title: Combined use of (18)F-FDG and (18)F-FMISO in unresectable non-small cell lung cancer patients planned for radiotherapy: a dynamic PET/CT study.
abstract: Aim of this study was to evaluate and compare, by means of dynamic and static PET/CT, the distribution patterns and pharmacokinetics of fluorine-18 fluorodeoxyglucose ((18)F-FDG) and of fluorine-18-fluoromisonidazole ((18)F-FMISO) in non-small cell lung cancer (NSCLC) patients scheduled for intensity modulated radiation therapy (IMRT). Thirteen patients suffering from inoperable stage III NSCLC underwent PET/CTs with (18)F-FDG and (18)F-FMISO for tumor metabolism and hypoxia assessment accordingly. Evaluation of PET/CT studies was based on visual analysis, semi-quantitative (SUV) calculations and absolute quantitative estimations, after application of a two-tissue compartment model and a non-compartmental approach. (18)F-FDG PET/CT revealed all thirteen primary lung tumors as sites of increased (18)F-FDG uptake. Six patients demonstrated also in total 43 (18)F-FDG avid metastases; these patients were excluded from radiotherapy. (18)F-MISO PET/CT demonstrated 12/13 primary lung tumors with faint tracer uptake. Only one tumor was clearly (18)F-FMISO avid, (SUVaverage = 3.4, SUVmax = 5.0). Mean values for (18)F-FDG, as derived from dPET/CT data, were SUVaverage = 8.9, SUVmax = 15.1, K1 = 0.23, k2 = 0.53, k3 = 0.17, k4 = 0.02, influx = 0.05 and fractal dimension (FD) = 1.25 for the primary tumors. The respective values for (18)F-FMISO were SUVaverage = 1.4, SUVmax = 2.2, K1 = 0.26, k2 = 0.56, k3 = 0.06, k4 = 0.06, influx = 0.02 and FD = 1.14. No statistically significant correlation was observed between the two tracers. (18)F-FDG PET/CT changed therapy management in six patients, by excluding them from planned IMRT. (18)F-FMISO PET/CT revealed absence of significant tracer uptake in the majority of the (18)F-FDG avid NSCLCs. Lack of correlation between the two tracers' kinetics indicates that they reflect different molecular mechanisms and implies the discordance between increased glycolysis and hypoxia in the malignancy.
authors.affiliation: Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center Heidelberg, Germany.
authors.forename: Christos
authors.initials: C
authors.lastname: Sachpekidis
authors.affiliation: Clinical Cooperation Unit Radiotherapy, German Cancer Research Center Heidelberg, Germany ; Department of Radiation Oncology, University Clinic Heidelberg Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Thieke
authors.affiliation: Clinical Cooperation Unit Radiotherapy, German Cancer Research Center Heidelberg, Germany ; Department of Radiation Oncology, University Clinic Heidelberg Germany.
authors.forename: Vasileios
authors.initials: V
authors.lastname: Askoxylakis
authors.affiliation: Clinical Cooperation Unit Radiotherapy, German Cancer Research Center Heidelberg, Germany ; Department of Radiation Oncology, University Clinic Heidelberg Germany.
authors.forename: Nils H
authors.initials: NH
authors.lastname: Nicolay
authors.affiliation: Clinical Cooperation Unit Radiotherapy, German Cancer Research Center Heidelberg, Germany ; Department of Radiation Oncology, University Clinic Heidelberg Germany.
authors.forename: Peter E
authors.initials: PE
authors.lastname: Huber
authors.affiliation: Department Thoracic Oncology/Internal Medicine, Thoraxklinik, University of Heidelberg Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Thomas
authors.affiliation: Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center Heidelberg, Germany.
authors.forename: Georgia
authors.initials: G
authors.lastname: Dimitrakopoulou
authors.affiliation: Clinical Cooperation Unit Radiotherapy, German Cancer Research Center Heidelberg, Germany ; Department of Radiation Oncology, University Clinic Heidelberg Germany.
authors.forename: Juergen
authors.initials: J
authors.lastname: Debus
authors.affiliation: Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center Heidelberg, Germany ; Division of Nuclear Medicine, University of Heidelberg Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Haberkorn
authors.affiliation: Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center Heidelberg, Germany.
authors.forename: Antonia
authors.initials: A
authors.lastname: Dimitrakopoulou-Strauss
keywords: 18F-FDG; 18F-FMISO; PET/CT; hypoxia; non-small cell lung cancer