Those new security scanners that take a picture of what's beneath travelers' clothes will get their first use at Tampa International Airport next week. The "millimeter wave" machines use harmless electromagnetic waves to create a murky image that shows hidden explosives and weapons, both metal and nonmetallic. Officers will randomly select passengers for the body scan after they clear a standard screening. Travelers can opt for a pat-down search instead. The machines will first go into use Oct. 24.