Disclosed are PARP-1 inhibitors, which can be 18 F-labeled for use as tracers in positron emission tomographic (PET) imaging. Further disclosed are methods of synthesis. Of the compounds synthesized, 2-[p-(2-Fluoroethoxy)phenyl]-1.3.10-triazatricyclo[6.4.1.04,13]trideca-2,4(13),5,7-tetraen-9-one (12) had the highest inhibition potency for PARP-1 (IC50= 6.3 nM). Synthesis of [18F]-12 is disclosed under conventional conditions in high specific activity with 40-50% decay-corrected yield. MicroPET imaging using [18F]-12 in MDA-MB-436 tumor-bearing mice demonstrated accumulation of [18F]-12 in a tumor. Binding can be blocked by olaparib. The compounds have utility for tumor imaging.