Exposure to External and Internal Radiation in’ Vivo Measurement of Radionuclides in Man; Body Burden and Project Title: Kinetic Factors, Computer Applications 14. Scope: (Cont'd.) RX-01-01-(b) curve between zero and the natural dose rate. Because at these levels the events of interest are very infrequent, it is necessary to work with bacteria or with tissue cultures to obtain statistically significant data. New research problems may require intensive work on computer programming for an initial period of time, Omce the computer program has been developed to the point of doing the basic job requested, its use in data processing may become a routine part of a sequence of operations. Further refinements of the program may be spread out over a longer period of time. In these applications the data processing is not an independent end point but is imbedded in other goals, Similarly the development and maintenance of special radiation detection instrumentation usually depends on requirements arising out of other studies. ’ ‘The physical facilities involved include the medical computing facility, the whole-body counter, the PuBe in vivo activation facility, the central colmting rooms, a multidetector positron coincidence system and an electronics repair shop. Some special equipment is associated with the electron paramagnetic resonance (EPR) system, the Nuclear Medicine Laboratory, and with other data acquisition devices in the Medical Department. (Robert son) 15, Relationship to Other Projects: Related kinetic studies of calcium metabolism have been performed by ' Bauer, Hospital for Special Surgery and Bronner, University of Louisville. Similar mathematical models have been used by Pak, NIH. As previously noted however, the conceptual basis of the work at BNL differs from that of the other investigators. Further, the use of sophisticated computer programs makes it possible to measure small changes in calcium metabolism not discern- ible by use of most other techniques. Considerable effort has been devoted to minimizing the variations in counting efficiency in whole-body counting by Dudley, International Atomic Energy Agency; Marinelli, Argonne National Laboratory; Naversten, Lund, and Genna, Massachusetts Institute of Technology. The BNL counter is the only known system which can correct simultaneously for both the spatial distribution and energy absorption of radionuclides by the body. ;Representative groups working on the same clinical studies are those ,» Laurentian University of Sudbury, Canada, studying treatment of patients. with Vitamin D analogues to combat osteodystrophic changes; @nd Bordier, Paris, France on effect of synthetic calcitonin on calcium metabolism in osteoporosis; and Heaney, Creighton University Medical School, on skeletal response to growth hormone, (See Continuation Sheet) LEVaids Boddy, Scottish Universities RX-15