Clinical aspects of image quality and doses in gated pulsed imaging

PURPOSE: The relations between image quality in last image hold images and dose in grid controlled fluoroscopy in comparison to the continuous mode need to be characterised and recommendations for the clinical application of this technique should be given. MATERIAL AND METHODS: Spatial resolution, signal-noise ratio and, contrast-detail visibility were evaluated by phantom measurements in grid controlled pulsed and continuous fluoroscopy. Dose was measured at the image intensifier entrance. Image quality of last image hold (LIH) images of clinical examinations was graded in relation to single shot exposures. RESULTS: Signal-noise ratio and contrast-detail visibility depend on the dose per puls. Spatial resolution and contrast-detail visibility in grid controlled fluoroscopy are superior than to in the continuous mode. Image quality of the LIH images from the grid controlled fluoroscopy was improved. Radiation exposure could be reduced to 10-46%. CONCLUSIONS: Combinations of puls-dose and -frequency are recommended for achieving extensive dose reduction and improved image quality of LIH images.