Baggage scanners are found at airports worldwide, customs, and government buildings such as courthouses and other security-critical buildings, so they are often readily available and require very little operator training. They work in a similar way to conventional medical X-rays in that an X-ray beam is directed at the object (usually a suitcase, briefcase, parcel, etc.) and those that pass through the object hit a detector and are converted into an image that can be seen by the operator. Unlike medical X-rays, baggage/security scanners create the image by mechanically passing the object through a fan-shaped X-ray beam that is directed onto a linear detector array that builds up the image.