Animal-based radiation absorbed dose evaluation of holmium-166 labeled hydroxyapatite particulates in liver malignancies

Objective(s): Liver malignancies are among the most prevalent causes of cancer-related deaths worldwide. Intra-arterial administration of particulates labeled with beta-emitting radionuclides is one of the non-surgical promising modalities for the treatment of liver cancer.Methods: In this work, the radiation absorbed dose of 166Ho-hydroxyapatite (166Ho-HA) radiopharmaceutical was estimated for adult men based on biodistribution data in normal Wistar rats. The MIRD dose calculation method and the Sparks and Aydogan methodology were applied.Results: The results show that more than 84% of the absorbed dose is localized in liver tissue (7.35 mGy MBq-1). Also, radiation absorbed doses of 166Ho-HA for red bone marrow, osteogenic cells, and spleen tissues were estimated to be about 0.18, 0.38, and 0.24 mGy MBq-1, respectively. The maximum administrated activity was obtained at 87.5 MBq kg-1 of body weight with an effective dose of 0.39 mSv MBq-1. The maximum tolerable dose (MTD) for liver tissue was 6.13 GBq (165.56 mCi).Conclusion: This study indicated that 166Ho-HA can provide an impressive dose for liver cancer malignancies with an insignificant dose to healthy tissues.