Portable X-ray Fluorescence Device Research Articles

O75 (not presented) Evaluation of a portable X-ray fluorescence device for a sustainable mineral nutrition in dairy herds

O75 (not presented) Evaluation of a portable X-ray fluorescence device for a sustainable mineral nutrition in dairy herds

On Blue and Green Pigments from the St. George Cathedral of Veliky Novgorod

This paper presents the first analytical data obtained from the examination of fragments of stunning Russian–Byzantine frescoes recovered from an archaeological excavation at Veliky Novgorod, one of the oldest cities in Russia and a UNESCO World Heritage Site. The archaeologists of the Institute of Archaeology of the Russian Academy of Sciences have been working on architectural excavations at Novgorod for more than 20 years. In the last seven years, they have unearthed fragments of frescoes in the layers of the twelfth century AD during excavation under the floor of the Cathedral of St. George in the Yuriev Princely Monastery (built in 1119).As a first step of this complex research, we decided to concentrate on blue and green pigments. A selection of 30 samples and around 30 parts of wall paintings still in situ, subdivided by technique and color nuance, were first autoptically examined and, where possible, studied by optical microscopy. In this way typical details, such as the use of additives to the mortars, different ways of treating and mixing the colors, and pigment layers, were recognized. For the first screening, the analytical data were collected using a portable X-ray fluorescence device. They indicated the use of a variety of pigments and mixtures to obtain different nuances of color. The samples were then analyzed by scanning electron microscopy with energy dispersive spectrometry. All phases of the study were recorded and documented by photos and micrographs of the most significant details. The data are discussed in the text and help explain the working habits of the painters of the time.

Feasibility of a 109Cd-based portable XRF device for measuring skin iron concentration in anaemic and β−Thalassaemic patients

Iron is an essential element vital for growth and development. The severe effects on the body due to iron deficiency or overload have prompted sustained research into accurate in vivo iron measurement techniques for the past several decades. X-ray fluorescence (XRF) analysis of iron in the body has been investigated in this work because of the non-invasive nature of the technique. A system has been designed using a silicon drift detector to measure the low-energy iron K α x-rays excited in the samples by the silver x-rays from 109Cd of energy 22 keV and 25 keV. The source is contained within a tantalum shielding cap designed to reduce the spectral background. The system was calibrated against 3D printed polylactic acid (PLA) phantoms filled with solutions of iron at various concentrations. The iron x-ray signals were normalized to a nickel x-ray signal which improved the system’s reproducibility. The 3D phantoms and normalisation resulted in a linear calibration line (p < 0.001 and r2 > 0.999). For a real-time measurement of 1800 s, the minimum detectable limit for the system was measured to be 1.35 ± 0.35 ppm which is achieved with a low radiation dose of 1.1 mSv to the skin surface. This low detection limit and low dose mean the system is feasible for application to human measurements in both iron deficiency and overload disease. The system will proceed to post-mortem validation studies prior to in vivo system efficacy testing.

In vivo quantification of strontium in bone among adults using portable x-ray fluorescence

Background and objectiveBone strontium (Sr) is a reliable biomarker for studying related bone health outcomes and the effectiveness of Sr supplements in osteoporosis disease treatment. In this study, we evaluated the sensitivity of portable x-ray fluorescence (XRF) technology for in vivo bone Sr quantification among adults. Materials and methodsSr-doped bone-equivalent phantoms were used for system calibration. Using the portable XRF, we measured bone Sr levels in vivo in mid-tibia bone in 76 adults, 38–95 years of age, living in Indiana, US; we also analyzed bone data of 29 adults, 53–82 years of age, living in Shanghai, China. The same portable XRF device and system settings were used in measuring their mid-tibia bone. We compared bone Sr concentrations by sex, age, and recruitment site. We also used multiple linear regression model to estimate the association of age with bone Sr concentration, adjusting for sex and recruitment site. ResultsThe uncertainty of in vivo individual measurement increased with higher soft tissue thickness overlying bone, and it ranged from 1.0 ug/g dry bone (ppm) to 2.4 ppm with thickness ranging from 2 to 7 mm, with a measurement time of 5 min. Geometric mean (95% confidence interval (CI)) of the bone Sr concentration was 79.1 (70.1, 89.3) ppm. After adjustment for recruitment site and sex, an increase in five years of age was associated with a 8.9% (95% CI: 2.5%, 15.6%) increase in geometric mean bone Sr concentration. Discussion and conclusionSr concentrations were consistently well above detection limits of the portable XRF, and exhibited an expected increase with age. These data suggest that the portable XRF can be a valuable technology to quantify Sr concentration in bone, and in the study of Sr-related health outcomes among adults, such as bone mineral density (BMD) and bone fracture risk.

