Airport Scanners Safe, When Working Properly

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Main Category: Radiology / Nuclear Medicine
Also Included In: Public Health;  Bio-terrorism / Terrorism
Article Date: 26 Nov 2010 - 11:00 PDT


Being scanned at an airport by a body scanner emits such a tiny amount of radiation, that there is no threat to health, as long as the machine is working properly, Peter Rez, Professor of Physics, Arizona State University says.

The chances of receiving a life-threatening cancer are approximately 1 in 30 million, Rez added. Compare that to a 1 in 5 million risk of being struck by lightning. Manufacturers say the radiation dose is one-thousandth of what one would receive during a dental x-ray.

These figures only refer to devices that are working properly and do not jam. Jamming is possible, during which a radiation dose can shoot up, Prof. Rez explained.

Even though body scanners have a safety mechanism that should shut off the machine if anything goes wrong, there is no guarantee that mechanism won't fail.

If the scanner jams and the safety mechanism fails, there is a chance a human could end up with a radiation burn.

In fact, Prof. Rez himself chooses not to go through the scanner because he has no idea what the risk of the safety mechanism failing is.

FDA Engineer Daniel Kassiday says:

"The dose from one screening with a general-use X-ray security screening system is so low that it presents an extremely small risk to any individual."

The FDA says that currently US airports use two possible scanning systems: 1. General-use X-ray security systems, or 2. Millimeter wave security systems.

General-use X-ray security systems are also called backscatter systems. Tiny amounts of X-ray (low dose ionizing radiation) bounce off the person who is being screened; the reflected energy is captured by a series of extremely sensitive detectors and then processed into an image via a computer. The radiation dose is so low, the FDA informs, that there is no limit on the number of screenings one person can have each year.

42 minutes of natural everyday-living radiation exposure is about equivalent to the radiation received from one general-use X-ray security system screening session, according to the FDA.

The full-body scanners used at airports are large enough for a person to walk into. The individual must remain inside for a few seconds while the scan is being done.

Kassiday explained:

"A person receives more radiation from naturally occurring sources in less than an hour of ordinary living than from one screening with any general-use X-ray security system."

Millimeter wave security systems use non-ionizing electromagnetic waves that bounce off the human body, the energy that bounces off generates an image. There are two types: active systems which expose the screened individual to tiny amounts of millimeter wave energy, and passive systems that sense naturally occurring millimeter wave emissions that radiate from a warm body.

Abiy Desta, an FDA scientist, said:

"Millimeter wave security systems that comply with the limits set by the Institute of Electrical and Electronics Engineers in the applicable non-ionizing radiation safety standard cause no known adverse health effects."

Source: FDA

Written by Christian Nordqvist
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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