Dosimetric evaluation of 153Sm-EDTMP, 177Lu-EDTMP and 166Ho-EDTMP for systemic radiation therapy: Influence of type and energy of radiation and half-life of radionuclides. (March 2015)

• Record Type: Journal Article
• Authors: Ranjbar, Hassan; Ghannadi-Maragheh, Mohammad; Bahrami-Samani, Ali; Beiki, Davood
• Is Part Of: Radiation physics and chemistry. Volume 108(2015:Mar.)
• Page Start: 60
• Page End: 64
• Publication Date: 2015-03
• Subjects: Dose distribution -- Dosimetry -- Monte Carlo simulation -- 153Sm-EDTMP -- 166Ho-EDTMP -- 177Lu-EDTMP; Radiation chemistry -- Periodicals; Radiometry -- Periodicals; Radiation -- Periodicals; Chimie sous rayonnement -- Périodiques; 539.2
• DOI: 10.1016/j.radphyschem.2014.11.015
• Languages: English
• ISSNs: 0969-806X

Abstract

Abstract: In radiopharmaceutical therapy, delivered doses to critical organs must be below a certain threshold therefore internal radiation dosimetry of radiopharmaceuticals is essential. Advantages and disadvantages of radionuclides with different characteristics were evaluated for selection of appropriate radionuclide. The Monte Carlo MCNPX simulation program was used to obtain radial dose and cumulative dose of 153 Sm, 177 Lu and 166 Ho used in radiotherapy of bone metastases. A cylindrical geometry with constant density materials was supposed for simulation of femur bone. The radius of bone marrow, bone, and surrounding soft tissue was considered 0.6 cm, 1.3 cm and 4 cm, respectively. It was assumed that the radionuclides were uniformly distributed throughout the tumor. "continuous energy spectrum" of beta particle was used instead of mean beta energy. Our simulations show that absorbed dose in target organ (bone) is greater than other organs and 166 Ho gives a higher dose to the critical organ of bone marrow than either 153 Sm or 177 Lu. Absorbed dose versus time demonstrate faster dose delivery for the short half-life radionuclides ( 153 Sm and 166 Ho). These results are in good agreement with clinical observations which show a pain relief within 1 week after intravenous administration of 153 Sm-EDTMP, whereas it occurs within 2 week in the case of 177 Lu-EDTMP. According to the results, combination of different radionuclides with different characteristics such as 153 Sm-EDTMP and 177 Lu-EDTMP could be more advantageous to patients with painful bone metastasis. Highlights: The radial dose and cumulative dose of 153 Sm, 177 Lu and 166 Ho are calculated. The effect of half-life of the radionuclide on the suitable activity for injection is studied. Dose delivery is fast for the short half-life radionuclides ( 153 Sm and 166 Ho). The results are in good accordance with clinical observations. The combination of different radionuclides with different characteristics could be more advantageous.