Comparison between two different methods used for IMRT plans QA of Prostate cancer

Introduction: The aim of this study is evaluation of two Quality Assurance methods in sliding window IMRT technique and Determination of gamma index in both methods   Materials and Methods: In this study two tools named" Delta۴" phantom and " Epiqa" software has been used to perform QA on the treatment plan before the actual treatment by Varian linear accelerator Clinac ۶۰۰C. For this purpose, ۲۰ patient’s treatment plan were assessed with the ۳% and ۳mm criteria.   Results: Each treatment field demonstrated that the gamma index in the delta۴ phantom was more than the Epiqa software for all patients. The most uncertainty for a treatment plan in delta۴ phantom was ۰.۸۸% and for Epiqa software was ۱.۵۳%. (p- value <۰.۰۵) Conclusion: In spite of these variations in results and also studying similar researches, these tools can be used as a reliable QA method in radiotherapy centers. Delta۴ phantom is preferred to Epiqa software because it is a dosimeter. However, Epiqa software is economical to install. therefore can be used for those centers which cannot afford delta۴ phantom due to economic consideration.

Keywords:

IMRT , Quality Assurance , Delta۴ , Epiqa