Publication:

Photon-counting computed tomography: a next-generation imaging technology and its clinical impact

Photon-counting computed tomography (PCCT) is the radically new technology in the X-ray imager that makes it possible to directly detect and energy-discriminate a photon. PCCT, in contrast to traditional energy-integrating detector (EID) CT systems, uses semiconductor-based detectors that transform X-ray photons directly into electrical signals, which means that it has better spatial resolution and lower electronic noise, sufficient contrast-to-noise ratio, and improved dose efficiency. The main benefit of PCCT is that it has intrinsic spectral imaging capacity that enables it to obtain multi-energy data during a single scan, enabling a material to be decomposed accurately, better tissue characterization and beam-hardening and metal artifact reduction. Recent clinical and preclinical trials have shown that PCCT also has a broad diagnostic potential in a broad spectrum of uses such as neuroimaging, cardiovascular imaging, thoracic imaging, musculoskeletal examination and oncologic imaging. The enhanced spatial resolution allows the visualization of small structures of the anatomy to be better and the spectral information is possible to support quantitative imaging and the characterization of the lesion. These abilities can lead to the earlier detection of a disease, the increased confidence of the diagnostic results, and the optimal management of the patients. Though this has been advantageous, the common clinical use of PCCT is still hampered by issues of high costs of the systems, large volume of data, computational requirement and limited accessibility. However, these limitations are set to be overcome by the ongoing improvement in detector technology, image reconstruction algorithms and clinical validation studies. The review gives a summary of the principles underlying photon-counting CT as well as the comparison that has been given between PCCT and conventional CT technology, limitation of PCCT, and its future in diagnostic imaging.