plan . Under existing protocols , full-body scans are optional at airport checkpoints . Travelers who decline the scans are funneled to a location where they may be given a pat down and subjected to other tests such as swabs that can detect minute traces of explosives on hands or luggage . The TSA said most passengers prefer a body scan to a pat down . But others have objected to the body scans , calling them electronic strip searches . Passenger privacy is maintained during the scannning process by blurring all images , deleting images after they are viewed and placing the screener viewing the images in a remote location , according to DHS officials . Acting TSA Administrator Gale Rossides testified before Congress on Thursday that the machines will not significantly slow the passenger screening process , saying it will be done at the same time as carry-on baggage screening . The TSA has spent years testing full-body imagers . Plans to deploy them this year were given added urgency after the arrest of a Nigerian man , Umar Farouk AbdulMutallab , who has been accused of attempting to detonate an explosive sewn into his underwear on a
-LRB- CNN -RRB- -- The federal government is starting to deploy full-body scanning machines to 11 airports across the United States , Homeland Security Secretary Janet Napolitano announced Friday . Forty body-imaging machines already have been put into use at 19 airports nationwide as part of a field test , according the Department of Homeland Security . The Transportation Security Administration expects to deploy 450 units by the end of this year . `` By accelerating the deployment of this technology , we are enhancing our capability to detect and disrupt threats of terrorism across the nation , '' Napolitano said in a statement . The first of the new units are being installed Friday at Boston 's Logan International Airport , according to a DHS statement . The list of other airports set to receive the scanners by the end of summer includes Chicago O'Hare International , Fort Lauderdale-Hollywood International , Cincinnati/Northern Kentucky International , Mineta San José International , Los Angeles International , Port Columbus International , Oakland International , San Diego International , Kansas City International and Charlotte Douglas International . The imaging machines are being funded through the Obama administration 's $ 862 billion economic stimulus