Fluoroscope and Roentgen ray

Fluoroscope noun - An X-ray machine that combines an X-ray source and a fluorescent screen to enable direct observation.

Roentgen ray and fluoroscope are semantically related In some cases you can replace phrase "Roentgen ray" with "Fluoroscope", this terms are similar.

Roentgen ray noun - Electromagnetic radiation of short wavelength produced when high-speed electrons strike a solid target.

Fluoroscope and roentgen ray are semantically related in picture of inside a body topic. You can use "Fluoroscope" instead a noun phrase "Roentgen ray".