What is the term for the blotchy appearance caused by an insufficient number of photons reaching the image receptor?

The term "quantum mottle" specifically refers to the blotchy or grainy appearance in a digital radiographic image that results from an insufficient number of photons reaching the image receptor. This phenomenon occurs because each pixel on the receptor may receive a varying number of photons, leading to fluctuations in the signal that is picked up. When the incident photon count is low, the statistical variability causes random variations in pixel brightness, resulting in a mottled appearance on the image.

It's important to understand that quantum mottle is a fundamental aspect of imaging techniques that rely on photon interactions. Adequate exposure is needed to ensure that a sufficient number of photons are captured, allowing for a smooth and uniform image without the undesired mottling effect. In contexts where exposure settings are too low or when the imaging equipment is not optimized for the conditions, quantum mottle is more likely to occur, indicating a need for adjustment in technique or equipment settings.