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Evaluation of Relative X-Ray Imaging Detector Performance Using the Metric of Relative Object Detectability (ROD)

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V Singh

V Singh*, A Jain, S Setlur Nagesh, D Bednarek, S Rudin, Univ. at Buffalo (SUNY) School of Med., Buffalo, NY

TU-A-116-5 Tuesday 8:00AM - 9:55AM Room: 116

Purpose:
To determine the relative detectability performance of two x-ray imaging detectors for specific clinical objects and devices.

Methods:
The relative object detectability (ROD) can be defined as the ratio of the integral of the detective quantum efficiency (DQE) of a detector weighted by the square of the Fourier Transform (or frequency spectrum) of the object to the same integral for a second detector. Three different detectors, namely the micro-angiographic fluoroscope (MAF), the solid state x-ray image intensifier (SSXII) and a flat panel detector (FPD), were assessed for their relative performance with respect to the detectability of wires and spheres. The RODs were calculated for three sets of detectors: MAF-FPD, MAF-SSXII and SSXII-FPD, for wires of a fixed length of 20 mm and solid spheres made of different materials (aluminum, titanium and nickel) ranging in diameters from 100 micron to 1.0 mm to simulate endovascular devices.

Results:
For the 100-micron diameter, the ROD is 1.4 [2.0] for the MAF-SSXII and SSXII-FPD sets and 1.9 [3.9] for the MAF-FPD for the wire [sphere] indicating superior performance of the MAF over the FPD and SSXII and of the SSXII over the FPD for small sized objects. However, the ROD decreased monotonically as the object diameter increased and showed equivalent performance for wires with diameter over 300 microns and spheres with diameters above 400 microns.

Conclusion:
The ROD depends upon the physical geometry of the object and is useful in quantifying the relative performance of detectors regarding detectability of specific objects. Because of their higher spatial resolution both the MAF and the SSXII perform better than the FPD for viewing wires with diameters under 300 microns and spheres with diameters under 400 microns; however, the MAF performance is shown to be superior to the SSXII as well.

Funding Support, Disclosures, and Conflict of Interest: NIH Grant 2R01EB002873

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