Biology of Large Dose per Fraction Irradiation

Experimental radiobiology has by happenstance focused on the implications of intraoperative and high-dose-per-fraction radiotherapy in more detail than it has standard fractionated radiotherapy. This is because the majority of radiobiological literature of tumor and normal tissue features in vivo and in vitro studies in which the radiation was administered in a single fraction. Similarly, when fractionation is used experimentally, fraction sizes near the clinical 1.8–2 Gy size used for most external beam irradiation therapy (EBRT) are rarely utilized. As a result, much of our radiobiological understanding of tumor and normal tissue response should and does relate well to that observed clinically for intraoperative irradiation therapy (IORT).