A NOVEL HYBRID INTENSITY MODULATED RADIATION THERAPY IN BREAST IRRADIATION —EFFECTs OF REDUCING HOT SPOT VOLUME—

Abstract

A hybrid intensity modulated radiotherapy with dose painting (HIMRT-DP) for whole breast irradiation was developed to decrease dose maximum level and hot spot volume. The HIMRT-DP is a combination of a conventional tangential two opposing irradiation (Conv.) and IMRT employing dose painting. The HIMRT-DP was compared with Conv.. Twenty-one cases, which were treated with Conv., were retrospectively analyzed for maximum dose, hot spot volume, volume of lung over 20 Gy and 95% dose coverage. As a result, the mean values of the maximum dose and hot spot volume for the HIMRT-DP were significantly lower than these of Conv. However, HIMRT-DP should take care of about 95% dose coverage because mean of 95% dose coverage for HIMRT-DP was significantly lower than that of Conv.