Design of radioimmunotherapy (RIT) studies. NOD/SCID or NRG mice were implanted s.c. with EGFR-positive PANC-1 human pancreatic cancer xenografts. Tumour-bearing NOD/SCID mice were treated with fractionated amounts of panitumumab (10 μg; ~ 0.07 nmoles), panitumumab-DOTA-[111In]In (10 MBq; 10 μg; ~ 0.07 nmoles) or panitumumab-MCP-[111In]In (10 MBq; 10 μg; ~ 0.07 nmoles) or normal saline every 3 weeks for 3 cycles. Tumour-bearing NRG mice were treated with a single amount of panitumumab-DOTA-[177Lu]Lu (6 MBq; 10 μg; ~ 0.07 nmoles) or panitumumab (10 μg; ~ 0.07 nmoles) or normal saline.