Comparison of two x-ray phase-contrast imaging methods with a microfocus source.

Area of Science:

• Physics
• Medical Imaging
• Materials Science

Background:

• X-ray phase-contrast imaging (XPCi) offers enhanced sensitivity for material differentiation compared to conventional radiography.
• Grating-based imaging (GBI) and propagation-based imaging (PBI) are two prominent XPCi techniques.
• Laboratory x-ray sources present unique challenges and opportunities for XPCi.

Purpose of the Study:

• To compare the radiation dose requirements of GBI and PBI for high-resolution imaging using a laboratory x-ray source.
• To evaluate the performance of both techniques under monochromatic and polychromatic radiation conditions.
• To assess the imaging quality and quantitative capabilities of GBI and PBI on biological samples.

Main Methods:

• Simulations and experimental investigations were conducted using a liquid-metal-jet x-ray microfocus source.
• Radiation doses were simulated as a function of sample diameter for both monochromatic and polychromatic radiation.
• Imaging performance was evaluated on a biological sample, assessing noise levels and quantitative reconstruction capabilities.

Main Results:

• Simulations indicated that PBI requires lower doses for small features and GBI for larger features under monochromatic radiation.
• Under polychromatic radiation (typical of laboratory sources), PBI demonstrated lower dose requirements across a wide range of feature sizes.
• GBI exhibited higher noise levels than PBI on a biological sample, but offered quantitative refractive index reconstruction for multi-material samples.

Conclusions:

• PBI is generally more dose-efficient than GBI for high-resolution XPCi with polychromatic laboratory sources, particularly for biological samples.
• GBI retains an advantage in quantitative multi-material analysis, despite potentially higher noise.
• The choice between GBI and PBI depends on the specific application, sample characteristics, and radiation constraints.