Evaluation of biological indicators of body burden of cadmium in humans.
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Biomedical subjects
D Vartsky
Publications and source records attributed to D Vartsky.
Silicon measurement in a lung phantom by neutron inelastic scattering.
A study was made to assess the feasibility of determining the silicon level in human lungs in vivo by measuring the gamma rays arising from the neutron inelastic scattering reaction 28Si(n, n' gamma)28Si. Neutron energies in the range 5--8 MeV represent the best compromise between the conflicting requirements of high energy for good detection statistics and low energy to minimize the dose to the subject. The sensitivity of measurement was enhanced by pulsing the neutron beam and counting only during the period of bombardment. This effectively reduced the background counts emanating from thermal neutron reactions in the phantom and from the fast neutron reaction 31P(n, alpha)28 A1. In measurements with an anthropomorphic phantom, no interference peaks from other prompt inelastic scattering reactions were observed. With one Ge(Li) detector of 19% relative efficiency, a detection limit of 0.6 g of silicon per 10 mSv was obtained. On this basis, it is estimated that six Ge(Li) detector of 25% efficiency each would be capable of measuring 0.15 g of silicon in the lungs, the average level found in nonoccupationally exposed adults.U
Humans↗
Feasibility of noninvasive analysis of lead in the human tibia by soft x-ray fluorescence.
A postmortem study was conducted to assess the feasibility of measuring bone lead concentrations noninvasively in vivo. Characteristic L x rays were induced with an external source of 125I in the superficial tibial cortex of the intact legs of six adults who had no history of occupational exposure to lead. Tibial lead concentrations in the same bones subsequently determined by flameless atomic absorption spectroscopy varied from 15 to 35 micrograms Pb/g wet weight. The upper limit for the modern normal range of lead in the bone is about 25 mg Pb/g wet tissue. The linear correlation coefficient (r) between the measurements made with x-ray fluorescence and lead concentration by absorption spectroscopy was 0.90. Radiation doses of 10 mGy (1 rad) to 1 cm2 of skin, with associated doses to the marrow of adjacent bone of about 0.6 mGy (60 mrad), yielded net lead fluorescence signals ranging from one to seven times the standard deviation of background.
Humans↗