DQE of image-intensifier-CCD fluoroscopic systems: a nonseparable case of the spatial-temporal approach

Rainer G. Kaltschmidt; Lothar Baetz; Markus Ludwig

doi:10.1117/12.465573

3 May 2002 DQE of image-intensifier-CCD fluoroscopic systems: a nonseparable case of the spatial-temporal approach

Rainer G. Kaltschmidt, Lothar Baetz, Markus Ludwig

Proceedings Volume 4682, Medical Imaging 2002: Physics of Medical Imaging; (2002) https://doi.org/10.1117/12.465573
Event: Medical Imaging 2002, 2002, San Diego, California, United States

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.

Citation Download Citation

Rainer G. Kaltschmidt, Lothar Baetz, and Markus Ludwig "DQE of image-intensifier-CCD fluoroscopic systems: a nonseparable case of the spatial-temporal approach", Proc. SPIE 4682, Medical Imaging 2002: Physics of Medical Imaging, (3 May 2002); https://doi.org/10.1117/12.465573

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available