Airports And X-Ray Machines: What You Need To Know

Airport security systems use a variety of methods to ensure the safety of passengers, including metal detectors, backscatter X-ray machines, millimeter wave scanners, and cabinet X-ray machines. These machines are used to scan passengers and their luggage for dangerous items such as weapons, chemicals, and liquids that are not allowed on flights.

X-ray machines, in particular, have been the subject of some controversy, with concerns raised about privacy and health risks. However, recent reports stress the safety of these machines, stating that the radiation exposure from one scan is equivalent to the natural background emission a passenger would receive during ten minutes of a flight.

Types of X-ray scanners

Airports use several types of X-ray scanners to ensure the safety of passengers and staff. Here are the different types of X-ray scanners:

Backscatter X-Ray Scanners

Backscatter X-ray scanners are commonly used in US airports to detect suspicious metallic and non-metallic objects hidden under clothing, shoes, or body cavities. They use low-dose radiation, typically emitting between 0.05 and 0.1 μSv of radiation per scan. The amount of radiation received from a backscatter machine is equivalent to the amount of cosmic radiation one would be exposed to during two minutes of flight. The risk of health effects from this type of scanner is considered very low.

Transmission X-Ray Scanners

Transmission X-ray scanners use higher doses of penetrating radiation that pass through the human body and are then captured by an array of detectors. This type of scanner can detect objects hidden not only under clothes but also inside the human body, such as drugs in the stomach or natural cavities. The radiation dose received is typically not higher than 0.25 μSv and is regulated by American radiation safety standards.

Millimeter Wave Scanners

Millimeter wave scanners use non-ionizing electromagnetic radiation similar to that used by wireless data transmitters. They operate in the extremely high-frequency radio band, which is a lower frequency than visible light. The health risks of these scanners are still being studied, but they do not generate ionizing radiation. These scanners are important for airport security as they can detect hidden threats such as guns and knives.

Cabinet X-Ray Scanners

Cabinet X-ray systems are used to screen luggage and carry-on items. They have thick walls and lead curtains at entry and exit points to prevent radiation from escaping. These machines must adhere to strict standards regarding radiation emission and typically include safety features such as locks, warning lights, and labels.

Privacy concerns

Airport security systems use backscatter X-ray machines, cabinet X-ray machines, millimeter wave scanners, and metal detectors to ensure the safety of passengers and staff. While these measures are important, they have also raised privacy concerns.

The use of full-body scanners in airports has sparked controversy, with passengers and advocates objecting to the display and recording of their naked bodies by screening agents and the government. Critics have described this as a virtual strip search without probable cause, alleging that it violates basic human rights and privacy. The imaging produced by these scanners can reveal intimate details about an individual's body, such as prosthetics, colostomy bags, and catheters. This has led to concerns about potential harassment, particularly within the transgender community.

In response to privacy concerns, some airports have implemented measures to protect the privacy of individuals undergoing screening. For example, the display of the scan may be located in a separate room where the operator cannot see the person being screened, or it may show a cartoon-like representation or a generic outline of a person rather than an actual image. Additionally, most airports allow individuals to opt out of the scanner and choose a traditional pat-down instead.

The storage of images from full-body scanners has also been a point of contention. While the Transportation Security Administration (TSA) initially stated that they did not store images of passengers, they later disclosed that their procurement of airport scanners required manufacturers to include image storage and transmission features, although these should be disabled before use in airports. However, there have been instances where images were recorded and disseminated, raising further privacy concerns.

In addition to privacy issues, the effectiveness of full-body scanners has been questioned. Critics argue that these scanners can be easily bypassed and may not detect all potential threats. There have been reports of firearms, explosives, and other prohibited items passing through the scanners undetected during internal testing and real-world usage.

To address these concerns, airports have implemented additional security measures, such as using sniffer dogs and employing passenger profiling techniques.

Health concerns

X-ray machines used in airports are typically backscatter X-ray scanners, which use low-dose radiation to detect objects hidden under clothing or in body cavities. The dosage of radiation received from these scanners is usually between 0.05 and 0.1 μSv, which is significantly lower than the radiation exposure from a standard medical X-ray. Additionally, the machines are designed with safety features to minimize radiation exposure, such as enclosed cabinets and lead curtains.

Despite the relatively low dosage, there is ongoing debate about the safety of backscatter X-ray scanners. Some critics argue that the radiation emitted by these scanners is higher than officially reported and poses a risk to children and at-risk populations. They claim that the radiation is focused on the skin and surrounding tissues, which could increase the risk of cancer. However, these concerns have been disputed by other experts, who state that the radiation dose is low and that the machines meet safety standards.

