Despite considerable recent progress in radiation therapy, radiation treatment of brain tumors is often associated with side effects due to damage to normal brain tissue. But scientists working at the National Synchrotron Light Source at Brookhaven Lab are developing a promising radiation therapy technique that is effective in destroying tumors in animal models while sparing normal tissues.

Called microbeam radiation therapy (MRT), this technique, which uses parallel, microscopically thin slices of synchrotron-generated x-rays, preferentially kills tumors in part by acting on blood vessels.

"The way it probably works," says Avraham Dilmanian, MRT's principal investigator and a member of the team that developed the therapy, "is that the endothelial cells, which line the inner walls of blood vessels, survive in the regions between the microbeams, so they can replace the endothelial cells killed by the microbeams. But this repair process somehow fails in the tumor's capillaries because they are very different from those of normal tissues. So, as the tumor's capillaries are destroyed, they cannot feed the tumor anymore, and it eventually dies."

The therapy has not yet been tested in humans and is years away from clinical application, but Dilmanian's results are encouraging. "MRT has proven highly effective in the treatment of certain experimental rat brain tumors, with minimal impact on adjacent normal brain tissue," he says. "Our results support the idea that MRT could offer control of brain cancer with fewer deleterious side effects."

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Brookhaven chemist Hua-Gen Yu has devised a n
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Contact: Mona Rowe
mrowe@bnl.gov
631-344-5056
DOE/Brookhaven National Laboratory
27-Mar-2003