title: 3'-Deoxy-3'-[(18)F]fluorothymidine and O-(2-[(18)F]fluoroethyl)-L-tyrosine PET in Patients with Suspicious Recurrence of Glioma after Multimodal Treatment: Initial Results of a Retrospective Comparative Study.
abstract: OBJECTIVE
  The purpose of this study was to compare the uptakes and diagnostic accuracies between 3'-deoxy-3'-[(18)F]fluorothymidine (FLT) and O-(2-[(18)F]fluoroethyl)-L-tyrosine (FET) PET in patients with a clinical suspicion of having a recurrence of glioma after multimodality treatment.
  
  
  METHODS
  Thirty-two patients who underwent FLT and FET PET due to abnormal enhancement on magnetic resonance (MR) images were included. According to surgical confirmation or follow-up results, patients were divided into those with therapy-related benign changes (TRBCs) and those with recurrence. Recurrences were divided again into initial low-grade glioma (LGG) and high-grade glioma (HGG). The uptakes of FLT and FET were compared with the maximum standardized uptake value (SUVmax) and lesion-to-normal ratio (LNR). The diagnostic accuracies were compared via a receiver-operating-characteristic (ROC) curve analysis.
  
  
  RESULTS
  The LNRs of FLT in recurrences with initial HGG (8.26 ± 5.02) were significantly higher than those in recurrences with initial LGG (3.43 ± 2.14) and TRBC (1.81 ± 0.60). The LNRs of FET in recurrence with initial HGG (2.70 ± 0.48) and LGG (3.03 ± 1.32) were significantly higher than those in the TRBC (1.60 ± 0.47). The areas under the ROC curve (AUCs) of FLT and FET for initial LGG were 0.768 and 0.893, respectively. The AUCs of FLT and FET for initial HGG were 1.000 and 0.964. However, there were no statistical significances. The results for comparing with SUVmax were the same as those with LNR.
  
  
  CONCLUSIONS
  Uptakes of FLT were different according to initial grade in patients with recurrent glioma, but those of FET were not. However, there were no statistical significances in the diagnostic accuracies according to initial grade between the two tracers in this study.
authors.affiliation: Department of Nuclear Medicine, Korea Institute of Radiological and Medical Sciences, 215-4, Gongneung-Dong, Nowon-Gu, Seoul, 139-706 South Korea.
authors.forename: Su Young
authors.initials: SY
authors.lastname: Jeong
authors.affiliation: Department of Radiology, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea.
authors.forename: Tae Hyun
authors.initials: TH
authors.lastname: Lee
authors.affiliation: Department of Neurosurgery, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea.
authors.forename: Chang Hun
authors.initials: CH
authors.lastname: Rhee
authors.affiliation: Department of Nuclear Medicine, Korea Institute of Radiological and Medical Sciences, 215-4, Gongneung-Dong, Nowon-Gu, Seoul, 139-706 South Korea.
authors.forename: A Ra
authors.initials: AR
authors.lastname: Cho
authors.affiliation: Department of Nuclear Medicine, Korea Institute of Radiological and Medical Sciences, 215-4, Gongneung-Dong, Nowon-Gu, Seoul, 139-706 South Korea.
authors.forename: Byeong
authors.initials: B
authors.lastname: Il Kim
authors.affiliation: Department of Nuclear Medicine, Korea Institute of Radiological and Medical Sciences, 215-4, Gongneung-Dong, Nowon-Gu, Seoul, 139-706 South Korea ; Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea.
authors.forename: Gi Jeong
authors.initials: GJ
authors.lastname: Cheon
authors.affiliation: Department of Nuclear Medicine, Korea Institute of Radiological and Medical Sciences, 215-4, Gongneung-Dong, Nowon-Gu, Seoul, 139-706 South Korea.
authors.forename: Chang Woon
authors.initials: CW
authors.lastname: Choi
authors.affiliation: Department of Nuclear Medicine, Korea Institute of Radiological and Medical Sciences, 215-4, Gongneung-Dong, Nowon-Gu, Seoul, 139-706 South Korea.
authors.forename: Sang Moo
authors.initials: SM
authors.lastname: Lim
keywords: FET; FLT; Glioma; Initial grade; PET; Recurrence