Prior receipt of PARP inhibitor was associated with lower SUVmax (4.7 vs. 6.4, P = 0.001), and prior receipt of systemic therapy was also associated with lower SUVmax (4.0 vs. 6.0, P = 0.01).<h4>Conclusions</h4>[<sup>18</sup>F]-FTT PET/CT may be useful as a noninvasive quantitative assessment of PARP1 enzyme activity in patients with solid tumors; uptake of [<sup>18</sup>F]-FTT varies based on tumor mutational status and receipt of prior PARP inhihbitor therapy and/or systemic therapy. This evidence concerns the gene PARP1 and neoplasm.