What phenomenon occurs when there is a low number of absorbed photons in a fluoroscopic image?

When there is a low number of absorbed photons in a fluoroscopic image, the phenomenon that occurs is known as quantum mottle. This is a forms of image noise that results from the statistical variation in the number of photons that reach the detector or image receptor. In essence, when the photon count is insufficient, it leads to grainy or mottled images, where areas with fewer incident photons appear more pronounced and exhibit fluctuations in brightness.

Quantum mottle specifically highlights the effect of insufficient signal or exposure, making it clear that a low number of absorbed photons contributes directly to this imaging artifact. Thus, understanding this phenomenon is crucial for optimizing image quality in fluoroscopy, as it directly relates to patient dosage and the accuracy of diagnostic imaging. By increasing the number of photons (through exposure time or dose adjustment), one can reduce the effect of quantum mottle and achieve a clearer, more uniform image.