Concord Medical Services Holdings Limited, through its subsidiaries, operates a network of radiotherapy and diagnostic imaging centers. Its services include linear accelerators external beam radiotherapy, gamma knife radiosurgery, head gamma knife systems, body gamma knife systems, proton beam therapy, and diagnostic imaging services. The company also offers other treatments and diagnostic services through the use of medical equipment comprising electroencephalography for the diagnosis of epilepsy; thermotherapy for pain relief after radiotherapy and chemotherapy; ultrasound therapy for the treatment of cancer; stereotactic radiofrequency ablation for the treatment of Parkinson's disease; and refraction and tonometry for the diagnosis of ophthalmic conditions. In addition, it provides clinical support services, such as developing treatment protocols for doctors; and organizing joint diagnosis between doctors in its network and clinical research. Further, the company offers radiotherapy and diagnostic equipment leasing and management services to hospitals, as well as engages in the sale of medical equipment. The company, through its subsidiaries, Cyber Medical and Shanghai Medstar, holds 52% equity interest in Chang'an Hospital with a capacity of 1,100 beds. It also focuses on establishing the Beijing Proton Medical Center and Guangzhou Taihe Cancer Hospital, two specialty cancer hospitals that would offer radiotherapy services to cancer patients, including proton beam therapy. As of March 31, 2013, the Company operated a network of 137 centers with 77 hospital partners in 54 cities and 24 provinces and administrative regions in China. Concord Medical Services Holdings Limited was founded in 1996 and is headquartered in Beijing, the People's Republic of China.