Development of automated delivery quality assurance analysis software for helical tomotherapy

Abstract

Abstract Background: To develop a fully-automated in-house gamma analysis software for the “Cheese” phantom-based delivery quality assurance (QA) of helical tomotherapy plans.Methods: The developed in-house software was designed to automate several procedures, which need to be manually performed using commercial software packages. The region of interest (ROI) for the analysis was automatically selected by cropping out film edges and thresholding dose values (>10% of the maximum dose). The film-measured dose was automatically aligned to the computed dose. An optimal film scaling factor was determined to maximize the percentage of pixels passing gamma (gamma pass rate) between the measured and computed doses (3%/3 mm criteria). This gamma analysis was repeated by introducing setup uncertainties in the anterior-posterior direction. For 73 tomotherapy plans, the gamma analysis results using the developed software were compared to those analyzed by medical physicists using a commercial software package.Results: The developed software successfully automated the gamma analysis for the tomotherapy delivery QA. The gamma pass rate calculated by the developed software was higher than that by the clinically used software by 3.0%, on average. While, for 1 of the 73 plans, the gamma pass rates by the manual gamma analysis were higher than 90% (pass/fail criteria), the gamma analysis using the developed software resulted in fail. Conclusions: The use of the automated and standardized gamma analysis software can improve both the clinical efficiency and veracity of the analysis results. Furthermore, the gamma analyses with various film scaling factors and setup uncertainties will provide clinically useful information for further investigations.