[18F]Rucaparib uptake in PSN1 tumour-bearing mice was reduced significantly by co-administration of a therapeutic dose of unlabelled PARP inhibitors rucaparib or olaparib (2.2 ± 0.34%ID/g to 1.16 ± 0.06%ID/g or 1.3 ± 0.09%ID/g, respectively; P < 0.05), indicating PARP-selective uptake in vivo (Fig. 4A). This evidence concerns the gene PARP1 and neoplasm.