American Shared Hospital Services engages in leasing radiosurgery and radiation therapy equipment to healthcare providers. Its equipment includes Gamma Knife, PBRT, and IGRT. The Gamma Knife radiosurgery equipment is a non-invasive treatment for malignant and benign brain tumors, vascular malformations and trigeminal neuralgia. The company was founded by Ernest A. Bates in 1977 and is headquartered in San Francisco, CA.