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PubMed2000

Total body calcium in obese women. Validation of dual-energy X-ray absorptiometry against in vivo neutron activation analysis.

In vivo neutron activation analysis (IVNA) allows in vivo measurement of total body calcium and is considered the gold standard technique. Dual-energy X-ray absorbtiometry (DXA) estimates total body calcium. Although there are a few comparisons of the two techniques, there are none with obese women. The present study compared the estimation of total body calcium by DXA with the measurement of Ca by IVNA in 69 obese women. Sixty-nine obese women (age 44 +/- 10 years, body weight [BW] 93 +/- 10.4 kg, body mass index [BMI] 35 +/- 4, fat mass 42 +/- 7 kg, 48 pre- and 21 postmenopausal, 30 Caucasian and 39 African-American) were recruited for a six-month body composition study without weight loss intervention. Total body (TB) Ca was measured by IVNA (CaIVNA) and by DXA (CaDXA) at baseline (n = 69) and again at six months (n = 40). At baseline, CaDXA was significantly higher than CaIVNA (1018 +/- 130 g vs. 706 +/- 92 g, p = 0.0001). The difference remained after six months (1028 +/- 153 g vs. 715 +/- 96 g). There was a small but significant increase in TBCa at six months by both DXA (16.5 +/- 40, p < 0.02) and IVNA (8 +/- 22 g, p < 0.03). However, this change was not significantly different between the two methods (p = 0.2365). The correlation between the two methods was very high (r = 0.937) and was independent of either race or menopausal status (p = 0.5163). We generated a regression equation: CaIVNA = 0.659 x CaDXA + 34.77; SEE = 32.2, R = 0.937. We present a model integrating the effect of weight and height on the relationship between CaIVNA and CaDXA. The higher the BMI, the bigger the difference between CaIVNA and CaDXA. In our population with a mean BMI of 35.3, CaIVNA = 69% CaDXA.

Absorptiometry, Photon↗
PubMed1984

Multi-element analysis of the obese subject by in vivo neutron activation analysis.

The Leeds facility for in vivo neutron activation analysis has been modified and calibrated for the simultaneous measurement of nitrogen, potassium, sodium, chlorine, phosphorus and calcium in obese patients weighing up to 210 kg. The effects of body size and shape were incorporated into the calibration by measuring 14 anthropomorphic phantoms of known composition representing individual patients being treated for obesity. The phantoms were constructed from tissue substitutes representing lean, skeletal and adipose tissues, arranged to simulate the distributions of the corresponding tissues within the patients, as visualised by CT scanning. The precision of the method, determined by measuring a single phantom ten times over a period of ten weeks, is between two and three per cent for all elements except calcium, for which it is 11.3%. Accuracy is estimated to be similar to precision. The procedure has been used to study changes in body composition of patients undergoing therapeutic starvation.

Activation Analysis↗
PubMed1996

[Neutron activation analysis of biological samples].

Multi-element analysis by neutron activation analysis (NAA) in respect to medical applications is discussed. Examples of trace element determinations in pathological human liver tissues, human serum, and rat liver are given. A very sensitive method for determining fluorinated drug in very small samples of human serum by neutron activation is also described. Each biological samples (ca. 100-200 mg, lyophilized matter) was irradiated for short time (10 s or 5 min.) and for long time (24 hrs) in Rikkyo University Research Reactor or Musashi Institute of Technology Research Reactor. Concentration of 12 elements (127I, 55Mn, 26Mn, 65Cu, 23Na, 41K, 37Cl, 27Al, 48Ca, 36S, 58Fe, 64Zn) in human pathological liver, Futraful (19F) (anti-cancer fluorinated drug) clearance of human serum, and calcium uptake (48Ca) in liver of rats were determined by NAA.

Animals↗
PubMed1980

The present state of in vivo neutron activation analysis in clinical diagnosis and therapy.

