Single Fraction Intraoperative Radiotherapy

Intraoperative radiotherapy (IORT) is delivered after completion of the lumpectomy and sentinel node procedure. IORT is performed on mobile or fixed linacs with variable electron energies in the range of 6-12 MeV prescribed to a dose of 21 Gy, with the prescription dose covering at least 90% of the Planning Target Volume (PTV). PTV is defined as a 3D volume of 1-2 cm beyond the former macroscopic tumor edge (excluding skin, limit to anterior rib surface: 5 Gy). The choice of electron energy as well as the cone applicator size has to account for minimum PTV requirements. Tissue depth measurement will be documented by intraoperative sonography.