According to safety standards, what must the exposure switch in fluoroscopy be designed as?

The correct answer is that the exposure switch in fluoroscopy must be designed as a dead-man type. This design is crucial for ensuring patient and operator safety. A dead-man type switch requires continuous pressure to maintain exposure; if the operator releases the switch, the exposure is immediately terminated. This feature minimizes the risk of accidental overexposure to radiation, as it encourages operators to remain vigilant and actively manage the exposure during the procedure.

In contrast, options such as on/off type switches, while functional, do not provide the same level of safety. An on/off switch could potentially allow for prolonged exposure if left in the on position by the operator. Foot-operated only switches limit the operator's ability to control exposure intuitively and may not be practical in all clinical situations. Remote-controlled switches, although they provide some distance from the radiation source, do not inherently ensure that the operator maintains active control over exposure during procedures.

The dead-man type requirement is thus a key component of safety standards designed to protect both patients and personnel from unnecessary radiation exposure.