In vivo neutron activation has opened a new era of research on the elemental composition of the human body. The techniques currently employed vary widely with respect to sources, moderators, site of activation and detection systems. Sources include cyclotrons, neutron generators and radioactive elements. Both partial body and total body neutron activation analysis (PBNAA and TBNAA, respectively) are commonly used to determine calcium levels. This review examines various aspects of the two techniques for delayed gamma neutron activation and the factors which affect the sensitivity of the measurements, uniformity of the neutron flux density, and the use of moderators. Portions of the body selected for partial body activation analysis are the hand, the arm and the trunk. Such measurement may be particularly useful for studying patients with diseases that affect various parts of the skeleton differently. However, to date, analyses based on TBNAA and PBNAA do not appear to favour one technique over the other. Comparison of the two techniques has to take into account a variety of factors: dose to the patient, cost reliability, availability of source, nature and cost of complementary facilities required, and the degree of expertise needed by the operating personnel. Neutron activation studies of body calcium have provided data useful for the diagnosis and management of a variety of metabolic disorders. Measurement of sodium, chlorine and nitrogen also appear to be useful clinically. A variety of clinical applications are discussed in this review. A recent development is prompt gamma neutron activation analysis, which can be used for the in vivo determination of cadmium in liver and kidney. Total body nitrogen (measured by prompt gamma neutron activation) and potassium measurements serve as indices of protein and muscle mass content, and hence are useful in assessing the roles of diet and nutrition in these body components.

Activation Analysis↗
PubMed2000

Multielement analysis in cereals and pulses by k0 instrumental neutron activation analysis.

The concentrations of some elements in a few varieties of cereals and pulses are determined by Instrumental Neutron Activation Analysis using a single comparator method (k0-standardised NAA method). A total of 15 elements are measured. The method was validated by analysing the Standard Reference Material (SRM-1571) of NIST; the results are within +/-10% of the reported values for the majority of the elements. The measured concentrations of major and minor elements are analysed in terms of the average intake of mineral content and the role of these elements in terms of the nutritional value.

Diet↗
PubMed2001

Determination of 232Th by neutron activation analysis using isotope-related ki factors.

Neutron activation analysis was applied to determine the 232Th activity in different matrices. Since in nature thorium consists of almost 100% of the long-lived 232Th, the instrumental trace element analysis method of neutron activation analysis can be applied to determine the thorium content in a sample. which can then be converted into the corresponding specitic activity. For the analysis about 100 mg of the sample was irradiated at a thermal neutron flux of phi(th) = 8 x 10(13) n.cm(-2) x s(-1). After irradiation the activity of the indicator nuclid 232Pa--produced by the (n,gamma) reaction--was measured by gamma spectrometry. The content of thorium was calculated using the activation equation and the isotope-related ki constant. Finally, the concentration of thorium in the sample was converted into the specific activity. The activities of 232Th measured by applying neutron activation analysis in different samples were compared with the results found by a spectrometry and gamma spectrometry for the daughter nuclides 228Ac and 224Ra.

Health Physics↗
PubMedDate not supplied

Charged-particle activation analysis of biological material.

Charged-particle activation analysis offers a number of interesting possibilities for the determination of trace elements in biological material. It allows the determination of those elements that are difficult or impossible to determine by neutron activation, such as Li, B, Al, Si, V, Cr, Ni, Cd, Sn, Tl, and Pb. Up to now, protons have been successfully applied to samples of both vegetal and human origin. A number of difficulties have to be overcome, one of which is excessive heating of the samples owing to the limited range of the charged particles, thus giving rise to a high energy deposition in a small volume. Moreover, the sample composition has to be known to allow the calculation of the range of the particles. An interesting alternative has been proposed using an internal standard together with a standard additions procedure. Proton activation analysis was tested on a wide variety of reference materials, giving evidence that accurate results can be obtained for many trace elements, even when applying a purely instrumental method. Thus, the method can also be applied in the certification of reference materials, since nuclear methods are independent of chemical properties of the sample.

Activation Analysis↗
PubMed1999

Elemental analysis of herbal preparations for traditional medicines by neutron activation analysis with the k0 standardization method.

