Radiation Detectors for Medical Imaging

Chapter 3

Medical X-Ray and CT Imaging with Photon-Counting Detectors

Polad M. Shikhaliev

3.1 Introduction

Projection radiography and computed tomography (CT) have been gold standards for screening, diagnostic, and therapeutic medical imaging in the last several decades [1–4]. Radiography and CT systems employ polyenergetic X-ray beams with broad energy spectra generated by conventional X-ray tubes. Until now, these systems use radiation detectors based on the energy integration principle, that is, X-ray photons (usually several thousand photons per pixel) are absorbed and energies of all photons summed up to provide a single analog signal. On the other hand, X-ray photons are inherently discrete, and it would be straightforward to detect (count) ...