for the quality control of radiopharmaceuticals produced in our facilities. Moreover, stability of stock solutions and frozen quality controls is achieved for at least 10 months. The use of a 98% aqueous mobile phase reduces the risk of coelution of radiolabeled compounds which makes this method suitable with most of them.

PP44
Comparison between two octreotide derivatives for somatostatin receptor scintigraphy A. In this study, we propose to compare between these two products according to our experience.
Methods: This comparative study focused on several criteria: method of preparation and administration of the product, dosimetry, patient exam preparation, image acquisition and quality. For this, we relied on the summary of products characteristics and on the examinations made at the department.
Results Both products require extemporaneous labeling; Tektrotyd® nevertheless has some preparation steps in addition to Octreoscan®. The preparations quality control is carried out for both of them by the same method (Thin Layer Chromatography) which is convenient for the hospital routine. The dosage varies from one product to another. Therefore, for an adult, the effective dose received for the maximum dose of 220 MBq of 111 In-pentreotide is 12 mSv while 740 MBq of 99m Tc-Octreotide gives an effective dose of 3.7mSv. Image Aim: 68 Ga-edotreotide, PET-agent for somatostatin receptor imaging in GEP-NET, has recently obtained a marketing authorization as a radiopharmaceutical kit (SomaKit TOC®). We wanted to compare the performance, ease of realization, radiation protection parameters of automated labeling of DOTANOC as compared to the labeling of DOTATOC (using SomaKit TOC) with Ga-68.
Methods: Automated radiolabeling of DOTANOC was performed on the ModularLab PharmTracer® module (Eckert & Ziegler) with C4-Ga68-PP cassette. Process is fully automatized and includes generator elution, cation exchange post-processing, heating, purification on C18 cartridge and dilution with sterilizing filtration. Manual preparation of SomaKit was performed according recommendations and with equipment supplied by AAA. The generator is eluted with a syringe pump directly into the SomaKit vial. Buffer is then added by hand before transferring the vial to a heating block with a forceps. Radiochemical purity (RCP) was evaluated with reverse HPLC for DOTANOC and ITLC for SomaKit. Overall yields, including elution yield and synthesis yield, were calculated corrected for decay in order to compare the labeling performance. Hand radiation exposure was evaluated using APVL-ED3 detector with two probes fixed on the first phalanx of each middle finger.
Results Overall yields were respectively 57.0 +/-11.3 % (n = 157) and 64.8 +/-5.6 % (n = 35) respectively for DOTANOC and SomaKit. RCP was always > 98 % for DOTANOC and 96.9 +/-6.9 % for Somakit include 5 (15 %) non-compliant RCP. To note that 30 to 35 min are required between generator elution and batch release for both process, but preparative step lasts at least 30 min for DOTANOC versus less than 10 min for Somakit. The radiation exposure measurements (extrapolated for a generator at calibration) gave 70 and 132 μSv for the middle finger (left and right hand) and 179 and 152 μSv respectively for DOTANOC and SomaKit. Conclusion: Somakit radiopharmaceutical kit not only allowed to turn the preparation of 68 Ga-DOTATOC into a straightforward routine process, but it also led to an increase in the overall synthesis yield compared to automated DOTANOC radiolabeling. However, the lack of purification step in Somakit radiolabeling process prevents its injection to patient in case of incomplete complexation of Ga-68. Also, process including purification provides PRC consistently higher for DOTANOC vs. Somakit. Shifting from an automated to a manual process in routine also raises the question of radiation safety. This last encourage automation of Somakit labeling which should also improve the reproducibility and allow moving towards full GMP. This work is in progress.

