A tool to include gamma analysis software into a quality assurance program

PurposeTo provide a tool to enable gamma analysis software algorithms to be included in a quality assurance (QA) program.MethodsFour image sets were created comprising two geometric images to independently test the distance to agreement (DTA) and dose difference (DD) elements of the gamma algorithm, a clinical step and shoot IMRT field and a clinical VMAT arc. The images were analysed using global and local gamma analysis with 2 in-house and 8 commercially available software encompassing 15 software versions. The effect of image resolution on gamma pass rates was also investigated.ResultsAll but one software accurately calculated the gamma passing rate for the geometric images. Variation in global gamma passing rates of 1% at 3%/3 mm and over 2% at 1%/1 mm was measured between software and software versions with analysis of appropriately sampled images.ConclusionThis study provides a suite of test images and the gamma pass rates achieved for a selection of commercially available software. This image suite will enable validation of gamma analysis software within a QA program and provide a frame of reference by which to compare results reported in the literature from various manufacturers and software versions.