title: FDG-PET and diffusion-weighted MRI in head-and-neck cancer patients: implications for dose painting.
abstract: OBJECTIVE
  The purpose of this study was to investigate if FDG-PET and DWI identify the same or different targets for dose escalation in the GTV of HN cancer patients. Additionally, the dose coverage of DWI-targets in an FDG-PET-based dose painting plan was analyzed.
  
  
  METHODS
  Eighteen HN cancer patients underwent FDG-PET and DWI exams, which were converted to standardized uptake value (SUV)- and apparent diffusion coefficient (ADC)-maps. The correspondence between the two imaging modalities was determined on a voxel-level using Spearman's correlation coefficient (ρ). Dose painting plans were optimized based on the 50% isocontour of the maximum SUV ( SUV(50%max)). Dose coverage was analyzed in three different SUV- and three different ADC-targets using the mean dose and the near-minimum and near-maximum doses.
  
  
  RESULTS
  The average maximum SUV was 13.9 and the mean ADC was 1.17 · 10(-3) mm(2)/s. The average ρ between SUV and ADC was -0.2 (range: -0.6 to 0.4). The ADC-targets were only partly overlapping the SUV(50%max)-target and the dose parameters were significantly smaller in the ADC-targets compared to the SUV(50%max)-target.
  
  
  CONCLUSIONS
  FDG-PET and DWI contain different information, resulting in different targets. Further information about failure patterns and dose relations can be obtained by adding DWI to currently ongoing dose painting trials.
authors: Department of Radiotherapy, The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands.
authors: Antonetta C
authors: AC
authors: Houweling
authors: Anne Lisa
authors: AL
authors: Wolf
authors: Wouter V
authors: WV
authors: Vogel
authors: Olga
authors: O
authors: Hamming-Vrieze
authors: Corine
authors: C
authors: van Vliet-Vroegindeweij
authors: Jeroen B
authors: JB
authors: van de Kamer
authors: Uulke A
authors: UA
authors: van der Heide
mesh_terms: D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D019788:Fluorodeoxyglucose F18; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D006801:Humans; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D061089:Radiotherapy, Image-Guided / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18