A growing number of privately insured U.S. patients are being referred for imaging scans, and much of the increase is due to physicians referring patients to their own facilities or machines, according to a study by researchers at Georgetown University. Researchers reviewed data collected between 2000 and 2004 by a large private insurer in California and compared that analysis to a report by the Medicare Payment Advisory Commission. The bulk of the increase was from patients with private insurance that provided the physician with a fee for service reimbursement.