Research Information System
Medical Imaging 2026: Physics of Medical Imaging, Vancouver, Canada, 15 - 19 February 2025, vol.13924, (Full Text)
Conventional thin-film-transistor (TFT) based indirect X-ray detectors are limited in applications requiring both high spatial and temporal resolution, such as high-frame-rate angiography (HFRA). Although photon-counting detectors operating at frame rates up to 1000 fps have demonstrated feasibility for HFRA, they remain costly, challenging to deploy in clinical environments, and difficult to scale to large imaging areas. In this work, we investigate the feasibility of a small-pixel, high-resolution, high-speed indirect complementary metal oxide semiconductor (CMOS) X-ray detector for high frame rate applications, capable of operating at frame rates up to 300 fps. The prototype system consists of a 1024 × 1024 pixel array with an 18 µm pixel pitch, coupled to a cesium iodide (CsI) scintillator, achieving a modulation transfer function of 4.7 lp/mm. Programmable windowing allows region-of-interest operation at frame rates up to 300 fps, while full-frame imaging operates at 30 fps. The readout chain achieves an input-referred noise of approximately 85 e−rms with a 17 fF integration capacitance and a conversion gain of 28.2 µV/e−. Temporal performance is evaluated through pixel time-series analysis under constant X-ray illumination, confirming stable frame spacing at 300 fps with negligible image lag. Spatial performance is demonstrated by imaging neurovascular stents, differentiating fine structural details. High-speed visible-light imaging further validates the detector’s ability to capture rapid dynamic events without motion blur. The detector’s high spatial and temporal resolution capabilities are further demonstrated by imaging the dynamic flow of an iodinated contrast agent through a tube. These results demonstrate that small-pixel indirect CMOS X-ray detectors can effectively balance high temporal resolution and superior spatial sampling, making them promising candidates for clinically practical high speed applications.