Detector Technology for Photon Counting CT

Photon Counting detectors is a logic next step for CT. This technique will enable higher contrast and/or lower radiation dose. In particular lower concentrations of Iodine can be detected and quantified which is important in angiography or perfusion imaging. Moreover beam hardening artefacts will disappear with material base decomposition. Electronic noise can be completely eliminated by using a minimum threshold which will help imaging of large patients and enable reduced radiation dose compared to what is possible today. We will outline the state-of-the-art for photon counting imaging detector technology and how the major challenges such as high rates (pile-up), charge sharing (energy resolution) and absorption efficiency can be addressed and what the tradeoffs are. The direct conversion detectors used for photon counting will enable smaller pixels than what is feasible with today's scintillators and we expect the higher spatial resolution in combination with the increased spectral performance to be a powerful combination for example in imaging of the coronary arteries.