A Columbia University professor who studies radiation effects believes we are underestimating the potential cancerous risk of going through airport X-ray scanners. "Skin cancers are a particular concern," says David J. Brenner.
The Director of the Center for Radiological Research's statements to DigitalJournal.com come at a critical time for travellers: the Transportation Security Administration in the U.S. is beefing up its X-ray scanner use, asking fliers to step through the scanner for security purposes. If travellers decline, they will be subjected to an intense pat-down.
But as intrusive as a pat-down may be to some travellers, is it safer than going through a scanner? According to Brenner, the "backscatter” X-ray machines used in some airports does deliver a low dose radiation but that figure has to be taken into context. Evaluating the risks comes with a hefty dose of uncertainty, Brenner points out.
Responding to the FDA statement that the radiation risk from these scanners are minuscule, Brenner replies, "When you multiply that minuscule risk by say two or three hundred to correspond to the potential annual usage of commercial air crew or a very frequent flier, the estimated individual risks for such people are still small, but perhaps would no longer be describable as 'minuscule'".
The TSA stands behind its machines. On a government website, it's written: "Manufacturers of any electronic products that emit x-rays, including these security systems, are required to: submit a radiation safety report to FDA before entering products into commerce and file annual radiation safety reports." Repeatedly, the TSA states there is no radiation risk found in their scanners.
But Brenner is concerned about the overall population risk. What if some activity involves a tiny cancer risk, Brenner wonders, perhaps one in ten million. Now suppose 10 people are exposed to that small risk: chances are none of them would get cancer as a result. But if a billion travellers are each exposed to that risk of one in ten million, then chances are that some of them "would get cancer as a result of that activity, even though the individual risk is extremely small."
Courtesy David Brenner
David Brenner, an expert on cancer radiation
He adds: "So even though the individual risk is very small, the impact on the population may not be small if the exposed population is large. This is potentially the case with airport X-ray scanners."
Skin cancers worry Brenner, he admits. He says the low-energy X-rays used in these scanners "deposit a significant fraction of their total dose, certainly not all, in the skin." He points out children are more sensitive than adults to radiation.
So should people opt for pat-downs instead of these scanners? Brenner believes the individual risk is quite small for infrequent fliers, but for those who fly often, "opting for pat-downs is perhaps a rational option."