Rapid HPGe well detector gamma bioassay of 137Cs, 60Co, and 192Ir method.

CDC designed a rapid HPGe Bioassay Method for 137Cs, 60Co, and 192Ir that is suitable for a public health response to a radiological incident where people may ingest or inhale radionuclides. The method uses a short count time, small sample volume, and a large volume detector and well size. It measures a patient's urine sample collected post-incident. The levels of concern are directly related to the Clinical Decision Guide levels recommended in the National Council of Radiation Protection 161.

Evaluating the performance of the ORTEC® Detective™ for emergency urine bioassay.

The performance of the ORTEC(®) Detective™ as a field deployable tool for emergency urine bioassay of (137)Cs, (60)Co, (192)Ir, (169)Yb and (75)Se was evaluated against ANSI N13.30. The tested activity levels represent 10 % RL (reference level) and 1 % RL defined by [Li C., Vlahovich S., Dai X., Richardson R. B., Daka J. N. and Kramer G. H. Requirements for radiation emergency urine bioassay techniques for the public and first responders. Health Phys (in press, 99(5), 702-707 (2010)]. The tests were conducted for both single radionuclide and mixed radionuclides at two geometries, one conventional geometry (CG) and one improved geometry (IG) which improved the MDAs (minimum detectable amounts) by a factor of 1.6-2.7. The most challenging radionuclide was (169)Yb. The measurement of the mixture radionuclides for (169)Yb at the CG did not satisfy the ANSI N13.30 requirements even at 10 % RL. At 1 % RL, (169)Yb and (192)Ir were not detectable at either geometry, while the measurement of (60)Co in the mixed radionuclides satisfied the ANSI N13.30 requirements only at the IG.

Selectivity of 90Sr urine bioassay technique over 241Am, 238/239PU, 210PO, 137CS and 60CO.

The selectivity of a rapid (90)Sr bioassay technique over (241)Am, (238/239)Pu, (210)Po, (137)Cs and (60)Co has been investigated. Similar to (90)Sr, these radionuclides are likely to be used in radiological dispersive devices. The purpose of this study was to demonstrate the degree to which the (90)Sr bioassay technique is free from interference by these radionuclides if present in a urine matrix. The interfering radionuclides were removed (from (90)Sr) by their retention on an anion exchange column. While, recovery of the target radionuclide ((90)Sr) was found to be >or= 90 %, contributions from (241)Am, (242)Pu and (208)Po were found to be

A field deployable high-resolution urine gamma analyzer.

The Human Monitoring Laboratory has extended the use of its portable whole body counters to portable gamma spectrometers for urinalysis. The protocol tested measured a 120-mL sample in a polypropylene sample container for 5 min. Minimum detectable activities were estimated for 241Am, 57Co, 137Cs, and 60Co. The former is 113 Bq per sample, and the latter three are between 27-29 Bq per sample. Assuming an intake 5 d before the measurement, and all other parameters as default, the committed effective doses are 517 Sv, 76 muSv, 402 muSv, and 1.5 mSv, respectively. Clearly, this instrument can be used as a field deployable gamma spectrometer for urinalysis for activation and fission products, but actinides (and other low energy photon emitters) remain problematic.

Effect of prior radiopharmaceutical administration on Schilling test performance: analysis and recommendations.

