This seems like an idea worth pursuing, from New York Times op-ed by Stephen E. Flynn and James M. Loy:

Since January 2005, every container entering the truck gates of two of the world’s busiest container terminals, in Hong Kong, has passed through scanning and radiation detection devices. Images of the containers’ contents are then stored on computers so that they can be scrutinized by American or other customs authorities almost in real time. Customs inspectors can then issue orders not to load a container that worries them.
The Department of Homeland Security has greeted this private-sector initiative with only tepid interest. But the Dubai deal provides an opportunity to adopt a system like the one in Hong Kong globally. Washington should embrace Dubai Ports World’s offer to provide additional guarantees to protect the five American terminals it wants to run. The company should agree to install scanning and radiation detection equipment at the entry gates of its 41 terminals in the Middle East, Europe, Asia, North America and South America within the next two years.
By making this commitment, the company could address head-on the anxiety of American lawmakers, governors and port city mayors that is fueling the uproar. The 45-day review period that has recently been agreed upon provides the breathing room to work out the details. Congress and the White House should appropriate the necessary funds to allay the concerns of the severely strained Customs and Border Protection agency, which, burdened by old and frail information systems, may worry that it can’t tap the revolutionary potential of such a comprehensive inspection approach.