Program Information
Demonstration of the Line Focus Principle Using the Generalized Measured-Relative Object Detectability (GM-ROD) Metric
M Russ*, A Shankar , A Lau , D Bednarek , S Rudin , University at Buffalo (SUNY), Buffalo, NY
Presentations
TU-FG-209-5 (Tuesday, August 2, 2016) 1:45 PM - 3:45 PM Room: 209
Purpose:Demonstrate and quantify the augmented resolution due to focal-spot size decrease in images acquired on the anode side of the field, for both small and medium (0.3 and 0.6mm) focal-spot sizes using the experimental task-based GM-ROD metric. Theoretical calculations have shown that a medium focal-spot can achieve the resolution of a small focal-spot if acquired with a tilted anode, effectively providing a higher-output small focal-spot.
Methods:The MAF-CMOS (micro-angiographic fluoroscopic complementary-metal-oxide semiconductor) detector (75μm pixel pitch) imaged two copper wire segments of different diameter and a pipeline stent at the central axis and on the anode side of the beam, achieved by tilting the x-ray C-arm (Toshiba Infinix) to 6° and realigning the detector with the perpendicular ray to correct for x-ray obliquity. The relative gain in resolution was determined using the GM-ROD metric, which compares images on the basis of the Fourier transform of the image and the measured NNPS. To emphasize the geometric unsharpness, images were acquired at a magnification of two.
Results:Images acquired on the anode side were compared to those acquired on the central axis with the same target-area focal-spot to consider the effect of an angled tube, and for all three objects the advantage of the smaller effective focal-spot was clear, showing a maximum improvement of 36% in GM-ROD. The images obtained with the small focal-spot at the central axis were compared to those of the medium focal-spot at the anode side and, for all objects, the relative performance was comparable.
Conclusion:For three objects, the GM-ROD demonstrated the advantage of the anode side focal-spot. The comparable performance of the medium focal-spot on the anode side will allow for a high-output small focal-spot; a necessity in endovascular image-guided interventions.
Funding Support, Disclosures, and Conflict of Interest: Partial support from an NIH grant R01EB002873 and an equipment grant from Toshiba Medical Systems Corp.
Contact Email: