Airport Scanners: Revealing Body Secrets?

Airport body scanners are used to detect objects on or inside a person's body for security screening purposes, without physically removing clothes or making physical contact. They use advanced imaging technology (AIT) to detect a wide range of metallic and non-metallic threats in a matter of seconds. The scanners use electromagnetic millimeter waves, which are reflected off the passenger's skin and create an image that is interpreted by the machine. This image is a generic outline of a human body, with indicators showing where potential threats are located. The scanners do not see inside the body and are unable to detect items inside body cavities.

Airport scanners use electromagnetic millimeter waves to detect objects

Airport body scanners use electromagnetic millimeter waves to detect objects on or inside a person's body for security screening purposes. These scanners can detect non-metal objects, which was a growing concern after various attempts to bomb airliners in the 2000s. Millimeter wave scanners use non-ionizing electromagnetic radiation, similar to that used by wireless data transmitters, in the extremely high-frequency radio band. This is a lower frequency than visible light and do not generate ionizing radiation.

Millimeter wave scanners work by projecting electromagnetic waves over the human body, which bounce back to create a three-dimensional image. The waves are reflected off the skin and do not penetrate the body, so they cannot see internal organs or body cavities. The resulting image is a generic outline of a person, with indicators of any potential threats. This is designed to protect privacy and is less intrusive than previous methods.

The technology is also used to scan carry-on luggage. X-ray scanners are used to build a picture of what's inside bags, allowing security staff to check anything that looks suspicious. X-rays are beamed from one side of the machine and picked up by detectors on the other side. As the bag passes through, it absorbs some of the energy carried by the X-rays. When the X-rays hit the detectors, their energy and position are recorded. A filter between the two detectors blocks low-energy X-rays, so only high-energy X-rays reach the second detector. By comparing the outputs of the two detectors, the machine can construct an image showing the position and rough composition of objects in the bag.

Different materials are coloured differently on the display monitor. Organic materials like paper, food, and explosives are shown in orange, while blue or green is used for metals and glass. The denser the material, the darker the colour. This allows security staff to identify potential threats, such as components of an improvised explosive device (IED).

Scanners can detect metallic and non-metallic objects

Airport scanners can detect metallic and non-metallic objects on or inside a person's body, without physically removing clothes or making physical contact. These scanners use either X-ray or millimetre wave technology.

X-ray scanners use electromagnetic waves to build an image of what's inside your bag. They can pass through soft materials but are blocked by denser objects like metal. The X-rays that pass through your bag are picked up by a detector, and their energy and position are recorded. These X-rays then pass through a filter that blocks low-energy X-rays, and the remaining high-energy X-rays hit a second detector. By comparing the outputs of the two detectors, the machine can construct an image that shows the position and rough composition of the objects inside your bag. Different materials are represented by different colours on the display monitor, with organic materials like paper, food, and explosives appearing as orange, and metals and glass appearing as blue or green.

Millimetre wave scanners use non-ionizing electromagnetic radiation in the extremely high frequency (EHF) radio band, which is a lower frequency than visible light. They do not generate ionizing radiation and do not penetrate the skin, but they can detect objects on the body's surface and just underneath it. These scanners do not produce images of the body's internal organs or cavities, but they do detect anomalies in the body's regular contour, which may be caused by things like baggy clothing, jewellery, or objects in pockets. When such anomalies are detected, the operator will be alerted, and the person may be subjected to a pat-down inspection.

Backscatter X-ray scanners use low-dose radiation to detect suspicious metallic and non-metallic objects hidden under clothing, in shoes, or in body cavities. Transmission X-ray scanners use higher-dose penetrating radiation to detect objects hidden under clothing or inside the body, such as drugs carried in the stomach. However, due to health and privacy concerns, several countries have banned the use of X-ray scanners.

They cannot see inside the body or under the skin

Airport body scanners use millimeter waves, a type of non-ionizing electromagnetic radiation in the radio frequency spectrum, which do not penetrate the skin and therefore cannot see anything inside the body or under the skin. They are designed to detect objects on a person's body for security screening purposes, without physically removing clothes or making physical contact.

The machine scans the body according to the gender and detects anything that may be outside the regular contour of the body. For example, if you wear baggy jeans, hoodies, or jewellery, or have items in your pockets, it highlights a yellow box on the avatar on the screen, indicating to the TSA person that there may be something there that warrants a second look and a potential pat-down.

The body scanners are not X-ray machines and do not see your bones or organs. They are also not able to see inside body cavities. The technology is less intrusive and, due to privacy issues, most people are allowed to refuse this scan and opt for a traditional pat-down instead.

The display is generally not visible to other passengers and, in some cases, is located in a separate room where the operator cannot see the face of the person being screened.

Scanners use an avatar to indicate areas that need further investigation

Airport scanners use a variety of technologies to detect objects on or inside a person's body for security screening purposes, without physically removing clothes or making physical contact. These include metal detectors, backscatter X-ray machines, millimeter-wave scanners, and cabinet X-ray machines.

Millimeter-wave scanners, in particular, use non-ionizing electromagnetic radiation in the radio frequency spectrum to scan individuals. This technology does not penetrate the skin and does not produce images of a person's naked body. Instead, it projects a neutral avatar on a screen, indicating areas that may require further investigation through a pat-down.

The avatar is typically a generic, cartoon-like representation of a person, with a yellow box highlighting areas of interest. For example, if a person is wearing a watch, a box may appear on the avatar's wrist, prompting a pat-down to confirm the presence of an object. This technology helps address privacy concerns while ensuring effective security screening.

It is important to note that millimeter-wave scanners do not generate ionizing radiation, addressing health concerns associated with other types of scanners. These scanners are widely used in airports and have contributed to enhancing security measures.

Scanners can detect drugs and pills

Airport scanners cannot detect drugs and pills outright, but they do make it very easy for security personnel to spot them. The scanners detect any suspicious items, and security personnel then investigate to confirm whether any illegal items are present. If drugs are found, law enforcement may then get involved.

There are three main types of scanners used in airports: Millimeter-Wave Scanners, Backscatter X-ray Scanners, and Baggage Scanners.

Millimeter-wave scanners, also known as Advanced Imaging Technology (AIT) scanners, use millimeter-wave imaging, which bounces electromagnetic waves off the transmitter to the object being scanned. The scanner transfers these reflections as images, employing colours to note places that need actual screening. This type of scanner is extremely sensitive and can easily detect traces of drug particles.

Backscatter X-ray scanners screen passengers with ionizing radiation deflected by the human body. This type of scanner is controversial due to privacy concerns, as it reveals a detailed image of the person being scanned. However, most airports have replaced these scanners with AIT scanners.

Baggage scanners typically use X-ray technology to form detailed images of the luggage content. It is not possible to hide any items inside a bag from the baggage scanner because they are very thorough and emphasise the edges of all items in a bag.

In addition to these scanners, airports also use metal detectors and probes for security personnel to detect drugs. These devices are designed to pick up tiny traces of metals, which could then alert authorities that something is suspicious. Probes can also be used to further examine the contents of luggage without invading passenger privacy.

Another device used in airports is the nuclear quadrupole resonance machine, which can detect specific substances such as drugs. Trace detection equipment is also used to detect drugs and other narcotics in passenger luggage. These machines release gas into containers such as suitcases and detect the presence of substances that match those on the scanner's library.

Frequently asked questions