Assessment of the effective absorbed dose of 4-benzyl-1-(3-[125I]-iodobenzylsulfonyl)piperidine in humans on the basis of biodistribution data of rats

OBJECTIVESThe aim of this study was to estimate the effective absorbed radiation dose to human organs following promising in-vivo results of intravenous administration of 4-benzyl-1-(3-[I]-iodobenzylsulfonyl)piperidine (4-B-[I]-IBSP) using normal biodistribution data obtained from rats. MATERIALS AND METHODSFive rats were killed at exact time intervals and the percentage of injected dose per gram of each organ was measured by direct counting from rat data. The medical internal radiation dose formulation was applied to extrapolate from rats to humans and to project the absorbed radiation dose for various human organs. RESULTSThe dose estimation shows that the organs that received the highest absorbed dose were the brain, bone surface, and red marrow (10.51, 0.69, and 0.08 μGy/MBq, respectively). Our prediction shows that a 185 MBq injection of 4-B-[I]-IBSP into humans might result in an estimated absorbed dose of 49.39 μGy for the whole body. The highest effective absorbed dose for 4-B-[I]-IBSP was in the brain (19.4 μSv) and the organs that received the next highest doses were the bone surface, red marrow, muscle, and thyroid, with magnitudes of 15.27, 1.81, 0.15, and 0.10 μSv, respectively. CONCLUSIONThe results of this study suggest that 4-B-[I]-IBSP is a suitable and safe candidate in clinical studies and in lung malignancies.