A groundbreaking material quietly reshaping how we see our insides—and the universe beyond it.
Hospitals, space telescopes, and security checkpoints are all benefiting from a remarkable compound few people know by name: cadmium zinc telluride, or CZT. At Royal Brompton Hospital in London, patients used to endure lengthy, uncomfortable lung scans that required lying still for 45 minutes with arms raised. After adopting a CZT-based scanner last year, those examinations now take about 15 minutes, thanks to sharper, three‑dimensional images that CZT helps produce. As Dr. Kshama Wechalekar, head of nuclear medicine and PET, puts it, the new system yields “beautiful pictures” and marks an impressive point of engineering and physics in action.
The CZT detector was developed by Kromek, a British company that remains among a small group of firms capable of producing this specialized material. According to Dr. Wechalekar, CZT is driving a major transformation in medical imaging, enabling more precise pictures while potentially reducing patient exposure. Beyond hospitals, CZT finds uses in X-ray telescopes, radiation detectors, and even certain airport security scanners, where its sensitivity can be a game changer.
In clinical practice, teams led by Dr. Wechalekar examine patients for tiny clots in the lungs—such as those seen in long Covid or a pulmonary embolism. The new scanner operates by detecting gamma rays emitted when a radioactive tracer is injected into the patient. Its heightened sensitivity means clinicians can lower the dose of that tracer by about 30%, lowering risk without compromising image quality. While CZT detectors have existed for years, their deployment in large, whole‑body scanners represents a relatively new frontier.
CZT’s production has historically been challenging. Arnab Basu, Kromek’s founding CEO, notes that scaling up manufacturing has required time and expertise. In Kromek’s Sedgefield facility, hundreds of small furnaces heat a powder into a molten state, which then solidifies into a single crystal. Over weeks, atoms reorganize to align perfectly, producing a pure CZT semiconductor capable of detecting tiny photons from X‑rays and gamma rays with exceptional precision. This one-step digital conversion preserves crucial information—timing and energy of each photon—allowing colorful, spectroscopic imaging.
Today, CZT isn’t only used in medicine. It’s already employed in security contexts, such as explosives detection at airports and advanced luggage scanners in the United States. Kromek envisions CZT expanding into hand luggage screening in the coming years.
Yet supply isn’t always smooth. Researchers such as Henric Krawczynski of Washington University in St. Louis have sought extremely thin CZT detectors (about 0.8 mm) for space‑based X‑ray telescopes, where minimizing background radiation is essential for a clear signal. The demand is high, and sourcing the exact detector specifications from a single supplier can be difficult. As Basu explains, every research project often requires a tailored detector design, and meeting a hundred different specifications simultaneously is a tall order.
For Krawczynski, no single source is a crisis; he can repurpose CZT from prior projects or switch to cadmium telluride when needed for future missions. Meanwhile, researchers relying on CZT are pushing forward ambitious upgrades across science facilities. In the United Kingdom, the Diamond Light Source—an iconic synchrotron—has announced a half‑billion‑pound upgrade driven by CZT detectors. In this facility, electrons race around a giant ring at nearly light speed, and when magnets slow them, X‑rays emerge to analyze materials, from metals to composites. A key goal of the upgrade, expected to complete in 2030, is to produce much brighter X‑rays, which existing detectors might miss without CZT’s enhanced sensitivity.
Matt Veale, who leads detector development at the Science and Technology Facilities Council, emphasizes that upgrading detection capabilities is essential to capitalize on the brighter X‑ray output. CZT is the natural fit for this next era of high‑fidelity imaging.
In short, CZT’s influence is broad and deep—from faster, safer medical scans that can catch serious conditions sooner, to sharper signals in space and security. Its unique ability to convert high‑energy photons into precise, information‑rich images is pushing multiple industries to rethink what’s possible—and raising new questions about access, cost, and the direction of future technological breakthroughs.
What do you think: should CZT’s high performance make it a standard in more hospitals and research facilities, or are there trade‑offs and risks we should examine more closely? Share your thoughts in the comments.
