X-Ray refers to the part of the electromagnetic spectrum whose radiation has somewhat greater frequencies and smaller wavelengths than those of ultraviolet radiation; namely, that radiation lying between ultraviolet and gamma-ray in the electromagnetic spectrum.

It is a type of high-energy radiation. In low doses, x-rays are used to diagnose diseases by making pictures of the inside of the body . In high doses, x-rays are used to treat cancer.

See also:
"X-ray" is in the HS Code "3006.30"
  - - Opacifying preparations for X-ray examinations; diagnostic reagents designed to be administered to the patient