Particle Accelerators in Cancer Therapy Current Status and Overview of the Planned Program for Heavy Particle Therapy

The goal of radiation therapy is uncomplicated local control of cancer. Practical approaches to this goal currently utilize a variety of electron accelerators which produce electron and photon beams at a range of energies for the treatment of cancer. To capitalize on the physical advantages of the available beams and the mechanical sophistication of isocentric mounting, treatment planning (tumor and organ localization, beam shaping, accuracy and reproducibility of setup, and computerized dosimetry) must be individualized and optimized so far as possible. An exciting potential for improvement in results of cancer treatment is the use of heavy particles for therapy (neutrons, protons, heavy ions, and negative pi mesons). These offer the potential for either or both an increased biological effect and improved dose distribution over standard photon or electron beam therapy. A program for heavy particle therapy has been proposed by the Committee for Radiation Oncology Studies and reviewed by the National Cancer Institute. The proposal and current status of the program are described briefly.