Preliminary Study on the Use of Fricke Gel Dosimeter for Verification of IMRT Beam Delivery

Abstract

The goal of intensity-modulated radiation therapy (IMRT) is to deliver a uniform dose to the tumor with minimal margins around the target, in order to increase local control of the disease while reducing secondary effects. The research performed in this work has shown the potential usefulness of the Fricke-gel dosimeter as a quality assurance (QA) tool to verify IMRT treatments produced by inverse treatment planning. First, the 3D integrating Fricke-gel dosimeter was successfully compared to an accepted dosimetric tool. It was then used to measure relative 3D dose distributions of simple treatment plans with multiple square or rectangular fields and specific inverse-planned IMRT treatment plans. By combining the CT anatomical information and the plan contours with the gel-measured data, it was possible to display the contours on the measured dose and the measured isodose lines on the CT, in addition to measuring dose-volume histograms (DVH) for the plans. This demonstrated the usefulness of the gel dosimeter as a QA tool for IMRT and inverse planning.