Compact Flash memory cards (like the ones used by many Nikon digital cameras), use a solid state system that has no moving parts and is not sensitive to X-rays or magnetic fields. There should be no danger in having these types of cards scanned by security devices like those found in airports.
Some Nikon cameras use the "Micro Drive" which is a tiny portable hard drive that fits into the Compact Flash card slot. These cards do use a magnetic storage drive to store images and there is the potential that these could be damaged by the large magnets in the motors that drive the belts in airport scanners. Having these hand checked may reduce the risk of image loss.
The digital cameras themselves are not sensitive to X-rays and will not be damaged by a properly operating security scanner.
منبع : سایت نیکون