Airport Scanners: What They See And How They Work

Airport scanners are designed to detect objects on or inside a person's body, without physically removing clothes or making physical contact. They use technologies such as X-ray backscatter, millimeter-wave, and metal detectors to identify threats, including weapons, explosives, and items in violation of carry-on rules. While early versions of scanners raised privacy concerns by revealing detailed images of the human body, today's scanners use avatars to ensure privacy, generating generic body outlines without specific identifying features. Scanners can detect metal and non-metal objects, including paper and organic materials, but cannot see inside the body. Concerns have been raised about the safety of ionizing radiation used in some scanners, particularly for certain populations like pregnant women and children.

Airport scanners can detect metal and non-metal objects

Airport scanners are designed to detect a wide variety of materials, from metals to plastics, organic compounds, and explosives. They can also detect items hidden in clothing, bags, or within the body, such as swallowed items or items hidden in body cavities.

Metal detectors use magnetic fields to identify metal objects. When a metal object is present, the magnetic field is reflected back to the machine, and a beeping noise alerts the agent. While metal detection remains a priority, non-metallic materials are increasingly being used to create weapons and other threats. Advanced X-ray scanners can identify such items by analyzing their shape, density, and other visual cues. For example, X-ray scanners can detect the presence of metal, but they cannot see through dense metal objects. Instead, metal objects appear as opaque or dark areas on the X-ray image, prompting further inspection by security personnel.

Millimeter-wave scanners, on the other hand, do not see through metal but can detect metal objects on a person's body. These scanners emit non-ionizing radiofrequency waves that are reflected by metal, creating an outline image. Security personnel use this information to determine if further inspection is required. Millimeter-wave scanners are also useful for detecting non-metallic objects, including weapons, explosives, and drugs hidden under clothing.

Additionally, full-body scanners can detect non-metal objects, which became a significant concern after several airliner bombing attempts in the 2000s. They can also detect medical equipment normally hidden, such as colostomy bags and catheters. Airport scanners are also designed to flag liquids, gels, and aerosols that exceed certain volume limits, as these are potential security threats.

Scanners can detect money

Airport scanners are primarily designed to detect items that could potentially threaten aviation security, such as weapons, explosives, and other contraband. However, they can also detect money.

X-ray scanners, for instance, can detect the presence of cash, albeit indirectly. When luggage passes through an X-ray scanner, the contents are displayed on a screen based on their density and material composition. Currency notes, especially in large amounts, have a distinctive appearance on the X-ray image. They may appear as stacks of uniform rectangular shapes that can be easily distinguished from other items.

Advanced Imaging Technology (AIT) Scanners, on the other hand, create detailed images of a passenger’s body to detect concealed items. While not designed to detect cash, these scanners might reveal unusual bulges or shapes that could prompt further inspection if a passenger is carrying large sums of money on their person.

Additionally, modern currency often incorporates various security features that interact with light, such as thin-film interference effects in US currency, or diffraction gratings found in polymer dollars in other countries like Australia, which could affect their appearance under scanning technology.

It is important to note that while airport scanners can detect money, their main goal is not to count cash but to ensure the safety and security of air passengers. Customs regulations in various countries dictate how much currency individuals can carry when traveling, so passengers should be aware of these limits to avoid penalties during inspections.

They can see under clothes

Airport body scanners can detect objects that are under clothes and layers. They can detect metal and non-metal objects, such as weapons, explosives, and drugs, and their exact location on the body. They can also detect other non-metal items, such as paper and money, and medical equipment like colostomy bags, catheters, breast prostheses, and prosthetic testicles.

Full-body scanners do not, however, reveal the naked body or the insides of the body. Instead, security staff see a generic human shape, without any specific identifying features, that resembles a doll. The scanners also do not pick up size, weight, or height. They do not detect health issues such as tumors or inflammation.

In the US, older machines that are no longer used in checkpoints allowed officers located away from passengers to see under clothing. However, the officer at the checkpoint was not the same one who saw the scan, and the remote officer was unable to see the identity of the person being screened. Today, if there is no alarm, officers don't see anything at all—simply a screen reading "OK."

There are health concerns about the radiation used in some scanners. The US and Canada use millimeter-wave technology, which is safe for pregnant people and those with pacemakers. It is also safe for travelers with breast implants, although breast prostheses will be detected. X-ray machines and metal detectors pose a very limited risk to those with pacemakers, but it is recommended to inform the security agent if you have a pacemaker implanted.

Scanners can detect drugs

Airport scanners can detect drugs, but not in the way you might think. Scanners don't specifically look for drugs, but they can provide visual clues that indicate the presence of drugs. This is because drugs often have distinct signatures that trained security officers can identify. For example, organic materials like drugs, food, explosives, or paper are marked with an orange colour.

Drugs, especially when compressed, may show up as dense, opaque masses on scanners. The software flags any dense material that doesn't match the expected density of normal items. Unusual packaging can also be detected by scanners, such as drugs concealed within electronics or hollowed-out items.

Millimetre-wave scanners can detect drugs hidden in clothing or strapped to the body by identifying unusual shapes or densities that stand out against the natural contours of the human body. These scanners can also detect swallowed items or items hidden in body cavities, as these differ in density from normal tissues.

X-ray scanners can also be used to detect drugs in luggage by identifying objects with different densities, as drugs will appear differently on X-ray images compared to metal or plastic.

They can detect breast implants

Airport scanners can detect breast implants. While this may be a cause for concern for some women, it is important to remember that security officers are professionals who are focused on ensuring safety and are not looking to embarrass passengers. Full-body scanners can detect numerous kinds of implanted medical devices, including pacemakers, artificial joints, and breast implants.

Passengers are not required to disclose the presence of breast implants to TSA officials. While older scanners may not have been able to detect such implants, newer scanners can indeed "see" them. However, it is worth noting that breast implants typically do not contain metal, with the exception of tissue expanders that may have a metal port. In such cases, it is advisable to notify the TSA agent and carry an implant identification card to confirm the medical necessity.

The detection of breast implants by airport scanners has raised privacy concerns among some women who prefer to keep their augmentation surgery confidential. However, it is important to emphasize that airport security personnel are trained to handle such situations discreetly and professionally.

The use of full-body scanners in airports has been a topic of debate, with some arguing that it violates basic human rights and privacy. Despite these concerns, the primary purpose of these scanners is to enhance security by detecting objects that could pose a safety risk. While the technology can detect breast implants, it is important to remember that the scanners are not primarily focused on this aspect and are used to ensure the safety of all passengers.

Frequently asked questions