Digital angiography system with automatically determined frame rates

Abstract

A subject is positioned on a patient support (12) between an x-ray source (10) and a radiation detector assembly (14). The x-ray source is gated (36) on or open prior to triggering (38) a video camera (26) of the x-ray detector assembly to generate an electronic frame image representation. The patient support is moved to generate reference images at positions (5, 4, 3, 2, 1) and the resultant reference images are stored in a reference image memory (42). A radiopaque dye is injected adjacent a first position (1) and the x-ray source and camera are triggered at a first rate indicated by a scan program memory (50). The generated images are displayed on a video monitor until a radiologist decides that the radiopaque dye has moved downstream sufficiently that it is time to index to a second position (2). The radiologist presses an index button (68) causing the patient to be indexed. A timer (48) compasses the actual dwell time that images were collected in the first position (1) with a set of reference dwell times (72). In accordance with the comparison, a second frame rate from the scan program memory is incremented or decremented (74). Images are then generated in the second position with the adjusted second frame rate. This process is repeated for each of a plurality, e.g., five or six positions.