Fig. 1From: The DOTA macrocyclic cavity in metallic radiopharmaceuticals: Mythology or reality?Idealized drawing of the structure of the H4DOTA ligand and of the location of the hypothetical ‘macrocyclic cavity’ assumed to be of spherical shape (not shown) and positioned at the center of the N4 plane. The red line is the circumference generated by the intersection of the sphere with the N4 planeBack to article page