Global fallout distribution in fireplace ashes.
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Biomedical subjects
Publications and source records attributed to J A Cardarelli.
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Previously described techniques for the measurement of the absorption of [57Co]vitamin B12 by total-body counting have required an iron room equipped with scanning or multiple detectors. The present study uses simplifying modifications which make the technique more available and include the use of static geometry, the measurement of body thickness to correct for attenuation, a simple formula to convert the capsule-in-air count to a 100% absorption count, and finally the use of an adequately shielded gamma camera obviating the need of an iron room.
Elevated levels of serum gastrin as a consequence of gastric achlorhydria are characteristic of clinical pernicious anemia. In a largely male hospitalized population with an average age of 64 years, 7.7% had low levels of serum B12 (less than 170 pg/mL); only 2.5% of these had frank pernicious anemia. In an attempt to separate a subgroup with low levels of serum B12 in whom pernicious anemia may later develop, their serum gastrin levels were determined. Twenty-two percent had high values and, of these, 70% had low B12 absorptions. In patients with low serum B12 levels, serum gastrin assays may be useful in determining those in whom clinical pernicious anemia seems likely to develop.
The use of Co-57-labeled B12 for whole-body measurement of B12 uptake in humans has the advantage over Co-58 of easy commercial availability and lower cumulative radiation to the liver, but the disadvantage of significant attenuation. Methods devised to correct for the attenuation have used inaccurate early 100% counts. A method is described here that uses a liver phantom, containing a dissolved Co-57 B12 capsule, in a water tank. The ratios of upper to lower detector counts is related to total counts; it varies at different depths in the tank, and with the overall tank depth that is selected to accord with measured body habitus. The ratio of detector counts in the final patient count is used to read off the appropriate 100% total count. With this technique there is a clear discrimination between normal patients and those with pernicious anemia.
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