UNLABELLED: Previously administered diagnostic and therapeutic radiopharmaceuticals may interfere with performance of the Schilling test for prolonged periods of time. Additionally, presence of confounding radionuclides in the urine may not be suspected if baseline urine measurements have not been performed before the examination. METHODS: We assumed that a spurious contribution of counts corresponding to 1% of the administered Schilling dose would begin to contribute clinically significant interference. Based on the typical amounts of radiopharmaceuticals administered, spectra of commonly used radionuclides and best available pharmacokinetic models of biodistribution and excretion, we estimated the interval required for 24-hr urinary excretion of diagnostic and therapeutic radiopharmaceuticals to drop below this threshold of significant interference. RESULTS: For previously administered 99mTc-based radiopharmaceuticals and 123I-Nal, the interval required for urinary levels of activity to fall below thresholds of allowable interference are between 2-5 days. For 67Ga-citrate, several 111In compounds, 131I-MIBG and 201Tl-thallous chloride, periods of 12-44 days are estimated. Estimates for 131I-Nal vary greatly between 4 and 115 days, depending on the amount administered, and the degree of thyroid uptake. CONCLUSION: Patients should be interviewed before performing the Schilling test to ensure that interfering radiopharmaceuticals have not been recently administered. The estimates developed in this paper can serve as guidelines for the necessary waiting time between prior radiopharmaceutical administration and the Schilling examination.

Reliability of a new technique for the determination of vitamin B12 absorption in children: single stool sample test--a double isotope technique.

The fractional vitamin B12 absorption (FAB12) was determined in 39 patients with various gastrointestinal diseases by a double-isotope technique, employing a single stool sample test (SSST), as well as a complete stool collection. The age of the patients ranged from 2.5 months to 16.2 years (mean 5.0 years). The test dose was administered orally and consisted of 0.5-4.5 micrograms of 57CoB12 (approximately 0.05 microCi), carmine powder, and 2 mg 51CrCl3 (approximately 1.25 microCi) as the inabsorbable tracer. The wholebody radiation to a 1-year-old child averaged only 20 mrad. The stool and napkin was collected and homogenized by addition of 300 ml "chromium sulfuric acid." A 300-ml sample of the homogenized stool and napkin, as well as 300 ml chromium sulfuric acid (75% v/v) containing the standards, were counted in a broad-based well counter. The FAB12 determined by SSST employing the stool with the highest content of 51Cr (which corresponded to the most carmine-colored stool) correlated closely to the FAB12 based on complete stool collection (r = 0.98, n = 39, p less than 0.001). The reproducibility of FAB12 determined by SSST was assessed from double assays in 19 patients. For a mean value of 12%, the SD was 3%, which corresponded to a coefficient of variation (CV) of 25%. The excretion of 57Co and 51Cr in the urine was examined in six patients with moderate to severe mucosal damage and was found to be low.(ABSTRACT TRUNCATED AT 250 WORDS)

Schilling evaluation of pernicious anemia: current status.

The Schilling examination remains a popular means of evaluating in vivo absorption of vitamin B12. When absorption is abnormally low, the test may be repeated with addition of exogenous intrinsic factor (IF) in order to correct the IF deficiency that characterizes pernicious anemia. A dual-isotope variation provides a means of performing both stages of the test simultaneously, thereby speeding up the test and reducing dependence on complete urine collection. The dual-tracer test depends on no exchange of B12 moieties on the IF molecule. In vitro studies suggest that this exchange does take place, in a manner dependent on time, temperature, and pH. Furthermore, in vivo studies indicate that, when administered simultaneously, the absorption of unbound B12 is elevated, and IF-bound B12 is reduced, in pernicious-anemia patients, relative to the classic two-stage examination. A number of clinical studies indicate significant difficulty in resolving clinical diagnoses with the dual-tracer test. The potential weaknesses of the test discussed herein can be overcome by temporally separating the administration of the two B12 doses and by treating secondary malabsorption where it exists. An algorithm is offered for selecting the most suitable variation of the Schilling test to improve the accuracy of test results and the ease of performance.

Metabolism of 51Cr, 54Mn, 59Fe and 60Co in lactating dairy cows.

