Correlation of thickness changes and daily dose detection of delivery analysis (DA) software in helical tomotherapy

Abstract

Abstract Purpose: To assess the correlation between the dose distribution provided by the delivery analysis (DA) software and the measured dose distribution using an ArcCHECK (AC) phantom in the presence of thickness variation. Materials and Methods: Two sets of targets were established within the phantom. Target A was placed on the detector areas, whereas Target B was positioned at the centre of the phantom. Bolus was applied to the surface of the phantom at different thicknesses ranging from 0 to 2 cm to verify the dose distribution in both TomoHelical (HT) and TomoDirect (TD) techniques. The gamma passing rate (GPRs) were evaluated against predefined thresholds of 3%/3 mm and 3%/2 mm. Correlation study evaluated the level of agreement between DA and AC values. Results: Both AC and DA exhibited a decline in GPRs as the bolus thickness decreased. Significant correlations were observed between AC and DA for both HT and TD techniques, with a p value of less than 0.001. Conclusion: The results indicate that DA software has the capability to detect anatomical changes during tomotherapy treatments. This is substantiated by the statistical association found between DA and the standard AC phantom system for dose distributions in both HT and TD methods.