American Shared Hospital Services, together with its subsidiaries, leases radiosurgery and radiation therapy equipment to health care providers. The company offers its radiosurgery equipment for the Gamma Knife stereotactic radiosurgery, a non-invasive procedure for the treatment of malignant and benign brain tumors, arteriovenous malformations, and functional disorders, including trigeminal neuralgia. It also provides financing services for Gamma Knife units. In addition, the company offers image guided radiation therapy systems and related equipment that integrate imaging and detection components into an accelerator, which enables clinicians to plan treatment, verify positioning, and deliver treatment. Further, it focuses on providing proton beam therapy services in Long Beach, California, as well as offers planning, installation, reimbursement, and marketing support services to its customers. As of March 1, 2013, the company operated 19 Gamma Knife units at 17 medical centers in 16 states in the United States, and 2 medical centers in Turkey. American Shared Hospital Services was founded in 1980 and is based in San Francisco, California.