A new innovative cancer treatment called Radioimmunotherapy or RIT joins conventional radiation therapy with immunotherapy. RIT uses monoclonal antibodies to target specific cancer cells and minimize damage to surrounding cells and tissue. Monoclonal antibodies (MAbs) are laboratory made immune proteins engineered to attach to antigens of specific cells. These antibodies mimic antibodies naturally produced as part of the immune system. Originally MAbs were made completely from mice cells and when these were introduced into the human body, the immune system would react against them. This decreased the success rate of the treatment and many times the immune system ...view middle of the document...
Even after patients are released they must still follow strict guidelines for approximately 5 days to minimize contamination of others. These guidelines are avoiding airplanes and buses, limit interaction with others, stay six feet or more away from children and pregnant women, a spouse must sleep in a separate bed and patients use a separate private bathroom.
Yttrium 90 decays with a half-life of 2.6 days or 64 hours and emits intense beta radiation. This radioisotope has 51 neutrons in the nucleus. There is only one stable form of Y90 and it is the only naturally occurring form. The stable form of Y90 is Y89 which has 49 neutrons. On decaying Y90 converts to Zr90. Since Y90 does not have a gamma emission it cannot be imaged directly, but this has a positive aspect as the patient will not have restrictions on human contact or have to remain in containment.
RIT has showed positive effects in the treatment of blood cancers, such as leukemia and lymphoma and although the RIT is mainly used as a cancer treatment, continued studies have shown promising result in treatment of many other diseases such as fungal, resistant bacteria, and viral infections. Scientists have also conducted studies of the use of RIT as a treatment in HIV infected cells.
Non-Hodgkin’s lymphoma is ranked fifth in cancer mortality in the United States. Lymphocytes or white blood cells are extremely sensitive to radiation. In traditional radiation and chemotherapy these cells and other rapidly dividing cells were destroyed. In RIT MAbs are engineered to target the antigen CD20 that expressed on surface of malignant B-cell lymphomas. MAbs can deliver radiation to B-lymphocytes expressing CD20, the target antigens as well as neighboring tumor cells reducing the risk of damage to non-cancer cells. Clinical trials have shown that RIT can achieve a high response rate in patients with relapse or refractory follicular lymphoma.
Researchers are also testing the use of RIT against HIV. By targeting the lymphocytes that contain the viruses rather than the viruses themselves, scientist have been able to effectively eliminate HIV infected cells in laboratory tests and animal studies. Current treatment for HIV is a combination of retroviral drugs (HAART) that are designed to keep the virus from replicating. This treatment can appear successful because the virus can disappear from the blood for a while. Unfortunately the virus can hide in immune cells because they are bits of RNA or DNA wrapped in a thin protein coat. This also allows the cells to resist radiation therapy and repair damage. In the RIT studies the isotope Bismuth 213 was bound by a ligand molecule to the antibody of glycoprotein 41 (gp41). Gp41 is a glycoprotein secreted by HIV infected cells that is usually not shed into the blood stream. By targeting the antibody instead of the virus, RIT is able to bypass the cells defense system and invade the structure and kill the virus. Researchers...