Automated Module Radiolabeling of Peptides and Antibodies with Gallium-68, Lutetium-177 and Iodine-131

Our objectives were to automate radiolabelin of therapeutic activities for safe, reliable, cost-effective, practical routine preparation of Lu-177-radiopeptides, I-131 radioimmunotherapeutic agents, and Ga-68-peptide PET diagnostics and, in particular, minimize radiation exposure to the radiopharmaceutical chemist. Reprogramming and adaptation of a commercially available synthetic module (IBA molecular; Synthera (R)) allowed high yield, fully automated, in-house radiolabeling of novel therapeutic and diagnostic radiopharmaceuticals under remote shielded sterile conditions. Radiochemical yield and purity was measured by instant thin-layer chromatography and high-performance liquid chromatography. Ga-68-octreotate and Lu-177-octreotate were synthesized, resulting in both radiochemical yield and radiochemical purity greater than 99%. Synthesis of I-131-rituximab resulted in a yield of 60%, with a radiochemical purity greater than 99%. Using 400 MBq (GaCl3)-Ga-68 per synthesis, the estimated absorbed body and hand dose for a manual synthesis was 2 and 27 mu Sv, contrasting with automated synthesis exposure of 1.3 and 7.9 mu Sv. Using 8000 MBq (LuCl3)-Lu-177 per synthesis, the estimated absorbed body and hand dose for a manual synthesis was 44.7 and 75 mu Sv, contrasting with automated synthesis exposure of 2.5 and 20 mu Sv. Using 6000 MBq I-131 per synthesis, the estimated absorbed body and hand dose for a manual synthesis was 83.7 and 335 mu Sv, contrasting with automated synthesis exposure of 10.9 and 54.7 mu Sv. The reduction in radiation exposure by automated synthesis of radiopharmaceuticals in the Synthera (R) module was at least five fold. Automated synthesis of therapeutic Lu-177 and I-131 radiopharmaceuticals and Ga-68 PET agents in the shielded sterile Synthera (R) module is simple, practical, and efficient and virtually eliminates radiation exposure to the radiopharmaceutical chemist.