title: Free isocentric 3d imaging and a novel approach for wobble trajectories using a modified standard c-arm.
abstract: In this article the authors describes the modifications of an standard c-arm for free isocentric 3d imaging. To provide an isocentric movement of the x-ray source and the x-ray detector the passive mechanism of a standard c-arm was equipped with additional motors and encoders. A robot control system moves the imaging system on an isocentric path around the patient. The acquired x-ray images are then processed with a reconstruction algorithm using the algebraic reconstruction technique. For speed issues the reconstruction algorithm is implemented on a modern PC-graphics board. To overcome the known artifacts produced by the c-arm's limited rotation of 135 degrees , the use of a novel wobble trajectory is proposed for theses systems. The presented robotic approach for the motion of the c-arm's mechanism allows it to expand the isocentric movement to the surface of a sphere. With the new wobble trajectory the reconstruction artifacts can be significantly reduced.
authors.affiliation: MIMED, Department of Micro Technology and Medical Device Engineering, Boltzmannstr. 15, D-85748 Garching. ralf.tita@tum.de
authors.forename: Ralf
authors.initials: R
authors.lastname: Tita
authors.forename: Tim C
authors.initials: TC
authors.lastname: Lueth
mesh_terms: D000465:Algorithms; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation / Q000379:methods*; D012371:Robotics; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*