ABSTRACT
The potential benefits of semiconductor detectors in medical imaging rely mainly on their spatial and spectral resolution. This chapter analyzes the signal transport in both a scintillator and a semiconductor detector. The primary interaction in a detector pixel is given by absorption of an incoming x-ray quantum by a gadolinium atom. The scintillation detector is an optical device using light photons as intermittent information carriers. The physics of the primary energy deposition are comparable with the indirect conversion detector. The main signal degradation mechanisms are comparable with indirect conversion scintillator detectors: first, fluorescence scattering takes place. High-resolution detectors on the other hand address applications in mammography, radiography, and computed tomography. The spatial resolution of x-ray detectors is mainly given by pixel pitch and aperture. Scintillator detectors are often limited by the required septa walls and the cost of the required number of electronic digitization channels.
