Which digital radiography system uses exposure indicators (S-number) to express the radiation dose received by the image receptor?

The system that utilizes exposure indicators, specifically the S-number, to communicate the radiation dose received by the image receptor is computed radiography. In computed radiography, a photostimulable phosphor (PSP) plate captures the image, and upon processing, it provides a numerical value (the S-number) that correlates with the amount of exposure the plate received. This indicator helps radiologic technologists assess whether the exposure was within the ideal range, aiding in image quality and patient safety.

In contrast, direct radiography uses flat-panel detectors that convert x-rays to digital signals, and although it also provides exposure indicators, the specific metrics and terminology differ from the S-number system. Film-screen radiography does not involve digital indicators as it uses traditional film. Digital fluoroscopy refers to real-time imaging and does not focus on exposure indicators in the same way as computed radiography does. Thus, the correct identification of the S-number in this context highlights the unique characteristics of computed radiography and its approach to managing and evaluating radiation dose.