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Dosimetric comparison of Y 90 , P 32 , and Re 186 radiocolloids in craniopharyngioma treatments
Author(s) -
Sadeghi Mahdi,
Karimi Elham,
Hosseini S. Hamed
Publication year - 2009
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3243085
Subject(s) - craniopharyngioma , nuclear medicine , medical physics , dosimetry , medicine , radiation therapy , radiology
Purpose: In the radionuclide treatment of some forms of brain tumors such as craniopharyngiomas, the selection of the appropriate radionuclide for therapy is a key element in treatment planning. The aim was to study the influence by considering the beta‐emitter radionuclide dose rate in an intracranial cyst. Methods: Dosimetry was performed using the MCNP4C radiation transport code. Analytical dosimetry was additionally performed using the Loevinger and the Berger formulas in the MATLAB software. Each result was compared under identical conditions. The advantages and disadvantages of using Y90 versus P32 and Re186 were investigated. Results: The dose rate at the inner surface of the cyst wall was estimated to be 400 mGy ∕ h for a 1 MBq ∕ ml concentration of Y90 . Under identical conditions of treatment, the corresponding dose rates were 300 mGy ∕ h for P32 and 160 mGy ∕ h for Re186 . For a well‐defined cyst radius and identical wall thickness, higher dose rates resulted for Y90 . Conclusions: To achieve the same radiological burden, the required amount of physical activity of injectable solution is lower for P32 . This is found to be a consequence of both the radionuclide physical half‐life and the pattern of energy deposition from the emitted radiation. According to the half‐life and dose‐rate results, Y90 would be a good substitute for P32 .