X-rays are the second-most energetic form of electromagnetic radiation known to science, falling between the very energetic gamma rays and the less-so ultraviolet radiation. And while this particular form of radiation isn’t necessarily rare in the cosmos, there’s a far more reasonable instance of X-rays that we might have seen at least once or twice in our lives: X-ray as part of radiography.
Radiography in medicine actually uses more than just X-rays; it uses either ionizing or non-ionizing radiation in order to achieve the imaging results desired by medical experts. Ionizing radiation in this case refers to the capability of a specific form of radiation to eject an electron from atoms that it hits, “ionizing” the atoms in the process.
X-ray radiography, in this case, usually works by placing some material that’s sensitive to X-rays behind the subject in question, like a patient. X-rays pass through material like your skin and organs just fine; bones, however, absorb them. As a result, the patient’s bones appear on X-ray imaging.
Similar radiography methods work in a similar way, and have been in use since the discoverers of X-rays, German physics professor Wilhelm Conrad Röntgen, found out that it can pass through most of your body but not bone back in 1895. Ever since, technologies have been constantly upgrading and changing, adding in newer features and possibilities that are available to people of that time, like computer processing. One example of such progression is technology called X-ray ptychography, which was recently used in our first-ever determination of the mass of human chromosomes.
2021 poses to end with one such form of progression in radiographic technology, as researchers from the European Synchrotron Research Facility (ESRF) just added a new entry into their scientific arsenal with the addition of the Extremely Brilliant Source (EBS) upgrade. The new implementation turns the ESRF into the world’s “first fourth-generation synchrotron,” as well as the world’s now-brightest source of X-rays—and as it should, apparently, as the X-rays produced by the ESRF-EBS are about 100 billion times brighter than X-rays found in conventional hospitals.
The ESRF-EBS facility’s new technology was used in a recent collaboration with the University College London, and is called Hierarchical Phase Contrast Tomography (HiP-CT; and yes, that’s the same “CT” in CT scanning). They used this new technology to scan a donated lung from a patient who suffered from COVID-19; their novel findings were published in the journal Nature Methods.
The scale of operation enabled by the new EBS implementation allowed researchers to view blood vessels, a mere five (5) microns wide, in the lung of a COVID-19 patient. The findings allowed the team to identify how COVID-19 “crosslinked” capillaries used for two instances: those for oxygenating blood, and those for feeding lung tissue. In doing so, the disease stymied blood oxygenation—a prospect that was “previously hypothesised but not proven,” according to a press release from the University College London to news source EurekAlert!.
“The ability to see organs across scales like this will really be revolutionary for medical imaging. As we start to link our HiP-CT images to clinical images through AI techniques, we will—for the first time—be able to highly accurately validate ambiguous findings in clinical images,” according to UCL Mechanical Engineering and primary author Dr. Claire Walsh.
According to Hannover Medical School Professor of Thoracic Pathology and fellow primary author Danny Jonigk: “By combining our molecular methods with the HiP-CT multiscale imaging in lungs affected by COVID-19 pneumonia, we gained a new understanding how shunting between blood vessels in a lung’s two vascular systems occurs in COVID-19 injured lungs, and the impact it has on oxygen levels in our circulatory system.”
In using the HiP-CT technology, the collaborators hope to establish a fully-detailed “Human Organ Atlas,” a resource that will be made available online for medical professionals and the public. The project entails detailed imaging of six particular control organs that were donated to the concerted effort, the very first of which being the lung of a COVID-19 patient from earlier. Future inclusions to the atlas include a brain, a lung, a heart, a pair of kidneys, and a spleen. The HiP-CT team hopes to provide both a detailed control lung biopsy and a biopsy from the COVID-19-infected lung.
Alongside these accomplishments, the new technology made possible by HiP-CT will enable more detailed insights into diseases like Alzheimer’s disease and cancers, according to the UCL press release. The authors also hope to complete the Human Organ Atlas, with it containing detailed insights into diseases and the organs that they affect. In doing so, they hope to be able to aid future researchers in diagnosing and treating these diseases.
Finally, Dr. Walsh noted in a statement: “being able to see tiny organ structures in 3D in their correct spatial context is key to understanding how our bodies are structured and how they therefore function.”
References
- Haridy, R. (2021, November 5). World’s brightest X-rays usher in medical imaging revolution. New Atlas. https://newatlas.com/medical/hipct-xray-imaging-human-organ-project/
- How do x-rays work? (2017, January 20). Independent Imaging. https://www.independentimaging.com/x-rays-work/
- University College London. (2021, November 4). Brightest ever X-ray shows lung vessels altered by COVID-19. EurekAlert! https://www.eurekalert.org/news-releases/933801
- Walsh, C. L., Tafforeau, P., Wagner, W. L., Jafree, D. J., Bellier, A., Werlein, C., Kühnel, M. P., Boller, E., Walker-Samuel, S., Robertus, J. L., Long, D. A., Jacob, J., Marussi, S., Brown, E., Holroyd, N., Jonigk, D. D., Ackermann, M., & Lee, P. D. (2021). Imaging intact human organs with local resolution of cellular structures using hierarchical phase-contrast tomography. Nature Methods, 1–10. https://doi.org/10.1038/s41592-021-01317-x
