RESPONSE OF RAT INTRACRANIAL 9L GLIOSARCOMA TO MICROBEAM RADIATION THERAPY

Radiotherapeutic doses for malignant gliomas are generally palliative because greater, supposedly curative doses would impart clinically unacceptable damage to nearby vital CNS tissues. To improve radiation treatment for human gliomas, we evaluated microbeam radiation therapy, which utilizes an array of parallel, microscopically thin (<100 μm) planar beams (microbeams) of synchrotron-generated X rays. Rats with i.c. 9L gliosarcoma tumors were exposed laterally to a single microbeam, 27 μm wide and 3.8 mm high, stepwise, to produce irradiation arrays with 50, 75, or 100 μm of on-center beam spacings and 150, 250, 300, or 500 Gy of in-slice, skinentrance, single-exposure doses. The resulting array size was 9 mm wide and 10.4 mm high (using three 3.8-mm Response of rat intracranial 9L gliosarcoma to microbeam radiation therapy