It is proposed to improve decision making in radiotherapy of cancer patients by the development of a computerized data bank and patient matching programs. These programs will match a given new patient as closely as possible with an idealized hypothetical protocol patient and/or with existing patients in the file based on details of the patient's history, present illness, therapy to date, etc. It is to give meaningful access to accumulated experience to the young inexperienced therapists while providing an unbiased aid to the memory for the experienced therapist. Its actual usefulness in decision making is to be evaluated.