title: [18F]FLT-PET and [18F]FDG-PET in the evaluation of radiotherapy for laryngeal cancer.
abstract: The evaluation of response to radiotherapy in patients with laryngeal cancer is a challenge because of the difficulty to differentiate between post-therapy changes and recurrent or residual tumor. Positron emission tomography is a non-invasive imaging tool that may be helpful in this differentiation. In this study, [(18)F]-fluoro-3'-deoxy-L-thymidine ([(18)F]FLT), a proliferation tracer is compared with 2-[(18)F]-fluoro-2-deoxy-D-glucose ([(18)F]FDG). Patients with primary laryngeal cancer, scheduled to undergo radiotherapy were included in this study. Patients underwent both [(18)F]FLT-PET and [(18)F]FDG-PET shortly before radiotherapy. Ten patients underwent [(18)F]FLT-PET and [(18)F]FDG-PET 2-3 months after radiotherapy. Scans were analyzed visually for areas of increased tracer uptake. The standardized uptake value (SUV) was measured as a semi-quantitative value of tracer uptake. Fourteen patients, all male, were included in this study. Both [(18)F]FLT-PET and [(18)F]FDG-PET showed increased tracer uptake in 12 out of 14 patients (86%). [(18)F]FDG uptake was significantly higher than [(18)F]FLT uptake (SUV(max): 4.5 vs. 2.4 (P=0.002); SUV(mean): 3.4 vs. 1.9 (P=0.002)). After radiotherapy, 3 patients had histologically proven residual or recurrent laryngeal cancer. [(18)F]FDG was true positive in 2 out of 3 patients, whereas [(18)F]FLT showed increased tracer uptake in only one. Of the remaining 7 patients, [(18)F]FLT was true negative in all, whereas [(18)F]FDG showed increased uptake in one (false positive). [(18)F]FLT-PET is feasible in visualizing laryngeal cancer and its evaluation of treatment. The overall uptake of this tracer is significantly lower as compared with [(18)F]FDG, but tumor to background ratios are comparable.
authors.affiliation: Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands. l.b.been@chir.umcg.nl
authors.forename: Lukas B
authors.initials: LB
authors.lastname: Been
authors.forename: Harald J
authors.initials: HJ
authors.lastname: Hoekstra
authors.forename: Albert J H
authors.initials: AJ
authors.lastname: Suurmeijer
authors.forename: Pieter L
authors.initials: PL
authors.lastname: Jager
authors.forename: Bernard F A M
authors.initials: BF
authors.lastname: van der Laan
authors.forename: Philip H
authors.initials: PH
authors.lastname: Elsinga
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015224:Dideoxynucleosides / Q000493:pharmacokinetics; D005240:Feasibility Studies; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006801:Humans; D007822:Laryngeal Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography / Q000379:methods*; D011379:Prognosis; D011446:Prospective Studies; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012680:Sensitivity and Specificity
chemical_list: D015224:Dideoxynucleosides; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; C002854:alovudine