Sensitivity analysis of a geometric calibration method using projection matrices for digital tomosynthesis systems.

Area of Science:

• Medical Imaging
• Tomography
• Geometric Calibration

Background:

• Digital tomosynthesis (DT) systems require precise geometric calibration for accurate image reconstruction.
• Previous work established a projection matrix-based calibration method using marker positions.

Purpose of the Study:

• To investigate the sensitivity of a projection matrix-based geometric calibration method for digital tomosynthesis.
• To determine the impact of marker quantity, 3D distribution, and positional accuracy on calibration quality.

Main Methods:

• Utilized a prototype breast tomosynthesis system and a CIRS breast phantom.
• Analyzed the effect of varying marker numbers (6-44) and their 3D spatial arrangement on reconstructed images.
• Quantified image quality changes using a detection mask to assess signal variations.

Main Results:

• High-quality reconstructions were achieved with accurate marker data, irrespective of marker count (6-44).
• Inaccurate marker positions led to image degradation, more pronounced with fewer markers and smaller volumetric coverage.
• Projection errors caused severe degradation; coplanar markers resulted in calibration failure.

Conclusions:

• Optimal geometric calibration phantom design necessitates numerous markers with extensive 3D volumetric coverage, avoiding coplanarity.
• Accurate detection of marker projections is critical for precise calibration and reliable reconstruction of small objects.