This invention relates to an inspection method and system that radiographs containers, vehicles and train carriages without having to break seals, open containers or physical control. The inspection method consists of an autonomous mobile scanning unit, installed on a chassis that has a remote controlled drive, steering and brakes and another autonomous mobile unit referred as "source robot", that moves synchronized with the scanning unit and whose drive, steering and braking are also remotely controlled. The two units are moving synchronized with low, constant speed, electronically controlled, framing the object that is to be inspected, in a protected perimeter where the access is managed by an automated traffic management subsystem. The system is made out of autonomous mobile scanning units, managed by a third mobile unit which is towable, that is a remote control centre. The system also includes an automated traffic management subsystem and an exclusion area protection subsystem.