[1] : The Collaborative International Dictionary of English v.0.48

radiograph \ra"diograph\ r=a"di^-ogra^f, n.
   radio- + -graph.
   1. an instrument for measuring and recording solar radiation.
      webster 1913 suppl.

   2. an image or picture produced upon a sensitive surface, as
      of a photographic or fluorescent plate, by some form of
      penetrating radiation other than light, as x-rays, beta
      rays, etc.; esp., a picture of the internal structure of
      opaque objects traversed by the rays; a skiagraph. when
      the picture is produced upon photographic film by x-rays,
      the picture is usually called an x-ray photo or x-ray.
      when an image is produced on photographic film by a
      radioactive substance in close proximity to the film, in a
      manner so as to record the spatial distribution of the
      radioactive substance, the resulting image is called an
      autoradiograph or autoradiogram.
      webster 1913 suppl. +pjc
see also:
x-ray photo x-ray autoradiograph autoradiogram 

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