Evaluation of dose distribution and dose gradient in brachytherapy cylindrical applicators using a dedicated Phantom for Iridium-192 and Cobalt-60 HDR sources

Document Type: Conference Proceedings

Authors

1 Islamic Azad University, Science and research branch, Tehran, Iran Mahdieh Radiotherapy and Oncology charity center, Hamadan, Iran

2 Department of Medical Physics, Royal Adelaide Hospital, Adelaide, SA 5000 AUSTRALIA. School of Physical Sciences, the University of Adelaide, SA 5005 AUSTRALIA. Department of Medical Physics, Reza Radiotherapy and Oncology Center, Mashhad, Iran

3 Department of radiation oncology, University of medical science, Hamedan, Iran

4 Department of Radiation Oncology, Tehran University of Medical Sciences, Tehran, Iran

5 MSc of Medical physics, Department of Medical physics, Kermanshah University of Medical sciences, Kermanshah, Iran

Abstract

Introduction: A study was performed to evaluate radiation dose distribution and dose gradient around cylindrical applicators for high-dose-rate (HDR) brachytherapy systems with 192Ir, 60Co 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 60Co source and 192IridumHDR sources. The phantom contains a film and TLD-100 position on the top and peripheral areas, and a rectum cylinder with 1.5 cm insert caps into the phantom. Dose coverage of 5-mm shell surrounding the cylinder, was then evaluated for both scenarios.
Results:A significant dose reduction from the expectation dose for 192Ir 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 60Co and 192Ir 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

Keywords