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Proceedings Paper

Generalized performance evaluation of x-ray image intensifier compared with a microangiographic system
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Paper Abstract

Standard objective parameters such as MTF, NPS, NEQ and DQE do not reflect complete system performance, because they do not account for geometric unsharpness due to finite focal spot size and scatter due to the patient. The inclusion of these factors led to the generalization of the objective quantities, termed GMTF, GNNPS, GNEQ and GDQE defined at the object plane. In this study, a commercial x-ray image intensifier (II) is evaluated under this generalized approach and compared with a high-resolution, ROI microangiographic system previously developed and evaluated by our group. The study was performed using clinically relevant spectra and simulated conditions for neurovascular angiography specific for each system. A head-equivalent phantom was used, and images were acquired from 60 to 100 kVp. A source to image distance of 100 cm (75 cm for the microangiographic system) and a focal spot of 0.6 mm were used. Effects of varying the irradiation field-size, the air-gaps, and the magnifications (1.1 to 1.3) were compared. A detailed comparison of all of the generalized parameters is presented for the two systems. The detector MTF for the microangiographic system is in general better than that for the II system. For the total x-ray imaging system, the GMTF and GDQE for the II are better at low spatial frequencies, whereas the microangiographic system performs substantially better at higher spatial frequencies. This generalized approach can be used to more realistically evaluate and compare total system performance leading to improved system designs tailored to the imaging task.

Paper Details

Date Published: 20 April 2005
PDF: 11 pages
Proc. SPIE 5745, Medical Imaging 2005: Physics of Medical Imaging, (20 April 2005); doi: 10.1117/12.594593
Show Author Affiliations
Girijesh K. Yadava, Toshiba Stroke Research Ctr./State Univ. of New York at Buffalo (United States)
State Univ. of New York at Buffalo (United States)
Iacovos S. Kyprianou, NIBIB/CDRH Lab. for the Assessment of Medical Imaging System (United States)
Stephen Rudin, Toshiba Stroke Research Ctr./State Univ. of New York at Buffalo (United States)
State Univ. of New York at Buffalo (United States)
Daniel R. Bednarek, Toshiba Stroke Research Ctr./State Univ. of New York at Buffalo (United States)
State Univ. of New York at Buffalo (United States)
Kenneth R. Hoffmann, Toshiba Stroke Research Ctr./State Univ. of New York at Buffalo (United States)
State Univ. of New York at Buffalo (United States)


Published in SPIE Proceedings Vol. 5745:
Medical Imaging 2005: Physics of Medical Imaging
Michael J. Flynn, Editor(s)

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