X-radiation is composed of X-rays, and represents a form of electromagnetic radiation. Wilhelm Conrad Roentgen is famous for discovering electromagnetic radiation in a wavelength range that we today know as X-rays. This achievement earned him the Nobel Prize in 1901, which made Wilhelm the very first recipient of the Nobel Prize in Physics.
X-radiation is also called Roentgen radiation often, after its discoverer. He named it X-radiation to signify an unknown type of radiation, and the name stuck throughout the years.
What is interesting is the fact that Wilhelm Conrad Roentgen discovered the X-ray by accident in 1895. During his experiments with with the cathode ray generator, he noticed that beam that the machine sent out was penetrating and reaching deeper layers than he though was possible. He thought there might be a new kind of ray that is responsible for this. Wilhelm spent many weeks in his laboratory, where he ate and slept, as he investigated many properties of the new rays he called “X-rays”.
He even experimented on his wife performing an X-ray scan on her hand and realizing that the machine captured a picture of her bones. When she saw the bones of her hand she exclaimed “I have seen my death!”
Since Wilhelm’s discovery that X-rays can identify bone structures, they have been used for medical purposes worldwide. With over 5 billion medical imaging studies done worldwide in 2010, it only goes to show how important this discovery was.