Conventional X-ray imaging only measures how much a sample absorbs. X rays are also waves: they are refracted and scattered, and these signals reveal what absorption cannot see. This is what we exploit.
Three signals, three sensitivities
| Signal | What it senses |
|---|---|
| Absorption | Hard tissue |
| Refraction (phase contrast) | Soft tissue |
| Scattering (dark-field) | Structures much smaller than the pixel, down to about one hundredth of its size |
Together they give multiscale 3D images of complete, unlabelled biological samples, from the whole organ down to a single cell and its environment.
Applications across scales
- Virtual histology, a 3D, non-destructive alternative to slicing and staining, for brain (including Alzheimer’s disease), osteoarticular tissue, liver and human embryonic and fetal organs.
- Joint disease. In mouse models of osteoarthritis, phase-contrast micro-CT shows cartilage and bone structure that MRI and conventional micro-CT miss. At clinically compatible scale, we studied the benefit of the technique for diagnosing osteoarthritis on human wrists, using synchrotron X rays at high energy.
- Lung function. With 4D synchrotron micro-tomography we map lung tissue deformation in vivo with microscopic resolution, and made the first observation of terminal bronchi closing during mechanical ventilation.
- Contrast agents. Spectral and dark-field imaging to track nanoparticle-labelled cells with small amounts of high-atomic-number or lower-atomic-number elements.
From the synchrotron to the clinic
The synchrotron remains the gold standard. Our goal is to bring its image quality to conventional sources, then to patients.
- Synchrotron. Where the methods are first demonstrated.
- Laboratory. The MUSITOX platform , the world’s first wave-based imaging platform using conventional X-ray sources. We simplified dark-field imaging down to a single, easy-to-make membrane that modulates the beam, with random or designed patterns.
- Clinic. Phase-contrast and dark-field CT for oral healthcare, developed in the ANR ROOTS project and by the spin-off project arXimed, supported by the SATT Linksium.
Oral healthcare
Compared with conventional cone-beam CT, phase-contrast CT of a jaw specimen shows teeth, gingiva, neurovascular bundles and even skin layers that conventional CT blurs. The arXimed project won the Grand Prix of the i-PhD innovation contest.What comes next
- Molecular contrast agents that produce X-ray scattering, to image vascularisation.
- Skin characterisation.
- Detection of boron in depth, in support of neutron capture therapy.