'Filter Grid' Searchterm 'Filter Grid' found in 1 term [ • ] and 3 definitions [• ]Result Pages : • Filter Grid
Filter grids are used to reduce scattered noise and increase contrast in x-ray images. Primary radiation passing through an object gets scattered caused by the various density of different materials. Scatter radiation produces noise (radiographic fog) on the film or detector, which degrades the diagnostic quality. Anti-scatter grids act as filters between patient and film (or receiver) to remove scatter radiation. The use of a grid is recommended with body parts thicker than 10 cm and kVp values about 60 kV. X-ray filter grids are available with focused or parallel strips. These two types are produced with linear or crossed grid configurations. The septa of filter grids consist of high radiation absorbing materials (e.g. lead) separated by permeable parts. During radiation exposure, movement of the grid blurs a projection of the septa. If the image receptor and x-ray tube (with the focal spot) are in a fixed position relative to one another the grid is automatically aligned. In mobile radiography, the position of the focal spot and the image receptor is variable. Additionally cassettes incorporating anti-scatter grids are also available. • •
Compton scattering is the deflection of gamma- and x-ray photons by electrons. See also Compton Continuum, Compton Effect, Air Kerma, Filter Grid, Focused Grid, Grid Efficiency, and Compton Arthur Holly. Further Reading: News & More:
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Grids are used in a test phantom to check the quality of x-ray images. Such a grid may consist for example, of gold structures on a silicon surface and a grid period length of 2 micrometer with space wide in between of 1 micrometer. Filter grids are also used in x-ray imaging to reduce noise contributed by scatter. Result Pages : |