Define the term "exposure index" in digital radiography.

The term "exposure index" in digital radiography refers to a numerical representation of the amount of radiation exposure that the receptor (the digital imaging plate or sensor) has received during the imaging process. This index helps radiologists and technicians assess the exposure level to ensure that it is within a desirable range for optimal image quality.

An accurate exposure index indicates whether the image was underexposed or overexposed based on the amount of radiation used. Proper management of radiation exposure is essential for patient safety, helping to minimize unnecessary radiation while still acquiring high-quality diagnostic images. This makes the exposure index a critical tool in the field of digital radiography for monitoring and maintaining image quality and patient safety.

In contrast, other options such as measures of image clarity or resolution do not directly relate to the exposure measurement itself, as they focus more on the visual aspects of the final image rather than the radiation dose it received.