| abstract |
A pencil beam of X-rays scans an object along a line of direction along a line X-ray detector to produce an image of the line along a picture tube. The object scanned and the line of scan are relatively displaced by rocking the X-ray source and line detector about an axis substantially passing through a slit which collimates the X-ray energy into a fan beam intercepted by a rotating disc with radial slits that provides the scanning pencil beam. The X-ray detector preferably comprises sodium iodide elements imbedded in a light pipe with a photocell at each end of the light pipe. |