A NEW MINIATURE X-RAY SOURCE FOR INTERSTITIAL RADIOSURGERY - DEVICE DESCRIPTION

A device that generates low-energy x rays at the tip of a needle-like probe was developed for stereotactic interstitial radiosurgery. Electr ons from a small thermionic gun are accelerated to a final energy of u p to 40 keV and directed along a 3 mm outside diameter drift tube to a thin Au target, where the beam size is approximately 0.3 mm. All high -voltage electronics are in the probe housing, connected by low-voltag e cable to a battery-operated control box. X-ray output, which is near ly isotropic, consists of a bremsstrahlung spectrum and several lines between 7 and 14 keV, with characteristic radiation contributing 15% o f the total energy output. To date, 14 patients with metastatic brain tumors have been treated with this device. (C) 1996 American Associati on of Physicists in Medicine.