Tissue inhomogeneity corrections in low-kV intra-operative radiotherapy (IORT)

Intra-operative radiotherapy (IORT) with low energy X-rays has been effectively used to treat breast cancer patients for more than a decade (1-3). A radiation source that has been employed for such treatments is a miniature 50-kV X-ray generator (INTRABEAM, Carl Zeiss Surgical, Oberkochen, Germany) producing nearly isotropic dose cloud (4-7). When fitted with an applicator, the radiation can be readily adapted to match the treatment area. For example, spherical applicators are ideally shaped for breast lumpectomy cavity, whereas, either flat or surface applicators may be used to treat a flat tumor area (8). Flat and surface applicators are available in a range of sizes (diameter: 1-6 cm)