What does "image noise" refer to in radiography?

"Image noise" in radiography refers to random variations in pixel values that can obscure the details of an image. This noise is typically caused by a variety of factors, such as electronic interference, insufficient exposure, or low radiation dose, which result in fluctuations in the digital signal recorded.

When noise levels are high, it reduces the overall image quality and can make it difficult to distinguish between actual anatomical structures and the random artifacts introduced by the noise. Therefore, a lower level of image noise is generally desired for clearer, more diagnostic images.

In contrast, excessive brightness in an image points to issues related to exposure but does not capture the concept of random variation in pixel values. Blurred images caused by motion would pertain more to the clarity and sharpness of an image, rather than the random distribution of pixel values. Artifacts caused by incorrect settings typically refer to systematic errors in the imaging process, which is a different issue from the inherent randomness associated with image noise.