Biomedical and health studies with the new Canadian SLOWPOKE reactor

Several features of the new SLOWPOKE⁺ pool-type nuclear reactor have made it very useful for instrumental neutron activation of tissues, blood and other body fluids. In this paper are reported results from studies on clinical patients who had malnutrition, cystic fibrosis and other related electrolyte disorders. Physical conditions in the irradiation sites within the beryllium reflector are such that liquids, slurries and wet tissues (the types of sample obtained from patients) can be irradiated in sealed polyethylene vials without pretreatment. This facilitates a precise semi-routine activation analysis for large numbers of samples from patients. A stable activable tracer technique has been developed to determine the extracellular fluid volume (ECV) of infants. A regulated dose of sodium bromide is injected into the patient and, following short-term equilibration and dilution of this sample, a small blood sample is taken, yielding 50 μl of plasma. The plasma bromide concentration is determined by⁸⁰Br (T=18 m) activation. In order to check the accuracy of this NAA technique, some samples were cross-checked by a microdiffusion method. The technique has been applied to 230 patients and controls, and has proved to be simple, rapid, accurate and sensitive for determining ECV to ±6%. Patients with cystic fibrosis (C. F.) were studied with respect to their growth, and their sodium and electrolyte balance. In related clinical studies, hair and nail clippings from 50 C. F. patients and control children of the same age groups were activated at SLOWPOKE and Cu, Ca, Br, Cl, K, Na and I, determined for use in differentiating C. F., along with a number of other elements including Zn, Mn, Al, Ti and Ni which showed little difference. A careful analysis of the data showed that clear differentiation of all C. F. patients from controls could be achieved by comparing the values of X-factor. A fairly good correlation of hair and nail concentrations was found for a number of the elements determined, suggesting that either tissue may be used in future studies.