Federal investigators have found that Rhode Island Hospital ordered medically unnecessary overnight stays over a five-year period. In a civil settlement, the hospital will reimburse Medicare and Medicaid approximately $2.6 million dollars and will pay the federal government approximately $2.7 million in double and triple damages. An investigation found that from Jan. 1 2004, through Dec. 31, 2009, medically unnecessary overnight hospital admissions were ordered for approximately 260 patients who underwent stereotactic radiosurgery, otherwise known as Gamma Knife treatment.