Salman_2021_J._Breath_Res._15_016004.pdf (1.65 MB)
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Breath markers for therapeutic radiation

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journal contribution
posted on 28.01.2021, 08:39 authored by Dahlia Salman, Michael Eddleston, Kareen Darnley, William H Nailon, Duncan B McLaren, Andria Hadjithekli, Dorota Ruszkiewicz, Jens Langejuergen, Yaser Alkhalifa, Iain PhillipsIain Phillips, Paul Thomas
Radiation dose is important in radiotherapy. Too little, and the treatment is not effective, too much causes radiation toxicity. A biochemical measurement of the effect of radiotherapy would be useful in personalisation of this treatment. This study evaluated changes in exhaled breath volatile organic compounds (VOC) associated with radiotherapy with thermal desorption gas chromatography mass-spectrometry followed by data processing and multivariate statistical analysis. Further the feasibility of adopting gas chromatography ion mobility spectrometry for radiotherapy point-of-care breath was assessed. A total of 62 participants provided 240 end-tidal 1 dm3 breath samples before radiotherapy and at 1, 3, and 6 h post-exposure, that were analysed by thermal-desorption/gas-chromatography/quadrupole mass-spectrometry. Data were registered by retention-index and mass-spectra before multivariate statistical analyses identified candidate markers.

A panel of sulfur containing compounds (thio-VOC) were observed to increase in concentration over the 6 h following irradiation. 3-methylthiophene (80 ng.m−3 to 790 ng.m−3) had the lowest abundance while 2-thiophenecarbaldehyde(380 ng.m−3 to 3.85 μg.m−3) the highest; note, exhaled 2-thiophenecarbaldehyde has not been observed previously. The putative tumour metabolite 2,4-dimethyl-1-heptene concentration reduced by an average of 73% over the same time. Statistical scoring based on the signal intensities thio-VOC and 3-methylthiophene appears to reflect individuals' responses to radiation exposure from radiotherapy. The thio-VOC are hypothesised to derive from glutathione and Maillard-based reactions and these are of interest as they are associated with radio-sensitivity. Further studies with continuous monitoring are needed to define the development of the breath biochemistry response to irradiation and to determine the optimum time to monitor breath for radiotherapy markers. Consequently, a single 0.5 cm3 breath-sample gas chromatography-ion mobility approach was evaluated. The calibrated limit of detection for 3-methylthiophene was 10 μg.m−3 with a lower limit of the detector's response estimated to be 210 fg.s−1; the potential for a point-of-care radiation exposure study exists.

Funding

European Union funding for the TOXI-triage project (H2020 funded project 653409)

History

School

  • Science

Department

  • Chemistry
  • Computer Science

Published in

Journal of Breath Research

Volume

15

Issue

1

Publisher

IOP Publishing

Version

VoR (Version of Record)

Rights holder

© IOP Publishing

Publisher statement

This is an Open Access Article. It is published by IOP Publishing under the Creative Commons Attribution 4.0 International Licence (CC BY 4.0). Full details of this licence are available at: https://creativecommons.org/licenses/by/4.0/

Acceptance date

21/07/2020

Publication date

2020-10-20

Copyright date

2020

ISSN

1752-7155

eISSN

1752-7163

Language

en

Depositor

Prof Paul Thomas. Deposit date: 27 January 2021

Article number

016004