Document Type : Original Paper
RESEARCH SCHOLAR,AIAS,AMITY UNIVERSITY,NOIDA,U.P.,INDIA
DEPARTMENT OF PHYSICS,AIAS,AMITY UNIVERSITY,NOIDA,U.P.
Netaji Subhas Chandra Bose Cancer Hospital,3081,Nayabal
Aim: To compare the measured surface dose in carcinoma breast patients using Gafchromic films and micro-MOSFET with the planned surface dose.
Material & method:
Twenty-three breast cancer patients were chosen for this study, 11 of whom underwent non-gated treatment, and others underwent RPM-gated treatment. Five reference points were selected during patient planning and marked on the patient's body. The dose at each reference point was calculated from the TPS, and the dose was measured at the same point using the MOSFET and film during the execution of the treatment plan on the patients.
Percentage variation in MOSFET measured surface dose to TPS calculated dose was overestimated by 19% with bolus in gated and non-gated patients While underestimated by a Maximum of 20.6% in Gafchromic films. Percentage variation in MOSFET measured surface dose to TPS calculated dose was underestimated by 19% without bolus in gated and non-gated patients While Gafchromic Films shows opposite trends, overestimation by 20%.
Measurements on the RPM-gated patient showed a similar trend to those treated with the non-gated technique in both cases, with and without bolus. The phantom study, on the other hand, revealed an opposite trend with respect to the measurements on the patient only in the bolus case.
This study also demonstrates the suitability of both detectors for surface dose measurements in megavoltage photon beams.
Breast Cancer, RPM Gating, MOSFET, Film dosimetry, invivo dosimetry