I'd really like to know what type is being used at SJU. I searched on the web and couldn't find any info. I hope it is the L-3 ProVision millimeter wave scanners, as I don't want to get doses of radiation from backscatter X-ray scanners each time I go through SJU which I do quite often.

Also, if radiation is a concern with the Rapiscan Systems backscatter X-ray scanners, what is the point of using them in addition to millimeter wave scanners, rather than using millimeter wave scanners exclusively? From what I heard, the TSA wants to support competition, however, L-3 Communications is no longer the only maker of MMW scanners. Smiths Detection, who was infamous for those puffer machines that were once used at some airports, has introduced their own MMW scanner, however, the TSA has yet to award them a contract. Why not replace those Rapiscan backscatter X-ray scanners with Smiths Detection MMW scanners? Doing so would allow competition to be maintained by having two suppliers of MMW scanners (L-3 Communications and Smiths Detection). The TSA did so with the puffer machines where the two suppliers were Smiths Detection and GE Security.