Quantum noise limits ability to see:

• A. Detail
• B. Contrast
• C. Fatty tissue
• D. Additive pathologies

Answer: (A)

Quantum noise comes from the random, particle-like nature of photons detected in an image. Because only a finite number of photons are recorded, their arrival varies from moment to moment, creating grainy fluctuations in the image known as shot noise. This noise blurs fine structures, so the ability to resolve small, closely spaced details is reduced when photon counts are low.

In practice, more photons (a higher dose) reduce this randomness, increasing the signal-to-noise ratio and allowing finer details to stand out clearly. That’s why quantum noise most directly limits the visibility of detail rather than, say, identifying fatty tissue or specific additive pathologies—the core effect is on how well small structures can be distinguished in the image, which is a matter of spatial detail.