my dad works as a baa security. he says polycarbon blades show up on x-ray. anything blade shaped will be looked into. people assume x-ray is black and white. it's not. different compounds and metals show up as different colors. chewing gum and an explosive will be different colors. so an explosive disguised as gum will be seen. explosive in a radio will be seen. a shape of a blade will be seen even if it's not a metal color. it's really not worth the effort of trying to disguise a blade, even if it's made out of plastic.
Supplement from 07/21/2008 05:05pm:
http://www.espionageinfo.com/Re-Se/Scanning-Technologies.html copy
Computed tomography. Computed tomography (CT, also known as computerized axial tomography, CAT) was first made commercially available in the mid-1970s. CT combines projection radiography with computer processing to recover the three-dimensional information that is lost in a traditional two-dimensional x ray. In a CT scanner, the object to be scanned (e.g., person or baggage item) is placed in a cylindrical or doughnut-shaped device. Inside the cylinder or doughnut is an x-ray source that is mechanically rotated entirely around the object. Also, the cylinder or doughnut is lined with detectors that measure the x rays that pass through the scanned object at all angles. By collating all the information that is gathered during a full revolution of the x-ray source, a computer can form a three-dimensional model of the irradiated volume of the object. This information can then be presented to the user on a video screen in any desired form; most commonly, a thin slice of the object is modeled, with the details of its structure imaged as a black-and-white cross-section. To examine more of the object, the user looks at multiple slices.