Validity of a portable X-ray fluorescence device for analyzing field dust wipe samples for lead

Interior dust lead loadings on floors and windowsills are reliable predictors of a child’s blood lead level and an important predictor in “clearance testing” of residences. The portable X-ray fluorescence device is an alternate technique that can provide fast, accurate, and precise results regarding the presence of dust lead hazards in residences. In this paper, we tested the comparability of the portable X-ray fluorescence device against Inductively Coupled Plasma Mass Spectrometry, using the newer lead hazard standards for dust wipe samples. Dust wipe samples (n = 109) collected from floors and interior windowsills of 13 homes were tested by means of a portable X-ray fluorescence device and subsequently analyzed for lead using Inductively Coupled Plasma Mass Spectrometry. Considering Inductively Coupled Plasma Mass Spectrometry as the “gold standard,” the portable X-ray fluorescence device produced an average false negative rate of 27.3% at the new dust lead hazard standards of 10 μg/ft2 for floors, and 100 μg/ft2 for windowsills. There were no false positive results from the portable X-ray fluorescence device at the new dust lead hazard standards. A Bland Altman analysis showed that 96.3% of the data points were within the lower and upper acceptable limits of agreement. The results of the study suggested that the portable X-ray fluorescence device has a good agreement with the Inductively Coupled Plasma Mass Spectrometry method at lower lead concentrations and is appropriate for measuring lead concentrations in field dust wipe samples from homes where lead concentrations are in a lower range.

In vivo Quantification of Bone Lead and Strontium using Portable X-ray Fluorescence (XRF)

BACKGROUND AND AIM: Exposure to lead (Pb) or strontium (Sr) is of concern due to potential neurotoxicity or impaired bone health, respectively. Human bone is reliable biomarker for cumulative Pb and Sr exposures and for studying associated health outcomes. However, the applicability of standard K-shell x-ray fluorescence (KXRF) bone Pb measurement technology is significantly limited by its lack of portability, long measurement times, and licensing - restricting its use in large-scale population studies. In this study, we measured Pb and Sr in two populations using portable x-ray fluorescence (XRF), compare bone Pb measurements from a portable XRF device and a KXRF device, and assess differences in bone Sr level across sex, age and ethnicity. METHODS: We measured bone Pb and Sr concentrations in mid-tibia bone using portable XRF in 76 Americans, age 38 – 95 years, living in Indiana, and bone Sr concentrations in 29 Chinese, age 53 – 82 years, living in Shanghai. RESULTS:The detection limits for 3-minute portable XRF measurements for in vivo bone Pb and Sr ranged from 4.0 to 12.6 ug/g dry bone (ppm) and 2.0 to 5.2 ppm, respectively, with overlying soft tissue (ST) thickness ranging from 2 to 6 mm. Bone Pb measurements via KXRF and portable XRF were highly correlated: R = 0.73 (95% CI, 0.28 to 0.70) among participants with ST thickness 6 mm (72% of the measured population). Furthermore, the mean bone Sr concentration for American participants was 66.1 ppm (95%CI: 56.5 ppm, 75.6 ppm) and for Chinese was 74.7 ppm (95%CI: 55.6 ppm, 93.8 ppm). Interestingly, the bone Sr in Chinese female participants decreased with age, while the bone Sr in American female participants increased with age. CONCLUSIONS:We conclude that portable XRF is a valuable technology to study health outcomes related to Pb and Sr exposures. KEYWORDS: Heavy Metals, Exposure Assessment, X-ray Fluorescence, Lead (Pb), Strontium (Sr)

