title: Alterations in anatomic and functional imaging parameters with repeated FDG PET-CT and MRI during radiotherapy for head and neck cancer: a pilot study.
abstract: BACKGROUND
  The use of imaging to implement on-treatment adaptation of radiotherapy is a promising paradigm but current data on imaging changes during radiotherapy is limited. This is a hypothesis-generating pilot study to examine the changes on multi-modality anatomic and functional imaging during (chemo)radiotherapy treatment for head and neck squamous cell carcinoma (HNSCC).
  
  
  METHODS
  Eight patients with locally advanced HNSCC underwent imaging including computed tomography (CT), Fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)-CT and magnetic resonance imaging (MRI) (including diffusion weighted (DW) and dynamic contrast enhanced (DCE)) at baseline and during (chemo)radiotherapy treatment (after fractions 11 and 21). Regions of interest (ROI) were drawn around the primary tumour at baseline and during treatment. Imaging parameters included gross tumour volume (GTV) assessment, SUVmax, mean ADC value and DCE-MRI parameters including Plasma Flow (PF). On treatment changes and correlations between these parameters were analysed using a Wilcoxon rank sum test and Pearson's linear correlation coefficient respectively. A p-value <0.05 was considered statistically significant.
  
  
  RESULTS
  Statistically significant reductions in GTV-CT, GTV-MRI and GTV-DW were observed between all imaging timepoints during radiotherapy. Changes in GTV-PET during radiotherapy were heterogeneous and non-significant. Significant changes in SUVmax, mean ADC value, Plasma Flow and Plasma Volume were observed between the baseline and the fraction 11 timepoint, whilst only changes in SUVmax between baseline and the fraction 21 timepoint were statistically significant. Significant correlations were observed between multiple imaging parameters, both anatomical and functional; 20 correlations between baseline to the fraction 11 timepoint; 12 correlations between baseline and the fraction 21 timepoints; and 4 correlations between the fraction 11 and fraction 21 timepoints.
  
  
  CONCLUSIONS
  Multi-modality imaging during radiotherapy treatment demonstrates early changes (by fraction 11) in both anatomic and functional imaging parameters. All functional imaging modalities are potentially complementary and should be considered in combination to provide multi-parametric tumour assessment, to guide potential treatment adaptation strategies.
  
  
  BACKGROUND
  ISRCTN Registry: ISRCTN34165059 . Registered 2nd February 2015.
authors.affiliation: Department of Nuclear Medicine, St. James' University Hospital, Leeds Teaching Hospitals NHS Trust, Leeds, UK. manil.subesinghe@gmail.com.|Department of Clinical Radiology, St. James' University Hospital, Leeds Teaching Hospitals NHS Trust, Leeds, UK. manil.subesinghe@gmail.com.
authors.forename: Manil
authors.initials: M
authors.lastname: Subesinghe
authors.affiliation: Department of Nuclear Medicine, St. James' University Hospital, Leeds Teaching Hospitals NHS Trust, Leeds, UK. andrew.scarsbrook@leedsth.nhs.uk.|Department of Clinical Radiology, St. James' University Hospital, Leeds Teaching Hospitals NHS Trust, Leeds, UK. andrew.scarsbrook@leedsth.nhs.uk.
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Scarsbrook
authors.affiliation: Division of Medical Physics, University of Leeds, Leeds, UK. s.sourbron@leeds.ac.uk.
authors.forename: Steven
authors.initials: S
authors.lastname: Sourbron
authors.affiliation: Department of Medical Physics, St. James' University Hospital, Leeds Teaching Hospitals NHS Trust, Leeds, UK. djw@medphysics.leeds.ac.uk.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Wilson
authors.affiliation: Department of Medical Physics, St. James' University Hospital, Leeds Teaching Hospitals NHS Trust, Leeds, UK. garry.mcdermott@nhs.net.
authors.forename: Garry
authors.initials: G
authors.lastname: McDermott
authors.affiliation: Department of Radiotherapy Physics, St. James' University Hospital, Leeds Teaching Hospitals NHS Trust, Leeds, UK. richard.speight@leedsth.nhs.uk.
authors.forename: Richard
authors.initials: R
authors.lastname: Speight
authors.affiliation: Department of Radiotherapy, St. James' University Hospital, Leeds Teaching Hospitals NHS Trust, Leeds, UK. neil.roberts@leedsth.nhs.uk.
authors.forename: Neil
authors.initials: N
authors.lastname: Roberts
authors.affiliation: Department of Clinical Radiology, St. James' University Hospital, Leeds Teaching Hospitals NHS Trust, Leeds, UK. brendan.carey@leedsth.nhs.uk.
authors.forename: Brendan
authors.initials: B
authors.lastname: Carey
authors.affiliation: Division of Medical Physics, University of Leeds, Leeds, UK. um09rcf@leeds.ac.uk.
authors.forename: Roan
authors.initials: R
authors.lastname: Forrester
authors.affiliation: Division of Medical Physics, University of Leeds, Leeds, UK. sandeepvg90@yahoo.co.uk.
authors.forename: Sandeep Vijaya
authors.initials: SV
authors.lastname: Gopal
authors.affiliation: Department of Radiotherapy Physics, St. James' University Hospital, Leeds Teaching Hospitals NHS Trust, Leeds, UK. jonathan.sykes@leedsth.nhs.uk.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Sykes
authors.affiliation: Department of Clinical Oncology, St. James' University Hospital, Leeds Teaching Hospitals NHS Trust, Leeds, UK. robin.prestwich@nhs.net.|St. James' Institute of Oncology, Level 4 Bexley Wing, Beckett Street, Leeds, LS9 7TF, UK. robin.prestwich@nhs.net.
authors.forename: Robin J D
authors.initials: RJ
authors.lastname: Prestwich
mesh_terms: D005260:Female; D019788:Fluorodeoxyglucose F18; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D010865:Pilot Projects; D049268:Positron-Emission Tomography / Q000379:methods; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D019788:Fluorodeoxyglucose F18