(CNN) — The Transportation Security Administration can now mandate some passengers go through a body scanner even if the travelers ask to opt out and get a full-body pat-down instead.

Mandated screening for some passengers would be "warranted by security considerations in order to safeguard transportation security," the TSA said in a document updating the protocol.

The change comes at a time of heightened concern about aviation security and terror plots against commercial aviation.

The TSA said the benefit of using the technology is it "improves threat detection capabilities for both metallic and nonmetallic threat objects." In other words, the scanners can catch weapons hidden in clothes that a pat-down might miss.

The agency said it does not store any personally identifiable information from the body scanner, known as Advanced Imaging Technologies, or AIT.