PRISM - A NEW APPROACH TO RADIOTHERAPY PLANNING SOFTWARE

Purpose: We describe the capabilities and performance of Prism, an inn ovative new radiotherapy planning system with unusual features and des ign. The design and implementation strategies are intended to assure h igh quality and clinical acceptability. The features include Artificia l Intelligence tools and special support for multileaf collimator (MLC ) systems. The design provides unusual flexibility of operation and ea se of expansion. Methods and Materials: We have implemented Prism, a t hree-dimensional (3D) radiotherapy treatment-planning system on standa rd commercial workstations with the widely available X window system. The design and implementation use ideas taken from recent software eng ineering research, for example, the use of behavioral entity-relations hip modeling and the ''Mediator Method'' instead of ad-hoc programming . The Prism system includes the usual features of a 3D planning system , including Beam's Eye View and the ability to simulate any treatment geometry possible with any standard radiotherapy accelerator. It inclu des a rule-based expert system for automated generation of the plannin g target volume as defined in ICRU Report 50. In addition, it provides special support for planning treatments with a multileaf collimator ( MLC). We also implemented a Radiotherapy Treatment Planning Tools Foun dation for Prism, so that we are able to use software tools from other institutions without any source code modification.Results: The Prism system has been in clinical operation at the University of Washington since July 1994 and has been installed at several other clinics. The s ystem is run simultaneously by several users, each with their own work station operating from a common networked database and software. In ad dition to the dosimetrists, the system is used by radiation oncologist s to define tumor and target volumes and by radiation therapists to se lect treatment setups to load into a computer controlled accelerator. Conclusions: Experience with the installation and operation has shown the design to be effective as both a clinical and research tool. Integ ration of software tools has eased the development and significantly e nhanced the clinical usability of the system. The design has been show n to be a sound basis for further innovation in radiation treatment pl anning software and for research in the treatment planning process. Co pyright (C) 1996 Elsevier Science Inc.