Katy Perry's Halftime Costume Scanned in Super Bowl Safety Bid

— -- The Super Bowl is supposed to be about fun and games, but law enforcement is planning for every possible security scenario.

High-tech scanners are being used to search every item entering the University of Phoenix Stadium -- from fixtures and food to the costume worn by halftime performer Katy Perry, customs and border protection program manager Ronald Nunn said.

"Katy Perry's stage came in last night," Nunn said. "We've got port-a-potties. We've got everything -- food, hot dogs, hamburgers, the NFL paraphernalia, jerseys, everything."

Officers will be wearing portable radiation detectors, and bomb-sniffing dogs will also be employed.

Secretary of Homeland Security Jeh Johnson, in an exclusive interview inside the stadium, told ABC News that security experts are on high alert, with a focus on smaller-scale and lone wolf-style attacks.

“Our challenges in Homeland Security are evolving. We have more concerns about domestic-based acts of violence, inspired by things people may see or read on the Internet,” Johnson said.

While Johnson said there are no credible threats against this weekend’s game, he said authorities are prepared to respond by any means necessary. That security involves a U.S. Customs Black Hawk helicopter, part of a fleet of aircraft guarding the Super Bowl from above. F-16 fighter jets will also be in the air.

Roughly 30 miles of airspace over the big game is restricted.