Reduction of flicker during video imaging of cine procedures

Abstract

A method and apparatus for use in a medical x-ray imaging system of the type including an x-ray source, an image intensifier tube for providing a momentary x-ray image of a patient exposed to x-rays and a video camera having video processing circuits for providing signals representative of a video image of the x-ray image on the intensifier tube to a video monitor provides a flickerless image presentation on the video monitor when the x-ray exposure repetition rate is different from the field scan rate of the video camera. The apparatus enables this result by sensing initiation of a first x-ray exposure and setting the amplification of the video processing circuits to a first value for obtaining a suitable presentation of the image. The apparatus then scans the image on the video camera to provide a first field of image presentation to the video monitor with the amplification set at the first value. The apparatus then directs initiation of a subsequent scan of the image on the video camera prior to a second x-ray exposure and concurrently increases the amplification of the video processing circuits to a second value such that a second field of image presentation is generated having substantially the same intensity as the first field. Since each field is then presented with the same intensity level, the flicker effect associated with a non-synchronized presentation is avoided.