Hybrid energy integrating and photon counting micro-CT
The maturation of photon-counting detector (PCD) technology promises to enhance routine CT applications with high-fidelity spectral information, transforming X-ray CT into a functional and molecular imaging modality, while maintaining the high spatial resolution, fast scanning times, and relatively low cost. We present our novel dual source pre-clinical micro-CT prototype system that combines a photon counting detector (PCD) and an energy integrating detector (EID) in a single system. We compare performance for PCD-only with combined hybrid (i.e. PCD and EID) CT imaging with equal dose. All CT data sets (EID-only, PCD-only, and hybrid) were reconstructed using our iterative, multi-channel algorithm based on the split Bregman method and regularization with rank-sparse kernel regression. We used a post-reconstruction decomposition method with iodine (I), gold (Au), gadolinium (Gd), and calcium (Ca) basis functions. Performance was assessed using micro-CT phantoms. Our results show the spatial resolution of the PCD-only and the hybrid reconstructions were similar and slightly better than for EID-only reconstruction with ~3.5 lp/mm (10% MTF). The NPS of the hybrid reconstruction was similar to PCD-only reconstruction. By co-reconstructing EID and PCD data, we achieved better image quality in the material decomposition but marginal differences in terms of concentration accuracy. Hybrid spectral micro-CT can benefit both nanotechnology and cancer research by providing imaging that can help test and optimize various NPs for theranostics.
