Home-made grid
Commercial collimator test tool
The light field is collimated to the same size as the grid and an exposure is
made. The developed film will show the deviation of the x-ray field to the
light field. The magnitude of the deviation can be calculated by knowing the
Focus-Film-Distance.
(f)
Automatic exposure control (AEC) functions
AEC reproducibility:
The reproducibility is evaluated by analysis of multiple test images or
exposure measurements obtained at fixed kVp, mA and attenuator thickness.
AEC field sensitivity matching:
The sensitivity matching of the AEC fields and combinations thereof is
evaluated by analysis of multiple test images or exposure measurements for
each field and combination of fields at fixed kVp, mA and attenuator
thickness.
AEC density control selector function:
The ability of the AEC density control selector to allow the intentional
variation in image optical density form the normal value is evaluated by
analysis of test images and/or milliampere-second (mAs) measurements
obtained at each position of the density control selector.
Image receptor field size compensation:
The ability of the AEC system to maintain constant image optical density as a
function of image receptor size is evaluated by analysis of test images
obtained at a fixed kVp, mA and attenuator thickness.
AEC system performance capability:
The capability of the AEC system to provide consistent image optical density
over a broad range of imaging techniques and attenuator thickness is
evaluated by analysis of test images obtained for attenuator thicknesses
ranging from 5 cm to 30 cm.
(g)
Phantom images
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