RadioimmunotherapyAn innovative new cancer treatment called radioimmunotherapy or RIT joins conventional radiotherapy with immunotherapy. RIT uses monoclonal antibodies to target specific cancer cells and minimize damage to surrounding cells and tissues. Monoclonal antibodies (MAbs) are laboratory-made immune proteins designed to bind to antigens in specific cells. These antibodies mimic antibodies produced naturally as part of the immune system. Originally, MAbs were made entirely from mouse cells and when these were introduced into the human body, the immune system reacted against them. This decreased the success rate of treatment, and in many cases the immune system destroyed the MAbs before treatment could even be administered. As studies progressed, 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 from fragments of human antibodies rather than whole antibodies. The researchers also found that by using smaller fragments, the antibodies were more likely to reach the targeted cells. Once the modified MAbs are made, the radioisotopes are attached via a process called labeling. Iodine 131 (I131) and yttrium 90 (Y90) are the most commonly used radioisotopes in RIT. These isotopes both emit beta particles through beta decay. Beta emissions cause DNA strand breaks, 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 iodine is I127 which contains 74 neutrons. On decay, I131 converts to XE131. Gamma radiation emission...... middle of paper ...... t for lymphoma. " The Leukemia & Lymphoma Society. March 18, 2004. Web. November 14, 2010 "Monoclonal Antibody Drugs for Cancer Treatment: How They Work - MayoClinic.com." Mayo Clinic Medical Information and Tools for a Lifetime healthy - MayoClinic.com. January 24, 2009. Web. November 14, 2010. DeNoon, Daniel "New AIDS therapy neutralizes HIV with radioactive antibodies | Natural remedies for HIV. "Natural remedies for HIV-AIDS | Alternative remedies for HIV-AIDS | Traditional treatment of HIV. Web. November 22, 2010." Monoclonal antibodies. " American Cancer Society :: Cancer information and resources: breast, colon, prostate, lung and other forms. October 12, 2010. Web. November 22, 2010. “Underutilized lymphoma smart bomb drugs”. Latest news, weather, business, health, entertainment, sports, politics, travel, science, technology, local, US and world news - Msnbc.com January 5, 2007. Web November 22.. 2010.