Analysis of Body Mass Index on Set Up Errors Rectal Cancer in Radiotherapy

To study the positioning error according to the use of belly board and body mass index (BMI) for rectal cancer radiotherapy, a retrospective study was conducted on 114 patients from January 2012 to March 2013. The median age of the patients was 58 (29-83 years), mean BMI was (), 31 patients used belly board and 83 did not use belly board. There were a total of 527 AP & LAT images of treatment (EPID), and the mean and standard deviation of each X, Y, Z axis were , , and , respectively. Based on the BMI of 24 or higher, error occurrence risk of higher or equal to 2mm on Z axis was 4.8 times higher compared to BMI of 24 or lower (p