On the usage of a photon counting CT detector for SPECT

Abstract: This work explores the possibility of using a photon counting silicon detector developedfor Computer Tomography (CT) in Single Photon Emission Computed Tomography(SPECT) applications. This would allow for a more versatile and a much cheapersystem. The main focus is on determining the efficiency and resolution of such a system.This is done initially via an geometric model evaluating the solid angle of the collimator,showing promising results versus a standard Low Energy High Resolution (LEHR)collimator. Secondly a Monte-Carlo simulation is used for a more in depth analysis ofthe detector response by using two different radionuclides. The performance is measuredwith reference to efficiency and scatter to primary ratio (s/p). The energy thresholdsfor binning is evaluated with a Signal-Difference-to-Noise Ratio (SDNR). A Point SpreadFunction (PSF) is simulated with and without the impact from a human-like phantom.The work concludes that an implementation would not likely to be able to compete withspecialised myocardium SPECT due too the high noise from the detector response whena high efficiency threshold is set. Further investigations in general SPECT applicationsis recommended.Sammanfattning