Clinical radiobiology of brachytherapy

Brachythrapy is a technique to implant radioactive isotype into or near tumors. The obvious properties of brachytherapy are a very high dose distribution of center, and rapid dose attenuation with the increasing of distance. Brachytherapy generally includes three major categories: low dose rate, high dose rate and pulse dose rate. The most significant clinical value of brachytherapy is that it could create dose distribution to tumor tissues, but decreased radiation injury of normal tissues close to tumor. The development of the clinical brachytherapy technique is always involved in the radiobiological characteristics. The basic concepts involving clinical brachytherapy radiobiology mainly includes: dose-rate effect, repair of radiation injury, re-oxygenation, cell cycle redistribution and repopulation. An amount of translational medical approach is needed to guide the application of clinical brachytherapy by exploring the interaction between brachytherapy radiobiology and clinical brachytherapy effect, as well as taking advantage of brachytherapy radiobiological characteristics. The ultimate goal is to improve tumor local control rate, reduce the occurrence of adverse reactions, and improve patients′ overall survival. Key words: Brachytherapy; Clinical treatment; Radiobiology