Medicinal herb preparations prescribed for specific treatment purposes were purchased from markets and were analyzed by instrumental neutron activation analysis with k0 standardization. Then, 500-700 mg of each sample was pelletized under a pressure of six tones and irradiated together with monitors for alpha and neutron flux ratio determinations for about 6 h in a thermal flux of 2.29 x 10(12) n/cm2/s. The accuracy of the method was established by analyzing standard reference materials. Twenty-nine elements, Ag, As, Au, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Mn, Mo, Na, Rb, Sb, Sc, Se, Sm, Sr, Th, U, Yb, and Zn, were measured in all the samples, and Hg was detected in some samples, with good accuracy and reproducibility. The concentration of elements determined was found to vary depending on the composition of the herbs used. Although the trend linking the element of the medicinal plants to its curative abilities could not be clearly determined, this study showed that the toxic elements found in the samples were below the levels prescribed by health regulations. Nevertheless, such data are important to understand the pharmacological action and the exact mechanisms of action and formation of active constituents for each medicinal plant and to decide the dosage of the herbs used in the final formulation.

Neutron Activation Analysis↗
PubMed1988

[Evaluation of intraocular metallic foreign bodies by multi-element neutron activation analysis].

Multi-element neutron activation analysis method was applied to the determination of metallic foreign bodies which penetrated into the eyes of workers while engaged in grinding and cutting work. A total of 23 small pieces ranging in size from 1 to 10(2) mg were surgically obtained and then analyzed non-destructively with only simple washing treatment. The components of 21 samples were mainly iron and the others were hard pieces of wolfram compound. Elements determined in samples over one weight percent were iron, manganese, chromium, wolfram, and cobalt. All the samples were divided into five classes according to their own elemental composition. It was considered that foreign bodies were composed of carbon steel, steel alloy, and tungsten carbide. These results are regarded to be useful in studying the mechanism of accidents and their effects on eyes.

Eye Foreign Bodies↗
PubMed2004

Application of spectral decomposition analysis to in vivo quantification of aluminum by neutron activation analysis.

The toxic effects of aluminum are cumulative and result in painful forms of renal osteodystrophy, most notably adynamic bone disease and osteomalacia, but also other forms of disease. The Trace Element Group at McMaster University has developed an accelerator-based in vivo procedure for detecting aluminum body burden by neutron activation analysis (NAA). Further refining of the method was necessary for increasing its sensitivity. In this context, the present study proposes an improved algorithm for data analysis, based on spectral decomposition. A new minimum detectable limit (MDL) of (0.7+/-0.1)mg Al was reached for a local dose of (20+/-1)mSv. The study also addresses the feasibility of a new data acquisition technique, the electronic rejection of the coincident events detected by a NaI(Tl) system. It is expected that the application of this technique, together with spectral decomposition analysis, would provide an acceptable MDL for the method to be valuable in a clinical setting.

Algorithms↗
PubMed1999

Neutron activation analysis of fluoride release after treatment with a fluoride varnish in vitro.

OBJECTIVE: To use neutron activation analysis to study a new type of cariostatic material, fluoride varnish, in terms of its anti-caries mechanism and its release in vitro. MATERIALS AND METHODS: Twenty enamel specimens were measured for baseline fluoride content using neutron activation analysis. The enamel specimens were then fluoridated with 1.5% sodium fluoride varnish for 24 hours, and their enamel fluoride content was measured again with neutron activation analysis. RESULTS: The baseline fluoride content in the enamel specimens was 161.7 micrograms/g; after fluoridation, the fluoride content in the enamel specimens increased to 277.8 micrograms/g, or about 1.7 times. CONCLUSION: It is evident that this sodium fluoride varnish can significantly increase enamel fluoride content. The neutron activation analysis is a good method for fluoride measurement in vitro.

Cariostatic Agents↗
PubMed1975

[Investigations of contact tissues of Blount vitallium staples using the instrumental neutron activation analysis (author's transl)].

Instrumental neutron activation analysis with Gamma-spectroscopy is a very sensitive method for testing trace elements. Specimens of contact tissue around 5 Blount's vitallium clamps were, after preparation at the Nuclear Research Institute Jülich irradiated with thermic neutrons and their element-specific gamma spectra were measured after 33 and 125 days. In contact tissue a significant rise in concentration of the alloy-specific elements cobalt and chromium was found. The unspecific elements silver, caesium, iron, rubidium, antimon, scandium and zink were either within or very close to the normal. The metallosis of contact tissue is due to corrosion of the surfaces of cobalt-chromium implants.

