1. Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States
2. Department of Chemistry and Biochemistry, California State University, Fullerton, California 92831, United States
3. Department of Chemistry and Biochemistry, Loyola University Chicago, Chicago, Illinois 60660, United States
4. Department of Biomedical Engineering, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States
5. Department of Radiology, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States