CORONARY ARTERIOGRAPHY - DEVICES FOR IMPROVEMENT OF CINERADIOGRAPHIC SYSTEM

The various elements through which an image is transmitted for final diagnostic viewing are highlighted, with emphasis on the following points: 1. 1. The level of radiation must be such that sufficient statistical data are present in the x-ray image. This is accomplished by grid switching in the x-ray tube working on a constant potential power source. 2. 2. The signal-to-noise ratio in the x-ray image is kept high by means of a good collimating system and by using as small a focal spot as possible. 3. 3. The x-ray image is converted to a high quality light-image by choosing a high gain, high solution image amplifier. 4. 4. Resolution is optimized by use of a variable focal length system that records an image magnified to a degree in keeping with the desired field of view. This makes visible fine vessel detail that otherwise would be lost in the grain structure of the film. The present image quality at the image amplifier output phosphor is such that optical magnification beyond three times produces little or no increase in fine vessel visibility because of the grain structure and scintillation pattern of the image amplifier. To some extent the scintillation pattern can be reduced by increasing radiation to the patient. As indicated in the Appendix, we believe that a reasonable optimum has been selected for the currently available components. The work presented here deals with only a few of the steps by which a cineradiographic system can be improved. We recognize that there are other areas for improvement which will be investigated in the future. © 1968.