Federal investigators have subpoenaed financial records related to Scott S. Reuben, a Massachusetts doctor accused of faking data used in at least 21 anesthesiology studies. The Springfield-based Baystate Medical Center, where Reuben was the head of the acute-pain unit, said it received a subpoena from the Boston U.S. attorney's office for financial records related to the anesthesiologist's work. A spokeswoman said Baystate Medical isn't a target of the investigation, and that the hospital is "fully cooperating."