Gyrodyne Company of America Inc., a New York-based real estate investment trust, has agreed to buy Fairfax (VA) Medical Center for $13.2 million. Fairfax Medical Center, which includes two four-story buildings on 3.5 acres, is home to 28 medical-related tenants, including imaging center specialists and opticians. Gyrdoyne was attracted to the medical property because of its closeness to an HCA Inc.-owned surgical center and Inova Health System's Fairfax and Fair Oaks hospitals.