การประเมินชุดโปรแกรมวิเคราะห์การฉายรังสีของเครื่องฉายรังสีตัดขวางแบบเกลียวหมุนสำหรับประยุกต์ใช้ในเทคนิคการฉายรังสีแบบปรับแผน

Abstract

The Delivery Analysis (DA) software is installed with tomotherapy systems to assess the radiation dose received by patients during each treatment fraction. The software uses data from the detector signals to calculate and analyze the radiation dose based on the machine's daily treatment operations. The program displays the dose distribution received by the patient, comparing it to reference data. Any deviations caused by patient positioning and anatomical changes during treatment are analyzed and displayed by the DA software. Therefore, to effectively use this software for monitoring anatomical changes in patients during treatment, this study aims to evaluate the dose distribution analyzed by the DA software by comparing it with measurements from the ArcCHECK (AC) phantom and cylindrical array detectors in situations with varying thicknesses of tissue-equivalent material (Bolus). Method: Treatment plans were created based on CT images of the ArcCHECK (AC) phantom with a total bolus thickness of 2 centimeters. The treatment plans were divided according to the simulated lesion positions and radiation techniques: one at the diode detector on the top of the phantom (Target A) and the other at the center of the phantom (Target B). Each lesion group was planned using both Helical Tomotherapy (HT) and TomoDirect (TD) techniques. The dose distribution was then measured using the AC phantom based on the treatment plan, with the thickness of the bolus reduced from 0.5 centimeters to 2.0 centimeters. Data were recorded to determine the correlation of the gamma passing rates at criteria of 3%/3mm and 3%/2mm obtained from the detector signal analysis using the DA software, comparing these to the measurements obtained from the AC phantom. Results: The treatment plans for Targets A and B demonstrated statistically significant correlations between the gamma passing rates obtained from the DA software and the measurements from the AC phantom for both HT and TD techniques at all bolus thickness levels. The gamma passing rates decreased as the bolus thickness varied from the initial value in both techniques. The gamma passing rates from the DA software fell below the acceptable threshold of 90% at the 3%/3mm criterion when the thickness changed by more than 2.0 centimeters and 1.5 centimeters for HT and TD techniques, respectively. Conclusion: The DA software can effectively display gamma passing rates obtained from analyzing the detector signal and treatment machine data by comparing the dose distribution of each fraction with reference values. There is a statistically significant correlation between the values obtained from the DA software and those measured in the phantom for both HT and TD techniques.