Cumulative Lead Exposure Resulting from Coal Power Plants in India

BACKGROUND AND AIM: Coal pollution can lead to a myriad of toxic exposures and toxicity resulting from coal power generation has not been well-defined. As part of this study, we sought to identify cumulative lead exposure measured as bone lead in communities living near coal power plants. METHODS: We chose three communities at 1 km (n=50), 9 km (n=50), and 38 km (n=50) from coal power plants near Chennai, India and measured their bone lead using a portable x-ray fluorescence device. RESULTS:The bone lead identified in all participants was significantly higher than that found in typical occupationally exposed populations in the United States. We identified a dependency on location with the community living within 1 km of coal power plants experiencing higher cumulative lead exposure than the community farthest from the coal power plants. Lead exposure decreased at a rate of 0.92 ug/g/km. From our models, a 40-year-old adult at 1 km from a coal power plant would have an average bone lead level of 22.3 ug/g, whereas a 40-year-old at 10 km would have an average bone lead level of 14.3 ug/g. Further, we identified a population of over 704,185 that would be living in communities within 1 km of a coal power plant, equivalent to our highest exposure group. CONCLUSIONS:Our study was the first to identify a relationship between cumulative lead exposure and coal pollution, demonstrating a dramatic increase in lead exposure for communities near coal power plants. The community within 1 km of the coal power plants experienced bone lead on average 1.5 times higher than our control group. The control group had higher cumulative lead exposure than typical occupational exposures in the United States. These exposures would lead to drastic consequences throughout the body including cardiovascular and neurologic health impacts while ultimately increasing mortality from all causes. KEYWORDS: Coal, lead, cumulative, xrf, India, bone lead

Validation of in vivo toenail measurements of manganese and mercury using a portable X-ray fluorescence device.

Background and Objective:Toenail metal concentrations can be used as an effective biomarker for exposure to environmental toxicants. Typically toenail clippings are measured ex vivo using inductively-coupled plasma mass spectrometry (ICP-MS). X-ray fluorescence (XRF) toenail metal measurements done on intact toenails in vivo could be used as an alternative to alleviate some of the disadvantages of ICP-MS. In this study, we assessed the ability of using XRF to measure toenail metal concentrations in real time without having to clip the toenails (i.e. in vivo) in two occupational settings for exposure assessment of manganese and mercury.Materials and Methods:The portable XRF method used a 3-minute in vivo measurement of toenails prior to clipping and was assessed against ICP-MS measurement of toenail clippings taken immediately after the XRF measurement and work history for a group of welders (n=16) assessed for manganese exposure and nail salon workers (n=10) assessed for mercury exposure.Results and Conclusions:We identified that in vivo XRF metal measurements were able to discern exposure to manganese in welders and mercury in nail salon workers. We identified significant positive correlations between ICP-MS of clippings and in vivo XRF measures of both toenail manganese (R= 0.59, p=0.02) and mercury (R= 0.74, p<0.001), as well as between in vivo XRF toenail manganese and work history among the welders (R=0.55, p=0.03). We identified in vivo XRF detection limits to be 0.5 μg/g for mercury and 2.6 μg/g for manganese. Further work should elucidate differences in timing of exposure using the in vivo XRF method over toenail clippings and modification of measurement time and x-ray setting to further decrease the detection limit. In vivo portable XRF measurements can be used to effectively measure toenail Mn and Hg in occupational participants in real time during study visits and at a fraction of the cost.

A Dosimetry Study of Portable X-ray Fluorescence in Vivo Metal Measurements.

