NCI Dictionary of Cancer Terms
The NCI Dictionary of Cancer Terms features 7,938 terms related to cancer and medicine.
- listen (I-soh-tope)
- A form of a chemical element in which the atoms have the same number of protons (part of the nucleus of an atom) but with a different number of neutrons (part of the nucleus of an atom). For example, carbon 12, carbon 13, and carbon 14 are isotopes of carbon. They all have six protons in the nucleus, but each has different number of neutrons. Isotopes may be used in certain medical tests and procedures.