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A Calibration method for the PIXSCAN: Small Animal X-ray CT Scanner

Abstract : Reconstruction in Cone Beam Tomography from scanner data requires a complete and precise description of the source-detector system. Small misalignment of the imaging system may cause severe distortion of the reconstructed image; it takes special care to ensure that the geometry of the system is well known. We present a high precision method for the geometric calibration in Cone-Beam CT for the PIXSCAN, a small animal X-ray-CT scanner based on hybrid pixel detectors (XPAD2). The specificities of the XPAD2 detectors (dead pixels, tilts and gaps between modules...) made the calibration of the PIXSCAN a hard stuff. The method uses a calibration object consisting of a hollow cylinder of polycarbonate on which we positioned four metallic balls (see Figure 1). It requires 360 X-ray images (1° increments). An analytic expression of the 3 image ellipses has been derived. It is used for a least squares regression of the 13 alignment parameters, after a correction of the internal XPAD2 geometry. Our method is rapid and completely automated; its precision is about 30μm (see Figure 3), a mouse reconstruction is shown in Figure 4.
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Contributor : Danielle Cristofol <>
Submitted on : Wednesday, November 14, 2007 - 10:08:20 AM
Last modification on : Thursday, January 18, 2018 - 2:21:05 AM


  • HAL Id : in2p3-00187259, version 1



M. Billault, J.C. Clemens, C. Meessen, C. Morel, E. Vigeolas, et al.. A Calibration method for the PIXSCAN: Small Animal X-ray CT Scanner. 4th International Conference on Imaging Technologies in Biomedical Sciences (ITBS 2007), Sep 2007, Island Milos, Greece. ⟨in2p3-00187259⟩



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