title: Comparing 18-fluoro-2-deoxyglucose positron emission tomography with a combination of technetium 99m tetrofosmin single photon emission computed tomography and computed tomography to detect recurrent or persistent nasopharyngeal carcinomas after radiotherapy.
abstract: BACKGROUND
  The diagnostic accuracy of combined computed tomography (CT) and technetium 99m tetrofosmin (Tc-TF) single photon emission computed tomography (SPECT) of head and neck to differentiate recurrent or residual nasopharyngeal carcinomas (NPCs) from benign lesions after radiotherapy was evaluated and compared with positron emission tomography (PET) with 18-fluoro-2-deoxyglucose (FDG).
  
  
  METHODS
  Four months after radiotherapy, 36 patients with NPC underwent Tc-TF SPECT and CT of head and neck to differentiate recurrent or residual NPC from benign lesions. Histopathologic examinations were performed on nasopharyngeal biopsies of all 36 patients.
  
  
  RESULTS
  Based on the biopsy results, the sensitivity, specificity, and accuracy of Tc-TF SPECT were 64%, 96%, and 86%, respectively, for differentiation of recurrent or persistent NPC from benign lesions. For CT and FDG-PET, the sensitivity, specificity, and accuracy were 73%, 88%, and 83% and 100%, 96%, 97%, respectively. For the 27 patients with NPC whose Tc-TF SPECT and CT results were congruent, the combination of Tc-TF SPECT and CT had the same sensitivity, specificity, and accuracy (100%, 96%, and 96%) as FDG-PET. For the nine patients with NPC with incongruent Tc-TF SPECT and CT results, FDG-PET correctly differentiated two benign lesions from seven recurrent/residual NPCs.
  
  
  CONCLUSIONS
  Although, FDG-PET is the best tool for detecting recurrent or residual NPC, combined congruent Tc-TF SPECT and CT results achieved the same accuracy as FDG-PET. Therefore, we concluded that FDG-PET could be considered only when Tc-TF SPECT and CT give incongruent results.
authors.affiliation: Department of Nuclear Medicine, Taichung Veterans General Hospital, Taichung, Taiwan. kaoch@vghtc.vghtc.gov.tw
authors.forename: C H
authors.initials: CH
authors.lastname: Kao
authors.forename: S C
authors.initials: SC
authors.lastname: Tsai
authors.forename: J J
authors.initials: JJ
authors.lastname: Wang
authors.forename: Y J
authors.initials: YJ
authors.lastname: Ho
authors.forename: R F
authors.initials: RF
authors.lastname: Yen
authors.forename: S T
authors.initials: ST
authors.lastname: Ho
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy; D003937:Diagnosis, Differential; D019008:Drug Resistance, Neoplasm; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging*; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014055:Tomography, Emission-Computed; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; C078700:technetium tc-99m tetrofosmin