Much less than most people assume. A security scanner is a shielded cabinet: the generator runs only while a bag is passing, and the enclosure is lined with lead. Measured at 5 cm from the surface, the leakage on our units is below 0.3 µSv/h — which is the same order as the natural background you are exposed to standing in a room.
Nobody needs to stand behind the machine, and nobody should. Operators work at the display, which sits beside or above the tunnel, not behind the cabinet. For passengers, the practical rule is simple: keep the queue outside the marked zone and do not reach into the tunnel while a bag is moving. A correctly installed unit does not require a separate radiation barrier — the cabinet is the barrier — but the installation must be checked on site, and the leakage test record should be kept with the machine.
Yes. The cabinet is shielded and the beam is only on during a scan; measured leakage is a small fraction of the occupational limit. Staff who are pregnant should still inform their employer, as they would for any workplace assessment.
For a properly installed cabinet scanner, usually no — the dose is too low to be measurable. Sites that also handle open sources or higher-power industrial systems have different rules.
The physics is the same, the dose is not. A medical chest X-ray gives roughly 0.1 mSv in one exposure; a baggage scanner is designed so that nobody is in the beam at all.
A radiation leakage test report for the unit, the declaration of conformity and, in most markets, registration with the local radiation authority. Ask for all three.
