20 April 2005 System characterization of the STATSCAN full body slit scanning radiography machine: theory and experiment
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This report presents a system model of the STATSCAN slit scanning full body radiography machine. A Cascaded Linear Systems model of the detector was developed and the theoretical DQE, MTF and NPS were compared to measured values for the RQA9 beam quality described in IEC 62220-1. The effect on detector DQE of various system parameters such as coupling efficiency, CCD noise and pixel binning was quantified. System performance for various thicknesses of Gd2O2S:Tb was analyzed. The notion of a “System DQE” has been suggested by several authors to facilitate the comparison of overall systems. An expression for the overall “System DQE” was developed by including the effects of scattered radiation, grid attenuation and focal spot unsharpness in the cascaded model. Scattered radiation was quantified as a function of system geometry parameters and was treated as an “additive noise stage”. A realistic model of the focal spot was used to calculate the MTF due to beam divergence in the scan direction and focal spot unsharpness in the slit direction. It was found that the “System DQE” is a valuable parameter for the purpose of comparing gridless slit scanning system performance to conventional geometry system performance.
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Martin Scheelke, Martin Scheelke, J. Herman Potgieter, J. Herman Potgieter, Mattieu de Villiers, Mattieu de Villiers, "System characterization of the STATSCAN full body slit scanning radiography machine: theory and experiment", Proc. SPIE 5745, Medical Imaging 2005: Physics of Medical Imaging, (20 April 2005); doi: 10.1117/12.595785; https://doi.org/10.1117/12.595785

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