19 March 2008 Two-dimensional anti-scatter grids for computed tomography detectors
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The use of two-dimensional, focused, anti-scatter-grids (ASGs) in computed tomography is one essential solution to reduce the scatter radiation for large area detectors. A detailed analysis of the requirements and related image quality aspects lead to the specification of the two-dimensional focused geometry of the X-ray absorbing grids. Scatter simulations indicated trade-off conditions and provided estimations for the expected scatter reduction performance. Different production technologies for focused two-dimensional structures have been evaluated. The presented technology of Tomo Lithographic Molding (TomoTM) shows good fulfilment of the specifications. TomoTM is a synthesis of lithographic micromachining, precision stack lamination, molding, and casting processes with application-specific material systems. Geometry, material properties, and scatter performance have been investigated. Different analysis methods will be presented and results of the investigations demonstrate the performance capability of this two-dimensional grid technology. Material composition of the tungsten-polymer composite, homogeneity of wall thickness, and precision of the focusing have the biggest influence on the X-ray behavior. Dynamic forces on the anti-scatter-grid during CT operations should not lead to dynamic shadowing or intensity modulation on the active pixel area. Simulations of the wall deformation have been done to estimate the maximum position deviation. Prototype two-dimensional ASGs have been characterized and show promising results.
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Gereon Vogtmeier, Gereon Vogtmeier, Ralf Dorscheid, Ralf Dorscheid, Klaus Juergen Engel, Klaus Juergen Engel, Randy Luhta, Randy Luhta, Rod Mattson, Rod Mattson, Brian Harwood, Brian Harwood, Michael Appleby, Michael Appleby, Bill Randolph, Bill Randolph, Jill Klinger, Jill Klinger, "Two-dimensional anti-scatter grids for computed tomography detectors", Proc. SPIE 6913, Medical Imaging 2008: Physics of Medical Imaging, 691359 (19 March 2008); doi: 10.1117/12.770063; https://doi.org/10.1117/12.770063

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