1. Department of Radiology, Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, 55 Fruit St, White 427, Boston, MA 02115.
2. Fred Hutchinson Cancer Center, Seattle, WA.
3. Department of Radiology and Imaging Sciences, Clinical Center, NIH, Bethesda, MD.
4. Department of Computer Science and Electrical Engineering, University of Maryland, Baltimore County, Baltimore, MD.
5. Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, PA.
6. Division of Nuclear Medicine and Molecular Imaging Center, Keck School of Medicine and Viterbi School of Engineering, University of Southern California, Los Angeles, CA.
7. Division of Abdominal Imaging, Massachusetts General Hospital, Boston, MA.