Concord Medical Services Holdings Limited (Concord Medical) operates a network of radiotherapy and diagnostic imaging centers in China. As of December 31, 2012,its network comprised 136 centers based in 76 hospitals, spanning 53 cities across 24 provinces and administrative regions in China. These hospitals are substantially comprised of 3A hospitals, the highest ranked hospitals by quality and size in China as determined in accordance with the standards of the Ministry of Health. In June 2012, the Company acquired through Cyber Medical and Shanghai Medstar 52% of the equity interest in Chang'an Hospital. In December 2012, the Company acquired 19.98% of equity interest in The University of Texas MD Anderson Cancer Center Proton Therapy Center, a proton treatment center in the world.