Enabling photon counting clinical X-ray CT

Photon counting x-ray detectors (PCXDs) with energy discrimination capabilities offer various advantages over the current intensity integrating detectors, such as improved accuracy in material decomposition, reduced image noise, reduced radiation dose, etc. The major problem of PCXDs, however, is the limited speed. The required count rate for clinical x-ray CT scanners may be 10⁹ counts-per-second-per-square-millimeters (cps), while the operational count rates (where a count rate loss is less than 5%) of available PCXDs are much lower, e.g., 5 × 10⁵ cps. In this study, we propose to enable PCXD-based clinical CT imaging using these slower-than-desired detectors by a combination of four methods that reduce the count rate requirements and compensate for the effect of pileup.