The artifact from exposure beyond the imaging latitude is called what?

• A. Quantum mottle
• B. Saturation artifact
• C. Quantum noise
• D. Geometric distortion

Answer: (B)

Imaging latitude is the range of exposures over which an image maintains usable density and detail. When exposure pushes beyond that range, the brightest parts of the image reach the maximum density the receptor can show, so those areas become clipped white and lose all detail. This is called a saturation artifact. It happens because the detector’s dynamic range is exceeded, so signal cannot be recorded any higher, even though the actual anatomy might be very bright.

This differs from quantum mottle and quantum noise, which arise from too little exposure and result in grainy, speckled areas due to insufficient photons reaching the detector. Geometric distortion, on the other hand, comes from misalignment or improper geometry of the X-ray beam and image receptor, not from exposure level.