Optimized effective dose from imaging system in radiotherapy

The study was conducted at Steve Biko Academic Hospital in the Radiotherapy department. Computed tomography dose index imaging dose measurements were performed using a head and body phantom with slots to insert a calibrated pencil ionisation chamber connected to an electrometer used to measure doses. The computed tomography dose index dose was measured for different cancer treatment setup verification imaging protocols, which included head and neck, pelvis and prostate protocols. Measurements were conducted for 90, 100, 110, 120 and 140 kV, respectively. The measured CBCT dose for each imaging protocol was converted into the effective dose by applying conversion factors. These factors were obtained from the American Association of Physicists in Medicine (AAPM) report no 96. The results were examined, using the mean, median, standard deviation, and confidence intervals, as well as specialized tests such as the Mann-Whitney U test and the intra-class correlation coefficient (ICC).