The broad objective of this research program is to develop methods which will allow the delivery of increased doses of photon beams to the tumor target volume without increasing complications in the normal tissues. This will be achieved by solving key technical problems in radiation therapy that limit the effectiveness of present treatment. Projects in previous years have contributed significantly to the development of the technical capability to deliver a complex treatment plan under computer control with safety and reliability. The eight proposals in this grant application are oriented toward the following three general areas. The first area includes treatment planning. Projects here involve the selection and modification of diagnostic data for definition of a complex three-dimensional target volume and methods for display and treatment planning utilizing this information. The second general area concerns treatment delivery. Complex tumor target volumes are developed utilizing computer controlled radiation therapy with evaluation of relative merits of different approaches. Finally, clinical trials of computer controlled radiation therapy will be carried out. Patients will be evaluated both clinically and by physiologic testing to determine the effects of the treatment on normal tissues. The effects of this form of treatment will be compared to those of optimum conventional radiation therapy. The projects selected will each contribute to an advance in the quality of radiation therapy and will contribute to improved capabilities in optimizing dose to the tumor while minimizing exposure of normal tissues.