title: Evaluating the use of optimally respiratory gated 18F-FDG-PET in target volume delineation and its influence on radiation doses to the organs at risk in non-small-cell lung cancer patients.
abstract: OBJECTIVE
  This radiotherapy planning study evaluated tumour delineation using both optimally respiratory gated and nongated fluorine-18 fluorodeoxyglucose-PET (F-FDG-PET).
  
  
  METHODS
  For 22 non-small-cell lung tumours, both scans were used to create the nongated and gated (g) gross tumour volumes (GTVg) together with the accompanying clinical target volumes (CTV) and planning target volumes (PTV). The size of the target volumes (TV) was evaluated and the accompanying radiotherapy plans were created to study the radiation doses to the organs at risk (OAR).
  
  
  RESULTS
  The median volumes of GTVg, CTVg and PTVg were statistically significantly smaller compared with the corresponding nongated volumes, resulting in a median TV reduction of 0.5 cm (interquartile range 0.1-1.2), 1.5 cm (-0.2 to 7.0) and 2.3 cm (-0.5 to 11.3) for the GTVg, CTVg and PTVg, respectively. For the OAR, only the percentage of lung (GTV included) receiving at least 35 Gy was significantly smaller after gating, with a median difference in lung volume receiving at least 35 Gy of 5.7 cm (interquartile range -0.8 to 30.50).
  
  
  CONCLUSIONS
  Compared with nongated F-FDG-PET, the TVs obtained with optimally respiratory gated F-FDG-PET were significantly smaller, however, without a clinically relevant difference in radiation dose to the OAR.
authors.affiliation: Departments of aRadiation Oncology bRadiology and Nuclear Medicine cPulmonary Diseases, Radboud University Medical Center, Nijmegen dDepartment of Radiology, Leiden University Medical Center, Leiden eBiomedical Photonic Imaging Group, MIRA Institute, University of Twente, Enschede, The Netherlands fInstitute of Radiooncology, Helmholtz-Zentrum Dresden-Rossendorf gDepartment of Radiotherapy and Radiooncology, University Hospital Carl Gustav Carus at the Technische Universität Dresden hOncoRay, National Center for Radiation Research in Oncology, Dresden, Germany.
authors.forename: Robin
authors.initials: R
authors.lastname: Wijsman
authors.forename: Willem
authors.initials: W
authors.lastname: Grootjans
authors.forename: Esther G
authors.initials: EG
authors.lastname: Troost
authors.forename: Erik H
authors.initials: EH
authors.lastname: van der Heijden
authors.forename: Eric P
authors.initials: EP
authors.lastname: Visser
authors.forename: Lioe-Fee
authors.initials: LF
authors.lastname: de Geus-Oei
authors.forename: Johan
authors.initials: J
authors.lastname: Bussink
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D058958:Organs at Risk / Q000528:radiation effects*; D049268:Positron-Emission Tomography; D011829:Radiation Dosage; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D055425:Respiratory-Gated Imaging Techniques; D012189:Retrospective Studies
chemical_list: D019788:Fluorodeoxyglucose F18