The x-ray scanners most people see in airports are for screening carry-on bags.
But these scanners are too small to scan all the luggage that goes into the cargo section of the plane.
In busy airports, large trucks with built-in X-ray scanners (up to 5-7 meters long) are used.
These trucks pull up beside containers that hold the suitcases,bags and other cargo.
The entire container is scanned at once.