• The Journal of the Korea Contents Association
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• v.13 no.10
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• pp.412-418
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• 2013

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 $23.35kg/m^2$ ($16.55-31.15kg/m^2$), 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 $1.66{\pm}1.55mm$, $1.64{\pm}1.56mm$, and $1.99{\pm}1.75mm$, 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<0.001), and when BMI was 24 or higher in case the belly board was not used, the error occurrence risk of higher or equal to 2mm on the z-axis was 3.6 times higher (p<0.011). Radiation therapy for rectal cancer patients, using Belly Board for both the ones wearing fistula and with high BMI may be effective in decreasing the positioning errors.