ABSTRACT
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.
Subject(s)
Angiography, Digital Subtraction/methods , Angiography, Digital Subtraction/instrumentation , Angiography, Digital Subtraction/statistics & numerical data , Biophysical Phenomena , Biophysics , Computer Simulation , Contrast Media , Humans , Iodine , Models, Structural , Sensitivity and SpecificityABSTRACT
A radiation source has been developed and implemented from Cerenkov emission that is intended to provide an intense continuum from the infrared to 600 A. Parasitic use of the primary electron beam at the Stanford Linear Accelerator Center (SLAC) together with a novel optical geometry for light collection can give a focused and tunable ultraviolet beam with 10(4) kW/m(2)sr brightness, 10(-2) spectral purity, and with the pulsed, 5 ps time structure of the SLAC electron beam. Measurements of emission characteristics in the visible part of the spectrum correlate closely with the predicted performance.
