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Results for “Neutron Activation Analysis”

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PubMedDate not supplied

A feasibility study of in vivo 14-MeV neutron activation analysis using the associated particle technique.

The feasibility of using the time correlated associated particle technique for in vivo 14-MeV neutron activation analysis has been investigated. Gamma rays following neutron inelastic scattering with nitrogen, carbon, and oxygen have been measured with a 12.5 x 10-cm NaI (T1) detector. The results have been scaled to a proposed facility comprising four such detectors past which the subject would be scanned. Based on counting statistics, the precision of estimation of these elements has been determined to be 2.1%, 1.0%, and 1.1%, respectively, for experimental measurements on a sample containing physiological concentrations of the major body elements. The average body dose level would be restricted to 0.3 mSv.

Alpha Particles↗

PubMed1987

[Determination of antimony in nail and hair by thermal neutron activation analysis].

The concentration of antimony in nail and hair was determined by thermal neutron activation analysis. Samples were collected from the workers of an antimony refinery, inhabitants near the refinery, and residents in control area. They were irradiated by Kyoto University 5 000 kW Reactor for 1 h, and cooled for 30 to 100 days. After cooling, the concentration of Sb in nail and hair was estimated by measuring the intensity of gamma-ray from 124Sb of the samples, then the samples were washed by 0.1% aqueous solution of nonionic surface active agent in an ultrasonic cleaner. The gamma-ray spectrometry was done again (after washing). The concentration of Sb in nail before washing was 730 ppm for the workers, 2.46 ppm for habitants near the refinery, and 0.19 ppm for the control; after washing, it became 230 ppm for the workers, 0.63 ppm for habitants, and 0.09 ppm for the control. The concentration of Sb in hair before and after washing was 222 ppm and 196 ppm for the workers, and 0.21 ppm and 0.15 ppm for the control, respectively.

Antimony↗

PubMedDate not supplied

The assessment of postmenopausal osteoporosis by total body neutron activation analysis.

Total body calcium (TBCa) was measured using a cyclotron for in vivo neutron activation analysis (IVNAA) in 20 healthy women, 15 women with vertebral compression fractures, and 8 women with wrist fractures. The precision of the technique, using phantoms, was 1.8% for a dose of 13 mSv. A formula for predicted TBCa (TBCap) was derived from the 20 normal women based on span and years postmenopause. The coefficient of variation of TBCa after normalization in the normal women was 6.6%. The mean TBCa values for the vertebral and wrist fracture groups were 69% and 84% of TBCap for women at the time of the menopause. The low TBCa in the wrist fracture group was attributable to post-menopausal bone loss. Of the low TBCa in the vertebral fracture group, about half the loss could be attributed to postmenopausal age and half to other factors.

Aged↗

PubMed1981

Neutron activation analysis of total diet food composites for iodine.

The iodine content of Total Diet food composites was measured using neutron activation analysis. The interfering element chlorine was separated using a modified combustion and gas phase procedure. The average recovery was 94.8% (standard deviation 2.9) for the 10 matrices that were tested. In addition, iodine was measured in National Bureau of Standards Standard Reference Materials, which have no certified values for this element. Preliminary findings of iodine content of adult Total Diet market baskets collected during Fiscal Year 1980 in different regions of the United States ranged from 292 to 901 micrograms/day for a 2900 kcal intake.

Food Analysis↗

PubMed1999

Radiochemical neutron activation analysis in the life sciences. A look back and ahead.

The contribution of radiochemical neutron activation analysis (RCNAA) to a better understanding of trace element analytics and physiology in the life sciences is outlined. Now, various non-nuclear powerful techniques for trace element analysis have become available, competing with RCNAA. This necessitates re-evaluation of the position of RCNAA, in particular versus inductively coupled plasma--mass spectrometry (ICP-MS). On basis of the characteristic features of RCNAA and the capabilities of various competing non-nuclear analytical techniques, future niches for RCNAA in the analytical market are indicated.

Biological Assay↗

PubMed1984

Vanadium in human serum, as determined by neutron activation analysis.

Vanadium concentrations have been measured in the serum of 23 healthy subjects by neutron activation analysis, with post-irradiation chemical separation. The values obtained fall in a fairly narrow range (260-1300 ng/L, mean 670 ng/L), which suggests a physiological role for this element. We checked the method by analysis of standard (U.S. National Bureau of Standards) water samples and serum samples supplemented with 48V, and we found excellent agreement with expected results in both cases. We consider the reported results for human serum to be more reliable than those obtained by atomic absorption spectroscopy.

