6. Conclusion: are X-ray security scanners safe?
Health risks are close to zero for individuals, but the risk cannot be ignored for populations.
The radiation doses to screened passengers are very low compared with other sources such as cosmic radiation received during a flight, even after taking into account the likely number of scans received by frequent flyers.
Doses from X-ray scanners pose no short-term risks such as tissue damage. The long-term effects such as cancer risks, cannot be entirely excluded but if they exist, they are orders of magnitude below the cancer risk due to other factors.
The annual dose limit for the general public is 1mSv. The radiation dose from a single backscatter scanner is tiny and even if someone was scanned 3 times a day, every working day, he would receive an annual dose well below the set limit. The dose from transmission scanners is at least 10 times higher than that from backscatter scanners but is still safe, even for vulnerable individuals. However, if transmission scanners are used routinely, frequently exposed individuals such as air crews, couriers or frequent flyers could receive doses higher than the limit set for the general public. Scanners using non-ionising radiation such as mm wave or THz scanners are not powerful enough to cause short-term tissue damage, and other health effects have not been proven. There is no scientific evidence to predict long-term effects. More...