Portable x-ray fluorescence devices have grown in popularity for possible metal exposure assessment using in vivo measurements of bone and toenail. These measurements are accompanied by a small radiation dose, which is typically assessed by radiation safety committees to be minimal. However, an understanding of precise dose under different instrument conditions is still needed. This study set out to do a thorough investigation of the exact dose measurements using optically stimulated dosimeters, thermoluminescent dosimeters, and simulation with a Monte Carlo N-Particle transport code to assess the skin and total-body effective dose typical of portable x-ray fluorescence devices. We showed normal linear relationships between measurement time, x-ray tube current, and radiation dose with the device, and we showed a second order polynomial relationship with increasing voltage and radiation dose. Dose was quantified using thermoluminescent dosimeters, optically stimulated dosimeters, and simulations, which gave similar dose estimations. Skin dose for a standard 50-kV, 40-μA measurement for bone and toenail in vivo was 48.5 and 28.7 mSv, respectively, according to simulation results. Total-body effective dose was shown as 3.4 and 2.0 μSv for in vivo bone and toenail measurements, respectively, for adults using the portable x-ray fluorescence device.

Comparison of bone lead measured via portable x-ray fluorescence across and within bones

BackgroundBone lead measured via x-ray fluorescence (XRF) has been used for decades in health studies. A portable XRF device for bone lead measurement is gaining in popularity for its ease of use and shorter measurement times. Previous XRF devices have measured different bone types in order to sample both cortical and trabecular bone, in which lead has different half residence times. ObjectiveThe portable XRF uses lower energy to measure bone lead than previous devices, and, thus, only measures the surface of the bone. Because all bones have a cortical shell, we hypothesized that portable XRF bone lead measurements would be similar regardless of the bone measured. MethodsThis study tested differences in portable XRF bone lead measurements across different cortical and trabecular bones in measurements made on 31 cadavers. We also compared tissue thicknesses overlying different bones, which can impact portable XRF measurements. ResultsThe correlation coefficients found between bones were higher (rho ~0.4) than previous K-shell XRF bone measurements in cortical and trabecular over the same range of values (rho~0.2). The concentrations were shown to vary non-significantly across different bones within individuals.

Assessing zinc from a nail clipping using mono-energetic portable X-ray fluorescence

A mono-energetic X-ray beam from a portable X-ray fluorescence device was used to excite characteristic X-rays from zinc in a series of nail clipping phantoms. Twenty nail clipping phantoms having equal zinc concentrations of ~40 µg/g, but with different physical characteristics, were measured individually for 300 s using a small diameter (~1 mm) X-ray beam. Energy spectra obtained from the measurements were analyzed using PyMca software. Zinc signal size varied widely between the different clippings, with a relative standard deviation of 41% observed in the combined signal from zinc Kα and Kβ characteristic X-rays. Three different normalization approaches were introduced to account for variation in the amounts of sample interrogated by the X-ray beam. All three approaches produced similar results, and successfully reduced the relative standard deviation to between 12% and 13%. A clear trend was still observed, however, between the normalized zinc signal and the thickness of clipping measured. To account for this effect, normalized signals were adjusted to calculate “thickness-corrected” values. The relative standard deviation of these thickness-corrected values was 6.2%. Reproducibility of measurement from individual clippings was excellent, with relative standard deviations on the order of 1%, with or without normalization. Overall, this new method of measuring zinc in nail shows promise for the assessment of zinc status in humans using a portable device. The method is sensitive, rapid, and requires only a single nail clipping.

