At http://www.tsa.gov/approach/tech/ait/index.shtm the tsa shows an "open" scanning machine, and at http://blogs.wsj.com/middleseat/2011...ogle_news_blog there appears to be a "closed" scanning machine. Are these different systems or different pictures of the same system?
[I recently departed from msy (New Orleans) and was "required" to go through the first type, no notification of radiation or signs that one could opt out and request a "grope" instead.]