Natural background radiation can cause fog to appear on the image

The reasons for rescue failure can be referred to by the mnemonic FAILURE. According to this mnemonic, the "U" stands for:

A. underutilizing personnel at the scene. B. unprepared to effectively manage the scene. C. underestimating the logistics of the incident. D. undertrained to correctly utilize equipment.

Which of the following is responsible for termination of exposure to avoid overexposure to the patient?

cumulative timer dead-man exposure switch ALARA backup timer