Death and Brain Death

To the Editor: Because Dr. Black's elegant review of criteria for and implications of brain death in the August 17 and 24 issues of the Journal will serve as a key reference to a complex subject, I believe that a comment should be made concerning his brief treatment and dismissal of radionuclide methodology for determining the presence or absence of cerebral blood flow. He correctly points out that the use of a scintillation probe positioned over the head to detect activity after the intravenous injection of an isotonic radionuclide bolus cannot distinguish activity contributed by the internal carotid circulation from.