Evaluation of dose distribution and dose gradient in brachytherapy cylindrical applicators using a dedicated Phantom for Iridium-۱۹۲ and Cobalt-۶۰ HDR sources

Introduction: A study was performed to evaluate radiation dose distribution and dose gradient around cylindrical applicators for high-dose-rate (HDR) brachytherapy systems with ۱۹۲Ir, ۶۰Co brachytherapy source applied for rectal and vaginal cancers treatments.   Materials and Methods: Two additional computed tomography (CT) based plans were generated using a dedicated Phantom for both ۶۰Co source and ۱۹۲IridumHDR sources. The phantom contains a film and TLD-۱۰۰ position on the top and peripheral areas, and a rectum cylinder with ۱.۵ cm insert caps into the phantom. Dose coverage of ۵-mm shell surrounding the cylinder, was then evaluated for both scenarios. Results:A significant dose reduction from the expectation dose for ۱۹۲Ir at the central points of the cylinder tip was observed. The results were then verified by measurements through radio- chromic film and TLDs.   Conclusion: Both ۶۰Co and ۱۹۲Ir sources were found to be suitable HDR sources for vaginal treatment using a cylindrical applicator with advantages of reducing radiation exposure to Organ At Risks (OARs) in the lower dose range, and appropriate prescribed dose to the target

کلیدواژه ها:

Dose Distribution ، Cylinder Applicators ، Brachytherapy ، High Dose Rate Brachytherapy