Adult↗

PubMed1984

Concentrations of trace elements in human blood serum from different places in Norway determined by neutron activation analysis.

The concentrations of As, Fe, Hg, Sb, Se and Zn in 281 serum samples from people living in nine municipalities in Norway were determined by radiochemical neutron activation analysis. The concentrations of Br, Cl, Cs, Na, Rb, Se and Zn were determined in another set of 157 serum samples from four of the municipalities by instrumental neutron activation analysis. Higher arsenic concentrations were found in the coastal districts than in inland municipalities; otherwise no significant difference in mean values was observed between the districts. Except for Na-Cl and Rb-Cs, none of the elements was significantly correlated with any other element studied.

Humans↗

PubMedDate not supplied

In vivo neutron activation analysis: state of the art and future prospects.

From the inauspicious beginning arising in the aftermath of a reactor accident in 1957, in vivo analysis of body elements by neutron activation has become an important tool in medical research. In particular, it provides a much needed means to make quantitative assessments of body composition of human beings in vivo. The data are useful both for basic physiological understanding and for diagnosis and management of a variety of diseases and disorders. The paper traces the development of the in vivo neutron activation technique in the past quarter of a century from basic systems to the present state of the art facilities, and discusses the advantages and disadvantages of the various systems. A scan of some of the numerous clinical applications that have been made of this technique reveals the broad potentialities of in vivo neutron activation. The paper also considers alternative routes of future development and raises some of the questions now faced in making the techniques more widely available to both medical practitioners and medical investigators.

Activation Analysis↗

PubMed1995

[Potential and limitations of neutron activation analysis methods for measuring elements of toxicological and environmental interest].

Merits and limits of neutron activation analysis are presented for the various classes of biological and environmental matrices and depending on the analytes to be quantified. In this framework the cases of mercury, cadmium, copper, arsenic, chromium, iodine are discussed in detail with particular reference to the most frequent analytical interferences and procedural pitfalls in sample pretreatment.

Chemistry, Bioinorganic↗

PubMedDate not supplied

Air quality status in Kinshasa as determined by instrumental neutron activation analysis, atomic absorption spectrometry, and ion-exchange chromatography.

Three independent analytical techniques: instrumental neutron activation analysis, atomic absorption spectrometry, and ion-exchange chromatography were applied to airborne particulates collected on filters, and to atmospheric acid gases collected in carbonate buffer solutions. Twenty trace elements and seven acid gases and acid aerosols were determined. Results were compared with those observed elsewhere and showed that air pollution is low in Kinshasa and should not cause anxiety. The main known sources of pollutants are vehicle exhaust and aeolian processes on stripped soils.

Acids↗

PubMed1990

A consideration of salt intake from foods based on the simultaneous measurement of sodium and chlorine by neutron activation analysis.

Ordinary hospital meals for adults were simultaneously measured for Na and Cl by neutron activation analysis (NAA). Results obtained are summarized as follows: 1. Daily Na intake was estimated to be 4 to 8 g, corresponding to 11 to 18 g of salt. Daily Cl intake was estimated to be 5 to 9 g, corresponding to 7 to 12 g of salt. Their ratio was 1.6. 2. The higher values of salt intake obtained by conversion from Na intake are attributable to food additives. 3. In rating Na content, which has been reported to affect blood pressure, on the basis of salt intake, attention must be given to the fact that salt content converted from Cl content is rated to be lower than that converted from Na content.

Chlorine↗

PubMedDate not supplied

Body-size corrections for in vivo neutron activation analysis.

Differences in body size and shape can cause large variances in the results of in vivo neutron activation analysis. Preliminary body-size correction data were obtained for the delayed-gamma neutron activation facility (DGNA) at Brookhaven National Laboratory (BNL), based on phantom standards of different sizes, used in combination with computer simulations on the effect of different body sizes.

Body Composition↗

PubMed1992

Rapid radiochemical neutron activation analysis for iodine in urine by different separation techniques.

In the present work on radiochemical neutron activation analysis for the determination of iodine in urine samples, the performance of three different radiochemical separation techniques, namely, direct extraction, use of an iodinated ion-exchange resin column and Schöniger combustion, were intercompared and validated. The practical advantages of the iodinated-resin technique make it most suitable for the rapid routine determination of iodine in urine. It was further verified by participation in an international intercomparison run of urine analysis, and used in a pilot study on iodine determination in the urine of 171 Slovenian schoolchildren, where it gave results in good agreement with the catalytic method.

