RT Journal Article SR Electronic T1 PET imaging of PARP expression using [18F]olaparib JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP jnumed.118.213223 DO 10.2967/jnumed.118.213223 A1 Thomas Wilson A1 Mary-Ann Xavier A1 James Knight A1 Stefan Verhoog A1 Julia Baguña Torres A1 Michael Mosley A1 Samantha Hopkins A1 Sheena Wallington A1 Danny Allen A1 Veerle Kersemans A1 Rebekka Hueting A1 Sean Smart A1 Veronique Gouverneur A1 Bart Cornelissen YR 2018 UL http://jnm.snmjournals.org/content/early/2018/11/01/jnumed.118.213223.abstract AB PARP inhibitors are increasingly being studied as cancer drugs, as single agents or as a part of combination therapies. Imaging of PARP using a radiolabeled inhibitor has been proposed for patient selection, outcome prediction, dose optimization, genotoxic therapy evaluation, and target engagement imaging of novel PARP-targeting agents. Here, via the copper-mediated 18F-radiofluorination of aryl boronic esters, we accessed, for the first time, the 18F-radiolabeled isotopologue of the Food and Drug Administration-approved PARP inhibitor olaparib. The use of the 18F-labeled equivalent of olaparib allows direct prediction of the distribution of olaparib, given its exact structural likeness to the native, non-radiolabeled drug. [18F]Olaparib was taken up selectively in vitro in PARP-1-expressing cells. Irradiation increased PARP-1 expression and [18F]olaparib uptake in a radiation-dose-dependent fashion. PET imaging in mice showed specific uptake of [18F]olaparib in tumors expressing PARP-1 (3.2±0.36%ID/g in PSN-1 xenografts), correlating linearly with PARP-1 expression. Two hours after irradiation of the tumor (10 Gy), uptake of [18F]olaparib increased by 70% (P = 0.025). Taken together, we show that [18F]olaparib has great potential for non-invasive tumor imaging and monitoring of radiation damage.