Superior spatial resolution in confocal X-ray techniques using collimating channel array optics: elemental mapping and speciation in archaeological human bone

Choudhury, Sanjukta; Agyeman-Budu, David N.; Woll, Arthur R.; Swanston, Treena; Varney, Tamara L.; Cooper, David M.L.; Hallin, E.; George, Graham N.; Pickering, Ingrid J.; Coulthard, I.

doi:10.1039/c6ja00297h

Cited by 26 publications

(13 citation statements)

References 32 publications

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“… Note: Antigua B19a has been previously published in Choudhury et al 2017 [ 34 ]. The intense Pb signal on the right side of B19a (a) may represent contamination as it does not reflect microstructural patterns.…”

Section: Resultsmentioning

confidence: 99%

“…Individuals not specified. b Keenleyside et al (1997) values from ICP-MS (ppm) [ 8 ] c Confocal XFI image data originally included in Choudhury et al (2017) [ 34 ] d Giffin et al (2017) values from ICP-MS (ppm) [ 24 ] …”

Section: Methodsmentioning

confidence: 99%

“…Prior to this study, bulk element concentrations were determined for a subset of the samples using ICP-MS at McMaster University Department of Geology [ 8 ]. The RNHC 19a sample included here has been scanned by conventional XFI [ 29 ] and confocal XFI [ 34 ] with the latter study providing the image data used here.…”

Section: Methodsmentioning

confidence: 99%

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Franklin expedition lead exposure: New insights from high resolution confocal x-ray fluorescence imaging of skeletal microstructure

et al. 2018

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In the summer of 1845, under the command of Sir John Franklin, 128 officers and men aboard Royal Navy ships HMS Erebus and HMS Terror sailed into Lancaster Sound and entered the waters of Arctic North America. The goal of this expedition was to complete the discovery of a northwest passage by navigating the uncharted area between Barrow Strait and Simpson Strait. Franklin and his crew spent the first winter at Beechey Island, where three crewmen died and were buried. In September 1846, the ships became stranded in ice off the northwest coast of King William Island, where they remained until April 1848. At that time, the crew, reduced to 105, deserted the ships and retreated south along the island’s western and southern shores in a desperate attempt to reach the mainland and via the Back River, to obtain aid at a Hudson’s Bay Company Post. Sadly, not one individual survived. Previous analyses of bone, hair, and soft tissue samples from expedition remains found that crewmembers’ tissues contained elevated lead (Pb) levels, suggesting that Pb poisoning may have contributed to their demise; however, questions remain regarding the timing and degree of exposure and, ultimately, the extent to which the crewmembers may have been impacted. To address this historical question, we investigated three hypotheses. First, if elevated Pb exposure was experienced by the crew during the expedition, we hypothesized that those sailors who survived longer (King William Island vs. Beechey Island) would exhibit more extensive uptake of Pb in their bones and vice versa. Second, we hypothesized that Pb would be elevated in bone microstructural features forming at or near the time of death compared with older tissue. Finally, if Pb exposure played a significant role in the failure of the expedition we hypothesized that bone samples would exhibit evidence of higher and more sustained uptake of Pb than that of a contemporary comparator naval population from the 19th century. To test these hypotheses, we analyzed bone and dental remains of crew members and compared them against samples derived from the Royal Navy cemetery in Antigua. Synchrotron-based high resolution confocal X-ray fluorescence imaging was employed to visualize Pb distribution within bone and tooth microstructures at the micro scale. The data did not support our first hypothesis as Pb distribution within the samples from the two different sites was similar. Evidence of Pb within skeletal microstructural features formed near the time of death lent support to our second hypothesis but consistent evidence of a marked elevation in Pb levels was lacking. Finally, the comparative analysis with the Antigua samples did not support the hypothesis that the Franklin sailors were exposed to an unusually high level of Pb for the time period. Taken all together our skeletal microstructural results do not support the conclusion that Pb played a pivotal role in the loss of Franklin and his crew.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Franklin expedition lead exposure: New insights from high resolution confocal x-ray fluorescence imaging of skeletal microstructure

et al. 2018

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“…An alternative option in background reduction is the use of a confocal XRF method. In this approach, a secondary PXL ( Malzer and Kanngießer 2005 ) or collimating channel array (CCA) ( Choudhury et al 2017 ) would guide the x-ray photons emergent from a small targeted volume to the x-ray detector. The limited photon pathways allowed by the secondary PXL would effectively enhance the signal-to-background ratio in the x-ray spectrum even when PXL transmission is taken into account.…”

Section: Discussionmentioning

confidence: 99%

A microbeam grazing-incidence approach to L-shell x-ray fluorescence measurements of lead concentration in bone and soft tissue phantoms

Gherase

Al-Hamdani²

2018

Physiol. Meas.

