Dosimetric evaluation of 170Tm-EDTMP for palliative therapy of bone metastases using Monte Carlo simulation

170Tm-EDTMP has been proposed as a radiopharmaceutical with desirable properties and an alternative to 89Sr-Cl2 for the palliative treatment of patients with bone metastasis. This study aimed to calculate the absorbed dose of 170Tm-EDTMP in the bone of patients with bone metastasis.

In this study, an adult human femur phantom and the GATE Monte Carlo toolkit were used for simulation. 170Tm-EDTMP was distributed in the bone compartment, and the absorbed dose per disintegration was calculated in the different phantom compartment. In order to comparison and validation of results, simulations with similar conditions were performed for 89Sr-Cl2. Then, the absorbed dose per administered activity of radiopharmaceuticals in the bone and bone marrow was calculated using the MIRD method and compared with each other.

The bone absorbed dose per administered activity for 170Tm-EDTMP was 5.52 times higher than 89Sr-Cl2, while the bone marrow absorbed dose by 170Tm-EDTMP was 2.11 times higher than 89Sr-Cl2.

According to the results obtained in this study, 170Tm-EDTMP is a suitable radiopharmaceutical for use in the palliative treatment of patients with bone metastases. However, in order to further investigation, there is a need for clinical trial in the patients.