What measurement is commonly used to express the quality of an image in radiography?

The measurement that is commonly used to express the quality of an image in radiography is Contrast-to-Noise Ratio (CNR). CNR is an important indicator of image quality as it assesses the contrast between the structures of interest against the background noise present in the image. A higher contrast-to-noise ratio suggests that the details of the image are more distinct and discernible, which is crucial for accurate diagnoses.

In radiography, having a sufficient CNR ensures that subtle differences in tissue densities can be effectively distinguished. This is particularly important in clinical settings, where a high-quality image can significantly impact the interpretation of findings and subsequent patient management.

While Signal-to-Noise Ratio (SNR) and Spatial Resolution (SR) are also critical parameters for evaluating image quality, they focus on different aspects. SNR relates to the overall clarity and visibility of the signal containing the useful image information in relation to the noise. Spatial Resolution defines the ability to discern fine details in the image, typically referring to the sharpness or the degree of detail visible. Dynamic Range (DR) refers to the range of exposure levels that a radiographic system can effectively capture, affecting the images' contrast quality.

Thus, the focus on contrast in the context of CNR makes it