From my involvement, again going back for many years as well as my current position in national security, we have never utilized this tool without prior judicial authorization.
Having said that, if a situation were to arise that required it, there are provisions that allow us and certain designated individuals to utilize this type of tool for the interception of communications in emergency situations, but I am not aware of any situation where that has been done, and the mere practicality of deploying this type of tool and technique would take it beyond the time period under which such an authorization would be valid.