Body Scanners: Airport Security's Inner Workings Explained

Airport body scanners are used to detect objects on or inside a person's body for security screening purposes. They can detect non-metal objects and items hidden in body cavities, which metal detectors cannot. There are two types of body scanners: passive and active. Passive scanners detect natural radiation emitted by a person's body, while active scanners add artificial radiation to improve detection. Both types of scanners use millimetre-wave technology, which bounces waves off an individual's skin to produce an outline image of their body, showing any concealed, potentially dangerous objects.

Millimeter-wave technology

Passive millimeter-wave scanners detect natural radiation that is emitted by a person's body and use it to locate objects worn or hidden on the body. Active millimeter-wave systems add artificial radiation to improve detection. Measurements have shown that both passive and active systems give rise to low exposures to high-frequency electromagnetic fields, and health effects are not expected.

Non-ionizing radiation

Millimeter-wave technology uses non-ionizing radiation in the form of low-level radio waves to scan a person's body. This technology does not use x-rays and does not add to a person's ionizing radiation dose. Millimeter-wave body scanners use two antennas that rotate around a person's body to construct a 3-D image that resembles a fuzzy photo negative. The image is then sent to a remote monitor.

Millimeter-wave technology uses low-energy non-ionizing radiation that releases thousands of times less energy than a cell phone. This technology is considered safe, with health effects not expected. The Transportation Security Administration (TSA) uses body-scanning units in airports across the United States.

There are two types of full-body scanners: passive and active. Passive scanners detect natural radiation emitted by a person's body to locate objects worn or hidden on the body. Active systems add artificial radiation to improve detection. Millimeter-wave scanners use non-ionizing electromagnetic radiation similar to that used by wireless data transmitters. This radiation is in the extremely high-frequency (EHF) radio band, which is a lower frequency than visible light.

Low-level radio waves

Airport body scanners use low-level radio waves in the form of millimetre-wave technology. This technology uses non-ionising radiation to scan a person's body. The scanner uses two antennas that rotate around the body to construct a 3D image. This image is sent to a remote monitor and resembles a fuzzy photo negative.

Millimetre-wave technology does not use x-rays and does not add to a person's ionising radiation dose. Instead, it uses low-energy non-ionising radiation that releases thousands of times less energy than a cell phone. This technology is considered safe and does not have any known health effects.

Millimetre-wave imaging offers a superior approach to screening people compared to existing methods such as metal detectors. It works by bouncing millimetre waves off an individual's skin to produce an outline image of the person's body, showing any concealed, potentially dangerous objects.

The image produced by millimetre-wave technology is not a detailed representation of the person's body. Instead, it shows a generic human shape, much like a gingerbread man, without any identifying features. This shape is the same for every traveller going through the airport scanner. The images are analysed digitally within the equipment and are never seen, stored, printed, or transmitted.

3-D image

The Transportation Security Administration (TSA) uses body-scanning units in airports across the United States. These body-scanning units traditionally use millimetre-wave technology. Millimetre-wave technology uses non-ionising radiation in the form of low-level radio waves to scan a person's body. The scanner constructs a 3-D image that resembles a fuzzy photo negative. The image is sent to a remote monitor.

Millimetre-wave technology does not use x-rays and does not add to a person's ionising radiation dose. The United States uses millimetre-wave technology in airport security scans. This form of technology uses low-energy non-ionising radiation that releases thousands of times less energy than a cell phone.

Millimetre-wave imaging offers a superior approach for screening people compared to existing methods such as metal detectors. It works by bouncing millimetre waves off an individual's skin to produce an outline image of the person's body, showing any concealed, potentially dangerous objects.

There are two types of full-body scanners: passive and active. Passive scanners detect natural radiation that is emitted by a person's body and use it to locate objects worn or hidden on a person's body. Active systems add artificial radiation to improve detection (backscatter technology).

Active and passive scanners

There are two types of body scanners used in airports: active and passive scanners. Passive scanners detect the natural radiation emitted by a person's body and use it to locate objects worn or hidden on a person's body. Active scanners add artificial radiation to improve detection. Both types of scanners use millimetre-wave technology, which uses non-ionising radiation in the form of low-level radio waves to scan a person's body. This technology does not use x-rays and does not add to a person's ionising radiation dose. The scanner constructs a 3D image that resembles a fuzzy photo negative. This image is sent to a remote monitor, where it is analysed digitally. The millimetre-wave image of the passenger is never seen, stored, printed, or transmitted. Instead, airport security staff see a generic human shape, much like a gingerbread man, without any identifying features. This generic human shape is the same for every traveller going through an airport scanner.

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