What happens when Automatic Brightness Control (ABC) maxes out?

When Automatic Brightness Control (ABC) maxes out, the system utilizes Automatic Gain Control (AGC) to adjust the image. ABC is designed to maintain image brightness by automatically adjusting the x-ray output during fluoroscopic procedures to compensate for changes in patient thickness or anatomy. When ABC reaches its maximum capability, it can no longer adequately respond to further increases in image brightness. At this point, AGC takes over and works to maintain image quality by amplifying the signal from the image receptor. AGC adjusts the overall gain of the system rather than changing the x-ray output, ensuring that the image brightness and quality remain as optimal as possible even in challenging conditions. This transition is crucial for maintaining a clear and diagnostic image under varying exposure conditions during fluoroscopy.