Development of a Total Body Chlorine Analyser Using a Bismuth Germanate Detector System and a ²⁵²Cf Neutron Source

Abstract

The initial method for in vivo determination of total body chlorine (TBCl) was total body neutron activation followed by whole body counting of residual products. The technique relied on the exposure of the subject to a sufficient fluence of neutrons to activate body sodium and chlorine. Subsequently, ³⁸Cl and ²⁴Na were quantified and correlated to the extracellular water (ECW) previously determined by tracer dilution analysis (Yasumura et al., 1983). The najor drawbacks of this technique are the following:

• a) the radiation exposure during the activation process is approximately 280 mrem (2.8 mSv);

• b) the method is time consuming as it consists of two separate operations, namely activation and a counting step;

• c) the unit cost is high because it requires two separate facilities and a number of high flux neutron sources; and

• d) the patient must be quickly moved iron one facility into another to be counted as ³⁸Cl, the chlorine activation product, which has a half-life of only 37.3 minutes.