Noninvasive digital energy subtraction angiography with a channeling-radiation x-ray source

Channeling radiation could provide a viable source for digital energy subtraction angiography (DESA). A signal to noise ratio (SNR) of 6.2 for a resolution of 0.5 mm x 0.5 mm could be achieved using a 6-mA 100-ms 20-MeV electron-beam pulse and a diamond channeling crystal as the x-ray source. This article investigates the choice of a DESA contrast agent and the parameters of a channeling-radiation x-ray source to develop a channeling-radiation DESA imaging system. The production of dual-energy peaks, the maximum available x-ray flux, the advantages of an area exposure, the necessity of a mosaic Bragg-crystal filter to reduce patient dose, the optimal energy separation of the peaks for a quasi-monochromatic x-ray source, and the reduction of the signal from bone are discussed, leading to estimated SNRs and image resolution for a channeling-radiation imaging system. The computer analysis developed to calculate the image quality is also discussed.