Comprehensive data set to include interference effects in Monte Carlo models of x-ray coherent scattering inside...

Area of Science:

• Physics
• Materials Science
• Biomedical Engineering

Background:

• X-ray coherent scattering models in Monte Carlo codes typically modify material form factors using interference functions derived from measured patterns.
• This method is effective for non-biological materials but impractical for biological tissues due to their compositional variability.

Purpose of the Study:

• To develop and validate a novel method for modeling x-ray coherent scattering in biological tissues by representing them as mixtures of basis materials.
• To demonstrate the effectiveness of this segmentation approach for accurate scattering profile and attenuation coefficient calculations.

Main Methods:

• Biological samples were modeled as mixtures of four basis materials: fat, water, collagen, and calcium hydroxyapatite.
• The sample form factor was calculated as a weighted mean of the basis material form factors, incorporating interference effects.
• Segmentation (determining optimal weights) was achieved using multiple linear regression or trial and error.
• Basis material form factors were enhanced and merged from wide and small-angle scattering data.

Main Results:

• The proposed segmentation method was applied to 31 biological tissue samples, showing good agreement between original and calculated mixture scattering profiles and attenuation coefficients (mean relative difference ~10%).
• The method was validated using an extended Geant4 model of x-ray coherent scattering, comparing simulated and experimental data.
• Developed Geant4 code and molecular form factors are available online.

Conclusions:

• The developed method provides an effective and practical approach for incorporating interference effects in x-ray coherent scattering models for biological tissues.
• This technique improves the accuracy of Monte Carlo simulations for biological samples by accounting for complex compositions.
• The open availability of the code and form factors facilitates further research and application in the field.