1. Department of Nuclear Medicine, University Hospital Heidelberg, INF 400, 69120 Heidelberg, Germany, Faculty of Pharmacy, Al-Baath University, P.O. Box 77 Homs, Syria, Clinical Cooperation Unit Nuclear Medicine, DKFZ, INF 280, 69120 Heidelberg, Germany, and Department of Radiopharmaceutical Chemistry, DKFZ, INF 280, 69120 Heidelberg, Germany