title: Improving the accuracy of target volume delineation by combined use of computed tomography, magnetic resonance imaging and positron emission tomography in head and neck carcinomas.
abstract: OBJECTIVE
  Conformal radiation therapy mandates accurate delineation of target volumes, which requires incorporation of modern imaging modalities like magnetic resonance imaging (MRI) and positron emission tomography (PET) in addition to conventionally used computed tomography (CT). This can resolve discrepancies in target delineation in head and neck carcinomas resulting in better local control. We hereby report the comparison of Gross Tumor Volumes (GTVs) (primary) drawn using PET, CT and MRI and their concordance indices.
  
  
  METHODS
  Twenty five patients with head and neck cancer were taken into this study. MRI, PET and CT planning scans were done as per standard guidelines. Three sets of primary GTVs namely GTV- PET, GTV-CT and GTV-MRI were contoured on fused images. All the three volumes and concordances among the volumes were analyzed.
  
  
  RESULTS
  The mean GTV-CT, GTV-PET and GTV-MRI volumes were 29.65 cc ± 31.27, 32.05 cc ± 33.75 and 24.85 cc ± 25.28 respectively. There was a significant difference in the GTV-MRI & GTV-CT volumes (P = 0.023) and GTV-PET & GTV-MRI volumes (P = 0.049). However, there was no significant difference in the GTV-PET & GTV-CT volume (P = 0.468). The mean CI (PET-MRI), CI (CT-MRI) and CI (PET-CT) was 0.42, 0.46 and 0.47 respectively, which depicts a moderate concordance.
  
  
  CONCLUSIONS
  PET and MRI are useful imaging tools in head and neck malignancies and should be used in conjunction with CT scan for improved target volume delineation.
authors.affiliation: Department of Radiation Oncology, Rajiv Gandhi Cancer Institute and Research Centre, New Delhi, India.
authors.forename: Deepika
authors.initials: D
authors.lastname: Chauhan
authors.forename: Sheh
authors.initials: S
authors.lastname: Rawat
authors.forename: Manoj K
authors.initials: MK
authors.lastname: Sharma
authors.forename: Parveen
authors.initials: P
authors.lastname: Ahlawat
authors.forename: Manoj
authors.initials: M
authors.lastname: Pal
authors.forename: Gourav
authors.initials: G
authors.lastname: Gupta
authors.forename: Abhinav
authors.initials: A
authors.lastname: Dewan
authors.forename: Manoj
authors.initials: M
authors.lastname: Gupta
authors.forename: Shelly
authors.initials: S
authors.lastname: Sharma
authors.forename: Chandragouda
authors.initials: C
authors.lastname: Dodagoudar
authors.forename: Anjali
authors.initials: A
authors.lastname: Pahuja
authors.forename: Swarupa
authors.initials: S
authors.lastname: Mitra
authors.forename: Surender K
authors.initials: SK
authors.lastname: Sharma
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy; D059248:Chemoradiotherapy; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography / Q000379:methods*; D011379:Prognosis; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed / Q000379:methods*; D047368:Tumor Burden
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18