The Evaluation of the Set-Up Differences Between Radiation Therapists for Head and Neck Patients

Abstract

OBJECTIVEThe aim of the present study was to determine the electronic portal imaging (EPI) evaluation differencesbetween the therapists in the reference of cone beam computed tomography (CBCT).METHODSIn the present study, 62 EPI images belonging to 13 head and neck patients were evaluated separately byfour therapists as offline, and the amount of shift in the center of fields was determined. CBCT obtainedat the same time with the EPI images was accepted as reference, and the amount of shift in the center offields was compared separately for each therapist with the results of EPI.RESULTSAccording to our results, the amount of shift in the center of fields had changed between therapists with0–9.4 mm in the reference of CBCT. The probability of shifting center of fields to be >3 mm was 60% forthe first therapist, 35% for the second therapist, 63% for the third therapist, and 50% for the fourth therapist. The probability of shifting center of fields to be >5 mm was 24%, 8%, 27%, and 14.5%, respectively.Analysis of variance for repeated measures test was applied to center shift values, and there were a significant difference in the groups (sig.