Child↗

PubMed1992

Design studies related to an in vivo neutron activation analysis facility for measuring total body nitrogen.

Design studies relating to an in vivo prompt capture neutron activation analysis facility measuring total body nitrogen are presented. The basis of the design is a beryllium-graphite neutron collimator and reflector configuration for (alpha, n) type radionuclide neutron sources (238PuBe or 241AmBe), so as to reflect leaking, or out-scattered, neutrons towards the subject. This improves the ratio of thermal neutron flux to dose and the spatial distribution of thermal flux achieved with these sources, whilst retaining their advantage of long half-lives as compared to 252Cf based systems. The common problem of high count-rate at the detector, and therefore high nitrogen region of interest background due to pile-up, is decreased by using a set of smaller (5.1 cm diameter x 10.2 cm long) NaI(Tl) detectors instead of large ones. The facility described presents a relative error of nitrogen measurement of 3.6% and a nitrogen to background ratio of 2.3 for 0.45 mSv skin dose (assuming ten 5.1 cm x 10.2 cm NaI(Tl) detectors).

Body Composition↗

PubMed1997

A modified bottle manikin phantom for in vivo neutron activation analysis.

An artificial skeleton was designed and placed inside a bottle manikin absorber phantom to provide a new reference standard for measurements of total body calcium by in vivo neutron activation analysis at Brookhaven National Laboratory. The composition of the epoxy-based calcium and phosphorus mixture used to construct the skeleton, the dimensions and weight of each bone are given for two phantoms representing an adult male and female. Also, the dimensions, composition, and weights of overlays designed to simulate the influence of obesity on in vivo neutron activation analysis are given for each.

Adult↗

PubMed1999

Determination of trace elements in tissue of human uterine cancer by instrumental neutron activation analysis.

In this article, the low-temperature freeze-drying pretreated technique and instrumental neutron activation analysis were used to determine 29 trace elements in samples of human uterine cancer tissue. The content of these trace elements in uterine cancer tissue was compared with that in cervicitis tissue and in healthy tissue, respectively. Preliminary results indicated that significant differences in contents of Au, I, and Se were observed in these tissues.

Female↗

PubMed1991

Factor for correcting the ruthenium interference in instrumental neutron activation analysis of barium in uraniferous samples.

The fission spectral interference of ruthenium on the instrumental neutron activation analysis of barium in samples containing uranium is extensively discussed. In particular the dependence of the correction factor on the phi epi/phi th ratio is studied. An excellent agreement between experimental and calculated values is achieved. A procedure is suggested for the resolution of multiple interferences in the general case where uranium, barium and/or ruthenium are present in samples to be analysed.

Barium↗

PubMed1986

Total body calcium measurements using neutron-activation analysis in Cushing's syndrome.

Total body calcium content (TBCa) was estimated by in vivo neutron activation analysis in 16 patients (14 female, 2 male) with active Cushing's syndrome, pituitary driven in all but two cases. Apart from being nonreproductive, patients were unselected. TBCa was below the predicted young normal value in all patients (mean +/- SD, 85.2 +/- 5.8% of predicted, P less than 0.01 vs. predicted) and in 13 of the 16 patients, was also below the predicted value when allowance was made for expected postmenopausal skeletal losses (mean +/- SD, 92.7 +/- 12.5% of predicted, P less than 0.02). However, individual values of TBCa were significantly lower (P less than or equal to 0.05) than the predicted normal range, corrected for postmenopausal losses, in only 3 patients (19% of the group). Initial TBCa apparently was not related to duration of the disease or to current urinary-free cortisol levels. At presentation, radiographic signs of significant osteoporosis (multiple vertebral and/or rib fractures) were present in four patients, three of whom had subnormal or borderline TBCa compared with the young normal predicted range. TBCa measurements were repeated in 9 patients 1-10 years after successful treatment, and were generally unchanged. During this period, only one vertebral fracture (consistent with simple postmenopausal osteoporosis) appeared in these patients. We conclude that bone mass tends to be low in newly diagnosed Cushing's syndrome, but that significant reduction beyond expected postmenopausal losses is relatively uncommon.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenalectomy↗