Evaluating intra-fractional prostate motion in radiotherapy of prostate cancer with four-dimensional real-time transperineal ultrasound / 西安交通大学学报(医学版)

ABSTRACT

Objective: To evaluate intra-fractional prostate motion by applying four-dimensional real-time transperineal ultrasound (TPUS) so as to provide reference evidence for the moderate hypofrectionation radiotherapy for prostate cancer. Methods: Ten patients with prostate cancer were randomly selected to be treated with volume modulated radiotherapy (VMAT). TPUS was utilized to collect 60 intra-fraction data. Prior to each treatment for all the patients, CBCT was adopted to correct inter-fraction setup errors. During treatment, four-dimensional real-time ultrasound images were acquired to monitor the 3D prostate motion. Results: Among all the data, the maximum distance of prostate motion was 1.85 mm in the left direction, 0.50 mm in the right direction, 1.83 mm in the anterior direction, 3.04 mm in the posterior direction, 2.68 mm in the cranial direction, and 1.75 mm in the caudal direction. The percentage of fractions in which the distance of prostate motion was more than 2 mm among all treatment fractions was 3% in the left and right (LR) direction, 11% in the anterior and posterior (AP) direction, and 5% in the cranial and caudal (CC) direction. The distance was greater in AP direction than in AP direction and CC direction. Results: TUPS is a non-invasive and reliable technique which can detect the real-time motion of the prostate during radiotherapy aiming to prevent tumor target areas from being missed or normal tissues from being overexposed.