angiography vs roentgenogram

angiography

noun
  • A medical imaging technique in which an X-ray image is taken to visualize the inside of blood vessels and organs of the body, with particular interest in the arteries, veins and the heart chambers. 

roentgenogram

noun
  • An X-ray image. 

How often have the words angiography and roentgenogram occurred in a corpus of books? (source: Google Ngram Viewer )