Dosimetry calculations of 166Dy/166Ho –Chitosan in vivo generator using GEANT4 and MCNPX

The Holmium-166 radionuclide is one of the most effective radionuclides used to treat bone marrow cancer and rheumatoid arthritis. Among the recommended radionuclides used in radiation synovectomy, 166Ho has got much attention due to suitable decay properties such as short half-life, its high beta energy, gamma-ray emission with suitable energy for nuclear imaging, and the possibility of large-scale production in medium flux reactor. One method to deliver 166Ho to the target tissue is via the 166Dy/166Ho-Chitosan in vivo generator. Compared with other similar radiopharmaceuticals, using the in vivo generator to deliver 166Ho, causes minimal non-target tissue exposure and increased absorbed dose in the target tissue. In this work, the absorbed dose of 166Dy/166Ho-Chitosan radio-complex for radio-synovectomy purposes was calculated by GEANT4 and MCNPX. The obtained results were compared with each other. In addition, the dosimetry results of the mentioned radio-complex have been compared with the common radio complexes used for radio-synovectomy.