RadioimmunotherapyAn innovative new cancer treatment called radioimmunotherapy or RIT combines conventional radiotherapy with immunotherapy. RIT uses monoclonal antibodies to target specific tumor cells and minimize damage to surrounding cells and tissues. Monoclonal antibodies (MAbs) are immune proteins produced in the laboratory and designed to bind to the antigens of specific cells. These antibodies mimic antibodies produced naturally as part of the immune system. MAbs were originally made entirely of mouse cells, and when these were introduced into the human body, the immune system reacted against them. This reduced the success rate of treatment and many times the immune system would destroy the MAbs even before treatment could be provided. As the studies progressed, the researchers were able to replace the mouse MAbs with a mixture of human and mouse cells called chimeric antibodies. Continued studies have now led to humanized antibodies. Humanized antibodies are made up of fragments of human antibodies rather than whole ones. The researchers also found that by using smaller fragments there was a greater chance of the antibodies reaching the target cells. Once the engineered MAbs are made, the radioisotopes are attached through a process called labeling. Iodine 131 (I131) and yttrium 90 (Y90) are the most common radioisotopes used in RIT. Both of these isotopes emit beta particles through beta decay. Beta emission causes DNA strand breaks, thereby killing tumor cells. Iodine 131 decays with a half-life of 8 days with beta and gamma emissions. The iodine nuclide has 78 neutrons in the nucleus. The most stable of iodine is I127 which has 74 neutrons. On decomposition I131 converts to XE131. The emission of gamma rays...... in the center of the sheet......t for lymphoma." The Leukemia & Lymphoma Society. 18 March 2004. Web. 14 November 2010"Drugs with monoclonal antibodies for Cancer Treatment: How They Work - MayoClinic.com." Mayo Clinic Medical Information and Tools for Healthy Living - MayoClinic.com. January 24, 2009. Web. November 14, 2010. DeNoon, Daniel. "The New Therapy for AIDS destroys HIV with radioactive antibodies | Natural Cures for HIV." Natural Cures for HIV-AIDS | Alternative Remedies for HIV-AIDS | Traditional HIV Treatment. Web. November 22, 2010. "Monoclonal Antibodies." American Cancer Society: Information and Resources for cancer: breast, colon, prostate, lung and other forms. October 12, 2010. Web. November 22, 2010. "Smart bomb drugs for lymphoma underused". Latest news, weather, business, health, entertainment, sports, politics, travel, science, technology news, local, US and world - Msnbc.com January 5, 2007. Web November 22. 2010.