Radiobiological considerations of brachytherapy.

The special radiobiological effects of low dose-rate radiation on tumors and normal tissue are in large part responsible for the effectiveness of brachytherapy. There is good reason to believe that improvement in local tumor control can be expected by the addition of chemotherapeutic agents, specifically designed radiation sensitizers, and differentiation-inducing agents, as well as by the manipulation of dose rates and dose distributions. This can be an important contribution to cancer management in the future and is an exciting area for further study.