%0 Journal Article %A Galldiks, Norbert %A Abdulla, Diana SY %A Scheffler, Matthias %A Wolpert, Fabian %A Werner, Jan-Michael %A Huellner, Martin W %A Stoffels, Gabriele %A Schweinsberg, Viola %A Schlaak, Max %A Kreuzberg, Nicole %A Landsberg, Jennifer %A Lohmann, Philipp %A Ceccon, Garry %A Baues, Christian %A Trommer, Maike %A Celik, Eren %A Ruge, Maximilian I %A Kocher, Martin %A Marnitz, Simone %A Fink, Gereon R %A Tonn, Joerg-Christian %A Weller, Michael %A Langen, Karl-Josef %A Wolf, Jürgen %A Mauch, Cornelia %T Treatment Monitoring of Immunotherapy and Targeted Therapy using 18 F-FET PET in Patients with Melanoma and Lung Cancer Brain Metastases: Initial Experiences %J Journal of nuclear medicine %V 62 %N 4 %@ 2159-662X %C New York, NY %I Soc. %M FZJ-2021-00862 %P 464-470 %D 2021 %X We investigated the value of O-(2-18F-fluoroethyl)-l-tyrosine (18F-FET) PET for treatment monitoring of immune checkpoint inhibition (ICI) or targeted therapy (TT) alone or in combination with radiotherapy in patients with brain metastasis (BM) since contrast-enhanced MRI often remains inconclusive. Methods: We retrospectively identified 40 patients with 107 BMs secondary to melanoma (n = 29 with 75 BMs) or non–small cell lung cancer (n = 11 with 32 BMs) treated with ICI or TT who had 18F-FET PET (n = 60 scans) for treatment monitoring from 2015 to 2019. Most patients (n = 37; 92.5%) had radiotherapy during the course of the disease. In 27 patients, 18F-FET PET was used to differentiate treatment-related changes from BM relapse after ICI or TT. In 13 patients, 18F-FET PET was performed for response assessment to ICI or TT using baseline and follow-up scans (median time between scans, 4.2 mo). In all lesions, static and dynamic 18F-FET PET parameters were obtained (i.e., mean tumor-to-brain ratios [TBR], time-to-peak values). Diagnostic accuracies of PET parameters were evaluated by receiver-operating-characteristic analyses using the clinical follow-up or neuropathologic findings as a reference. Results: A TBR threshold of 1.95 differentiated BM relapse from treatment-related changes with an accuracy of 85% (P = 0.003). Metabolic responders to ICI or TT on 18F-FET PET had a significantly longer stable follow-up (threshold of TBR reduction relative to baseline, ≥10%; accuracy, 82%; P = 0.004). Furthermore, at follow-up, time to peak in metabolic responders increased significantly (P = 0.019). Conclusion: 18F-FET PET may add valuable information for treatment monitoring in BM patients treated with ICI or TT. %F PUB:(DE-HGF)16 %9 Journal Article %$ 32887757 %U <Go to ISI:>//WOS:000658416500008 %R 10.2967/jnumed.120.248278 %U https://juser.fz-juelich.de/record/890281