Improved volumetric imaging in tomosynthesis using combined multiaxial sweeps.

Area of Science:

• Medical Imaging
• Radiology
• Image Reconstruction

Background:

• Tomosynthesis offers potential for volumetric imaging but faces challenges in achieving high fidelity.
• Limited-angle rotational acquisitions are common in tomosynthesis systems.
• Cone-beam CT (CBCT) is a standard for volumetric imaging, serving as a benchmark.

Purpose of the Study:

• To evaluate the volumetric reconstruction fidelity of a tomosynthesis system with a unique isocentric rotation capability.
• To investigate combining multiple limited-angle rotational acquisition sweeps for improved volumetric imaging.
• To compare tomosynthesis-based reconstructions with CBCT for assessing volumetric accuracy.

Main Methods:

• Utilized the Digital Integrated Brachytherapy Unit (IBU-D) for image projection acquisition.
• Employed a phantom with spherical objects of varying contrast for testing.
• Performed reconstructions using filtered backprojection from isocentric sweeps.
• Assessed reconstruction fidelity using effective eccentricity of sphere intersections and manual volume contouring, compared to CBCT.

Main Results:

• The optimal configuration involved two orthogonally-offset 60° L-arm sweeps and a single C-arm sweep.
• This configuration demonstrated superior volumetric reconstruction fidelity compared to CBCT.
• The addition of the C-arm sweep significantly improved delineation of volumes along the transverse axis.

Conclusions:

• Volumetric reconstruction using multiple, unconstrained orthogonal tomosynthesis sweeps can surpass traditional CBCT accuracy.
• The described tomosynthesis system can provide high-quality volumetric imaging suitable for surgical scenarios, even with rotational limitations.
• This approach offers a promising alternative for intraoperative imaging without necessitating patient motion.