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(RAY-dee-oh-I-suh-tope)
![](https://webarchive.library.unt.edu/eot2008/20081103222220im_/http://www.cancer.gov/images/spacer.gif)
| An unstable form of a chemical element that releases radiation as it breaks down and becomes more stable. Radioisotopes may occur in nature or be made in a laboratory. In medicine, they are used in imaging tests and in treatment. Also called radionuclide. |
Previous Definitions: | radioimaging, radioimmunodiagnostics, radioimmunoguided surgery, radioimmunotherapeutics, radioimmunotherapy | Next Definitions: | radiolabeled, radiologic exam, radiologist, radiology, radionuclide |
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