Detectors for the future of X-ray imaging

TL;DR

This paper reviews advancements in photon-counting X-ray detectors, emphasizing their benefits in dose reduction, spectral imaging, and scatter rejection, along with challenges like charge sharing and high-rate operation.

Contribution

It provides a comprehensive overview of state-of-the-art photon-counting detectors, their applications in medical imaging, and discusses technical challenges and mitigation strategies.

Findings

Photon-counting detectors eliminate electronic noise, improving low-dose imaging.

Spectral imaging enables material differentiation and quantitative analysis.

Scatter rejection remains a challenge, with ongoing mitigation proposals.

Abstract

In recent decades, developments in detectors for X-ray imaging have improved dose efficiency. This has been accomplished with for example, structured scintillators such as columnar CsI, or with direct detectors where the X rays are converted to electric charge carriers in a semiconductor. Scattered radiation remains a major noise source, and fairly inefficient anti-scatter grids are still a gold standard. Hence, any future development should include improved scatter rejection. In recent years, photon-counting detectors have generated significant interest by several companies as well as academic research groups. This method eliminates electronic noise, which is an advantage in low-dose applications. Moreover, energy-sensitive photon-counting detectors allow for further improvements by optimising the signal-to-quantum-noise ratio, anatomical background subtraction or quantitative analysis of object constituents. This paper reviews state-of-the-art photon-counting detectors, scatter control and their application in diagnostic X-ray medical imaging. In particular, spectral imaging with photon-counting detectors, pitfalls such as charge sharing and high rates and various proposals for mitigation are discussed.