41. Such radioactive isotopes are used in imaging of industrial equipment, medicine and food sterilization. 42. Radioactive isotopes can be incorporated into immunoassay reagents to produce a radioimmunoassay ( RIA ).43. Seven smaller reactors are used for research and to produce radioactive isotopes for nuclear medicine. 44. Detection of certain radioactive isotopes in the environment could signal prohibited work on nuclear weapons. 45. All but two tested positive for actinium-227, the radioactive isotope the workers were cleaning up. 46. This involves feeding radioactive isotopes or " seeds " through a catheter into the tumor. 47. The longest lived radioactive isotope of lead is lead-205. 48. Cesium-137, a radioactive isotope , is a fission product used in cancer research and radiation therapy. 49. Chlorine has two stable isotopes and one radioactive isotope : the cosmogenic isotope 36 Cl. 50. It generated radioactive isotopes for biological and medical research.
