Quantitative phase retrieval with low photon counts using an energy resolving quantum detector.

Area of Science:

• Medical Imaging
• Physics
• Materials Science

Background:

• X-ray phase contrast imaging (PCI) offers potential for enhanced soft-material imaging.
• Phase retrieval methods are crucial for reconstructing quantitative phase information.
• Existing methods may face limitations in accuracy, image quality, and robustness.

Purpose of the Study:

• To evaluate the accuracy, image quality improvements, and robustness of a novel spectral phase retrieval method for PCI.
• To assess the method's performance with poorly attenuating materials.
• To demonstrate the potential for dose reduction and improved material discrimination.

Main Methods:

• Spectroscopic PCI measurements were performed on a physical phantom with four poorly attenuating materials.
• State-of-the-art photon-counting detectors and a polychromatic X-ray source were utilized.
• A spectral phase retrieval algorithm was applied to reconstruct material properties.

Main Results:

• The spectral phase retrieval method accurately determined complete refractive properties (absorption, attenuation, phase).
• Retrieved images showed approximately 10 times higher signal-to-noise ratio (SNR) compared to original PCI intensity images.
• The method demonstrated robustness against quantum noise, even with short acquisition times (1s) and low flux.

Conclusions:

• The spectral phase retrieval method significantly enhances soft-material visibility and discrimination in PCI.
• The technique offers substantial SNR gains and robust performance under noisy conditions.
• This adaptable method holds promise for dose reduction and improved material characterization in clinical and industrial X-ray imaging.