Variable filters used with radiation source to reduce unobstructed detector area

摘要

A variable filter arrangement wherein differently sized and shaped filters are automatically selected and installed from a collection of filters housed within a configuration for use with a radiation source. The line source is typically used for transmission scanning to collect attenuation correction factors. A line source is utilized in the preferred embodiment and a series of filters (e.g., differently sized "bow-tie" filters) are rotatably attached to a central junction so that a particular filter can be rotated into an installed position. When installed, the filter acts to attenuate the radiation emitted from the line source to reduce radiation emitted on an otherwise unobstructed area of a scintillation detector. Differently sized filters are advantageously used to accommodate differently sized patents and also to accommodate different unobstructed parts of a detector for different angles of rotation during an ECT transmission scan. The system includes processing intelligence to automatically select the proper filter given body contour (e.g., profile) information.