Image reconstruction from truncated fan-beam projections along a circular trajectory using the virtual fan-beam...

Area of Science:

• Medical Imaging
• Computational Imaging
• Image Reconstruction

Background:

• Truncated projections in fan-beam CT limit region-of-interest (ROI) reconstruction.
• Existing methods struggle with accurate reconstruction from one-sided truncated data.

Purpose of the Study:

• To develop and validate novel virtual fan-beam (VFB) reconstruction formulas for 2D ROI reconstruction.
• To address challenges posed by truncated fan-beam projections acquired on a circular scan.
• To extend the applicability of VFB methods for improved imaging accuracy.

Main Methods:

• Developed virtual fan-beam (VFB) trajectories and virtual projections.
• Applied super-short-scan (SSS) formulas to derive VFB reconstruction formulas.
• Implemented five VFB formulas, including two novel ones with backprojection in acquisition geometry.
• Validated formulas using numerical simulations (Forbild head and thorax phantoms).

Main Results:

• Presented five VFB reconstruction formulas for one-sided truncated fan-beam projections.
• Achieved accurate reconstruction in a larger ROI compared to previous methods.
• Demonstrated formula efficacy through numerical simulations and spatial resolution analysis.
• Introduced two new VFB formulas with backprojection in the fan-beam acquisition geometry.

Conclusions:

• Multiple VFB formulas enable mathematically correct 2D ROI reconstruction from truncated fan-beam data.
• The novel VFB formulas with acquisition geometry backprojection show promise for 3D reconstruction extension.
• This work expands the capabilities of VFB methods in medical imaging.