PP46
Optimization of automated 68  Aim: The value of 68 Ga-PSMA-directed PET imaging as a diagnostic procedure for recurrent prostate cancer is assessed and more particularly in early biochemical relapse. Synthesis of 68 Ga-PSMA-11 is relatively straightforward due to HBED-CC chelation allowing significant synthetic yield even at room temperature. Automation of 68 Ga-PSMA-11 synthesis can nevertheless be optimized to increase overall radiochemical yield i.e. increase of the available activity to inject more patients by synthesis during the shelf life of gallium-68 generator. Methods: PSMA-11 was purchased from IASON and gallium-68 chloride was obtained by elution of GalliaPharm® generator. Current preparation process has been developed on the ModularLab Standard® (Eckert&Zielger AG, Berlin) tubing synthesizer in a procedure similar to that described by Ceci et al. Briefly, the process includes an acetone-free cation exchange post-processing purification (Mueller et al.), 95°C heating for 5 min in acetate buffer (2 M, pH 4.5) and purification on disposable Sep-Pak C18 Plus® cartridge (Waters SAS France) by elution with 2 mL ethanol/water (1:1). The resulting product is sterilized by filtration and diluted in physiological saline. Then, the process was transferred on the ModularLab PharmTracer® (Eck-ert&Ziegler AG) cassette-based synthesizer with the C4-Ga68-PSMA cassette and the same steps and reagents as above. Radiochemical purity was evaluated by reversed-phase HPLC.
Results Up to now, 62 syntheses were performed on the tubing synthesizer. Mean observed radiochemical yields (RCY) was 86.1 +/-4.6 % and mean radiochemical purity (RCP) was 99.0 +/-0.9 %. Among 10 % of the initial activity is retained on the C18 cartridge. With this process, synthesis is completed in 14 min. Validation of the GMP-cassette synthesis is ongoing. First results were 96.8 % RCY and 99.2 % RCP in 17 min process. Conclusion: Optimization of the process was motivated by safety improvement by using GMP cassettes. Transfer from tubing to cassette module lead also to an increase in RCY. This is explained by the opportunity of using a Sep-Pak C18 Light® cartridge with a lower residual 68 Ga-PSMA-11 retention. In spite of the intrinsic longer time process, the final product activity is increased and should allow to inject more patient per batch. a high number of low energetic conversion-and auger-electrons. Therefore, Tb-161 could be a promising radionuclide for treatment of small tumors and metastases. Methods: PSMA-617 was purchased from ABX, Germany, and used without further modifications. The PSMA-617 was radiolabeled with 177 Lu (ITG, Germany) and 161 Tb (IFE, Norway). Cell toxicity studies with 177 Lu-PSMA-617 and 161 Tb-PSMA-617 were conducted on the cell line LVCaP (ATCC, USA). Results In this study, PSMA-617 was labeled with Lu-177 and Tb-161 using different reaction conditions to optimize radiochemical yield and purity. The formed complexes 177 Lu-PSMA-617 and 161 Tb-PSMA-617 were compared with regard to specific activity, stability and shelf-life. Conclusion: 177 Lu-PSMA-617 and 161 Tb-PSMA-617 complexes have been obtained in high radiochemical yield and purity. In the next step, we will use an AR-positive hormone responsive prostate cancer cell line to investigate the therapeutic efficacy of 177 Lu-PSMA-617 and 161 Tb-PSMA-617 in vitro. Aim: Breast cancer is the most common cancer in women and causes over 500 000 deaths worldwide every year. Overexpression of HER2 receptor tyrosine kinase occurs in 30 % of metastatic breast cancers and correlates with poor prognosis. Trastuzumab (Herceptin ® , Roche, United Kingdom) is a recombinant humanized anti-HER2 monoclonal antibody used for treatment of HER2-positive breast cancer. Studies have shown that anti-HER2 radioimmunotherapy (RIT) with 177 Lu-labelled trastuzumab is effective in treatment of breast cancer in vitro. 