Picker International, Inc.

Robert E Shroy, Jr

Richard A Sones

Joseph S Deucher

Leonard F Plut

David Nicolay

Karen L Lauro

Marc Piscitelli

Charles G Cassudakis

Donald T Green

Louis A Paradiso

Steven C Kapp

In an x-ray imaging system, an x-ray detector assembly includes an x-ray detector and a support assembly secured to the x-ray detector for supporting an antiscatter grid assembly. The x-ray detector preferably includes a matrix of crystal detectors. The support assembly includes a foam bezel having one or more magnets disposed therein. The antiscatter grid assembly includes an antiscatter grid secured to a metal frame. The one or more magnets disposed in the bezel are situated so as to align with the metal frame of the antiscatter grid assembly when the antiscatter grid assembly is coupled to the x-ray detector assembly. The strengths of the one or more magnets are such as to allow the antiscatter grid assembly to be removably secured to the x-ray detector assembly. Alternatively, the one or more magnets may be secured to the metal frame of the antiscatter grid assembly and corresponding metal plates may be placed in the support assembly.

Magnetic support for removable antiscatter grid

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.

Digital angiography system with automatically determined frame rates

An x-ray imaging system incorporating a television imaging chain is disclosed. The system includes automatic gain control circuitry, operable upon the video signal produced by the camera of the television imaging chain. The gain control circuitry affords automatic gain control capability for increasing the video gain in response to an undesired decrease in video output signal level. The gain control circuitry, however, is constrained in that it includes circuitry for establishing a minimum video gain which is always maintained during a study, irrespective of increases in brightness of an overall sample window area of the image, which could otherwise cause undesirable darkening of areas of interest in the image when the sample window also includes uninteresting structure which happens to exhibit a bright field.

Radiation imaging automatic gain control

An artifact inducing image acquisition mapping system and technique is described for use in connection with digital imaging. A gray scale mapping technique is employed to indicate to an operator the brightness function of each pixel of an image. Where the brightness function is less than 95% of saturation, the image is displayed normally. Where the brightness function is at least equal to the saturation full scale value, that portion of the image is displayed in total black. Where the brightness function is between 95% and 100% of saturation full scale value, the image portion is displayed as mixed dark and light, i.e., a speckled region. An alternate embodiment simply displays saturated regions to total black.

Medical imaging system and method having gray scale mapping means for

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Willoughby, OH, United States of America

Robert E Shroy, Jr