Oblique reconstructions in tomosynthesis. I. Linear systems theory.

Area of Science:

• Medical Imaging
• Radiology
• Image Reconstruction

Background:

• Conventional tomosynthesis reconstructions create slices parallel to the detector.
• Generating oblique slices, similar to computed tomography (CT), has not been demonstrated.
• This study explores oblique reconstructions in tomosynthesis, which uses a smaller angular range than CT.

Purpose of the Study:

• To provide proof-of-principle for oblique reconstructions in tomosynthesis.
• To investigate the visibility of frequencies in oblique reconstructions.
• To generalize the linear systems (LS) model for tomosynthesis analysis.

Main Methods:

• Developed a theoretical framework to reconstruct sinusoidal inputs at various pitches.
• Calculated the modulation transfer function (MTF) to assess modulation detectability.
• Analyzed the effect of object thickness on MTF in oblique reconstructions.
• Assessed the accuracy of object length estimation in oblique reconstructions using a pitched rod.

Main Results:

• Pitched sinusoidal objects are resolved when slice pitch matches object pitch.
• Modulation is detectable over a broad pitch range for thin objects, but a narrower range for thick objects.
• Object length estimation is accurate for thin objects across a broad pitch range, and for thick objects over a narrower range.

Conclusions:

• Oblique reconstructions are feasible in tomosynthesis.
• Pitched objects are better visualized with oblique reconstructions compared to conventional ones.
• Object thickness is critical for maintaining image quality across various pitches in oblique reconstructions.