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The x‐ray fovea, a device for reducing x‐ray dose in fluoroscopy
Author(s) -
Labbe Michael S.,
Chiu MingYee,
Rzeszotarski Mark S.,
BaniHashemi Ali R.,
Wilson David L.
Publication year - 1994
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.597309
Subject(s) - fluoroscopy , collimator , optics , x ray , image quality , physics , attenuation , glare , nuclear medicine , materials science , medicine , computer science , computer vision , image (mathematics) , layer (electronics) , composite material , nuclear physics
The x‐ray fovea (U.S. patents pending) is a device for reducing x‐ray dose to patients and operators during x‐ray fluoroscopy. It consists of a semitransparent collimator with an open, circular, central hole. The fovea collimator is placed at the exit of the x‐ray tube, and the attenuation of the peripheral x‐ray beam reduces x‐ray exposure to patients and operators. The shadow caused by the x‐ray fovea can be compensated using real‐time image processing hardware. Accurate compensation is demonstrated for both linearly and logarithmically acquired images using a model that accounts for beam hardening in the fovea collimator. The central fovea region has improved image quality due to reduced scatter and veiling glare from the periphery. From beam‐stop measurements, a 40% reduction in scatter plus veiling glare is measured using the fovea. A contrast improvement ratio of 1.5 is measured throughout the central region. In the compensated periphery, noise is increased by a factor of 1.66 because fewer photons are detected, but a small amount of temporal filtering compensates this degradation. The Roentgen area product (RAP) exposure to patients is reduced by ≊70%, while scattered exposure to operators is reduced by ≊60%.