161 Tb exhibits similar radiochemical properties to 177 Lu, but also yields a significant number of short-range Auger/conversion electrons (≤50 keV). In this study, we want to label and compare the therapeutic efficacy of 177 Lu-DOTA-trastuzumab and 161 Tb-DOTA-trastuzumab on the HER2-overexpressing cell line SKBR3. Methods: Trastuzumab was conjugated with p-SCN-Bz-DOTA (Macrocyclics, USA) to give the DOTA-trastuzumab conjugate, which was radiolabelled with 177 Lu (ITG, Germany) and 161 Tb (IFE, Norway) under identical reaction conditions. Immunoreactivity studies with 177 Lu-DOTA-trastuzumab and 161 Tb-DOTA-trastuzumab on the SKBR3 cell line (ATCC, USA) are ongoing. Results The average number of p-SCN-Bz-DOTA molecules per antibody was determined radiochemically to 5.4 ± 1.1. Radiochemical yield and purity >98 % was achieved for both 177 Lu and 161 Tb. Quality control parameters like pH, appearance, radiochemical purity and in vitro stability were studied. The radiolabeled preparations were stable up to 120 h within the tested range of specific activities. Conclusion: This study indicates that the used conjugation and radiolabeling procedures give preparations of high stability and high radiochemical purity. Further evaluation of the efficacy of  Aim: The aim of this overview was to evaluate the regulations in Republic of Macedonia dealing with radiopharmaceuticals with emphasis on Marketing authorisation, keeping in mind that the way how radiopharmaceuticals is developed and introduced to the users are completely different from what was typical for conventional pharmaceutical products. Specific issues: The quality of the radiopharmaceuticals is defined in the applicable pharmacopeia monographs of individual radiopharmaceuticals. Regarding the processes of registration of radiopharmaceuticals and production of radiopharmaceuticals according to Good Manufacturing Practises, similar uniformity is not present in all countries. The Good Radiopharmaceutcial Practice Code was defined to comprise the application of the GMP guidelines for Pharmaceuticals with the relevant guidelines for radiation protection during production, distribution and hospital handling of radiopharmaceuticals to ensure the safety and efficacy of the product administered to the patient. Over the years the need for regulation of the radiopharmaceuticals became necessary. The discussions lead to the realisation that radiopharmaceuticals could not be considered as something extraordinary, and that the same quality standards would have to apply for these products as for conventional Pharmaceuticals. The first formal systems for obtaining market authorisation for radiopharmaceuticals were established in the USA, United Kingdom and Denmark. It was obvious that the requirements 653 used for non-radioactive drugs could not be applied directly to the radiopharmaceuticals. Most countries have established national registration procedures to obtain official market authorisation for a radiopharmaceutical. In Republic of Macedonia radiopharmaceuticals are include under the general legislation for medicinal products. Republic of Macedonia is a small country and use of radiopharmaceuticals is small. Therefore the interest in registering these products is small. Status of radiopharmaceutical regulations in Republic of Macedonia

Conclusion:
The Law on medicinal products and medical devices of the Republic of Macedonia is completely in compliance with the EU regulative. But, it is obvious that the requirements used for non-radioactive drugs could not be applied directly to the radiopharmaceuticals. Several special characteristics of the radiopharmaceuticals had to be taken into consideration. Keeping in mind that recently in Republic of Macedonia PET centre was established and we have our own production of radiopharmacuticals it is necessary to take some steps forward and make the effort to separate radiopharmaceuticals from general legislation for medicinal products. Most requirements concerning documentation of the safety and efficacy of a non-radioactive drug must be also appled to radiopharmaceuticals. But, it must be recognised that radiopharmaceuticals do not have a measurable pharmacodynamic effect. In the same time radiopharmaceuticals have a changing composition with time due to the radioactive decay of the ultra-short lived radionculides, so sometimes it is impossible to perform quality control. Studies of chronic toxicity would only be required in special cases. Clinical documentation would normally be more limited than for non-radioactive drugs. Therefore, Republic of Macedonia must to establish national registration procedures to obtain official market authorisation for a radiopharmaceutical, taking bearing in mind that we did not have a drug legislation that did also cover radiopharmaceuticals.