Health Physics

Valdivia, Arnolfo A.

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A case-control study was conducted to describe lung cancer risk in a cohort of New Mexico underground U miners. The subjects included 65 cases and 230 age-matched controls, most with exposures below 3.50 J h m

Chung, Chien

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A substantial increase in fission product activity was observed in various environmental samples taken in Taiwan after the Chernobyl accident. The concentrations of long-lived fission products in air above ground, precipitation, grass, vegetation and milk were monitored in the next 7 wk. The individual effective dose equivalent committed by the first year of exposure and intake following the accident were evaluated. Average individual doses for the population in Taiwan are estimated at 0.9 μSv due to global fallout from the Chernobyl accident. This value is lower than that reported in neighboring countries in the Far East and poses no increased health impact to the public in Taiwan.

Burkart, W.

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The indoor

Adriano, D. C.

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The accuracy of three radionuclide transfer models for predicting the interception and retention of airborne particles by agricultural crops was tested using Pu-bearing aerosols released to the atmosphere from nuclear fuel facilities on the U.S. Department of Energy's Savannah River Plant, near Aiken, SC. The models evaluated were: 1) NRC, the model defined in U.S. Nuclear Regulatory Guide 1.109; 2) FOOD, a model similar to the NRC model that also predicts concentrations in grains; and 3) AGNS, a model developed from the NRC model for the southeastern United States. Plutonium concentrations in vegetation and grain were predicted from measured deposition rates and compared to concentrations observed in the field. Crops included wheat, soybeans, corn and cabbage. Although predictions of the three models differed by less than a factor of 4, they showed different abilities to predict concentrations observed in the field. The NRC and FOOD models consistently underpredicted the observed Pu concentrations for vegetation. The AGNS model was a more accurate predictor of Pu concentrations for vegetation. Both the FOOD and AGNS models accurately predicted the Pu concentrations for grains.

Long, S. A. T.

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Previous Monte Carlo calculations for the energy spectra of electrons produced in water irradiated by photons are extended to 1 GeV. All of the physical processes believed to be important in the transport of electrons and positrons above 100 keV and photons starting with the ejection of L photoelectrons are considered. The results are presented in tabular form and can be conveniently used to compute kerma in water. The contributions of several physical processes, such as Compton scattering and pair-production to electron spectra, are separately tabulated. The results are compared with those of Todo et al. (1982) for the single interactions of monoenergetic photons. It is found that the inclusion of processes such as multiple Compton scattering, bremsstrahlung production, positron annihilation in flight, Moller and Bhabha scattering from electrons and Moliere multiple scattering from atomic nuclei make a considerable difference in the inferred electron spectrum in water.

Cornett, R. J.

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Literature data for the half-times of Cs in one-, two-, and three-compartment models have been collated and regressed to yield general descriptions of clearance for homeotherms (warm-blooded animals) and poikilotherms (cold-blooded animals) of different sizes. Cesium half times increase with body weight and are longer in poikilotherms than in homeotherms. These trends and the values of the associated regression coefficients imply that Cs clearance is a function of metabolic rate. The patterns are especially visible in analyses of the larger compartments, perhaps because the curve splitting required to analyze smaller, more rapidly cleared pools is necessarily subjective. The route by which acutely contaminated animals receive their Cs also influences clearance. Inhaled Cs appears to be retained longer than injected Cs, which is in turn retained longer than ingested Cs. This suggests that Cs is discriminated against in biological transfers, so that Cs dust remains in the lungs whereas Cs in the food is less readily absorbed. These patterns of Cs clearance suggest that large animals, poikilotherms, and animals contaminated by inhalation or injection may receive a greater dose.

Gibbs, S. Julian

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The ICRP effective dose equivalent has been compared with a weighted dose equivalent, computed by treating the entire remainder instead of the sample of five remainder organs in the ICRP method as uniformly radiosensitive, for dose distributions from three common diagnostic exposures: chest, dental full-mouth and dental panoramic. Complete dose distributions were computed by a Monte Carlo model. In all three cases the effective dose equivalent was greater than the weighted dose equivalent. The difference was only 20% for the chest exam but was more than fivefold for both dental exposures. Dose distributions for the dental exposures were less homogeneous than for the chest examination. Selection of organs to be included in the remainder markedly affects the effective dose equivalent. In the case of highly inhomogeneous dose distributions, the effective dose equivalent probably significantly over-estimates radiation detriment.

Fraley, Leslie

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We measured

Moeller, Dade W.

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Improved health effects models have been developed for assessing the early effects, late somatic effects and genetic effects that might result from low-LET radiation exposures to populations following a major accident in a nuclear power plant. All the models have been developed in such a way that the dynamics of population risks can be analyzed. Estimates of life years lost and the duration of illnesses were generated and a framework recommended for summarizing health impacts. Uncertainty is addressed by providing models for upper, central and lower estimates of most effects. The models are believed to be a significant improvement over the models used in the U.S. Nuclear Regulatory Commission's Reactor Safety Study, and they can easily be modified to reflect advances in scientific understanding of the health effects of ionizing radiation.

Porter, D.

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In recent years, there has been increased concern regarding effects of operator exposure to the electromagnetic (EM) field associated with shortwave diathermy devices. The present study was designed to investigate the effects, on rats, of repeated exposure to such an EM field. Following repeated exposure for 5 wk, a reduction in fertility occurred as indicated by a reduced number of matings. in exposed rats compared to sham-irradiated rats and a reduction in the number of rats that conceived after mating. The data suggest that female operators could experience reduced fertility, if they remained close to the console for prolonged periods. This has particular significance for the physiotherapy profession.