Pseudo optimization of radiotherapy treatment planning.

A chain consisting of three computer programs has been developed for treatment planning of external beam radiotherapy without manual intervention. Apart from the data necessary to identify the patient, the institute, etc., the input consists only of the anatomical information indicated on an outline sheet. Firstly, combinations of incidence directions for a two or three-beam set-up are judged by the first program. Then a limited number of these combinations is selected by this program. For every beam of each selected combination a set of wedges and weights is calculated. Next the dose distributions belonging to each combination with wedges and weights are judged by the second program. Finally, the isodose pattern of the dose distribution judged the best is determined by the third program. The judgement of incidence directions is done by coarse score functions corresponding to a set of criteria. The judgement of dose distribution is done by detailed score functions corresponding to another set of criteria. These criteria with their score functions are treated in some detail. The use of the programs in the clinic is discusses and results are shown.