The Physics of Computed Tomography: Past, Present, and Future

Computed tomography celebrated its fiftieth anniversary in 2022 and it continues to draw on new physics as a source of technical innovation. Recent years have seen the clinical emergence of multi-energy CT using a variety of technical solutions, including the use of photon counting detectors that record the energy of individual x-rays at remarkably high count rates. On the horizon lies phase-contrast CT, which seeks to exploit for contrast the complex index of refraction of a sample, including the phase-shifting real part in addition to the traditional absorbing imaginary part. Phase contrast imaging holds promise of achieving higher soft-tissue contrast at lower radiation doses, but many practical challenges most be solved to bring it to the clinic. This talk will consider CT in a variety of contexts, including human-scale clinical machines, specimen imaging systems, and synchrotron-based microCT.