Feasibility of the use of a handheld XRF analyzer to measure skin iron to monitor iron levels in critical organs

There exists a need for accurate, non-invasive point-of-care tests to detect body iron burden. This study investigated the use of x-ray fluorescence (XRF) measurements of skin iron as a marker for organ iron content in rats. This study also evaluated a novel application of a commercial XRF device, commonly used in mining and construction, as a rapid, portable, and non-invasive measurement tool. Rats (n = 32) were loaded with iron dextran and the iron signal of each animal’s skin, liver, and kidney was measured using a conventional XRF system. A quadratic correlation was observed between liver and skin iron signal (R2 = 0.92) and a linear correlation was observed between kidney and skin iron signal (R2 = 0.65). As such, it is concluded that skin iron content can act as a marker for both liver and kidney iron content. The same skin samples were measured using the portable XRF device and compared to the liver and kidney samples measured in the conventional XRF system. Again, a quadratic correlation was observed between liver and skin iron signal (R2 = 0.91) and a linear correlation was observed between kidney and skin iron signal (R2 = 0.83). Thus, the portable XRF device can provide rapid non-invasive, skin XRF measurements. Dosimetry was performed using the portable XRF device to assess the radiological hazard associated with its use. The average skin equivalent dose from this device is 30 ± 10 mSv/min, when the device is collimated and operated at 40 kV. In conclusion, skin iron XRF measurements can act as a surrogate marker for liver iron content, and can be measured using a commercial XRF device for a portable, fast, and non-invasive measurement.

Characterization of soil contamination by lead around a former battery factory by applying an analytical hybrid method.

Former battery factories have created environmental and health problems for years and the exposure to lead in surface soils has been underestimated. Nonetheless, the identification of lead contamination and its spatial distribution is crucial. The determination of heavy metals in soils can be performed using inductively coupled plasma mass spectrometry (ICP-MS). However, alternative techniques such as X-ray fluorescence (XRF) have been used lately in environmental studies since measurements can be taken in the field in a prompt manner, despite its lower accuracy. In this study, a former battery factory site in Monterrey, Mexico, has been studied in order to detect lead contamination. Soil samples were assessed for contamination by using an analytical hybrid method that comprises both analytical techniques, namely, ICP-MS and XRF. Samples were taken in 215 locations and, after a simple homogenization process, they were analyzed by using a portable XRF device. Within those 215 sampling points, 25 samples were analyzed concurrently by using ICP-MS according to international sampling guidelines. Results obtained were adjusted in order to define an analytical hybrid method, which encompasses the advantages of each technique. An improved characterization was achieved by using the proposed analytical hybrid method since maps of lead distribution and calculated areas of concern showed better predictability. The combination of spectroscopic techniques is of great applicability for environmental agencies and decision makers.

Feasibility of measuring zinc in human nails using portable x-ray fluorescence

A variety of adverse health effects have been identified as resulting from zinc deficiency. Zinc supplementation may therefore be indicated for certain individuals or populations. A rapid and straightforward means of assessing zinc status in humans would be of considerable medical benefit. In this study, the feasibility of measuring zinc levels in human fingernails or toenails using a portable x-ray fluorescence technique was assessed. Whole nail models (or phantoms) were constructed from resin, and dosed with various concentrations of zinc. These different concentration “nails” were cut into small slices of 4.4 ± 0.2 mm width. The combination of these various slices into different arrangements allowed the modeling of different time-dependent zinc exposure scenarios. A portable x-ray fluorescence device was tested using an “open beam” configuration having a beam diameter of ∼9 mm, and using a “weld mask” configuration with the beam width reduced to 2.9 mm. Minimum detection limits were determined to be 0.15 ± 0.01 ppm for the open beam, and 1.13 ± 0.08 ppm when using the weld mask. By scanning across the length of the model nails, it was demonstrated that differences in zinc levels deposited over time could be detected, and that the weld mask configuration was better suited to resolving spatial changes. The x-ray fluorescence approach was found to be highly sensitive for detecting zinc in nail, and capable of differentiating patterns of zinc uptake over time.

