الفهرس 
1. IntroductionOnly 14 pages are availabe for public view
 |  | from | 109 |  |  |
| | | from | 109 | | |
Abstract
Patient-specific QA is vital to the successful implementation of advanced techniques in radiotherapy. It checks the accuracy of MLCs calculation, dose calculation, plan transfer, and treatment delivery to ensure correct machine-sided delivery of the prescribed dose.
Treatment plans for thirty prostate cancer patients who received 76 Gy in 38 fractions with IMRT and VMAT were generated by TPS “Eclipse” V 13.7.14 was used to generate. These plans were calculated using photon beams with an energy of 10 MV from the Clinac® iX System. Five fields IMRT(140⁰, 60⁰, 0⁰, 300⁰, and 220⁰) were optimized by setting the collimator and couch to zero. Whereas VMAT plans used clockwise (CW) and counterclockwise (CCW) partial arcs (from 230⁰ to 130⁰) with collimator rotation (15⁰/ 345⁰) respectively. Using the anisotropic analytical algorithm (AAA), all dose calculations were performed in Eclipse planning system. Verification plans were created in the TPS using the ArcCHECK phantom. ArcCHECK phantom is a cylindrical phantom with a 3D array of 1386 diode detectors organized in a spiral design and spaced at 10 mm. The predicted distribution of dose was interpreted using ArcCHECK V6.7.3 and 3DVH.
This study aims to use 3DVH software (Sun Nuclear Corporation, Melbourne, FL, USA) to compare the dose that was predicted by treatment planning system (TPS) with the measured dose obtained by ArcCHECK dosimetric device using two advance treatment techniques: Volumetric Modulated Arc Therapy (VMAT) and Intensity Modulated Radiation Therapy (IMRT). Thirty prostate cancer patients who were treated with VMAT and re- planned with IMRT using Eclipse planning system were studied. The percentage dose differences (%DDs) were calculated using 3DVH software for planning target volume (PTV) and risk organ (OARs). The correlations between %DD and the gamma pass rate (GPR) (3%/3mm, 2%/2mm and 1%/1mm) criterion were examined. Both the DVHs calculated by 3DVH and the one projected by TPS were compared using the different parameters for PTV and OAR. In VMAT technique, the %DD was less than 3% for PTV and 4% for OAR while the IMRT technique recorded %DD less than 2% for PTV and 4% for OAR. 3DVH was somewhat more consistent with the planned VMAT verification data compared to ArcCHECK, with a mean gamma pass rate of 99.34% for the 3%/3 mm criterion. This study’s findings support the adoption of VMAT treatment technique for prostate cancer patients