Breath markers for therapeutic radiation

Area of Science:

• Biochemistry
• Analytical Chemistry
• Oncology

Background:

• Radiotherapy effectiveness and toxicity depend on precise radiation dosing.
• Personalized radiotherapy requires biochemical monitoring of treatment effects.
• Exhaled breath volatile organic compounds (VOCs) offer a non-invasive window into physiological changes.

Purpose of the Study:

• To evaluate changes in exhaled breath VOCs following radiotherapy.
• To assess the feasibility of using gas chromatography-ion mobility spectrometry for point-of-care breath analysis in radiotherapy.
• To identify potential breath biomarkers for personalizing radiotherapy and monitoring radiation exposure.

Main Methods:

• Collected 240 breath samples from 62 participants before and after radiotherapy.
• Analyzed samples using thermal desorption/gas chromatography/quadrupole mass spectrometry.
• Employed multivariate statistical analysis to identify candidate VOC markers.
• Evaluated gas chromatography-ion mobility spectrometry for rapid breath analysis.

Main Results:

• A panel of sulfur-containing VOCs (thio-VOCs) increased post-irradiation, including 3-methylthiophene and 2-thiophenecarbaldehyde.
• Concentration of the tumor metabolite 2,4-dimethyl-1-heptene decreased by 73%.
• Statistical scoring based on thio-VOCs and 3-methylthiophene correlated with individual radiation response.
• Gas chromatography-ion mobility spectrometry showed potential for point-of-care detection of 3-methylthiophene.

Conclusions:

• Exhaled thio-VOCs are promising biomarkers for monitoring radiotherapy response and radio-sensitivity.
• Breath analysis offers a non-invasive method for personalizing radiotherapy.
• Further research with continuous monitoring is needed to optimize breath biomarker detection timing.
• Gas chromatography-ion mobility spectrometry holds potential for point-of-care radiotherapy monitoring.