During radiation therapy, the mobility of the multi-leaf collimator varies according to the shape of the tumor
and the angle of the collimator. Therefore, the purpose of this study is to understand the change in surface dose
according to the collimator angle and the shape of the tumor. Using 10MV electromagnetic radiation, a treatment
plan was implemented according to the length and short axis ratio of the tumor and the collimator angle,
and the surface dose was compared with the actual measured value. As a result of the evaluation, the surface
dose increased as the length of the tumor decreased and the angle of the collimator increased. If it is necessary
to reduce the surface dose through this, the collimator angle should be applied in consideration of the short/
long ratio.