Airport body scanners, primarily using millimeter wave technology, are widely considered safe for travel, emitting extremely low-power, non-ionizing radiation.
Preparing for a flight often involves a mental checklist: passport, tickets, packing essentials. Right up there with these considerations is navigating airport security, and for many, the body scanner is a point of curiosity and sometimes concern. Understanding the technology and its implications can make your pre-flight experience smoother and more confident.
Understanding Airport Body Scanners
The security scanners at airports are designed to detect metallic and non-metallic objects concealed under clothing. There are two primary types of advanced imaging technology (AIT) scanners you might encounter, though one is far more prevalent.
Most modern airports utilize millimeter wave scanners. These devices employ radiofrequency electromagnetic waves, similar to those used in Wi-Fi and cell phones, but at much higher frequencies and very low power. The waves reflect off the body and any concealed items, creating a generic, privacy-protective outline for security officers to review.
Millimeter Wave Technology Explained
- Non-Ionizing Radiation: Millimeter wave scanners use non-ionizing radiation. This means the energy emitted is too low to remove electrons from atoms or molecules, which is the process that can cause DNA damage.
- Low Power Output: The power output of these scanners is extremely low, comparable to or less than a cell phone signal. Exposure is brief, typically lasting only a few seconds.
- Surface Interaction: Millimeter waves penetrate only a fraction of a millimeter into the skin’s surface. They do not penetrate deeper tissues or organs.
The Science Behind Millimeter Wave Safety
The safety of millimeter wave scanners is a topic extensively studied by various scientific and regulatory bodies. Their findings consistently indicate minimal risk to human health.
The Food and Drug Administration (FDA) is responsible for regulating electronic products that emit radiation, including airport security scanners. According to the FDA, millimeter wave scanners meet applicable safety standards and are not known to pose health risks. This assessment is based on extensive research and a thorough understanding of the electromagnetic spectrum.
The energy from millimeter wave scanners dissipates rapidly, meaning the amount of exposure decreases significantly with distance from the source. Given the brief exposure time and the non-ionizing nature of the radiation, the overall dose is negligible.
Phasing Out Backscatter Scanners
While millimeter wave scanners are now standard, some travelers might recall an older technology: backscatter scanners. These devices used very low-dose X-rays, a form of ionizing radiation.
Due to privacy concerns and public perception regarding X-ray exposure, the Transportation Security Administration (TSA) phased out backscatter units from major airports. All AIT units currently deployed by the TSA in US airports are millimeter wave technology. This shift reflects a commitment to advanced, privacy-enhanced, and widely accepted security methods.
Why Backscatter Scanners Were Different
- Ionizing Radiation: Backscatter scanners used ionizing radiation (X-rays), which carries a theoretical risk of cellular damage at higher doses.
- Extremely Low Dose: Even with X-rays, the dose from a backscatter scanner was exceptionally low, often compared to the radiation exposure from a few minutes of flying at cruising altitude.
- Privacy Concerns: The images generated by backscatter scanners were more detailed, leading to privacy objections, despite efforts to obscure identifying features.
Comparing Scanner Technologies
Understanding the differences between the two main types of scanners can clarify why current systems are considered safe.
| Feature | Millimeter Wave Scanners | Backscatter Scanners (Phased Out) |
|---|---|---|
| Radiation Type | Non-ionizing radiofrequency | Ionizing X-ray |
| Primary Concern | Extremely low power, surface interaction | Theoretical risk of cellular damage (at higher doses) |
| Prevalence in US Airports | Standard and widely used | No longer in use |
Radiation Exposure: A Broader Perspective
It’s helpful to put airport scanner radiation into context by comparing it to other common sources of radiation exposure in everyday life and during travel.
We are constantly exposed to natural background radiation from cosmic rays, the earth, and even certain foods. Flying itself significantly increases radiation exposure due to reduced atmospheric shielding at high altitudes. A single cross-country flight can expose a traveler to more radiation than a full-body X-ray or multiple airport scanner passes.
Sources of Radiation Exposure
- Cosmic Radiation: Higher at cruising altitudes during flights.
- Terrestrial Radiation: From natural radioactive materials in the earth.
- Medical Procedures: X-rays, CT scans, and other diagnostic imaging.
- Consumer Products: Some building materials, smoke detectors.
Special Considerations for Travelers
While millimeter wave scanners are generally safe, some travelers may have specific concerns or conditions that warrant discussion with security personnel.
Travelers with implanted medical devices, such as pacemakers, defibrillators, or cochlear implants, often worry about interference. Manufacturers of these devices typically design them to withstand common electromagnetic fields, including those from airport scanners. However, if you have concerns, it’s always appropriate to inform the security officer.
Who Might Exercise Caution?
- Pregnant Travelers: Although millimeter wave scanners are deemed safe, pregnant individuals might still prefer a pat-down for personal reassurance.
- Individuals with Medical Devices: While generally safe, inform officers if you have an implanted device.
- Children: Children’s developing bodies are often more sensitive to radiation, though the non-ionizing nature and low power of millimeter wave scanners minimize this concern.
Your Options at the Security Checkpoint
Every traveler has the right to refuse the advanced imaging technology scanner. This is a standard procedure and not an indication of suspicion.
If you opt out of the scanner, you will undergo an alternative screening method, which is typically a pat-down search. This is a thorough physical search conducted by a security officer of the same gender. It’s designed to be respectful and efficient while ensuring no prohibited items are concealed.
Choosing Your Screening Method
- Advanced Imaging Technology (AIT) Scanner: The most common and quickest method for most travelers.
- Pat-Down Search: An alternative for those who prefer not to use the scanner or cannot due to physical limitations.
- Metal Detector: Used in conjunction with AIT or as a primary screen in some situations, primarily for metallic items.
| Source of Exposure | Estimated Dose (microSieverts) | Context / Comparison |
|---|---|---|
| Millimeter Wave Body Scanner | 0.0001 | Extremely low, non-ionizing |
| Backscatter Body Scanner (Old) | 0.02 – 0.1 | Equivalent to 2-10 minutes of flight at cruising altitude |
| Cross-Country Flight (US) | 30 – 50 | Significant due to cosmic radiation |
| Natural Background Radiation (Annual) | 3000 | Average annual exposure from environment |
Regulatory Oversight and Continuous Monitoring
The safety of airport security equipment is not left to chance. Multiple government agencies and international bodies are involved in setting standards, conducting research, and continuously monitoring these technologies.
In addition to the FDA, the Federal Aviation Administration (FAA) sets guidelines related to aviation safety, which indirectly includes aspects of airport operations. International organizations also contribute to global standards, ensuring a consistent approach to security and safety across borders. This multi-layered oversight provides reassurance that these systems are subject to rigorous evaluation and are updated as technology and understanding evolve.