[Current status and future prospects of the radiation oncology treatment planning system].

Treatment planning is the most essential radiation oncology practice and has been developing owing to various technological innovations such as faster computing speed, advanced computer graphics and enormous data storage capacity. Treatment planning consists of CT data retrieval, target input, selection of treatment techniques and dose calculation, evaluation of dose distribution, and data transfer to the accelerator, each of which has been progressing quite rapidly. In particular, ongoing topics in treatment planning include multi-leaf conformation, non-coplanar technique, CT scanner dedicated to treatment planning and data transfer through LAN. Target delineation using PACS, and megavoltage verification imaging represented by portal imaging, are also useful. Higher local control rates as well as lower complication probabilities are expected with the sophisticated treatment planning system.