16 March 2007 Cone beam CT image quality measurements: PSF de-convolution
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Abstract
The Modulation Transfer Function (MTF) of any system is the frequency response to a delta signal. Ideally, this response should be a step function for a flat panel detector (FPD); it should be one for frequencies less than the Nyquist frequency and zero for frequencies above. Yet, this response is degraded by several factors such as the veiling glare of the detector and the focal spot size. Consequently, the MTF has been one of the physical characteristics that are commonly used to quantitatively measure the physical performance of a system. One of the standard techniques to evaluate the MTF is by using an edge of a metal with a high atomic number. For instance, it has been suggested by IEC 62220-1 to use an opaque edge to evaluate the MTF of FPDs. In a previous study, it was found that different metals yield slightly different evaluation of the MTF. The effects of these slightly different MTFs on image quality were investigated. The evaluation of the MTFs of a PaxScan 4030CB and PaxScan 2520 from a previous study were used in this study. A ball, a cylindrical water phantom, a breast phantom, a living mouse and three breasts of patients from a pilot study were analyzed for improvements in image quality after PSF deconvolution post-processing. The results of this study suggest that the detector's MTF de-convolution post-processing achieved a CNR's increase while it also enhanced the edges and uniformity.
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Ricardo Betancourt Benítez, Ricardo Betancourt Benítez, Ruola Ning, Ruola Ning, David Conover, David Conover, } "Cone beam CT image quality measurements: PSF de-convolution", Proc. SPIE 6510, Medical Imaging 2007: Physics of Medical Imaging, 65104Z (16 March 2007); doi: 10.1117/12.710215; https://doi.org/10.1117/12.710215
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