Guiding kVp optimization using a μCT simulation tool designed for a small-pixel photon-counting detector

Abstract X-ray micro-CT (µCT) is a widely used technique for non-destructive imaging, yet optimal selection of acquisition parameters remains challenging. X-ray tube power is often constrained by focal spot size requirements, and for weakly attenuating samples the choice of tube voltage (kVp) at constant tube power represents a key trade-off: lower kVp increases attenuation contrast, while higher kVp increases photon flux and reduces noise. Recent simulations with PEPIsim, the MATLAB-based simulation tool developed for X-ray phase-contrast, spectral μCT with a small-pixel photon-counting detector, demonstrated that, under constant power conditions, higher tube voltages can yield improved signal-to-noise ratio (SNR) in both attenuation and phase-retrieved images of weakly attenuating plastics. Building on these findings, we performed exploratory acquisitions at the PEPI Lab of a formalin-fixed, paraffin-embedded pedunculated colonic polyp with adenocarcinoma, scanned across a range of tube voltages (45–100 kVp) at constant power for the purpose of virtual histology. Consistent with the simulation predictions, the measured SNR values tended to increase with tube voltage for both attenuation and phase-retrieved images. While the dataset is limited and further work is required to confirm broader applicability, these results suggest that PEPIsim can provide useful guidance for acquisition parameter selection and may help establish simple experimental guidelines, such as minimum kVp thresholds, for biological samples.