Photon-counting CT with silicon detectors: feasibility for pediatric imaging

TL;DR

This study uses a Monte Carlo model to evaluate the feasibility of silicon-based photon-counting CT detectors for pediatric imaging, showing promising detection efficiency and effective scatter management at low voltages.

Contribution

It demonstrates the potential of silicon detectors for pediatric CT, highlighting their efficiency and scatter separation capabilities at low x-ray energies.

Findings

Detection efficiency of 0.74 at 80 kVp

Effective scatter blocking with thin metal shielding

Feasibility of silicon detectors at low voltages for pediatric imaging

Abstract

X-ray detectors made of crystalline silicon have several advantages including low dark currents, fast charge collection and high energy resolution. For high-energy x-rays, however, silicon suffers from its low atomic number, which might result in low detection efficiency, as well as low energy and spatial resolution due to Compton scattering. We have used a monte-carlo model to investigate the feasibility of a detector for pediatric CT with 30 to 40 mm of silicon using x-ray spectra ranging from 80 to 140 kVp. A detection efficiency of 0.74 was found at 80 kVp, provided the noise threshold could be set low. Scattered photons were efficiently blocked by a thin metal shielding between the detector units, and Compton scattering in the detector could be well separated from photo absorption at 80 kVp. Hence, the detector is feasible at low acceleration voltages, which is also suitable for pediatric imaging. We conclude that silicon detectors may be an alternative to other designs for this special case.