ĐÁNH GIÁ ĐỘ DI LỆCH TRONG QUÁ TRÌNH XẠ TRỊ UNG THƯ CỔ TỬ CUNG SỬ DỤNG HỆ THỐNG EPID

Abstract

Objective: Evaluate the cervical cancer patient setup errors during radiation therapy, and calculate random errors, systematic errors during radiotherapy for cervical cancer. Subjects and methods: Quantitative descriptive study on 30 cervical cancer patients receiving pelvic external radiation therapy at K Hospital from March 2019 to December 2019. Patient setup errors in different dimensions superior - inferior, left - right, anterior - posterior were determined by comparing weekly digitally reconstructed X-rays and port film images of the patient with EPID system. Results: Average displacement in 3 directions superior - inferior; left - right; anterior - posterior are 4.5mm; 3.6mm and 3.3mm respectively. In which, patient setup errors in the superior - inferior direction has the largest rate and displacement. Patient setup errors tend to occur more in the group of patients with large weight changes, the difference is not statistically significant. No association was found between the use of fixation devices and the patient's displacement. Random error and systematic error in 3 dimensions are 3,6mm; 2,8mm; 3,2mm and 3,3mm; 2,6mm và 2,0mm respectively. Conclusion: Taking a portfilm to check the patient's position and projection field before radiotherapy using the EPID system is a reliable and effective method to improve accuracy during radiotherapy for cervical cancer patients.