1. Department of Urology, Stanford University School of Medicine, Stanford, CA 94305, USA.
2. Stanford Center for Biomedical Ethics, Stanford University, Stanford, CA 94305, USA.
3. Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
4. Department of Radiology, Stanford University School of Medicine, Stanford, CA 94305, USA.
5. Molecular Imaging Program at Stanford, Stanford University School of Medicine, CA 94305 USA.