Alliance Healthcare Services, Inc. (Alliance), formerly Alliance Imaging, Inc., is a provider of outpatient diagnostic imaging services and radiation oncology services. The Company’s principal sources of revenue are derived from magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT). The Company provides imaging and therapeutic services primarily to hospitals and other healthcare providers on a shared-service and full-time service basis. Its also provides services through a number of fixed-site imaging centers, primarily to hospitals or health systems. In March 2008, Alliance Radiosurgery, LLC, a wholly owned subsidiary, acquired six CyberKnife robotic radiosurgery facilities from Accuray, Inc. In July 2008, it acquired Medical Outsourcing Services, LLC (MOS). In December 2008, it acquired Shared PET Imaging, LLC (SPI). During the year ended December 31, 2008, it also acquired the remaining 20% minority interest in Alliance Oncology, LLC (AO).