Study of Image Quality and Positioning Accuracy for Image-guided Radiation Therapy System in Taiwan

• Main Authors: YANG, CHENG-JYUN, 楊程鈞
• Other Authors: CHEN, HSIN-HSIUNG
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/y3q8s5

碩士 === 中臺科技大學 === 醫學影像暨放射科學系暨研究所 === 106 === Image-guided radiation therapy (IGRT) use imaging technology to acquire anatomical images of patients after the completion of patient set-up, and adjust patient position by comparing these images with those in the treatment planning before the treatment. This study aimed to establish the IGRT quality assurance program and to survey on the image quality and positioning accuracy of the IGRT systems in Taiwan accordingly. Referring to reports of the AAPM TG-142, TG-58, and TG-104, and consulting to the clinical department, the initial version of IGRT QA program was established. The QA program included check items, operating procedures, and recommended tolerance value. A total of 79 linear accelerators and 19 Tomotherapy IGRT systems were surveyed in this study. Major items of the QA program included mechanical position accuracy of the imaging device, image quality, and accuracy of the image-guided positioning. The survey data were analyzed and the QA procedure, especially for the recommended tolerance values were adjusted accordingly. The data collection of IGRT equipments in Taiwan, personnel training, the IGRT QA program, and the recommended tolerance values were accomplished in this study. According to the results in item of imaging and treatment coordinate coincidence, the differences were less than 2 mm for the all survey data. For 2D MV or kV imaging systems had more than 85% and the cone-beam computed tomography (CBCT) system had approximately 73% of the surveys with the differences within 1.0 mm. Regarding the accuracy of image-guided positioning, the CBCT systems in two major imaging mode showed more than 85% of the surveys were within 1.0 mm. This study is the first to develop the IGRT QA program in Taiwan. Based on the statistical analysis of the survey data, appropriate adjustments for the recommended tolerance values were applied. The present study will be provided to the AEC as a reference for the improvement of radiation safety and dosimetry quality.