To track BPA in brain cells, the Cornell scientists used an imaging technique known as subcellular secondary ion mass spectrometry (SIMS). The technique yields three-dimensional images of the electrically charged atoms, or ions, present in a sample, sorting the ions by mass and charge and producing separate images for each type of ion.
The sensitivity of the technique is so high that it can even distinguish between different isotopes -- atoms of the same element, but with different masses. It is extremely well suited to cancer research, since cancer-fighting drugs can be "tagged" with isotopes that serve as chemical markers, showing the location of the drug within tissues subjected to SIMS imaging.
Boronophenylalanine is used in an experimental treatment for glioblastoma, an especially virulent form of brain cancer that strikes about 17,000 people a year in the United States. The disease is always fatal, usually within a year or two of diagnosis.
What makes glioblastoma so difficult to treat -- and so deadly -- is its tendency to spread aggressively, forming clusters of malignant cells far from the main tumor. While the main tumor mass can be surgically removed, the small clusters of invading cancer cells eventually will grow and form new tumors. In order for treatment to be successful, not only the main tumor mass must be eradicated but also the tiny invading cell clusters.
In the treatment, called boron neutron capture therapy (BNCT), patients are given a drug (such as BPA) containing an isotope of boron attached to an amino acid, which is taken up into cancerous cells at a rate three to four times that of the uptake by normal brain tissue.
A beam of low-energy neutrons is then directed at the patient's brain. When a boron atom is hit by a neutron, it "captures" the neutron and undergoes nuclear fission, releasing two smaller particles. These particles travel 5 to 10 microns -- approximately the width of a ce
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Contact: David Brand
deb27@cornell.edu
607-255-3651
Cornell University News Service
1-Aug-2002