코발트-60 감마선의 다문선속에 의한 식도암치료의 선량 평가

Abstract

CT technique was used to provide tumor depth, lung thickness and tissue density for the calculation of delivered radiation dose to various points on the esophagus, spinal cord and interest points of lung tissue. In treatment planning, in the to avoid excess dose at the spinal core, we usually set the prone position of patient. The angle of the incidence beams were used for three portals : LPO, RPO and AP. The percentage depth dose changes by the inhomogeneity of various tissue structures, such as lung, mediastinum and other thoracic contents. Therefore the correction factor of 4% increase should be applied as being with 1cm of lung tissue in Co-60 gamma radiation therapy. With known accuracy of the CT representation of the RANDO section, the treatment planning was computed to predict the dose to a point in the same section which was selected as representative of normal esophagus location in the TLD measurements in the phantom studies.