 The CTX-5000 SP scanning system, an improved version of the CTX-5000 for checked baggage, was delivered to the FAA in 1997 and placed at several of the US's busiest and largest airports.From 1997 to 2000, more than 100 of the systems have been purchased by the FAA to install in US airports, according to InVision.The CTX-5500DS is an automated explosives detection system that uses computed tomography to characterize materials in checked bags and automatically identify objects that could be improvised explosive devices.