title: The use of deformable image registration to integrate diagnostic MRI into the radiotherapy planning pathway for head and neck cancer.
abstract: To assess the accuracy of gross tumour volume (GTV) delineation for head and neck squamous cell carcinoma (HNSCC) using a diagnostic position MRI (MRI-D) deformably registered to the planning CT (pCT), by comparison with a dedicated planning position MRI (MRI-RT).
  
  
  
  Fourteen patients with HNSCC underwent a T1-weighted MRI-D and MRI-RT. A reference GTV was defined as that delineated on MRI-RT rigidly registered to pCT. GTVs were delineated on: MRI-D and then registered to pCT by deformable image registration over the whole image (DIR-whole); MRI-D and then registered to pCT with rigid registration over a region of interest defined as GTV+3cm (Rigid-ROI); and on the pCT alone. These were compared using positional metrics to the reference.
  
  
  
  GTVs delineated on MRI-D followed by DIR-whole were significantly more accurate than those delineated on CT alone. The mean Dice Similarity Coefficient was 0.6 and 0.72 for pCT and DIR-whole respectively. Use of MRI-D with Rigid-ROI provided no advantage over CT-only delineation.
  
  
  
  Contouring on MRI-RT rigidly registered to pCT should be considered as the gold standard for HNSCC. In radiotherapy centres lacking a dedicated MRI-RT, the use of an MRI-D with DIR-whole offers a significant advantage for the accuracy of GTV delineation over contouring on pCT alone.
authors: Medical Physics and Engineering, Bexley Wing, St. James's University Hospital, Leeds Teaching Hospitals Trust, United Kingdom; Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, United Kingdom. Electronic address: Robert.Chuter@christie.nhs.uk.
authors: Robert
authors: R
authors: Chuter
authors: Clinical Oncology, Bexley Wing, St. James's University Hospital, Leeds Teaching Hospitals Trust, United Kingdom.
authors: Robin
authors: R
authors: Prestwich
authors: Medical Physics and Engineering, Bexley Wing, St. James's University Hospital, Leeds Teaching Hospitals Trust, United Kingdom.
authors: David
authors: D
authors: Bird
authors: Radiology and Nuclear Medicine, Bexley Wing, St. James's University Hospital, Leeds Teaching Hospitals Trust, United Kingdom.
authors: Andrew
authors: A
authors: Scarsbrook
authors: Radiation Oncology, Blacktown Hospital, Australia.
authors: Jonathan
authors: J
authors: Sykes
authors: Medical Physics and Engineering, Bexley Wing, St. James's University Hospital, Leeds Teaching Hospitals Trust, United Kingdom.
authors: Daniel
authors: D
authors: Wilson
authors: Medical Physics and Engineering, Bexley Wing, St. James's University Hospital, Leeds Teaching Hospitals Trust, United Kingdom.
authors: Richard
authors: R
authors: Speight
mesh_terms: D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D005260:Female; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D000077195:Squamous Cell Carcinoma of Head and Neck; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Diagnostic MRI; Head and neck; Image registration