  Image-guided navigation of catheter devices to anatomic targets within large
3D cardiac chambers and vessels is challenging in the interventional setting
due to the limitations of a conventional 2D x-ray projection format.
Scanning-beam digital x-ray (SBDX) is a low-dose inverse geometry x-ray
fluoroscopy technology capable of real-time 3D catheter tracking. SBDX performs
rapid tomosynthesis using an electronically scanned multisource x-ray tube and
photon-counting detector mounted to a C-arm gantry. However, SBDX currently
lacks the ability to perform volumetric computed tomography from a rotational
C-arm scan. This work develops a novel volumetric CT capability for the SBDX
platform, termed C-arm inverse geometry CT, suitable for rotational scans of
the beating heart. The work is divided into three tasks: development of image
reconstruction algorithms, implementation on the SBDX hardware, and performance
assessment for the example task of 3D cardiac chamber mapping. SBDX-CT data
acquisition is performed by simultaneous x-ray source scanning at 15 scan/s and
C-arm rotation over a 190 degree short-scan arc in 13.4 seconds. An iterative
reconstruction method was developed to accommodate fully truncated projections
and data inconsistency resulting from cardiac motion during rotation. Hardware
implementation included development of a C-arm angle measurement method,
development of a geometric calibration method to account for non-ideal C-arm
rotations, and detector response nonlinearity correction. The geometric
calibration procedure mitigated artifacts from C-arm deflection during
rotation. SBDX-CT image quality was evaluated in phantom studies. Feasibility
of in-vivo SBDX-CT was demonstrated in a porcine model.
