Some problems in medicine and biology which can be studied by the use of particle accelerators

Problems in understanding the role of trace elements in functioning of life processes are discussed. The use of particle accelerators in the study of problems in medicine and biology has been long recognized as a specific and powerful tool. For several decades, accelerators designed primarily for research in nuclear and high energy physics have been adopted for biomedical research including radiotherapeutic treatment of human diseases. Treatment of diseases is done by particles like electrons, neutrons (1), protons (2, 3), pions and heavier ions. No single particle (or energy) can be identified as universally superior to all others. Recently there is also an increased demand for accelerator produced ''medical'' radionuclides. A list of interesting radioisotopes for medical research and diagnosis includes: /sup 11/C, /sup 13/N, /sup 15/O, /sup 18/F, /sup 19/Ne, /sup 43/K, /sup 55/Co, /sup 64/Cu, /sup 68/Ge, /sup 75,76/Br, /sup 81/Rb, /sup 97/Ru, /sup 197/Hg, /sup 203/Pb and /sup 205,206/Bi (4). These two subject areas, production of short-lived isotopes and labelled compounds and clinical application of ionizing radiation, as well as a number of imaging techniques, will not be discussed in this paper. We shall focus attention to some open problems in our understanding of functioning of life processes, some of which can be studied in the accelerator laboratory