Investigation of uniform exposure to surface lesion using ir-192 source

Ir-192 sources have been widely used in clinical brachytherapy. For example, an intracavitary radiation therapy, an endovascular brachytherapy and a surface radiation therapy were performed using the Ir-192 sources. However, the appropriate step size, the catheter distance and reference points in the surface radiation therapy have not been investigated. The purpose of this study is to determine the appropriate treatment parameters, such as the step size, the catheter interval and the reference point for the uniform exposure to a surface lesion using the Ir-192 sources. To determine appropriate alignment of radiation sources, treatment planning systems (TPS) and Monte Carlo calculations were used. Active source dwell positions were investigated at intervals of 0.5 cm and 1.0 cm for each applicator and each step, and reference points were investigated at distance of 1.0 cm and 2.0 cm from the center of each source. The results of this study revealed that the step size and the catheter distance of 1.0 cm, and reference points placed at 1.0 cm distance from the center of each source are appropriate for the uniform exposure to the surface lesion.