The Northcentral and the Midwest Chapters of the American Association of Physicists in Medicine, sponsored by the parent national organization (the AAPM), will plan, organize and conduct a 3 1/2 day conference on """"""""Prediction of Response in Radiation Therapy: Physical, Biological and Analytical Basis."""""""" The symposium will provide an update on the current status of the biological, physical, clinical and modeling aspects of time, dose and fractionation schemes in radiation therapy. The invited faculty and other participating speakers will present the progress in predictive assays; recent cellular and animal data on normal tissue toxicity/repair and tumor kinetics; advances in analytical models and modeling techniques; concepts and methods of modern data analysis; treatment optimization schemes; and basic mechanisms of response. The clinical relevance of the above to clinical procedures will be emphasized. Evening workshops will provide tutorials in the basics, as well as providing a forum for discussion and identification of issues needing further investigation. As a concluding session, cooperative experimental designs will be developed to resolve the identified issues.