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ObjectiveL-shell x-ray fluorescence (LXRF) is a non-invasive approach to lead (Pb) concentration measurements in the human bone. The first studies were published in the early 1980s. In the same period the K-shell x-ray fluorescence (KXRF) method using a Cd-109 radionuclide source was developed and later improved and refined. Lower sensitivity and calibration difficulties associated with the LXRF method led the KXRF to be the most adopted method for in vivo human bone Pb studies. In the present study a microbeam-based grazing-incidence approach to Pb LXRF measurements was investigated.ApproachThe microbeam produced by an integrated x-ray tube and polycapillary x-ray lens (PXL) unit was used to excite cylindrical plaster-of-Paris (poP) bone phantoms doped with Pb in seven concentrations: 0, 8, 16, 29, 44, 59, and 74 µg g−1. Two 1 mm- and 3 mm-thick cylindrical shell soft tissue phantoms were made out of polyoxymethylene (POM) plastic. Three bone-soft tissue phantom sets corresponding to the 0, 1, and 3 mm POM thickness values resulted. Each phantom was placed between the microbeam and the detector; its position was controlled using a positioning stage. Small steps (0.1–0.5 mm) and short 30 s x-ray spectra acquisitions were used to find the optimal phantom position according to the maximum observed Sr Kα peak height. At the optimal geometry, five 180 s x-ray spectra were acquired for each phantom set. Calibration lines were obtained using the fitted peak heights of the two observed Pb Lα and Pb Lβ peaks.Main resultsThe lowest detection limit (DL) values were (2.9 ± 0.2), (4.9 ± 0.3), and (23 ± 3) µg g−1, respectively. The order of magnitude of the absorbed radiation dose in the POM plastic for the 180 s irradiation was estimated to be <1 mGy.SignificanceThe results are superior to a relatively recently published LXRF phantom study and show promise for future designs of in vivo LXRF measurements.

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“…Additionally, it would be expected that biogenic and diagenetic TE distributions would vary due to their different mechanisms of uptake. Element mapping of bone and tooth samples can be achieved through techniques such as synchrotron radiation X-ray fluorescence imaging (SR-XFI; Carvalho et al 2004 ; Martin et al 2004 , 2007a , b ; Wittmers et al 2008 ; Swanston et al 2012 , 2015 , 2018 ; Dolphin et al 2013 ; Choudhury et al 2016 , 2017 ), LA-(MC-)ICP-MS (Humphrey et al 2008 ; Galinová et al 2013 ; Dudgeon et al 2016 ; Willmes et al 2016 ; Maurer et al 2019 ; Rasmussen et al 2019 ), or proton-induced X-ray emission (PIXE; Coote et al 1982 ; Buoso et al 1992 ; Elliott and Grime 1993 ).…”

Section: Resurgence Of Trace Element Analysis? Techniques With Growinmentioning

confidence: 99%

Historical overview and new directions in bioarchaeological trace element analysis: a review

Simpson

Cooper

Swanston

et al. 2021

Archaeol Anthropol Sci

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Given their strong affinity for the skeleton, trace elements are often stored in bones and teeth long term. Diet, geography, health, disease, social status, activity, and occupation are some factors which may cause differential exposure to, and uptake of, trace elements, theoretically introducing variability in their concentrations and/or ratios in the skeleton. Trace element analysis of bioarchaeological remains has the potential, therefore, to provide rich insights into past human lifeways. This review provides a historical overview of bioarchaeological trace element analysis and comments on the current state of the discipline by highlighting approaches with growing momentum. Popularity for the discipline surged following preliminary studies in the 1960s to 1970s that demonstrated the utility of strontium (Sr) as a dietary indicator. During the 1980s, Sr/Ca ratio and multi-element studies were commonplace in bioarchaeology, linking trace elements with dietary phenomena. Interest in using trace elements for bioarchaeological inferences waned following a period of critiques in the late 1980s to 1990s that argued the discipline failed to account for diagenesis, simplified complex element uptake and regulation processes, and used several unsuitable elements for palaeodietary reconstruction (e.g. those under homeostatic regulation, those without a strong affinity for the skeleton). In the twenty-first century, trace element analyses have been primarily restricted to Sr and lead (Pb) isotope analysis and the study of toxic trace elements, though small pockets of bioarchaeology have continued to analyse multiple elements. Techniques such as micro-sampling, element mapping, and non-traditional stable isotope analysis have provided novel insights which hold the promise of helping to overcome limitations faced by the discipline.

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Superior spatial resolution in confocal X-ray techniques using collimating channel array optics: elemental mapping and speciation in archaeological human bone

Abstract: A novel X-ray collimating optic enables improved spatial resolution in confocal X-ray fluorescence imaging and X-ray absorption spectroscopy.

Cited by 26 publications

References 32 publications

Franklin expedition lead exposure: New insights from high resolution confocal x-ray fluorescence imaging of skeletal microstructure

Franklin expedition lead exposure: New insights from high resolution confocal x-ray fluorescence imaging of skeletal microstructure

A microbeam grazing-incidence approach to L-shell x-ray fluorescence measurements of lead concentration in bone and soft tissue phantoms

Historical overview and new directions in bioarchaeological trace element analysis: a review

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