Towards an expert system for treatment planning

A course of treatment by radiation therapy is usually planned by computing the dose distribution throughout the target volume for various combinations of beam shapes, locations, angles, and weights. In a break with previous practice, the authors have incorporated into the planning process those parameters that are to be used in the assessment of alternative plans. The therapist is required to define tolerance doses for each organ, and the computer program OSCAR compares the calculated dose distribution with these limits. Regions of noncompliance are displayed as colored ´areas of regret´, a parametric representation of the type and degree of discrepancy between the required and the predicted dose distributions. In addition, score functions are used to provide a quantitative measure of the acceptability of the dose distribution within the target and each organ at risk.<>