![](https://webarchive.library.unt.edu/web/20130216075345im_/http://1.bp.blogspot.com/_himdawV7crE/TNl5q07QerI/AAAAAAAAAOQ/mokKfYyukcQ/s200/ostp_300.jpg)
The detailed description was requested by OSTPC’s Director, Dr. John Holdren, after receiving a letter from professors at the University of California-San Francisco seeking more information on the safety of the technology. You can read those letters and the resulting detailed description here: Backscatter Back-Story
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