Analyzing the performance of the URT treatment planning system and URT-Linac 506C for flattening filter (FF) and flattening filter free (FFF) photon beams of Monte Carlo algorithm by use of AAPM TG 119 test cases

The objective in this study was to create AAPM TG 119 test plans for Intensity-modulated radiation therapy (IMRT), burst mode and volumetric modulated arc therapy (VMAT) in convolution study in order to investigate accuracy of the United Imaging Healthcarechr('39')s URT treatment planning system (URT-TPS).

The plans were delivered to the phantom using the United Imaging Healthcarechr('39')s URT-Linac 506C. For there treatment mode as IMRT, Burst Mode and VMAT, with two kind of beams as flattening filter (FF) photon beam and flattening filter free (FFF) photon beam, calculated by uRT-TPS Monte Carlo algorithm, the overall accuracy was measured, and analyzed with five test geometries provided in TG 119. The point measurements were measured by a Farmer type ion chamber and fluence measurements were done with film respectively.

For the FF photon beams, the difference between measured point doses and planned doses of static multi-leaf collimator (MLC), dynamic MLC, Burst Mode and VMAT were within±3.92%,±3.26%, ±4.11%and±3.31% respectively. Gamma passing rates of Static IMRT, Dynamic IMRT Burst Mode and VMAT were >93.08%, 90.93%, 90.40% and> 92.00% respectively. For the FFF photon beams, the deviation between measured point doses and planed dose of static MLC, dynamic MLC, Burst Mode and VMAT were within 1.84%, 3.36%, 2.65%and 3.11% respectively. Gamma passing rates of Static IMRT, Dynamic IMRT Burst Mode and VMAT were>92.60%, 94.07%, 93.54% and 94.39% respectively and all confidence limits of the TG 119 report were matched.

Based on this analysis which were performed in accordance with the TG 119 recommendations, it is evident that the URT treatment planning system and URT-Linac 506C have commissioned IMRT and VMAT techniques with adequate accuracy.