Different radionuclides which can be released by nuclear installations (Na2(51) CrO4 , 54MnCl2 , 59FeCl3 and 60CoCl2 ) were given to lactating dairy cows either orally or by intravenous (i.v.) injection. Excretion into feces and urine as well as secretion into milk were followed for several weeks. Distribution of activity in organs was determined at sacrifice 102 days after oral and 70 days after i.v. administration. After ingestion, excretion of chromate followed a three-term exponential function with half-lives of 0.88, 3.7 and 26 days. Intestinal absorption was on the order of 0.1-0.2%. About 63% of injected chromate was excreted into urine, about 18% into feces and about 3.6% into milk. Orally administered chromate was concentrated in liver, intestine and spleen. The transfer coefficient into milk was about 1 X 10(-5) days/1. Less than 1% of an ingested dose of manganese was absorbed. Excretion occurred mainly into feces and followed a three-term exponential function. Very little manganese was excreted into urine or secreted into milk. Manganese is concentrated in brain, pancreas, kidney and heart but the differences in concentration are small. The body burden is, therefore, mainly determined by manganese in muscle, skin and bone. The transfer coefficient of manganese into milk is about 3 X 10(-5). Excretion of iron into feces after oral administration follows a three-term exponential function with a small component having a half-life of 72 days. Intestinal absorption is on the order of 0.5-2% of the dose. After i.v. administration, 7% of the dose is excreted in the feces displaying two components of turnover. Very little iron is excreted into urine. Secretion into milk also follows a two-term exponential function. The transfer coefficient of iron into milk is about 3 X 10(-5). About 0.6% of an oral and about 94% of an i.v. dose were recovered from the cows at sacrifice. Most activity was present in blood, liver and spleen. Excretion of radiocobalt into feces after oral administration is described by a three-term exponential function, while excretion into milk and urine is described by two-term exponential functions. Long-lived components in urine and milk represent about 5-10% of the activity absorbed. Only 1-2% of an oral cobalt dose is absorbed and 0.05% of an oral and 5.85% of an i.v. dose is recovered from the cow at sacrifice where concentrations are highest in kidney and thyroid. The body burden depends mainly on cobalt in muscle, skin and bone. The transfer coefficient of cobalt into milk is about 7.5 X 10(-5).

[The urinary elimination of cobalt 57 in iron-deficiency anemia and in iron-overload states]. / L'élimination urinaire du 57cobalt dans les anémies hyposidérémiques et les états de surcharge en fer.

The authors used the 57 Co urinary excretion test to assess the intestinal absorption of iron in anemia associated with hypoferrinemia and in iron overload states. Among the anemia associated with hypoferrinemia, a high elimination of 57 Co had been found in all patients (15) with post-haemorrhagic iron deficiency anemia. Conversely, this elimination was very low in all 10 patients with anemia due to chronic inflammatory diseases. Moreover the test detected few iron deficiency anemia due to a decreased intestinal absorption of iron. In the iron overload states, the test had been performed in 2 subgroups of patients : chronic anemic patients with transfusional iron overload and hemochromatosis without anemia. In the transfusional iron overload group, 19 patients with thalassemia major who are routinely transfused have a moderate decrease of the 57 Co excretion. This finding probably reflects a continuing intestinal absorption of iron. On the other hand, 6 patients with acquired idiopathic sideroblastic anemia have a very low excretion. In the non anemic hemochromatosis, a high urinary level of 57 Co was present in 5 patients with idiopathic hemochromatosis when it was lower and variable in 6 patients with alcoholic siderosis. Using Wilcoxon, Mann and Whitney's non parametric test, there is a significant difference between the results of both groups. So, in idiopathic hemochromatosis, the high urinary level of 57 Co reflects an inappropriately high absorption of iron in spite of the iron overload and the test may be of value in detecting asymptomatic carriers of the disease.

[Changes during the six years after an experimental radioactive contamination in man]. / Evolution sur six ans d'une contamination radioactive humaine expérimentale

One of us has inhaled, in very well defined conditions, a mixture of radioactive substances originating from the heart of an electronuclear reactor and able to lead to a corresponding irradiation of the magnitude of the maximum permissible quarterly dose for the lungs. This internal contamination has been monitored for six years.