Large-angle x-ray scatter in Talbot-Lau interferometry for breast imaging.

Area of Science:

• Medical Imaging
• Computational Physics
• Biomedical Engineering

Background:

• Differential phase contrast (DPC) imaging offers enhanced soft-tissue contrast for breast cancer detection.
• Talbot-Lau interferometry is a key technique in DPC imaging, but x-ray scatter can degrade image quality.
• Understanding and mitigating scatter is crucial for optimizing DPC imaging performance.

Purpose of the Study:

• To investigate large-angle x-ray scatter in DPC breast imaging using Monte Carlo simulations.
• To quantify the impact of breast thickness and composition on scatter.
• To evaluate the scatter reduction capabilities of analyzer gratings.

Main Methods:

• Monte Carlo simulations were performed at 25 keV for small field-of-view DPC imaging.
• Homogenous, adipose, and fibroglandular breast models (2-8 cm thickness) were simulated.
• X-ray scatter was classified as coherent (Rayleigh) or incoherent (Compton) interactions.

Main Results:

• Monte Carlo simulations showed good agreement with theoretical transmission efficiencies.
• Scatter-to-primary ratio increased with breast thickness, from 0.11-0.22 (adipose) and 0.12-0.28 (fibroglandular).
• Coherent scatter was the dominant component, with ratios of 2.2-3.1 (adipose) and 2.7-3.4 (fibroglandular).

Conclusions:

• Coherent scatter significantly contributes to the total x-ray scatter in DPC breast imaging.
• Analyzer gratings reduce incoherent scatter, with effectiveness increasing for thicker, denser breasts (~18% to ~35%).
• These findings aid in optimizing DPC imaging parameters for improved breast cancer detection.