title: [Diagnostic value of dual-head 18F-FDG imaging in metastatic lesion with unknown primary tumour].
abstract: OBJECTIVE
  To investigate the diagnostic value of dual-head (18)F-fluorodeoxyglucose ((18)F-FDG) imaging in metastatic lesion with unknown primary tumour (UPT).
  
  
  METHODS
  Seventy patients with UPT underwent dual-head (18)F-FDG imaging after iv (18)F-FDG 1.85 MBq/kg. The primary tumour was diagnosed according to the FDG uptake and T/N value.
  
  
  RESULTS
  Of the 70 patients, the primary tumour was identified by positive FDG imaging and finally confirmed pathologically in 58 patients (82.9%), and 12 patients had a negative FDG imaging (17.1%). Forty-two of the 58 positive patients were found to have lung cancer (72.4%). Among the 12 negative patients, their primary tumour was then identified by other diagnostic procedures in 5 patients (41.7%), in 1 patient, the primary site was detected during follow-up, however, the primary tumour was never detected in the rest 6 patients.
  
  
  CONCLUSIONS
  Dual-probe (18)F-FDG imaging is a simple, quick, non-invasive and sensitive technique with an accuracy over 80% in the diagnosis of unknown primary tumour. The lung is found to be the most frequent primary site. Dual-probe (18)F-FDG imaging can be recommended as the first diagnostic choice for UPT.
authors.affiliation: Department of Radiatiion Oncology, First Foshan People's Hospital, Foshan 528041, China.
authors.forename: Yan-ji
authors.initials: YJ
authors.lastname: Pan
authors.forename: Guang-yu
authors.initials: GY
authors.lastname: Wei
authors.forename: Yan-lin
authors.initials: YL
authors.lastname: Feng
authors.forename: Feng-wen
authors.initials: FW
authors.lastname: Yu
authors.forename: De-jun
authors.initials: DJ
authors.lastname: Liu
authors.forename: Ning
authors.initials: N
authors.lastname: Zhang
mesh_terms: D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D009382:Neoplasms, Unknown Primary / Q000000981:diagnostic imaging* / Q000473:pathology; D049268:Positron-Emission Tomography
chemical_list: D019788:Fluorodeoxyglucose F18