Fig. 2From: The DOTA macrocyclic cavity in metallic radiopharmaceuticals: Mythology or reality?Idealized drawing of the coordination of a Ga3+ ion inside the hypothetical spherical cavity (not shown) located at the center of the plane defined by the four coordinated nitrogen atoms. L is the Ga–N bond distance, R is the radius of the cavity, and the red circle is the circumference generated by the intersection of the spherical hole with the N4 planeBack to article page