Segmented separable footprint projector for digital breast tomosynthesis and its application for subpixel...

Area of Science:

• Medical Imaging
• Image Reconstruction
• Digital Breast Tomosynthesis

Background:

• Iterative image reconstruction accuracy relies heavily on digital projectors.
• Digital breast tomosynthesis (DBT) commonly uses ray-tracing (RT) projectors, which neglect finite detector element size, impacting image quality.

Purpose of the Study:

• To introduce and evaluate the segmented separable footprint (SG) projector for DBT.
• To assess the SG projector's effectiveness in reducing projection error and enhancing DBT reconstruction quality, especially for voxels with high height-to-width ratios.

Main Methods:

• Compared projection error of RT and SG projectors in regular and subpixel DBT reconstruction.
• Simulated DBT projections of a phantom with line patterns and spheres using CatSim.
• Reconstructed images using simultaneous algebraic reconstruction technique (SART) and subpixel SART, comparing resolution, contrast, and computation times.

Main Results:

• SG projector reduced projection error by 1-2 orders of magnitude, with a minimum of 50% reduction.
• SG projector improved contrast, reduced artifacts, and created smoother images in DBT slices.
• Subpixel reconstruction with SG projector significantly increased object contrast and computation speed compared to RT projector.

Conclusions:

• The SG projector is more accurate and faster than the RT projector.
• SG projector substantially reduces computation time and improves image quality in DBT, with or without subpixel reconstruction.