ABSTRACT
A hypofractionated approach has several theoretical advantages in comparison with single-dose radiosurgery. Fractionation serves to exploit fundamental radiobiological principles such as repopulation and reoxygenation. e therapeutic ratio is shifted, leading to improved tumor control and decreased late normal tissue e‰ects through repair of normal tissue sublethal DNA damage, enhanced reoxygenation of tumor cells, and redistribution of tumor cells to more radiosensitive portions of the cell cycle between radiotherapy treatments (Hall and Brenner, 1993). It is important that the physical dosimetric advantages and steep dose fallo‰ that are a hallmark of single-fraction stereotactic radiosurgery (SRS) are maintained with a fractionated approach.
