title: 18F-FDG PET/CT in the assessment of carcinoma of unknown primary origin.
abstract: OBJECTIVE
  Metastatic cancers of unknown primary origin are characterised by a poor prognosis, with a survival rate from diagnosis of approximately 12 months. Conventional radiological imaging allows detection of 20%-27% of primary cancers, whereas the detection rate with positron emission tomography (PET) is 24%-40%. The aim of this study was to assess the role of 18F-fluorodeoxyglucose (FDG) PET/computed tomography (CT) in the identification of occult primary cancers.
  
  
  METHODS
  The study population consisted of 38 consecutive patients with histologically proven metastatic disease and negative or nonconclusive conventional diagnostic procedures. All patients were studied by 18F-FDG PET performed according to the standard procedure (6 h of fasting, intravenous injection of 370 MBq 18F-FDG, and image acquisition with a PET/CT scanner for 4 min per bed position).
  
  
  RESULTS
  18F-FDG-PET/CT detected the occult primary cancer in 20 cases (53%), showing higher sensitivity than that reported for any other imaging modality, including PET.
  
  
  CONCLUSIONS
  The encouraging results, if validated by larger series, support the use of PET/CT in patients with carcinoma of unknown primary origin and negative conventional imaging results.
authors.affiliation: Unità Operativa di Medicina Nucleare, Padiglione 30, Policlinico S. Orsola-Malpighi, Via Massarenti 9, I-40138, Bologna, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Ambrosini
authors.forename: C
authors.initials: C
authors.lastname: Nanni
authors.forename: D
authors.initials: D
authors.lastname: Rubello
authors.forename: A
authors.initials: A
authors.lastname: Moretti
authors.forename: G
authors.initials: G
authors.lastname: Battista
authors.forename: P
authors.initials: P
authors.lastname: Castellucci
authors.forename: M
authors.initials: M
authors.lastname: Farsad
authors.forename: L
authors.initials: L
authors.lastname: Rampin
authors.forename: G
authors.initials: G
authors.lastname: Fiorentini
authors.forename: R
authors.initials: R
authors.lastname: Franchi
authors.forename: R
authors.initials: R
authors.lastname: Canini
authors.forename: S
authors.initials: S
authors.lastname: Fanti
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000556:secondary*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009382:Neoplasms, Unknown Primary / Q000175:diagnosis* / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography / Q000379:methods*; D011379:Prognosis; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18