Quality assurance of Leksell gamma units.

A Leksell Gamma Unit was commissioned and a Lars Leksell Center for Radiosurgery was established at the University of Virginia Health Sciences Center in March 1989. At that time a formal quality assurance program designed for the Leksell Gamma Unit was put into effect. This paper will review the components of suggested daily, monthly, semiannual and annual quality assurance reviews of United States Nuclear Regulatory Commission regulatory as well as nonregulatory items for Leksell Gamma Units. The acceptance criterion for each quality assurance test has been established based on federal requirements and the recommendations of national scientific organizations as well as the practical experience gained from this quality assurance program.