
Proceedings Paper
DQE of image-intensifier-CCD fluoroscopic systems: a nonseparable case of the spatial-temporal approachFormat | Member Price | Non-Member Price |
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Paper Abstract
In a real fluoroscopic system experimental evaluations of the DQE may pretty soon run into difficulties. Easy as it might be to satisfy the need for linearity by means of correction look-up tables, the evaluation of the NPS is more tricky, because of various time integration mechanisms. In order to deal with such effects in a quantitatively correct manner the concept of a spatial-temporal1 DQE has been suggested. We have performed computer-aided DQE-evaluations 2,4,5 on a surgical C-arm, using MTF and NPS. Furthermore, we have attempted to estimate the time behavior of the spatial-temporal system transfer function. Using X-ray pulses in the ms regime, we have generated nearly 'lag-free' flat-field images. Our experiments showed two interesting results. The comparison of flat-field images in the continuous 'Fluoro' mode and the 'lag-free' mode revealed the theoretically expected highly overestimated DQE in the first case. The corresponding scaling factor could be derived quantitatively from the motion experiments with an X-ray contrast pulse (Cu-rod). More worth while noticing is the fact that we observed structural anomalies in the two-dimensional NPS that could not compensated for by a simple scaling factor but vanished only in the 'lag-free' mode. This can be explained theoretically by taking into account a mixing behavior between the spatial and temporal NPS components, i.e. the failure of the spatial-temporal separability of the system transfer function.
Paper Details
Date Published: 3 May 2002
PDF: 12 pages
Proc. SPIE 4682, Medical Imaging 2002: Physics of Medical Imaging, (3 May 2002); doi: 10.1117/12.465573
Published in SPIE Proceedings Vol. 4682:
Medical Imaging 2002: Physics of Medical Imaging
Larry E. Antonuk; Martin Joel Yaffe, Editor(s)
PDF: 12 pages
Proc. SPIE 4682, Medical Imaging 2002: Physics of Medical Imaging, (3 May 2002); doi: 10.1117/12.465573
Show Author Affiliations
Rainer G. Kaltschmidt, Siemens Medical Solutions (Germany)
Lothar Baetz, Siemens Medical Solutions (Germany)
Lothar Baetz, Siemens Medical Solutions (Germany)
Markus Ludwig, Siemens Medical Solutions (Germany)
Published in SPIE Proceedings Vol. 4682:
Medical Imaging 2002: Physics of Medical Imaging
Larry E. Antonuk; Martin Joel Yaffe, Editor(s)
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