title: Characterization of neuroblastic tumors using 18F-FDOPA PET.
abstract: Neuroblastic tumors are childhood neoplasms that possess amino acid decarboxylase (AADC) activity and can theoretically be imaged by (18)F-fluorodihydroxyphenylalanine ((18)F-FDOPA) PET, a new diagnostic tool for neuroendocrine tumors. In this study, we explored the accuracy and clinical role of (18)F-FDOPA PET in neuroblastic tumors.
  
  
  METHODS
  From 2008 to 2011, patients with tissue-proven neuroblastic tumors receiving (18)F-FDOPA PET at initial diagnosis or during follow-ups were enrolled. The sensitivity and specificity of (18)F-FDOPA PET were compared with those of (123)I-metaiodobenzylguanidine ((123)I-MIBG) scintigraphy and (18)F-FDG PET, using tumor histology as the standard. The maximum standardized uptake value and tumor-to-liver uptake ratio on (18)F-FDOPA PET were measured and correlated with AADC messenger RNA level in tumor tissue.
  
  
  RESULTS
  Fifty tumors from 34 patients, including 42 neuroblastic tumors and 8 lesions without viable tumor cells, were eligible for analysis. (18)F-FDOPA PET successfully detected neuroblastic tumors of different histologic types in various anatomic sites, at a sensitivity of 97.6% (87.4%-99.9%) and a specificity of 87.5% (47.3%-99.7%). In tumors with concomitant studies, (18)F-FDOPA PET demonstrated a higher sensitivity than (123)I-MIBG scintigraphy (n = 18; P = 0.0455) or (18)F-FDG PET (n = 46; P = 0.0455). Among the 18 tumors with concomitant (123)I-MIBG scans, 4 tumors with viable cells were (123)I-MIBG-negative but were successfully detected by (18)F-FDOPA PET. The tumor uptake of (18)F-FDOPA significantly correlated with AADC expression (n = 15 nonhepatic tumors; maximum standardized uptake value, P = 0.0002; tumor-to-liver uptake ratio, P < 0.0001).
  
  
  CONCLUSIONS
  (18)F-FDOPA PET showed high sensitivity and specificity in detecting and tracking neuroblastic tumors in this preliminary study with a small cohort of patients and might be complementary to (123)I-MIBG scintigraphy and (18)F-FDG PET. By correlating with AADC expression, (18)F-FDOPA PET might serve as a useful imaging tool for the functional assessment of neuroblastic tumors.
authors.affiliation: Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Meng-Yao
authors.initials: MY
authors.lastname: Lu
authors.forename: Yen-Lin
authors.initials: YL
authors.lastname: Liu
authors.forename: Hsiu-Hao
authors.initials: HH
authors.lastname: Chang
authors.forename: Shiann-Tarng
authors.initials: ST
authors.lastname: Jou
authors.forename: Yung-Li
authors.initials: YL
authors.lastname: Yang
authors.forename: Kai-Hsin
authors.initials: KH
authors.lastname: Lin
authors.forename: Dong-Tsamn
authors.initials: DT
authors.lastname: Lin
authors.forename: Ya-Ling
authors.initials: YL
authors.lastname: Lee
authors.forename: Hsinyu
authors.initials: H
authors.lastname: Lee
authors.forename: Pei-Yi
authors.initials: PY
authors.lastname: Wu
authors.forename: Tsai-Yueh
authors.initials: TY
authors.lastname: Luo
authors.forename: Lie-Hang
authors.initials: LH
authors.lastname: Shen
authors.forename: Shiu-Feng
authors.initials: SF
authors.lastname: Huang
authors.forename: Yung-Feng
authors.initials: YF
authors.lastname: Liao
authors.forename: Wen-Ming
authors.initials: WM
authors.lastname: Hsu
authors.forename: Kai-Yuan
authors.initials: KY
authors.lastname: Tzen
mesh_terms: D019797:3-Iodobenzylguanidine; D001692:Biological Transport; D002262:Carboxy-Lyases / Q000235:genetics; D002395:Catecholamines / Q000378:metabolism; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives* / Q000378:metabolism; D005260:Female; D019788:Fluorodeoxyglucose F18; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007223:Infant; D008297:Male; D009447:Neuroblastoma / Q000000981:diagnostic imaging* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D049268:Positron-Emission Tomography; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014642:Vanilmandelic Acid / Q000652:urine
chemical_list: D002395:Catecholamines; D019788:Fluorodeoxyglucose F18; C043437:fluorodopa F 18; D019797:3-Iodobenzylguanidine; D014642:Vanilmandelic Acid; D004295:Dihydroxyphenylalanine; D002262:Carboxy-Lyases