In Dr. Soria’s class last week, we discussed boron neutron capture therapy (BNCT). BNCT is an alternative form of treatment for various kinds of cancer (head and neck) and malignant brain tumors. The method is still in its beginning stages because it has not yielded a higher success rate than other methods of treating these complications.
In BNCT, a neutron beam collides and interacts with boron-containing molecules that have been injected to the patient, which then decomposes the tumor. An isotope of boron, boron-10, is used because it locates the tumor cells, tags the cells, and interacts with the neutrons beamed in. Dr. Soria stressed that B-10 is beneficial since it in nonpolar and lipophilic. Because of these traits, the cells properly cross the blood brain barrier without being metabolized. The neutrons are sent in low energy thermal waves so they can pass through the tissue without harming the patient (Japanese scientists have unluckily killed a few patients with high energy levels). The neutrons react with the boron-10 atoms in the compounds, forming boron-11. Boron-11 is radioactive and undergoes fission, decomposing into small particles and energy. In this reaction, the new compounds break down the surrounding cells, resulting in the breakdown of the tumor cells.
Another great chemical used in neutron capture therapy is gadolinium (Gd). The future goal is to have Gd or B on a needle that we can directly place on the brain tumor. Also, new compounds are being developed to increase the success rate of the procedure and decrease the amount of chemicals taken by the patient. Some chemists suggest that adding more boron atoms per molecule would reduce the total number of molecules needed. Further research is still in the works to make BNCT a leading method of treating cancer and brain tumors.
Ver good explanation Anthony, it is very interesting how they modify the molecule conaining the boron to make it suitable for its function and for its crossing accross the blood brain barrier. They also have to be very careful when exposing the patient with the radiation not only because they could made inmediate damage to the epthitelial cells but also cause mutations in the surronding cells. Also it is vital that when the fission of B11 happens only the tumor cells are destroyed and healthy tissue is not damaged. Researchers have recenty found a boron-containing molecule called nido OPDs (nido-carboranyl oligomeric phosphate diesters) that carries boron only into the cell but ensures that the boron does not get transported out of the specific cell.
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