An x-ray anti-scatter grid alignment aid has been developed and its performance evaluated for portable chest
radiographic exams. The grid alignment aid consists of one line laser and one cross-hair laser mounted on a supporting
frame. During an x-ray exam, the two lasers generate a predetermined light pattern on the x-ray collimator to indicate the
optimal x-ray source position in the three-dimensional (3D) space. Two grids commonly used in portable chest exams
(40 lp/cm resolution, 6:1 and 8:1 ratio, and 130 cm focal distance) were characterized in terms of the signal-to-noise ratio
improvement factor (SIF), as a function of the source image distance (SID), and x-ray tube lateral displacement from
which the optimal grid operation range was determined. Data indicated the grid alignment aid was able to provide
sufficient accuracy for positioning the x-ray tube to achieve optimal grid usage.
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