Tomographic reconstruction from an uncontrolled sensor trajectory

For many medical procedures 3D bone models are built from computed tomography (CT) or magnetic resonance imaging (MRI) data, both of which are expensive and time consuming, and unavailable in most operating rooms. We propose 3D tomographic reconstruction from fluoroscopy as an alternative to CT and MRI. Although there are fluoroscopy machines that can perform 3D reconstruction, they must be instrumented and constrained to gather images along a pre-defined path. We present a methodology for 3D reconstruction from imagery collected along an arbitrary path on standard fluoroscopy machines. Using metal beads on the scanned object as fiducial markers, we can recover the path of the X-ray from the image data and apply cone-beam tomographic reconstruction methods. In this paper we describe our cone-beam tomographic reconstruction algorithm and demonstrate reconstruction of a phantom and a cadaver knee from data collected on a standard fluoroscopy unit.