Investigation of radial dose distribution and cumulative dose of radiopharmaceuticals used for pain palliation of bone metastases

A cancer that begins in an organ, such as breast or prostate, and then spreads to the bone, results in metastatic bone. The treatment of the bone metastases is one of the most important challenges of nuclear medicine. Using radiopharmaceuticals has increased the hope for the cure or at least palliation of the bone metastases. The aim of this work is the comparison of the radial dose distribution and cumulative dose due to 153Sm, 177Lu and 166Ho. Also, the side effects due to the energetic emitted particles of this radionuclide were evaluated. By the use of MCNPX computer code, a model was designed to calculate the absorbed dose in the bone phantom. The results showed that the maximum and minimum absorbed dose due to beta particles belong to 166Ho and 177Lu, respectively. The absorbed dose related to the 153Sm gamma radiation is more than other radionuclides. Therefore, 166Ho can be suitably used for treatment of the massive tumors and 177Lu can be more useful for small tumors. 153Sm is more reliable for tumors of differect sizes because of its medium energy radiation.