Varian Medical Systems will feature its Trilogy image-guided radio surgery instrument at the upcoming annual meeting of the American Association of Neurological Surgeons (AANS) that starts Saturday and runs through Thursday, at the Moscone Convention Center in San Francisco.

Varian's Trilogy radiosurgery system incorporates a low-dose, high resolution x-ray imager that facilitates accurate patient positioning and makes it possible to rapidly deliver powerful, precisely placed beams to small areas in the brain and other parts of the body. Beam shaping can be accomplished using conventional radiosurgical cones with tiny apertures or with a dynamic multileaf collimator, a computerized mechanical device that uses many individually controlled tungsten leaves or fingers to sculpt the radiation beam and vary its intensity according to the neurosurgeon's treatment plan, the company said.

In addition to the Trilogy radiosurgery technology, Varian will be exhibiting an assortment of hardware and software products for the neurosurgery market, including:

• Patient immobilization and motion management devices for stereotactic radiosurgery;
• The SonArray 3-D ultrasound patient positioning systems; and
• Treatment planning software for stereotactic radiosurgery.