Propagation-based phase-contrast breast computed tomography: a visual grading assessment of the performance of photon-counting and flat-panel X-ray detectors

Abstract

Rationale and objectives: Breast cancer represents the leading cause of death from cancer in women worldwide. Early detection of breast tumours improves the prognosis and survival rate. Propagation-based phase-contrast computed tomography (PB-CT) is a technique that uses refraction and absorption of the X-ray to produce images for clinical applications. This study compared the performance of photon‐counting and flat panel X-ray detectors in PB‐CT breast imaging using synchrotron radiation. Materials and methods: Mastectomy specimens underwent PB-CT imaging using the Hamamatsu C10900D Flat Panel and PIXIRAD-8 CdTe single-photon-counting detectors. PB-CT images generated at different imaging conditions were compared to absorption-based CT (AB-CT) reference images acquired with the same detectors to investigate the image quality improvement delivered by PB-CT relative to AB-CT. The image quality of the different image sets was assessed by eleven readers in a visual grading characteristics (VGC) study. Results: The intraclass correlation coefficient showed a moderate/good interobserver agreement for the image set analysed (ICC = 0.626, p = <0.001). The area under the curve showed that the image quality improvement in PB-CT images obtained by the PIXIRAD-8 CdTe single-photon counting detector were consistently higher than the one for flat-panel Hamamatsu detector. The level of improvement in image quality was more substantial at lower radiation doses. Conclusion: In this study, the PIXIRAD-8 photon-counting detector was associated with higher image quality scores at all tested radiation dose levels, which was likely a result of the combined effect of the absence of dark current noise and better spatial resolution, compared to the flat-panel detector.