It is worth noting that alternative screening methods are available for individuals who are concerned about X-ray exposure. Passengers can opt for a pat-down search instead of walking through the X-ray machine. Additionally, airports may use other types of screening equipment, such as metal detectors and millimeter wave scanners, which do not emit ionizing radiation.

Overall, while there are health concerns associated with the use of X-ray machines in airports, the risks are generally considered low, and the benefits of ensuring security and safety are believed to outweigh the potential negative consequences. However, it is important to continuously monitor and evaluate the safety of these technologies, especially for vulnerable groups.

Effectiveness of X-ray machines

X-ray machines are highly effective at detecting items that may be hidden on a person or in their luggage. They are used to check carry-on items and checked luggage for items that are not approved for air travel. X-rays are electromagnetic waves that are more energetic than light waves, allowing them to penetrate many materials. Dual-energy X-ray systems, which are typically used in airports, have a single X-ray source that emits X-rays in the range of 140 to 160 kilovolt peak (KVP). The higher the KVP, the further the X-ray penetrates.

After passing through the item, the X-rays are picked up by a detector, which then passes them through a filter that blocks out the lower-energy X-rays. The remaining high-energy X-rays hit a second detector, and a computer circuit compares the data from both detectors to better represent low-energy objects, such as most organic materials. As different materials absorb X-rays at different levels, the resulting image on the monitor allows the operator to see distinct items inside the bag.

X-ray machines are particularly useful for detecting metallic and non-metallic objects, including weapons, chemicals, and liquids. They can also detect items hidden in body cavities or swallowed items, which has become an increasing concern following several airliner bombing attempts in the 2000s.

However, it is important to note that the effectiveness of X-ray machines also depends on human operators. In one instance, an undercover TSA agent was able to carry a handgun through an X-ray machine multiple times without detection because the operator was not paying attention.

While X-ray machines are highly effective, there are ongoing concerns about the health risks associated with their use, particularly the exposure to ionizing radiation. While the dosage of radiation received is usually low, between 0.05 and 0.25 μSv, the long-term health effects of exposure to active transmission waves are still unknown. Some critics argue that the radiation emitted by X-ray machines is up to 20 times stronger than officially reported and poses a risk to children and at-risk populations. However, several radiation safety authorities, including the National Council on Radiation Protection and Measurements and the American College of Radiology, have stated that they are "not aware of any evidence" that full-body scans are unsafe.

To address these concerns, many airports have implemented safety measures to minimize radiation exposure. For example, cabinet X-ray systems used to screen luggage have thick walls and lead curtains to prevent radiation from escaping. These machines must also meet strict standards for radiation exposure and include safety features such as locks, warning lights, and labels. Additionally, the Transportation Security Administration (TSA) in the United States regularly tests and maintains its X-ray equipment to ensure it meets federal, state, and local safety standards.

Alternatives to X-ray machines

Airports use X-ray machines to screen carry-on items and checked luggage. They are also used as full-body scanners to detect objects on or inside a person's body for security screening purposes.

Millimeter Wave Scanners

Millimeter wave scanners use non-ionizing electromagnetic radiation to create an image of the body, which shows objects hidden under clothes. This technology uses a lower frequency than visible light and does not generate ionizing radiation. However, the health risks posed by these machines are still being studied, and evidence is mixed.

Backscatter X-ray Scanners

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. The dosage of radiation received is typically between 0.05 and 0.1 μSv. Due to concerns about the safety of this method, multiple countries have banned their usage.

Transmission X-ray Scanners

Transmission X-ray scanners use higher doses of penetrating radiation that pass through the human body and are then captured by an array of detectors. This type of scanner can detect objects hidden not only under clothes but also inside the human body, such as drugs in the stomach or natural cavities. The dosage received is usually not higher than 0.25 μSv and is regulated by American radiation safety standards.

Infrared Thermal Conductivity Scanners

Infrared thermal conductivity scanners do not use electromagnetic radiation to penetrate the body or clothing. Instead, they rely on slight temperature differences on the surface of clothing to detect foreign objects. The rate at which the contraband hidden under the clothing heats or cools the surface of the clothing is used to identify foreign objects. These scanners are less commonly used compared to X-ray-based and millimeter wave-based scanners.

Metal Detectors

Metal detectors use magnetic fields to identify metal objects. They create a magnetic field by using a brief pulse of electrical current. If there are any metal objects present, the magnetic field will reflect back to the machine, triggering an alert. Metal detectors can ignore very small amounts of metal, such as buttons or small earrings.

Chemical Sniffers

Chemical sniffers are essentially automated chemistry labs that can detect trace residues of chemicals used to make bombs. They are used to analyze electronic devices or swipe surfaces for potential bomb-making chemicals. These can be in the form of desktop, handheld, or walk-through models.

Frequently asked questions