shad·ow·graph /ˈʃædoˌgræf, dəˌgræf/
  將影子投射影幕上的技術,皮影戲,放射線透視照相
  shadowgraph
       n : a photographic image produced on a radiosensitive surface by
           radiation other than visible light (especially by X-rays
           or gamma rays) [syn: radiogram, radiograph, skiagraph,
            skiagram]