TARGET VOLUME DEFINITION IN RADIATION-THERAPY

Target volume definition in radiation therapy is a broad field of inte rdisciplinary research. We give a brief history of clinical research i n this field and outline some remarkable steps which led to the well-d efined target volume concepts. The challenges in target volume definit ion for high-precision conformal radiation therapy are discussed, and possibilities of improving target volume definition, such as the integ ration of modern imaging modalities and the use of computer-based syst ems to support the radiation oncologist are indicated, as well as nove l techniques for increasing the accuracy of patient positioning. All t hese tools should be evaluated with regard to their potential for incr easing the therapeutic ratio and, as appropriate, should be implemente d in clinical practice. However, target volume definition is a complex process influenced by many factors, currently under investigation. Wh ile questions remain in this field, and the impact of the influencing factors is not defined, the process of target volume definition should remain the subject of clinical research.