[Considerations on intraoperative radiation therapy and therapeutic ratio]

In conjunction with the clinical development of intraoperative radiation therapy (IORT), the ability to demonstrate an improvement in therapeutic ratio is critical and an evaluation of treatment complications is essential. The tolerance dose of the normal tissue in IORT is discussed, and if small field is applied, the greater part of tissues or organs tolerate intraoperative irradiations up to 25 Gy. The optimal dose has been estimated on each organs with malignant tumors. Intraoperative "boost" dose electron therapy given in combination with external beam irradiation has been demonstrated as good treatment modalities concerning with therapeutic ratio.