SSDs/flash media in general are completely safe from X-ray scanner damage regardless how often they are scanned.
I don't think even traditional hard drives are prone to X-ray damage from airport security equipment.
Now any photographic film, that's a different story, but it would have to be scanned a dozen times or more before it suffered damage. The fact that neither the airport staff or the public have to wear protective clothing shows just how weak the X-ray scanners must be compared to hospital machines.