Radiobiology of stereotactic radiosurgery and stereotactic body radiotherapy

The initial description of clinical radiation biology arose in an era where most external beam treatments comprised multiple fractions of radiation delivered over a protracted period of time. The increasing adoption of image guided techniques has permitted the delivery of much larger single doses over shorter time periods. In this chapter we discuss those biological factors thought to impact clinical outcome, repair, reoxygenation, redistribution, repopulation, and radiosensitivity and compare and contrast their relevance in the era of hypofractionated treatment.