10 Things You Didnât Know About Chronic Fatigue Syndrome. Chronic Fatigue Syndrome (CFS) is undeniably complicated in every conceivable way. The disorder has been around for decades, but the medical community has yet to assemble a clear picture of it. The condition is characterized by extreme fatigue that canât be explained by any underlying medical condition.
A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is an atom that has excess nuclear energy, making it unstable.
Radioactive materials used in medicine: radionuclides and radioactive isotopes. A radionuclide is any type of radioactive material, including elements and the isotopes of elements. An isotope of an element is a particular atomic version of it. Isotopes are atoms of the same element with different atomic structures.