Therapeutic use of radionuclides

Radionuclides are ideally suitable for targeted radiotherapy. There are several beta emitters with different energy to penetrate from a fraction to several millimeters to deliver high absorbed dose to the target tissue. As against external radiotherapy, the radiation does not have to pass through the skin and hence there is practically no limit for the total dose. Several benign conditions like hyperthyroidism or acute joint inflammation can be treated by administering lower doses of a suitable radionuclide whereas malignant tissues can be completely eliminated by giving a higher dose. Some radionuclides emit apart from beta rays a small quantity of gamma rays which enable post therapy imaging to visualize the actual distribution of the agent. Some of the monoclonal antibodies or fragments specific to tumor cells can be tagged with a suitable radionuclide and used to deliver a high dose and destroy the target tissue. (author)