A team of researchers, jointly led by the Universities of Oxford and Cambridge, have discovered that a solar cell material—bismuth oxyiodide (BiOI)—is capable of detecting X-ray dose rates over 250 times lower than the current best performing detectors used commercially. This has the potential to make medical imaging safer, and open up new opportunities in non-invasive diagnostics, such as X-ray video techniques. Their results are reported in the journal Nature Communications.