The European Union adopted new guidelines Monday on using body scanners at airports, hoping to address the privacy concerns that have delayed their implementation across the continent.
Siim Kallas, the EU commissioner responsible for transport, said under the rules the technology will only be used with strict safeguards to protect health and fundamental rights.
"Security scanners are not a panacea but they do offer a real possibility to reinforce passenger security," he said.
The scanners, some of which produce nude-like images of passengers, are already used in the United States and elsewhere as a more effective screening of passengers than metal detectors.
Scanner technology is developing rapidly and has the potential to significantly reduce invasive pat-downs. The latest machines are equipped with software that displays a generic outline of a human body, with a red box around the area where a passenger may be concealing an object.
EU member states and airports do not have an obligation to deploy security scanners, but if they decide to use them, they will have to comply with the EU-wide operational standards.
Under the new EU law, security scanners must not store or copy any of the images, and the security staff analyzing the images will be in a room separate from where the actual screening is conducted. In addition, passengers must be informed and be given the right to choose an alternative method of screening.
And in order not to risk citizens' health and safety, only security scanners that do not use X-ray technology can be used at EU airports.
"The most important provision is that every passenger has the right to opt out and ask for the use of an alternative method," said Helen Kearns, spokeswoman for the transport commission.
EU states have been mulling the use of security scanners ever since Umar Farouk Abdulmutallab, a 24-year-old Nigerian, attempted in 2009 to blow up a plane flying from Amsterdam to Detroit with plastic explosives he had hidden in his underwear.
Until now, security scanners were used in a limited way under a patchwork of different national operational procedures. The scanners have tested in France, Italy, Finland and other countries, and been used at airports in Britain and the Netherlands.
But the whole body imaging machines have sparked outrage among some passengers and privacy advocates because the explicit images they display. Germany has already said it won't introduce them.
Authorities tested the scanners at Hamburg airport for 10 months on passengers who volunteered. Among the findings, they said the machines' software proved too sensitive to things such as creases in suits.