Full-body scanners and the alternative of invasive pat downs are needed to provide security for all air travelers, the top federal transportation security official said Wednesday.

Transportation Security Administrator John S. Pistole told a panel of Senators that he had personally received the enhanced pat down procedures authorized by his agency starting in October.

It is thorough, he said. It was more invasive than what I was used to.

Pistole, a 26-year veteran of the Federal Bureau of Investigation, said he was very sensitive to people's privacy concerns but added that it was necessary.

Bottom line is we need to provide the best possible security, he said.

The pat down procedures, which can involve touching on intimate areas of the body, are an option when air travelers opt out of full body imaging scanners installed at airports. Pat downs have recently come under greater attention by the public after recent incidents when some travelers refused the scan and pat down, ultimately being escorted from the airport and missing their flights.

Pistole said the normal procedure is that if an alarm is set off by the full body scanner, TSA officers may scan again or proceed to a pat down procedure. However in a very small percentage of cases, a pat down may be required randomly even if no alarm goes off, he said.

Pistole said he did not want to discuss the pat down procedure in detail at the open hearing due to security concerns.

I don't want to give people a road map and how to defeat that, he said.

The decision to put in place more thorough pat downs was made after recent security scares including a 2009 Christmas Day incident where Umar Farouk Abdulmutallab, an 18-year-old Nigerian, tried to detonate plastic explosives hidden in his underwear.

Pistole said another factor which contributed to the decision was that in various undercover tests, people were were able to get through security largely because we were not being thorough enough in pat downs. His agency was also working with other nations to improve security practices.

Most Senators at the Senate Committee on Commerce, Science & Transportation hearing were supportive of the TSA's security policies. One, however, was unconvinced.

I wouldn't want my wife to be touched that way, said George Lemieux R-FL.

There are limits and there has to balance, Lemieux said. I think we've gone too far afield.

Pistole said reasonable people can disagree on how to balance privacy and security.

Several senators said the agency needed to do a good job of communicating its policies to the public.

The traveling public is significantly upset, said Sen. Johnny Isakson, R-GA.

Sen. Amy Klobuchar, D-MN, concurred.

We need some education with the public so they're not caught off guard. Clearly people are going to feel uncomfortable with this but they must understand that this is being done for their safety, she said.

Pistole said once-a-year air travelers set to make trips during the holidays should learn more about the TSA protocols.

I would make an appeal to the American people to go to the TSA website to see the latest practices and be best informed, he said.

Pistole said children 12 and under are exempted from the more thorough pat downs and that radiation exposure from the scanners were well within safety standards.

He said there are currently 385 scanners installed at 70 airports and he expects to have up to 1,000 installed across the country by the end of next year.