Medical isotopes are used in medicine in three distinct ways:
1. Radioactive isotopes can be injected into a patient, and their emitted energy can then be captured on film. The resulting image is an important diagnostic tool.
2. Gamma rays emitted from a radioactive source can be directed onto a tumour, destroying the cancerous cells.
3. Radioactive isotopes can be manufactured into drugs. Once injected into a patient, the drug will accumulate in a certain part of the body, such as a tumour. As the isotopes decay and release energy, that energy destroys the tumour.
4. Nuclear medicine is a medical specialty that involves the application of radioactive substances to diagnose or treat disease.
5. Nuclear medicine can be used to image physiological functions. In addition to imaging, radionuclide therapy can be used to treat conditions such as hyperthyroidism, thyroid cancer, and blood disorders. 6. Common isotopes that are used in nuclear imaging include: fluorine-18, gallium-67, krypton-81m, rubidium-82, nitrogen-13, technetium-99m, indium-111, iodine-123 (pictured above), xenon-133, and thallium-201. For therapy, yttrium-90 and iodine-131 are commonly used.
Many radioisotopes are made in nuclear reactors, some in cyclotrons. Generally neutron-rich ones need to be made in reactors, neutron-depleted ones are made in cyclotrons. Nuclear medicine is a branch of medicine that uses radiation to provide information about the functioning of a person’s specific organs or to treat disease. In most cases, the information is used by physicians to make a quick, accurate diagnosis of the patient’s illness. The thyroid, bones, heart, liver and many other organs can be easily imaged, and disorders in their function revealed.
In some cases radiation can be used to treat diseased organs, or tumours. In developed countries (26% of world population) the frequency of diagnostic nuclear medicine is 1. 9% per year, and the frequency of therapy with radioisotopes is about one tenth of this. Nuclear medicine was developed in the 1950s by physicians with an endocrine emphasis, initially using iodine-131 to diagnose and then treat thyroid disease. In recent years specialists have also come from radiology, as dual CT/PET procedures have become established.