Study of Bone Surface Absorbed Dose in Treatment of Bone Metastases via Selected Radiopharmaceuticals: Using MCNP4C Code and Available Experimental Data.

Bone metastases are major clinical concern that can cause severe problems for patients. Currently, various beta emitters are used for bone pain palliation. This study, describes the process for absorbed dose prediction of selected bone surface and volume-seeking beta emitter radiopharmaceuticals such as (32)P, (89)SrCl2,(90)Y-EDTMP,(153)Sm-EDTMP, (166)Ho-DOTMP, (177)Lu-EDTMP,(186)Re-HEDP, and (188)Re-HEDP in human bone, using MCNP code. Three coaxial sub-cylinders 5 cm in height and 1.2, 2.6, and 7.6 cm in diameter were used for bone marrow, bone, and muscle simulation respectively. The *F8 tally was employed to calculate absorbed dose in the MCNP4C simulations. Results show that with injection of 1 MBq of these radiopharmaceuticals given to a 70 kg adult man, (32)P, (89)SrCl2, and (90)Y-EDTMP radiopharmaceuticals will have the highest amount of bone surface absorbed dose, where beta particles will have the greatest proportion in absorbed dose of bone surface in comparison with gamma radiation. These results demonstrate moderate agreement with available experimental data.