Access Restriction

Author Choi, Jang-Hwan ♦ Maier, Andreas ♦ Berger, Martin ♦ Fahrig, Rebecca
Source CiteSeerX
Content type Text
File Format PDF
Subject Domain (in DDC) Computer science, information & general works ♦ Data processing & computer science
Subject Keyword Involuntary Motion ♦ Step-iterative Fiducial Marker-based Compensation ♦ Weight-bearing C-arm Cone-beam Ct Scanning ♦ Warping Method ♦ Projection Matrix ♦ Background Noise ♦ Projection Shifting ♦ Motion Compensation ♦ Projection Frame ♦ Flat Panel ♦ Bone-tissue Interface ♦ Noise Level ♦ Projection Warping ♦ Patient Involuntary Motion ♦ Body Motion ♦ Landweber-type Iteration ♦ Improved Visibility ♦ Healthy Volunteer ♦ Distance-related Weighting ♦ C-arm Cone-beam Ct System ♦ Metallic Marker-caused Streak ♦ Translational Movement ♦ Entire Image ♦ Different Fiducial Marker-based Correction Method ♦ Projection Image ♦ Weight-bearing C-arm Ct Scanning ♦ Bilateral Filtering ♦ Soft Tissue Structure ♦ Image Warping ♦ Various Flexion Angle ♦ Metal-generated Streak ♦ Sharp Edge ♦ Static Reference Marker ♦ Method Applies
Abstract We previously introduced three different fiducial marker-based correction methods (2D projection shifting, 2D projection warping, and 3D image warping) for patients ’ involuntary motion in the lower body during weight-bearing C-arm CT scanning. The 3D warping method performed better than 2D methods since it could more accurately take into account the lower body motion in 3D. However, as the 3D warping method applies different rotational and translational movement to the reconstructed image for each projection frame, distance-related weightings were slightly twisted and thus result in overlaying background noise over the entire image. In order to suppress background noise and artifacts (e.g. metallic marker-caused streaks), the 3D warping method has been improved by incorporating bilateral filtering and a Landweber-type iteration in one step. A series of projection images of five healthy volunteers standing at various flexion angles were acquired using a C-arm cone-beam CT system with a flat panel. A horizontal scanning trajectory of the C-arm was calibrated to generate projection matrices. Using the projection matrices, the static reference marker coordinates in 3D were estimated and used for the improved 3D warping method. The improved 3D warping method effectively reduced background noise down below the noise level of 2D methods and also eliminated metal-generated streaks. Thus, improved visibility of soft tissue structures (e.g. fat and muscle) was achieved while maintaining sharp edges at bone-tissue interfaces. Any high resolution weight-bearing cone-beam CT system can apply this method for motion compensation.
Educational Role Student ♦ Teacher
Age Range above 22 year
Educational Use Research
Education Level UG and PG ♦ Career/Technical Study