State of the art of high energy photon treatment planning.

A virtual revolution in computer capability has occurred in the last few years, based largely on rapidly decreasing costs and increasing reliability of digital memory and mass-storage capability. These developments have now made it possible to consider the application of both computer and display technologies to a much broader range of problems in radiation therapy including dose computation, therapy planning and treatment verification. Various similar methods of three-dimensional dose computations in heterogeneous media capable of 2-3% accuracy are likely to be available, but significant work still remains especially for high energy X-rays where electron transport, and possibly pair production, needs to be considered. Innovative display and planning techniques are emerging and show great promise for the future. No doubt these advances will lead to substantially improved treatment planning systems in the next few years. However, it must be emphasized that for many of these applications a tremendous software and hardware development effort is required. Yet it is not clear whether the investments and efforts for improved capabilities and accuracies are warranted with respect to clinical outcome. The question must be addressed for the advancement in the practice of radiotherapy.