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PROGRESS IN ATOMIC MEDICINE ~
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-a considerable effort and supporting staff and utilizes procedures that
are not currently utilized in day to day clinical medicine. For these |
reasons, relatively few laboratories have engaged in studies of body
composition involving all these measurements. However, with improvements in technique. clinical investigators may undertake these studies
with the goal that the basie tenets that emerge can be widely utilized
clinically,
At present. probably the most significant contribution to body compo-
sition studies would be a simple and reliable means of directly determining body fat. The gas dilution methods’? do not appear to meet the
criterion of simplicity and they have not been sufficiently studied to
determine their reliability. In’ general. the relatively low blood-perfusion
rate and the lowefficiency of extraction of fat-soluble diluents from the
blood by adipose tissue preclude the development of a simple direct
determination of body fat content by the isotope dilution principle.
An entirely new approach is needed for the direct determination of
body fat.
A promising application of neutron-activation analysis in vivo for
estimating total quantities of certain elements in the body has been
tested recently by Anderson and his associates at Harwell, England.**
The method calls for exposure of the subject to a uniform dose of about
0.1 rad of 14 MeV neutrons and subsequent determination of the
induced radioactivities with a whole-body counter. Total quantities of sodium, chlorine. and calcium were readily estimated in preliminary
tesis on two human subjects. Estimates of the quantities of nitrogen,
potassium, and possibly other elements may also become practicable
with further improvements in technique.
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REFERENCES
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1009, 1959.
>
3. ANDERSEN. S. B.: Clin. Sci. 23: 221, 1962.
4. Anpernsow, E. C.: Ann. N.Y. Acad. Sci. 110: 189. 1963.
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da. Anpbersox, J., Ossorx, S. B., Towtinsoxs, R. W. SS. Newtos. BD. Rexpo, J.,
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Baker. N.. Surecve, W. W.. SHiptery. R. A., [xcery, G. E.. ano Miter, M.: J.
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