Whole body imaging technology based on backscatter X-Rays that is being used at some airport security checkpoints around the world presents a low risk of cancer to persons that are screened by the technology, according to a recent study by a scientific group that is part of the European Commission.
While the report points to difficulties in precisely measuring the health effects from the security scanners, which are called Advanced Imaging Technology (AIT) by the Transportation Security Administration (TSA) in the U.S., the risks from radiation aren’t any different from those found naturally.
“The potential magnitude of cancer risk from doses received from security scanners cannot be estimated with any precision, but are likely to remain so low that they cannot be distinguished from the effects of other exposures including both ionizing radiation from other sources and background risk due to other factors,” says the report, Health Effects of Security Scanners for Passenger Screening (Based on X-Ray Technology), which was prepared by the Scientific Committee on Emerging and Newly Identified Health Risks. Later in the report, it says that “The radiation dose from a single passenger being scanned is approximately equivalent to natural background radiation received within an hour on the ground or during 10 minutes of flight at a typical cruising altitude.”
However, the report points to potential concerns with certain groups of people.
“The expected health detriment will probably be very close to zero for any scanned person, but at the population level the possible effect cannot be ignored in the assessment of acceptability of the introduction of the security scanners using x-rays for passenger screening,” the report says. “Due to the substantial uncertainty regarding the potential occurrence of any health effects, risks for special groups within the population could not be evaluated meaningfully, although a higher risk related to exposure in childhood was noted.”
The report says that it is difficult to provide reliable estimates for children up to 14 years old although in its conclusions it notes that for the backscatter technology it emits such low doses that “there is no scientific basis to separately consider potentially vulnerable groups (e.g. pregnant women, children) in risk assessment.” It adds that even “cumulative doses” for frequently scanned individuals “are very likely to remain below the constraints.”
In the U.S. concerns have been raised by some in Congress and in the health community regarding the use of backscatter X-Ray-based AIT systems to screen passengers for explosives and weapons that may be hidden beneath their clothing. TSA operates two types of AIT systems at airport checkpoints, one based on millimeter wave technology and supplied by L-3 Communications [LLL] and other based on the backscatter technology and supplied by OSI Systems [OSIS]. It is the backscatter systems that are at the point of concern regarding the risks posed by exposure to ionizing radiation.
Several countries in Europe including Italy, France, Germany and Austria prohibit the use of ionizing radiation for non-medical purposes, according to the report.
As for frequent fliers, air crews and the operators of the AIT machines, the report says that “annual cumulative effective doses would remain below” the public dose limit, even if these individuals were subject to three scans per day. However, if transmission X-Ray technology is being used then the public dose limit would be exceeded based on three scans per day, it says.