What does the term "quantum mottle" refer to in fluoroscopic imaging?

The term "quantum mottle" refers specifically to variability in brightness that occurs in fluoroscopic imaging due to insufficient x-ray exposure. This phenomenon results from the statistical nature of x-ray photon detection; when the exposure is low, the random arrival of x-ray photons can cause certain areas of the image to appear brighter or darker, leading to a grainy or mottled appearance. This variability arises because not enough photons are available to produce a uniform image, meaning that areas receiving fewer photons appear darker, while those with adequate exposure appear lighter.

In contrast, loss of contrast pertains to the inability to distinguish between different tissues or densities in the image, which is a separate issue primarily related to the settings of imaging parameters or the quality of the imaging medium. Increased image distortion relates to inaccuracies in the representation of the anatomical structures, often due to issues with the equipment or positioning. Improved resolution refers to the clarity of the image and the ability to discern fine details, which is not what quantum mottle describes. Thus, the correct understanding of quantum mottle aligns directly with the concept of variability in brightness in fluoroscopic imaging.