Whole-body Mass Research Articles

Application of the occupancy principle in studies of the metabolism of vitamin B12 in man.

1. The long-term clearance of radioactive vitamin B12 from serum and from whole body was measured in control subjects and patients with treated pernicious anaemia and the data were analysed by the occupancy principle to provide estimates of dietary intake, daily requirements and whole-body mass of vitamin B12. 2. In six cases the daily requirement for vitamin B12 ranged from 0.15 to 1.9 microgram with an average of 1.0 microgram. The whole-body vitamin B12 in four cases ranged from 780 to 1350 microgram with an average of 1060 microgram. 3. Estimates of the whole-body vitamin B12 on the assumption of single-pool equilibrium gave constantly changing results, which, together with discrepant half-lives for serum radioactivity and whole-body radioactivity, constitute evidence against the concept of single-pool equilibrium.

Application of a theorem by Bright to the generalized tracer system.

Bright (1973) has proved a theorem for a specific class of compartment systems. The theorem is here generalized, and it suggests that, occasionally, the steady-state whole-body mass of certain substances can be estimated from measurements of the mass concentration (e.g. specific activity) in blood alone, i.e. without cumbersome recordings of whole-body retention curves.

Radiopharmaceutical dosimetry in pediatrics

The increasing use of radionuclides In diagnostic, procedures and the importance of minimizing radiation exposure in infants` and children necessitate accurate and detailed information concerning the radiation doses sustained from these procedures. This paper presents available information on the various parameters involved in radiopharmaceutical dosimetry in pediatrics. The age groups selected are the newborn and 1, 5, 10, and 15 yr. Measured and calculated parameters for these groups include: mass of whole body and target organs; effective halflives and cumulative activities for the various radiopharmaceuticals; equilibrium dose constants; and absorbed fractions for spheres and ellipsoids for target masses down to 1. Radiation doses to whole body and to certain target organs for the various radiopharmaceuticals are included. Some consideration is given to adjustment of the activities administered to children relative to that normally administered to adults.

Cumulative dose from diagnostic irradiation.

CUMULATIVE DOSE FROM DIAGNOSTIC IRRADIATIONW. D. NORWOOD, M.D., F. L. RISING, C. W. KIRKLIN, ALLEN BRODSKY, Sc.D., B. S. SANDERS, PH.D. and T. F. MANCUSO, M.D.Audio Available | Share