X-Ray Fluorescence Imaging of Nanoparticle Systems

X-ray fluorescence imaging integrates the elemental specificity of X-ray fluorescence with spatially resolved detection, enabling quantitative mapping of metal-labelled nanoparticles within diverse matrices. When irradiated, high-atomic-number elements within nanoparticles emit characteristic fluorescent X-rays that are detected and reconstructed to yield three-dimensional distributions. Recent advances encompass benchtop systems that replace synchrotron sources with polychromatic tubes, novel collimation schemes to enhance sensitivity, and computational algorithms to mitigate spectral background arising chiefly from multiple Compton scattering. Applications range from in vivo molecular imaging in small animals and immune cell tracking to environmental analyses and plant sciences. The technique offers sub-millimetre spatial resolution, element-specific quantification and deep penetration, bridging the gap between morphological imaging modalities and molecular contrast techniques.

Research from Nature Portfolio

Advanced in vivo tracking of immune cells has been achieved by optimising monochromatic pencil-beam excitation on a synchrotron source. By modelling and subtracting the multiple-scattering background in mouse-scaled objects, researchers attained sufficient sensitivity to monitor labelled immune cell accumulation at sites of inflammation, demonstrating quantitative cell tracking beyond the capabilities of conventional modalities. A complementary study employed synchrotron-based imaging to probe endogenous iodine distribution in murine thyroids under in vivo conditions. Through spectral optimisation and background-reduction protocols, minimal detectable concentrations were lowered, enabling non-invasive mapping of physiological element distributions. These efforts highlight the maturation of synchrotron X-ray fluorescence imaging for preclinical applications and set benchmarks for sensitivity and spatial resolution in live-animal studies.

X-Ray Fluorescence Imaging of Nanoparticle Systems publication trend

The graph below shows the total number of articles in x-ray fluorescence imaging of nanoparticle systems across all publications each year (not limited to Nature Index journals).

Technical terms

X-ray fluorescence computed tomography (XFCT): A three-dimensional imaging modality that reconstructs elemental distributions by detecting characteristic X-ray emission following excitation.

Compton scattering: An inelastic scattering process where incident X-rays lose energy upon interacting with matter, contributing to background noise in spectra.

Photon-counting detector: A detector that individually counts X-ray photons and discriminates their energies, improving spectral resolution and sensitivity.

Compound-eye collimator: An array of multiple pinholes that directs emitted fluorescence to detectors, enhancing sensitivity and spatial coverage.

Synchrotron radiation: High-brightness, tunable X-ray beams generated in a synchrotron facility, used for monochromatic excitation in high-sensitivity applications.

References

1. A High-Sensitivity Benchtop X-Ray Fluorescence Emission Tomography (XFET) System With a Full-Ring of X-Ray Imaging-Spectrometers and a Compound-Eye Collimation Aperture. IEEE Transactions on Medical Imaging (2024).
2. Relevance of using portable X-ray fluorescence to identify gold hyperaccumulator plants. Environmental Advances (2024).
3. Review of Development and Recent Advances in Biomedical X-ray Fluorescence Imaging. International Journal of Molecular Sciences (2023).
4. Enabling X-ray fluorescence imaging for in vivo immune cell tracking. Scientific Reports (2023).
5. In-situ x-ray fluorescence imaging of the endogenous iodine distribution in murine thyroids. Scientific Reports (2022).