title: Multimodality functional imaging in radiation therapy planning: relationships between dynamic contrast-enhanced MRI, diffusion-weighted MRI, and 18F-FDG PET.
abstract: OBJECTIVE
  Biologically guided radiotherapy needs an understanding of how different functional imaging techniques interact and link together. We analyse three functional imaging techniques that can be useful tools for achieving this objective.
  
  
  METHODS
  The three different imaging modalities from one selected patient are ADC maps, DCE-MRI, and 18F-FDG PET/CT, because they are widely used and give a great amount of complementary information. We show the relationship between these three datasets and evaluate them as markers for tumour response or hypoxia marker. Thus, vascularization measured using DCE-MRI parameters can determine tumour hypoxia, and ADC maps can be used for evaluating tumour response.
  
  
  RESULTS
  ADC and DCE-MRI include information from 18F-FDG, as glucose metabolism is associated with hypoxia and tumour cell density, although 18F-FDG includes more information about the malignancy of the tumour. The main disadvantage of ADC maps is the distortion, and we used only low distorted regions, and extracellular volume calculated from DCE-MRI can be considered equivalent to ADC in well-vascularized areas.
  
  
  CONCLUSIONS
  A dataset for achieving the biologically guided radiotherapy must include a tumour density study and a hypoxia marker. This information can be achieved using only MRI data or only PET/CT studies or mixing both datasets.
authors: Medical Physics Department and Radiological Protection, Galaria-Hospital do Meixoeiro-Complexo Hospitalario Universitario de Vigo, 36200 Vigo, Spain.
authors: Moisés
authors: M
authors: Mera Iglesias
authors: Medical Physics Department and Radiological Protection, Galaria-Hospital do Meixoeiro-Complexo Hospitalario Universitario de Vigo, 36200 Vigo, Spain.
authors: David
authors: D
authors: Aramburu Núñez
authors: Medical Physics Department and Radiological Protection, Galaria-Hospital do Meixoeiro-Complexo Hospitalario Universitario de Vigo, 36200 Vigo, Spain.
authors: José Luis
authors: JL
authors: Del Olmo Claudio
authors: Medical Physics Department and Radiological Protection, Galaria-Hospital do Meixoeiro-Complexo Hospitalario Universitario de Vigo, 36200 Vigo, Spain.
authors: Antonio
authors: 0000-0003-0919-2566
authors: A
authors: López Medina
authors: Signal Theory and Communications Department, University of Vigo, 36310 Vigo, Spain.
authors: Iago
authors: 0000-0003-1509-4911
authors: I
authors: Landesa-Vázquez
authors: Medical Physics Department and Radiological Protection, Galaria-Hospital do Meixoeiro-Complexo Hospitalario Universitario de Vigo, 36200 Vigo, Spain.
authors: Francisco
authors: F
authors: Salvador Gómez
authors: Radiation Medicine Program, Princess Margaret Cancer Centre and University Health Network, Toronto, ON, Canada M5T 2M9.
authors: Brandon
authors: B
authors: Driscoll
authors: Radiation Medicine Program, Princess Margaret Cancer Centre and University Health Network, Toronto, ON, Canada M5T 2M9.
authors: Catherine
authors: C
authors: Coolens
authors: Signal Theory and Communications Department, University of Vigo, 36310 Vigo, Spain.
authors: José L
authors: JL
authors: Alba Castro
authors: Radiation Oncology Department, Galaria-Hospital do Meixoeiro-Complexo Hospitalario Universitario de Vigo, 36200 Vigo, Spain.
authors: Victor
authors: V
authors: Muñoz
mesh_terms: D019540:Area Under Curve; D003287:Contrast Media / Q000737:chemistry*; D038524:Diffusion Magnetic Resonance Imaging; D019788:Fluorodeoxyglucose F18 / Q000737:chemistry*; D006801:Humans; D000860:Hypoxia; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D064847:Multimodal Imaging; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology; D049268:Positron-Emission Tomography; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results
chemical_list: D003287:Contrast Media; D019788:Fluorodeoxyglucose F18