Radiation safety rests on three principles — time, distance and shielding — supported by dose monitoring:
1. Time: Shorten exposure time to reduce the radiation dose received.
2. Distance: Operators should keep a safe distance from the radiation source; for X-ray machines, at least 1 metre is recommended.
3. Shielding and isolation: Use shielding such as lead plates and concrete walls, and set up controlled areas (dose rate > 15 μSv/h) and supervised areas (> 2.5 μSv/h).
4. Monitoring: Wear personal dosimeters to monitor radiation dose in real time, and install fixed dose alarms in the workplace.