Blood and urine samples are collected at 5, 10, 20, 30, and 45 minutes at baseline and at 1, 2, 3, 4, and 6 hours after ^99mTc DB4 IV infusion for pharmacokinetic studies. Tumor tissue samples obtained during radical prostatectomy and surgical lymph node biopsies are analyzed for gastrin-releasing peptide receptor by IHC.