Radiotherapy treatment planning using ultrasound‐sonic graph pen‐computer system

We have developed an on‐line, interactive, computer‐based radiotherapy planning system, employing a modified ultrasound device with gray scale, two sonic graph pen digitizers for data acquisition, and a multicolor video monitor for output display. Information on patient anatomy is extracted by the ultrasound device and displayed in one color. After determining the location and volume to be treated, the information regarding plan of irradiation is specified using the sonic graph pen. The computed isodose curves are displayed in a second color, superimposed on the ultrasound‐ and computer‐drawn image of the anatomical structures. The treatment plan is modified until satisfactory, and the final plan is recorded on paper or color film. The patient, remaining in treatment position on the simulator table, is marked in reference to the accepted plan displayed on the video screen. The system enables the therapist to develop the treatment strategy firsthand and thereby meaningfully adapt specific requirements to the individual patient.