Multivariate Mapping of Heavy Metals Spatial Contamination in a Cu–Ni Exploration Field (Botswana) Using Turning Bands Co-simulation Algorithm

With a mining-driven economy, Botswana has experienced increased geochemical exploration of minerals around existing mining towns. The mining and smelting of copper and nickel around Selibe-Phikwe in the Central Province are capable of releasing heavy metals including Pb, Fe, Mn, Co, Ni and Cu into the soil environments, thereby exposing humans, plants and animals to health risks. In this study, turning bands co-simulation, a multivariate geostatistical algorithm, was presented as a tool for spatial uncertainty quantification and probability mapping of cross-correlated heavy metals (Co, Mn, Fe and Pb) risk assessment in a semiarid Cu–Ni exploration field of Botswana. A total of 1050 soil samples were collected across the field at a depth of ~ 10 cm in a grid sampling design. Rapid elemental concentration analysis was done using an Olympus Delta Sigma portable X-ray fluorescence device. Enrichment factor, geoaccumulation index and pollution load index were used to assess the potential risk of heavy metals contamination in soils. The partially heterotopic nature of the dataset and strong correlations among the heavy metals favors the use of co-simulation instead of independent simulation in the probability mapping of heavy metal risks in the study area. The strong correlation of Co and Mn to iron infers they are of lithogenic origin, unlike Pb which had weak correlation pointing to its source in the area being of anthropogenic source. Manganese, Co and Fe show low enrichment, whereas Pb had high enrichment suggesting possible lead pollution. We, however, recommend that speciation of Pb in the soils rather than total concentration should be ascertained to infer chances of possible bioaccumulation, and subsequent health risk to human by chronic exposure.

Feasibility of a portable X-ray fluorescence device for bone lead measurements of condor bones

Lead based ammunition is a primary source of lead exposure, especially for scavenging wildlife. Lead poisoning remains the leading cause of diagnosed death for the critically endangered California condors, which are annually monitored via blood tests for lead exposure. The results of these tests are helpful in determining recent exposure in condors and in defining the potential for exposure to other species including humans. Since condors are victim to acute and chronic lead exposure, being able to measure both would lend valuable information on the rates of exposure and accumulation through time. A commercial portable X-ray fluorescence (XRF) device has been optimized to measure bone lead in vivo in humans, but this device could also be valuable for field measurements of bone lead in avian species. In this study, we performed measurements of bone Pb in excised, bare condor bones using inductively coupled plasma mass spectrometry (ICP-MS), a cadmium 109 (Cd-109) K-shell X-ray fluorescence (KXRF) system, and a portable XRF system. Both KXRF and portable XRF bone Pb measurement techniques demonstrated good correlations with ICP-MS results (r=0.93 and r=0.92 respectively), even with increasing skin thickness (r=0.86 between ICP-MS and portable XRF at 1.54mm of soft tissue). In conclusion, our results suggest that a portable XRF could be a useful option for measurement of bone Pb in avian species in the field.

Detection of lead in bone phantoms and arsenic in soft tissue phantoms using synchrotron radiation and a portable x-ray fluorescence system

The differences and commonalities between x-ray fluorescence results obtained using synchrotron radiation and a portable x-ray fluorescence device were examined using arsenic in soft tissue phantoms and lead in bone phantoms. A monochromatic beam energy of 15.8 keV was used with the synchrotron, while the portable device employed a rhodium anode x-ray tube operated at 40 kV. Bone phantoms, dosed with varying quantities of lead, were made of Plaster of Paris and placed underneath skin phantoms of either 3.1 mm or 3.9 mm thickness. These skin phantoms were constructed from polyester resin, and dosed with varying amounts of arsenic. Using an irradiation time of 120 s, arsenic Kα and Kβ, and lead Lα and Lβ characteristic x-ray peaks were analysed. This information was used to calculate calibration line slopes and minimum detection limits for each data set. As expected, minimum detection limits were much lower at the synchrotron for detecting arsenic and lead. Both approaches produced lower detection limits for arsenic in soft tissue than for lead in bone when simultaneous detection was attempted. Although arsenic Kα and lead Lα emissions share similar energies, it was possible to detect both elements in isolation by using the arsenic Kβ and lead Lβ characteristic x-rays. Greater thickness of soft tissue phantom reduced the ability to detect the underlying lead. Experiments with synchrotron radiation could help guide future efforts toward optimizing a portable x-ray fluorescence in vivo measurement device.

