First human imaging with MARS photon-counting CT

This study demonstrates the translation of small-bore MARS photon-counting CT technology to live human spectral imaging within a clinical radiation dose level. We used the same spectral CT technology platform (hardware and software) for the acquisition of spectral CT data, image reconstruction, material decomposition and visualisation as used in small-bore MARS photon-counting CT. Small-bore MARS photon-counting CT has been used to produce promising results in the fields of cancer, bone and cartilage health, and cardio-vascular diseases. With the development of large-bore MARS photon-counting CT, small-animal studies can now be translated to humans, sheep, or pigs. Spectral CT data at eight energy-channels were acquired simultaneously to scan body-parts of a human volunteer. Two scans were performed, the first a part of the lower-leg, and the second of the wrist. After reconstructing the spectral CT images with voxel dimensions of 90 × 90 × 90 μm
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, a constrained leastsquare based material decomposition was applied to estimate the density of soft-tissue components (water and fat) and bone (calcium) in each voxel. The computed tomography dose index was measured to assess the radiation dose delivered in scanning the lower-leg of a live human. The previous studies conducted on small-bore MARS photon-counting CT have indicated that spectral information is beneficial for the assessment of cancer, bone and cartilage health, and cardio-vascular diseases. This study also demonstrates that spectral information obtained with the large-bore MARS photon-counting CT provides a similar level of material information to that obtained with small-bore MARS photon-counting CT. The measured weighted computed tomography dose index for scanning the two body-parts in this study was below 5 mGy in each scan. Obtaining diagnostic quality spectral CT images of a human within a clinical radiation dose level demonstrates the potential for using large-bore MARS photon-counting CT in human clinical trials.