Development and evaluation of a digital subtraction angiography system using a large-area flat panel detector

Abstract

We developed prototype Digital Subtraction Angiography (DSA) System with a new large area FPD. Dynamic range, MTF, Contrast ratio and line noise were much improved. The improved FPD is a scintillator-type detector, and has a 40 x 30 cm active area, 2048 x 1536 matrix with 194um pixel pitch. The Prototype DSA system has two x-ray detectors, the FPD and the I.I.-CCD camera, and we can choose them on demand. All images captured from both detectors at 3 frames/sec in DSA mode and 30 frames/sec in Fluoroscopy mode are forwarded to our image-processing unit. We applied the new DSA system to more than 150 studies and compared the results with images from the I.I.-CCD. In DSA mode, FPD System, which has a wide dynamic range, large detecting area, and good contrast ratio yielded superior angiogram images compared with the I.I-CCD system. In Fluoroscopy mode, we improved line noise and increased the contrast of catheters and guide wires with a new image processing technique. With these improvements, the image quality of the FPD System is superior to the I.I.-CCD system at the exposure range of over 2uR/frame (17.4 nGy/frame).