In radiology, what is meant by image brightness?

Image brightness in radiology refers to the level of illumination of the displayed image on a monitor or film. It is typically controlled by the window level setting in digital imaging systems. The window level determines the midpoint of the range of grayscale values displayed, which directly affects how bright or dark the image appears to the viewer.

When the window level is adjusted, it shifts the brightness of the entire image, allowing for better visualization of structures depending on their density and the amount of attenuation they cause. This setting is crucial when interpreting images, as it helps radiologists discern details that may be obscured due to poor brightness.

The overall exposure of the film, enhancing contrast, and total absorption of x-rays each play significant roles in radiographic imaging but do not directly define image brightness. Overall exposure relates to the quantity of radiation that reaches the film, contrast concerns the difference between various densities within the image, and absorption pertains to how x-rays are absorbed by different tissues. Thus, window level is the most precise term related to adjusting image brightness.