Alliance Healthcare Services, Inc., is a national provider of advanced outpatient diagnostic imaging and radiation therapy services. The Company provides imaging and therapeutic services primarily to hospitals and other healthcare providers on a shared-service and full-time service basis. The Company also provides services through fixed-site imaging centers, primarily to hospitals or health systems. The Company�s services normally include the use of its imaging systems, technologists to operate the systems, equipment maintenance and upgrades and management of day-to-day shared-service and fixed-site diagnostic imaging operations. The Company also provides non scan-based services, which include only the use of its imaging systems under a short-term contract. In April 2011, the Company acquired 24/7 Radiology, a professional radiology services Company. In April 2011, the Company purchased all of the outstanding membership interests of US Radiosurgery, LLC .