1. Imaging Biomarkers and Computer-Aided Diagnosis Laboratory, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Building 10, Room 1C224, Bethesda, MD 20892-1182, USA
2. Molecular Imaging Program, National Cancer Institute, National Institutes of Health, Building 10, Room B3B69F, Bethesda, MD 20892-1088, USA