Activation Analysis↗
PubMed1994

Neutron activation analysis of biological samples at the radiochemistry division of IPEN-CNEN/SP.

Neutron activation analysis is a very useful method for determination of a great number of elements in biological samples. At the Radiochemistry Division of the IPEN-CNEN/SP, this method is being extensively applied to study several materials, such as extracts from medicinal plants, human hair, snake venoms, human lungs, food-stuffs, and corn samples. Both instrumental neutron activation analysis (INAA) and radiochemical neutron activation analysis (RNAA) are used to analyze real samples, as well as biological standard reference materials to evaluate the accuracy and precision of the results.

Brazil↗
PubMedDate not supplied

Bone mineral measurements of the central skeleton by in vivo neutron activation analysis for routine investigation os osteopenia.

In vivo neutron activation analysis has been used to measure bone mineral content in the central skeleton where osteoporotic fractures occur. To be of diagnostic value, the results must be normalized for body size. From data obtained from 74 healthy children and adults up to 55 years of age, we have found that the calcium in the central skeleton is approximately proportional to the cube of the subject's height. The correlation for the adults alone has an r value of 0.81. When data from both adults and children are used, r = 0.95. The validity of this cubic height relationship to the Ca concentration measurements has been further substantiated by studies on rats. The total femur calcium content of 110 rats from weanling to 25 weeks of age was proportional to the overall femur (length) 3.6 (or (length)2.6 per unit length) with r = 0.99. When the level of Ca content is related to data on normal subjects of the same body size (giving the Calcium Bone Index or CaBI) a good separation is obtained between normal volunteers and osteoporotic subjects. Volunteers who were 20 to 55 years of age had CABI 1.0 "/- .12 (SD) while osteoporotics had CaBI 0.69 +/- .10 (SD). When the calcium content as determined by in vivo activation analysis is expressed as a CaBI, it provides a powerful tool for the diagnosis of osteopenia. We suggest that all bone measurements, including peripheral ones, be normalized for body size in order to increase their diagnostic value.

Activation Analysis↗
PubMed2005

Determination of selenium in Libyan food items using pseudocyclic instrumental neutron activation analysis.

Cyclic and pseudocyclic instrumental neutron activation analysis (INAA) has been used to determine the Se content of 40 Libyan food items. The selected samples include different varieties of local and imported foods such as wheat and barley products (bran and flours), rice, bread, almond, peanuts, vegetables as bean and peas, tea, coffee, sugar, and commonly used spices such as red and black paper, curry, cumin, mixture of spices, thyme, coriander, and fenugreek. Both conventional and anticoincidence gamma-ray spectrometry techniques have been employed. Pseudocyclic INAA in conjunction with anticoincidence counting has been found to provide the most reliable results. The precision of the method has been significantly improved by recycling the samples up to three times. The accuracy has been evaluated by analyzing a number of certified reference materials of varied Se levels. The detection limit has been found to vary between 26 and 90 ppb Se depending on the sample composition. The range of daily dietary intake has been calculated as 13-44 microg of Se per day.

Adult↗
PubMed1999

Multielement analysis of human hair and kidney stones by instrumental neutron activation analysis with the k0-standardization method.

This paper focuses on the evaluation of the k0 method of instrumental neutron activation analysis in biological materials. The method has been applied in multielement analysis of human hair standard reference materials from IAEA, No. 085, No. 086 and from NIES (National Institute for Environmental Sciences) No. 5. Hair samples from people resident in different parts of Malaysia, in addition to a sample from Japan, were analyzed. In addition, human kidney stones from members of the Malaysian population have been analyzed for minor and trace elements. More than 25 elements have been determined. The samples were irradiated in the rotary rack (Lazy Susan) at the TRIGA Mark II reactor of the Malaysian Institute for Nuclear Technology and Research (MINT). The accuracy of the method was ascertained by analysis of other reference materials, including 1573 tomato leaves and 1572 citrus leaves. In this method the deviation of the 1/E1+ alpha epithermal neutron flux distribution from the 1/E law (P/T ratio) for true coincidence effects of the gamma-ray cascade and the HPGe detector efficiency were determined and corrected for.

Citrus↗