Photon-counting, energy-resolving and super-resolution phase contrast X-ray imaging using an integrating detector

Area of Science:

• Medical Imaging
• Photon Counting Detectors
• X-ray Imaging Technology

Background:

• Scientific CMOS (sCMOS) detectors are typically energy-integrating, facing limitations from dark current and read-out noise.
• Conventional X-ray imaging struggles with simultaneous high spatial and energy resolution.
• Photon-counting detectors offer advantages in noise reduction and spectral information but can be complex and costly.

Purpose of the Study:

• To demonstrate the conversion of an sCMOS detector into a photon-counting detector.
• To achieve simultaneous energy resolution and sub-pixel spatial resolution in X-ray imaging.
• To overcome the inherent noise limitations of traditional energy-integrating detectors.

Main Methods:

• Analyzing visible light photon clouds generated by X-ray interactions with a scintillator.
• Identifying the centroid of individual X-ray photon interactions using low-fluence monochromatic projections.
• Calculating deposited charge to determine X-ray photon energy.
• Integrating with propagation-based phase contrast imaging and phase retrieval techniques.

Main Results:

• Achieved a tripling of spatial resolution to 6.71 ± 0.04 µm.
• Obtained an energy resolution of 61.2 ± 0.1% at 17 keV.
• Reached a signal-to-noise ratio of up to 15 ± 3 at low X-ray fluences (< 3 photons/mm²).
• Successfully eliminated dark current and read-out noise.

Conclusions:

• sCMOS detectors can be effectively utilized as photon-counting detectors for high-performance X-ray imaging.
• This approach offers a pathway to advanced imaging with improved resolution and reduced noise.
• The method holds promise for low-fluence and phase-contrast X-ray imaging applications.