Methodology using a portable X-ray fluorescence device for on-site and rapid evaluation of heavy-atom contamination in wounds: a model study for application to plutonium contamination.

Workers decommissioning the Fukushima-Daiichi nuclear power plant damaged from the Great East Japan Earthquake and resulting tsunami are at risk of injury with possible contamination from radioactive heavy atoms including actinides, such as plutonium. We propose a new methodology for on-site and rapid evaluation of heavy-atom contamination in wounds using a portable X-ray fluorescence (XRF) device. In the present study, stable lead was used as the model contaminant substitute for radioactive heavy atoms. First, the wound model was developed by placing a liquid blood phantom on an epoxy resin wound phantom contaminated with lead. Next, the correlation between the concentration of contaminant and the XRF peak intensity was formulated considering the thickness of blood exiting the wound. Methods to determine the minimum detection limit (MDL) of contaminants at any maximal equivalent dose to the wound by XRF measurement were also established. For example, in this system, at a maximal equivalent dose of 16.5 mSv to the wound and blood thickness of 0.5 mm, the MDL value for lead was 1.2 ppm (3.1 nmol). The radioactivity of 239Pu corresponding to 3.1 nmol is 1.7 kBq, which is lower than the radioactivity of 239Pu contaminating puncture wounds in previous severe accidents. In conclusion, the established methodology could be beneficial for future development of a method to evaluate plutonium contamination in wounds. Highlights: Methodology for evaluation of heavy-atom contamination in a wound was established. A portable X-ray fluorescence device enables on-site, rapid and direct evaluation. This method is expected to be used for evaluation of plutonium contamination in wounds.

Comparison of the detection limits in the analysis of some medium atomic number elements measured with a portable XRF and an external proton beam PIXE spectrometer system

AbstractA portable X‐ray fluorescence (XRF) spectrometer system was constructed using an Amptek Mini‐X X‐ray tube and an X‐123 compact spectrometer. The spectrometer is optimised for the best limits of detection. Its analytic properties are tested and compared with an analogous laboratory‐based instrument, an external beam proton‐induced X‐ray emission spectrometry (PIXE) setup. Depending on elements in question the thick target detection limits of this portable XRF device are comparable or even lower than the PIXE setup. Copyright © 2011 John Wiley &amp; Sons, Ltd.

In vivo quantification of lead in bone with a portable x-ray fluorescence system—methodology and feasibility

This study was conducted to investigate the methodology and feasibility of developing a portable x-ray fluorescence (XRF) technology to quantify lead (Pb) in bone in vivo. A portable XRF device was set up and optimal settings of voltage, current, and filter combination for bone lead quantification were selected to achieve the lowest detection limit. The minimum radiation dose delivered to the subject was calculated by Monte Carlo simulations. An ultrasound device was used to measure soft tissue thickness to account for signal attenuation, and an alternative method to obtain soft tissue thickness from the XRF spectrum was developed and shown to be equivalent to the ultrasound measurements (intraclass correlation coefficient, ICC = 0.82). We tested the correlation of in vivo bone lead concentrations between the standard KXRF technology and the portable XRF technology. There was a significant correlation between the bone lead concentrations obtained from the standard KXRF technology and those obtained from the portable XRF technology (ICC = 0.65). The detection limit for the portable XRF device was about 8.4 ppm with 2 mm soft tissue thickness. The entrance skin dose delivered to the human subject was about 13 mSv and the total body effective dose was about 1.5 µSv and should pose minimal radiation risk. In conclusion, portable XRF technology can be used for in vivo bone lead measurement with sensitivity comparable to the KXRF technology and good correlation with KXRF measurements.