About this Article
Written by: Farzana Ansari
Written on: July 11th, 2005
Tags: electrical engineering, security & defense
Thumbnail by: Adam Ciesielski/SXC
About the Author
In the summer of 2005, Farzana Ansari was a sophomore majoring in Biomedical Engineering at the University of Southern California. Her love of traveling compelled her to take a deeper look into the airport security systems she has encountered.
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Volume IX Issue II > Security Versus Privacy: The Engineering of X-Ray Vision
SmartCheck and other backscatter devices are currently being tested in major airports in the United States and Europe. Phoenix Sky Harbor Airport has already implemented the device into its operations, earning an overall "good" reaction from tested passengers, according to AS&E Vice President of Marketing, Joe Reiss [16]. Los Angeles International and New York's John F. Kennedy airports are next in line to test the device in secondary screening efforts. With these trials, TSA officials hope to gauge the effectiveness of backscatter technology against public response to this seemingly invasive technique.
The debate over privacy, respect, and backscatter X-ray technology thus comes down to trusting TSA's promise to passengers. Backscatter X-ray scans are currently voluntary and secondary screening procedures; a passenger's alternative is a physical pat down. Both options present significant privacy concerns and have limitations. Low X-ray frequencies that meet "negligible" radiation standards limit screeners from viewing weapons hidden in body folds or cavities [12]. Frisking depends on the effectiveness and training of the security official performing the pat down. By enabling the passenger to choose, TSA recognizes the controversy posed by both forms of security, and ultimately leaves the debate open to individual travelers.

Other Uses of Backscatter Technology

While privacy concerns have hindered the widespread use of backscatter X-ray machines in passenger scanning, this technology has demonstrated its value in scanning luggage and vehicles for explosive material. EDS technology penetrates dense materials to produce "shadowgram" images, similar to those produced by medical radiology. However, this system is limited to detecting only transmitted X-ray frequencies. AS&E thus incorporated Z Backscatter technology into the EDS, providing detection systems for both transmitted and deflected X-rays. The new system highlights and classifies organic and inorganic materials to expedite the scanning process. AS&E's devices enable security officials to scan any size object, from small carry-on luggage to semi-trucks [11].


Backscatter X-ray technology demonstrates progress in airport safety and security while renewing questions regarding the privacy rights of individuals. This realistic form of X-ray vision has the potential to become a true superpower for airport security engineers. However, while Superman may have reserved his ability for good, the employment of backscatter technology does not have such guaranteed results in today's world. It will ultimately be up to screeners and TSA officials to earn the trust of wary passengers.


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