title: Modality-specific target definition for laryngeal and hypopharyngeal cancer on FDG-PET, CT and MRI.
abstract: The goal of this study was to improve target definition by deriving modality-specific margins for clinical target volumes (CTV) for laryngeal and hypopharyngeal cancer on CT, MRI and 18-FDG-PET.
  
  
  
  Twenty-five patients with T3/T4 laryngeal/hypopharyngeal cancer underwent CT, MRI and 18-FDG-PET scans before laryngectomy. HE-sections were obtained from the surgical specimen and tumor was delineated (tumorHE). The GTVs on CT and MRI were delineated in consensus. PET-based GTVs were automatically segmented. The three-dimensionally reconstructed specimen was registered to the various images. Modality-specific CTV margins were derived and added to the GTVs to achieve adequate tumor coverage. The resulting CTVs were compared with each other, to tumorHE, and to CTVCT10constructed on CT with the clinical margin of 10mm.
  
  
  
  CTV margins of 4.3mm (CT), 6.1mm (MRI) and 5.2mm (PET) were needed to achieve adequate tumor coverage. The median volumes of the resulting modality-specific CTVs were 44ml (CT), 48ml (MRI) and 39ml (PET), while the CTV10mmwas 80ml.
  
  
  
  For laryngohypopharyngeal tumors, 45-52% target volume reduction compared with CTV10mmis achievable when modality-specific CTV margins are used. PET-based CTVs were significantly smaller compared to CT- and MRI-based CTVs.
authors.affiliation: Department of Radiotherapy, University Medical Center Utrecht, The Netherlands. Electronic address: h.ligtenberg@umcutrecht.nl.
authors.forename: Hans
authors.initials: H
authors.lastname: Ligtenberg
authors.affiliation: Department of Radiotherapy, University Medical Center Utrecht, The Netherlands.
authors.forename: Elise Anne
authors.initials: EA
authors.lastname: Jager
authors.affiliation: Department of Radiotherapy, University Medical Center Utrecht, The Netherlands.
authors.forename: Joana
authors.initials: J
authors.lastname: Caldas-Magalhaes
authors.affiliation: Department of Radiotherapy, University Medical Center Utrecht, The Netherlands.
authors.forename: Tim
authors.initials: T
authors.lastname: Schakel
authors.affiliation: Department of Radiology, University Medical Center Utrecht, The Netherlands.
authors.forename: Frank A
authors.initials: FA
authors.lastname: Pameijer
authors.affiliation: Department of Radiotherapy, University Medical Center Utrecht, The Netherlands.
authors.forename: Nicolien
authors.initials: N
authors.lastname: Kasperts
authors.affiliation: Department of Pathology, University Medical Center Utrecht, The Netherlands.
authors.forename: Stefan M
authors.initials: SM
authors.lastname: Willems
authors.affiliation: Department of Radiotherapy, University Medical Center Utrecht, The Netherlands.
authors.forename: Chris H J
authors.initials: CH
authors.lastname: Terhaard
authors.affiliation: Department of Radiotherapy, University Medical Center Utrecht, The Netherlands.
authors.forename: Cornelis P J
authors.initials: CP
authors.lastname: Raaijmakers
authors.affiliation: Department of Radiotherapy, University Medical Center Utrecht, The Netherlands.
authors.forename: Marielle E P
authors.initials: ME
authors.lastname: Philippens
mesh_terms: D000368:Aged; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007012:Hypopharyngeal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D007013:Hypopharynx / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D021621:Imaging, Three-Dimensional / Q000379:methods; D007822:Laryngeal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D007825:Laryngectomy; D007830:Larynx / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D011300:Preoperative Care / Q000379:methods; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: CTV; GTV; Head and neck cancer; Imaging; Pathology