Which technologist mistake is most likely to cause processing errors within a computed radiography (CR) system?

• A. Incorrect focal spot selection
• B. Asymmetrical collimation
• C. Incorrect source-to-image distance (SID)
• D. Failure to include a radiographic marker

Answer: (B)

In CR, the image is processed by the computer using histogram analysis to determine exposure and set the final brightness and contrast. The processing assumes the exposed area is properly framed and centered with symmetrical margins. If the beam is asymmetrically collimated, the exposed portion of the plate isn’t balanced within the field, which distorts the histogram the processor relies on. That mismatch can lead to incorrect rescaling, brightness/contrast errors, or other processing artifacts. The other factors mainly affect image geometry or labeling rather than the processing algorithm: focal spot choice and SID influence sharpness and magnification, while omitting a radiographic marker affects documentation but not the automatic processing steps.