MO‐FF‐A4‐03: Testing of the High‐Resolution ROI Micro‐Angio Fluoroscope (MAF) Detector Using a Modified NEMA XR‐21 Phantom

• Published in: Medical Physics 2009-06, Vol.36 (6), p.2713-2713
• Main Authors: Ionita, C, Keleshis, C, Jain, A, Bednarek, D, Rudin, S
• Format: Article
• Language: English
• Subjects: Aluminium; Charge coupled devices; Digital subtraction angiography; Image detection systems; Image intensifiers; Image sensors; Phosphors; Testing procedures; Vascular system
• ISSN: 0094-2405; 2473-4209
• DOI: 10.1118/1.3182297

Purpose: To test the MAF in conditions and tasks specific to minimally invasive neurovascular procedures. Materials and Methods: A high‐sensitivity, high‐resolution MAF detector was built and incorporated into a standard angiographic C‐Arm system. This detector consists of a 300μm CsI input phosphor coupled to a dual stage GEN2 micro‐channel‐plate light image intensifier, followed by minifying fiber‐optic taper coupled to a CCD chip. The detector is attached to a very stable detector‐changer onto a Flat‐Panel (FP) C‐arm angiographic unit to allow facile placement of the detector into the field‐of‐view whenever high resolution is needed. A NEMA XR21‐2000 phantom was modified to evaluate neurovascular x‐ray imaging systems. The phantom was restructured to be head‐equivalent; two aluminum plates shaped to fit into the NEMA phantom geometry were added to a 15cm thick section. Digital subtraction angiography (DSA) testing was enabled by adding a removable central section with a hollow slot which allows insertion of various angiographic test blocks. DSA and DA were tested using a standard removable insert having simulated arteries with thicknesses of 4, 2 and 1 mm and 15mg/cm3 iodine contrast and with stenoses and aneurysms (AAPM Report 15). Features on the central plates of the NEMA XR21 phantom such as bar pattern and iodine‐detail‐contrast‐targets were also imaged. The results of the evaluation of the MAF with the modified phantom were compared with the images obtained with a standard flat panel. Results: The phantom imaging results presented as (MAF‐detected‐features/Flat‐Panel‐detected‐features) are: bar pattern — (5.0/3.1) lines/mm; smallest iodine‐contrast target group detectable — (10/10) mg/cm2, details of smallest simulated vessel in DSA — (1/2) mm. Conclusions: The MAF detector performs at least as well as a standard FP in detection of low‐contrast objects, and is superior in the visualization and identification of the small details. (Support: NIH grant R01‐EB002873, R01EB0008425).