Internal Dosimetry assessment for monoclonal antibodies and antibody fragments labeled by Lutetium-177

Abstract

In this research, the behaviour of monoclonal antibodies (MAbs) and their fragments labeled by 177Lu after injecting into the body is simulated for diagnostic and therapy. The absorbed doses in organs and tissues with maximum radiation exposure are presented. On the base of reference data in the literature, a biokinetic model is built-in for MAb and their fragments. The cumulative activity of 177Lu in organs and tissues per Bq of administered activity is calculated. Spleen, liver, and red bone marrow have the highest doses when 177Lu associated with intact monoclonal antibodies is injected into human body. The estimated doses on these organs are 1.95, 1.17 and 0.54 mGy/MBq, respectively. For the fragments of monoclonal antibodies is considered with 177Lu, the most exposed organs are the kidneys with the doses of 0.78 mGy/MBq for F(ab')) and 1.27 mGy/MBq for F(ab′)2.