X-ray image vs radiograph

X-ray image

radiograph

noun
  • An instrument for measuring and recording solar radiation. 

  • An image, often a photographic negative, produced by radiation other than normal light; especially an X-ray photograph. 

verb
  • To produce a radiograph image. 

How often have the words X-ray image and radiograph occurred in a corpus of books? (source: Google Ngram Viewer )