Which is NOT a step in a pre-exposure safety check?

The correct answer identifies a step that is not typically part of a pre-exposure safety check. Ensuring that all cassettes are in the room is generally considered a part of the overall procedure for preparing to take an x-ray but does not directly relate to safety measures prior to exposure.

Pre-exposure safety checks focus on ensuring that the environment and personnel are safe before an x-ray is taken. Closing the x-ray room door is critical to prevent exposure to radiation for anyone outside the room. Confirming the absence of nonessential persons in the x-ray room is vital to avoid unnecessary radiation exposure to individuals who do not need to be present during the procedure. Ensuring that all personnel in the control booth are behind the lead barrier also serves to protect them from radiation during the exposure, which is a fundamental safety requirement.

Focusing on these specific safety measures makes it clear that the presence of cassettes, while important for the imaging process, does not fit the criteria for immediate safety before an exposure is made. This distinction highlights the priority given to radiation safety protocols over equipment readiness in the context of a pre-exposure safety check.