Three‐dimensional noise characteristics of clinical photon counting detector CT

The 3D NPS provides new insight into the noise characteristics of PCD-CT: Noise in the native PCD-CT projection data is uncorrelated across detector rows, but clinical reconstruction processes introduce noise spatial correlation along both axial and z directions, particularly at higher QIR strengths, lower radiation doses, or with larger image objects that increase the percentage of scattered photons. Compared to the Standard mode, UHR mode reconstruction exhibits stronger noise correlation due to its superior detector spatial resolution, allowing for more aggressive spatial smoothing to achieve the desired spatial resolution in the final image.