Role of self-made auxiliary device in precise radiotherapy for pelvic tumor

Abstract

Objective To investigate the role of self-made auxiliary device in pelvic tumor radiotherapy with phantom immobilization using Varian cone-beam CT (CBCT). Methods A total of 50 patients with pelvic tumor were enrolled and randomly divided into study group and control group according to the order of enrollment. The patients in the study group were immobilized with thermoplastic phantom and self-made auxiliary device, and those in the control group were immobilized with thermoplastic phantom. CBCT scan and online matching were regularly performed before radiotherapy to obtain the setup errors of the left-right (x), cranial-caudal (y), and anterior-posterior (z) directions. The independent-samples t-test was used for comparison between groups. Results The set-up errors in the x-, y-, and z-directions in the study group were 1.56±1.00 mm, 1.60±1.29 mm, and 1.36±1.00 mm, respectively, and those in the control group were 1.76±1.33 mm, 2.76±1.69 mm, and 1.92±0.91 mm, respectively (P=0.551, 0.009, and 0.043). Conclusions Self-made auxiliary device helps to eliminate the errors in the cranial-caudal direction and solve the problem of involuntary activities of the lower limbs. Key words: Auxiliary device; Precise radiotherapy; Tomography, X-ray computed, cone beam; Setup error