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Papers Published

1. Johnston, SM; Johnson, GA; Badea, CT, Geometric calibration for a dual tube/detector micro-CT system., Med Phys, vol. 35 no. 5 (May, 2008), pp. 1820-1829 [18561657], [doi] .
   (last updated on 2025/02/12)

   Abstract:
   The authors describe a dual tube/detector micro-computed tomography (micro-CT) system that has the potential to improve temporal resolution and material contrast in small animal imaging studies. To realize this potential, it is necessary to precisely calibrate the geometry of a dual micro-CT system to allow the combination of projection data acquired with each individual tube/detector in a single reconstructed image. The authors present a geometric calibration technique that uses multiple projection images acquired with the two imaging chains while rotating a phantom containing a vertical array of regularly spaced metallic beads. The individual geometries of the imaging chains are estimated from the phantom projection images using analytical methods followed by a refinement procedure based on nonlinear optimization. The geometric parameters are used to create the cone beam projection matrices required by the reconstruction process for each imaging chain. Next, a transformation between the two projection matrices is found that allows the combination of projection data in a single reconstructed image. The authors describe this technique, test it with a series of computer simulations, and then apply it to data collected from their dual tube/detector micro-CT system. The results demonstrate that the proposed technique is accurate, robust, and produces images free of misalignment artifacts.

   Keywords:
   Algorithms • Animals • Artifacts • Calibration • Equipment Design • Humans • Metals • Mice • Models, Statistical • Models, Theoretical • Phantoms, Imaging • Radiographic Image Interpretation, Computer-Assisted • Reproducibility of Results • Tomography Scanners, X-Ray Computed • Tomography, X-Ray Computed • X-Rays • instrumentation* • methods • methods*