Automatic brightness control (ABC)

Automatic brightness control (ABC) is a device incorporated into the fluoroscopic unit. Its function is to maintain a consistent overall appearance of the image by automatically adjusting the kVp and/or mAs.

In this regard, ABC systems are analogous to the AEC systems utilized in radiography.

Note that modifying either of the above parameters will directly affect patient dose.

The first generation of ABC systems involves the use of a photosensor to measure the image intensifier light output signal. Newer ABC systems electronically sample the video signal.