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A K α dual energy x‐ray source for coronary angiography
Author(s) -
Manning Herbert L.,
Shefer Ruth E.,
Klinkowstein Robert E.,
Mistretta Charles A.
Publication year - 1991
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.596648
Subject(s) - physics , electron , optics , monte carlo method , spectral line , detector , atomic physics , materials science , nuclear physics , statistics , mathematics , astronomy
The use of characteristic‐line radiation from rare‐earth targets bombarded by high‐energy (up to 1 MeV) electron beams has been evaluated as an x‐ray source for dual energy K ‐edge subtraction imaging of the human coronary arteries. Two characteristic‐line x‐ray sources, one using the split K α1 and K α2 lines of lanthanum excited by a high‐energy electron beam and the other using the K α lines of barium and cerium, were studied. A Monte Carlo electron–photon simulation was used to calculate x‐ray spectra and energy deposition profiles from targets of these elements bombarded by electrons in the energy range 140 keV to 1 MeV. A general dual‐energy imaging model was developed that used these calculated source spectra to numerically investigate the dependence of the subtraction image signal‐to‐noise ratio on such factors as the ratio of K ‐line to x‐ray continuum yield, continuum spectral shape, x‐ray filtering, and detector response. A signal averaging technique for enhancing the signal‐to‐noise ratio was also evaluated. The results of these calculations were used to identify an optimum electron beam, target, filter, and detector configuration. A compact electron accelerator capable of providing the required electron beam parameters was designed. Calculations indicate that under ideal conditions the optimized system would be capable of imaging 2 mg/cm 2 of iodine contrast agent in 20 g/cm 2 of tissue with a signal‐to‐noise ratio of 5, a detector pixel size of 0.25 mm 2 , and a total image acquisition time of 10 ms. These parameters are consistent with those needed to image the human coronary arteries after an intravenous injection of iodine contrast agent. These capabilities, along with the relatively modest hardware requirements of this system, make it attractive as an x‐ray source for dual energy transvenous coronary angiography.