What phenomenon is described by random fluctuations of signal often caused by low x-ray dose to the detector?

The phenomenon described by random fluctuations of signal caused by low x-ray dose to the detector is quantum mottle. Quantum mottle refers specifically to the statistical nature of x-ray photons, as they interact with the imaging detector. When the x-ray dose is low, fewer photons reach the detector, leading to an inconsistent signal, which manifests as random noise in the image. This randomness is due to the counting statistics of photons, meaning that fluctuations are normal and expected with low levels of radiation exposure. As the dose increases, more photons are detected, which reduces the appearance of quantum mottle and results in a clearer image.

Quantum noise is a broader term that relates to variances in signal due to photon interactions but does not explicitly convey the scenario of fluctuations due to low exposure in the same way that quantum mottle does. Signal distortion refers to alterations in the original image signal, typically due to equipment issues rather than low dose effects. Radiation interference involves unwanted variations caused by other radiation sources, which is not the situation being described in the context of low x-ray dose effects on the detector.