The 1991 George Edelstyn Memorial Lecture: needles, wires and chips--advances in brachytherapy.

The majority of quantitative data on the effects of dose-rate come from experiments with cultured cells in vitro. These data are reviewed, and it is concluded that results obtained from the in vitro experience may be carried over, in a quantitative manner, to guide clinical radiotherapeutic design. As an example, there are contradictory guidelines suggested to compensate for changes in dose-rate in interstitial wire-implant brachytherapy. The Paris group has suggested no dose correction is required for implant times from 3 to 8 days, while the Paterson/Ellis school suggests a significant correction. It is shown that, based on known radiobiological principles, this controversy can be resolved. These same radiobiological notions, as well as advances in computer technology, have led to the technique of pulsed brachytherapy, which allows the average dose-rate to be maintained at a constant rate, even when the wire activities have decayed.