title: Optimal timing of post-treatment [18F]fluorodeoxyglucose-PET/CT for patients with head and neck malignancy.
abstract: OBJECTIVE
  The aims of this study were to evaluate the ability of [F]fluorodeoxyglucose (F-FDG)-PET/computed tomography (CT) to identify tumor recurrence, nodal metastases, and distant metastases for surveillance and discuss the optimal timing of F-FDG-PET/CT examination after the completion of treatment for head and neck malignancy.
  
  
  METHODS
  A total of 319 patients who underwent a post-treatment F-FDG-PET/CT examination for head and neck malignancy were studied. F-FDG-PET/CT findings were compared with the final diagnosis confirmed by histopathological examinations or clinical and radiological follow-up for at least 6 months. Patients were divided into two groups according to the presence or absence of clinical suspicion of recurrent disease. The diagnostic accuracy of F-FDG-PET/CT was analyzed for each group. Patients were also categorized according to the time interval between the completion of treatment and the post-treatment F-FDG-PET/CT examination. Differences in diagnostic accuracy due to the time interval were also evaluated.
  
  
  RESULTS
  The diagnostic accuracy of F-FDG-PET/CT was high for both groups. The overall accuracy of F-FDG-PET/CT performed within 2 months (69%) after the completion of treatment was significantly inferior to that performed after 2 months (93%).
  
  
  CONCLUSIONS
  F-FDG-PET should be performed immediately for patients with clinically suspected recurrent disease. In others, it should be performed at later than 2 months after the completion of the treatment.
authors.affiliation: Department of Oral and Maxillofacial Radiology, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. shin.orad@tmd.ac.jp
authors.forename: Shin
authors.initials: S
authors.lastname: Nakamura
authors.forename: Akira
authors.initials: A
authors.lastname: Toriihara
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Okochi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Watanabe
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Shibuya
authors.forename: Tohru
authors.initials: T
authors.lastname: Kurabayashi
mesh_terms: D000368:Aged; D005260:Female; D019788:Fluorodeoxyglucose F18; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy*; D006801:Humans; D008297:Male; D064847:Multimodal Imaging / Q000379:methods*; D009362:Neoplasm Metastasis; D049268:Positron-Emission Tomography; D012008:Recurrence; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013997:Time Factors; D014057:Tomography, X-Ray Computed
chemical_list: D019788:Fluorodeoxyglucose F18