Local excision followed by adjuvant radiotherapy has become standard treatment for women with early-stage breast cancer. Adjuvant radiotherapy may encounter technical difficulties in patients with pendulous breasts when treated in supine position.~Based upon literature and our own preliminary experiences, we hypothesize that for large pendulous breasts, breast irradiation in supine and prone position are equivalent with regard to coverage of the PTV, but with a better dose homogeneity in prone position and a smaller radiation exposure of lung and heart. However, no quantitative data are yet available to test this hypothesis. Therefore, the aim of our study is to compare the 3-D dose distribution in PTV and normal tissues in prone position versus supine position. For treatment in prone-position an in-house developed device, the mammaboard was used.
We hypothesize that for large pendulous breasts, breast irradiation in supine and prone position are equivalent with regard to coverage of the PTV, but with a better dose homogeneity in prone position and a smaller radiation exposure of lung and heart.The purpose of this study is to compare the 3-D dose distribution in PTV(Planning Target Volume) and normal tissues in prone position versus supine position.