Applications of “edge-on” illuminated porous plate detectors for diagnostic X-ray imaging

Abstract

Scanning X-ray imaging systems for non-invasive diagnostics have several advantages over conventional imaging systems using area detectors. They significantly reduce the detected scatter radiation, cover large areas and potentially provide high spatial resolution. Applications of one-dimensional gaseous detectors and “edge-on” illuminated silicon strip detectors for scanning imaging systems are currently under intensive investigation. The purpose of this work is to investigate “edge-on” illuminated Porous Plate (PP) detectors for applications in diagnostic X-ray imaging. MicroChannel Plate (MCP), which is a common type of PP, has previously been investigated as a detector in surface-on illumination mode for medical X-ray imaging. However, its detection efficiency was too low for medical imaging applications. In the present study, the PP are used in the “edge-on” illumination mode. Furthermore, the structural parameters of different PP types are optimized to improve the detection efficiency in the diagnostic X-ray energy range. The MCP, porous dielectrics, microspheric plates, a-Si-based MCPs, microcolumnar and microgranular dielectrics are considered as detector materials in the “edge-on” illumination mode. The following are some potential advantages of the “edge-on” PP detectors from the standpoint of medical imaging applications: direct quantum-to-charge conversion; high internal charge amplification; very low noise; total absorption of the X-ray photons; minimal strip size and variable shape of the strips. The results of the application of “edge-on” MCP detectors for 122 and 662 keV gamma-ray detection and the initial results of imaging a radioactive source are discussed.