The MRI machine can track the flow of blood into certain areas of the brain, indicating increased activity consistent with lying. One company, Cephos Corp., is being advised by former O.J. Simpson lawyer Robert Shapiro, who says, "I'd use it tomorrow in virtually every criminal and civil case on my desk." So far, however, the reliability of the tests has yet to be proven, and they haven't been used in any court proceeding. And bioethicists worry about the potential of the new technology to "change ... our ability ... to invade what has been the last untouchable sanctuary, the contents of your own mind," in the words of Hank Greely of the Stanford Center for Law and the Biosciences.