Characterization of a Dual Energy Angiographic System with CCD+FOS and Si-strips Detectors

We have investigated a non-conventional angiographic imaging methodology called dual energy angiography (DEA) based on a quasi-monochromatic X-rays source. An experimental DEA apparatus was developed. The Bragg monochromator, mounted on a standard W-anode X-ray tube, generates two thin parallel beams with energies peaked before (at EL=31.1 keV) and after (at EH=35.3 keV) the iodine K-edge (EK=33.2 keV). Images result as the difference between the logarithms of the transmitted intensities of the two beams. A dedicated dynamic phantom, simulating different tissues absorption and containing calibrated vessels, was scanned under the monochromator slits by a PC-controlled scanning system. Two types of detectors were used and tested: a linear CCD coupled with FOS and a Si-strips detector with energy window discriminator. In this work resulting imaging capabilities of the DEA experimental system were compared with those of a commercial SIEMENS ANGIOSTAR digital subtraction angiographic apparatus.