NovaRay has designed a high-efficiency detector that produces higher-quality images for a given radiation level. Conventional real-time x-ray detectors used in cardiac catheterization systems use a thin layer of scintillator crystals to convert x-ray radiation to light. To minimize image blur, the scintillator layer must be kept thin, so that it typically absorbs only 65% of the incident x-ray photons, with the balance passing through undetected. Light intensity from the scintillator layer is measured using analog light sensors in an amorphous-silicon flat-panel array and analog-to-digital converters.

NovaRay’s detector uses a semiconductor crystal to convert the energy of each incident x-ray photon directly to electrical charge. Since there is negligible charge spreading in the crystal, it can be made thick enough to absorb more than 95% of the incident x-ray photons. This is approximately 50% more efficient than a conventional detector. Each incident x-ray photon produces a discrete packet of electrical charge that is detected by a simple circuit. The x-ray intensity is measured by simply counting photons and requires no analog-to-digital converter.