Airport full body scanners, primarily millimeter wave technology, emit non-ionizing radiation considered safe by health organizations and regulatory bodies.
Navigating airport security is a routine part of travel, and those full body scanners often spark questions. Many travelers wonder about the technology behind them and, more importantly, their safety. Let’s break down what these scanners do and what the science says.
Understanding Airport Full Body Scanners
Airport full body scanners, officially known as Advanced Imaging Technology (AIT) devices, are designed to detect metallic and non-metallic objects concealed under clothing. These systems became prevalent after 9/11 to enhance security measures beyond traditional metal detectors.
There have been two primary types of AIT scanners used: millimeter wave and backscatter. The Transportation Security Administration (TSA) phased out backscatter units in 2013 due to privacy concerns and has exclusively deployed millimeter wave technology across airports.
- Millimeter Wave Scanners: These are the standard AIT devices found in airports. They use radio frequency energy, similar to that used in cell phones, to create a generic outline of a person’s body.
- Purpose: AIT scanners aim to identify potential threats such as weapons, explosives, or other prohibited items that might be hidden on a passenger’s person, without requiring physical contact.
How Millimeter Wave Scanners Operate
When you step into a millimeter wave scanner, you typically stand with your arms raised for a few seconds. The machine then emits low-power radio waves that reflect off your body and any objects you might be carrying. These reflected waves are then processed by a computer.
Automated Threat Detection
The scanner’s software uses the reflected signals to construct a generic, privacy-protective outline of your body. This outline highlights any anomalies or areas where objects might be concealed. Security officers view this standardized image on a remote monitor, never seeing a naked image of the passenger.
- The system is designed to identify potential threats automatically.
- If an anomaly is detected, the specific area on the generic outline is marked for further inspection by a security officer.
- No personal identifying features are displayed, ensuring passenger privacy.
According to the TSA, Advanced Imaging Technology (AIT) scanners use millimeter wave technology, which emits non-ionizing electromagnetic waves.
Radiation Exposure: A Closer Look
The core concern for many travelers revolves around radiation exposure. It is important to distinguish between the two main types of radiation: ionizing and non-ionizing.
- Ionizing Radiation: This type, found in medical X-rays or CT scans, has enough energy to remove electrons from atoms, potentially causing damage to DNA and increasing cancer risk with sufficient exposure. Backscatter scanners, now phased out, used a very low dose of ionizing radiation.
- Non-Ionizing Radiation: Millimeter wave scanners use non-ionizing radiation. This type of radiation, which also includes radio waves, microwaves, and visible light, does not have enough energy to break chemical bonds or damage DNA. It primarily interacts with the body by causing molecular vibration, which can generate heat, but at the low power levels used in AIT scanners, this effect is negligible.
The FDA, responsible for radiation-emitting product safety, confirms that these scanners operate within established safety guidelines. Their assessments indicate that the energy levels are well below international and national safety standards.
| Radiation Type | Characteristics | Airport Relevance |
|---|---|---|
| Ionizing Radiation | High energy, can damage DNA, used in medical X-rays. | Not used in current AIT scanners (was in phased-out backscatter). |
| Non-Ionizing Radiation | Low energy, causes molecular vibration, similar to radio waves. | Used in all current millimeter wave full body scanners. |
Putting Scanner Radiation into Perspective
To truly understand the safety of millimeter wave scanners, it helps to compare their radiation exposure to other everyday sources. The amount of radio frequency energy a person receives from a single AIT scan is extremely small.
- Everyday Electronics: Exposure from a millimeter wave scanner is often less than what you receive from a brief cell phone conversation or Wi-Fi router usage.
- Cosmic Radiation During Flight: A single commercial flight at cruising altitude exposes passengers to significantly more cosmic radiation than a full body scan. For example, a flight from New York to Los Angeles exposes a passenger to approximately 0.035 mSv (millisieverts) of cosmic radiation, whereas a full body scan is estimated to be in the range of 0.00001 mSv.
- Natural Background Radiation: People are constantly exposed to natural background radiation from the earth, rocks, and even food. The dose from a scanner is a tiny fraction of this daily exposure.
Major health organizations, including the World Health Organization (WHO) and the International Commission on Non-Ionizing Radiation Protection (ICNIRP), have reviewed the technology and concluded that millimeter wave scanners are safe for the general public, including vulnerable populations.
Passenger Choices and Opt-Out Procedures
Travelers always have the option to decline an AIT scanner screening. This is a passenger right established by the TSA.
Requesting a Pat-Down
If you prefer not to go through the full body scanner, you can inform the TSA officer that you would like to opt for a pat-down instead. This will involve a thorough physical search by an officer of the same gender.
- Procedure: Clearly communicate your preference to the TSA officer before entering the scanner.
- Time Expectation: A pat-down typically takes longer than a scanner screening due to its comprehensive nature. Plan for a few extra minutes at the checkpoint.
- Thoroughness: The pat-down is a standardized procedure designed to detect any concealed items. It involves touching various parts of the body, including sensitive areas, over clothing.
While the choice is yours, it’s worth noting that opting out does not exempt you from enhanced screening. The alternative is a physical search, which is equally effective in detecting potential threats.
| Screening Method | Primary Technology | Time Estimate |
|---|---|---|
| Full Body Scanner (AIT) | Millimeter Wave Radio Frequencies | ~5-10 seconds |
| Pat-Down | Manual Physical Search | ~2-5 minutes |
Addressing Specific Concerns
Many individuals have specific health or personal situations that lead them to question the safety of full body scanners. Here’s what the science and regulatory bodies indicate for common concerns.
Pregnancy and Children
Millimeter wave scanners are considered safe for pregnant individuals and children of all ages. The non-ionizing radiation does not have the energy to penetrate the body deeply enough to affect a fetus or developing child. The exposure is superficial and minimal.
- Pregnant Travelers: No known risks to pregnancy or a developing fetus. The option for a pat-down remains available if preferred.
- Children: Safe for infants, toddlers, and older children. Parents can request a pat-down for their child if they wish.
Medical Implants and Devices
Individuals with pacemakers, defibrillators, cochlear implants, joint replacements, or other medical devices can safely pass through millimeter wave scanners. These scanners use radio waves, not magnetic fields, so they will not interfere with electronic medical devices or cause issues with metal implants.
- Pacemakers/Defibrillators: Not affected by millimeter wave technology.
- Metal Implants: Joint replacements, surgical pins, etc., will not be damaged or affected. They may trigger an alert on the scanner, leading to a targeted pat-down of that specific area.
It’s important not to confuse AIT scanners with airport walk-through metal detectors, which use magnetic fields. While even metal detectors are generally safe for most implants, AIT scanners pose no known risk.
Navigating the Security Checkpoint Efficiently
A smooth security experience begins with preparation. Knowing what to expect and how to prepare can significantly reduce stress and wait times.
- Empty Pockets: Remove all items from your pockets, including wallets, keys, and phones, and place them in your carry-on or a bin.
- Remove Bulky Items: Take off bulky jackets, sweaters, and any large jewelry that might cause an alert.
- Footwear: Be prepared to remove shoes, belts, and sometimes light jackets, depending on your screening status.
- Liquids Rule: Adhere to the 3-1-1 rule for liquids, gels, and aerosols in carry-on bags.
- Cooperation: Listen carefully to the instructions from TSA officers. Their guidance helps maintain security and keeps the line moving.
For frequent travelers, programs like TSA PreCheck or Global Entry offer expedited screening, which often allows participants to use traditional metal detectors instead of AIT scanners and keep on shoes, belts, and light jackets.