What is the role of an analog-to-digital converter (ADC) in digital radiography?

• A. Converts digital values to analog
• B. Converts analog electrical signals to digital values
• C. Stores latent image
• D. Processes image data

Answer: (B)

Converting a continuous signal into digital values is what an analog-to-digital converter does. In digital radiography, the detector outputs an analog voltage that varies with the amount of x-ray exposure. The ADC samples that voltage at a chosen rate and quantizes its amplitude into a finite number of levels, producing digital numbers that represent the image data. This digital form can be stored, displayed, and processed by computer systems. The sampling rate and the bit depth determine how accurately the original signal and the image’s dynamic range are captured.

This differs from other roles: turning digital data back into analog would require a digital-to-analog converter, while storing a latent image or performing data processing is done after the data are already digital.