title: Impact of residual (18)F-fluoride in (18)F-FDOPA for the diagnosis of neuroblastoma.
abstract: OBJECTIVE
  PET imaging with (18)F-FDOPA has been successfully applied in the diagnosis and surveillance of neuroblastoma (NB) by targeting the overexpression of aromatic L-amino acid decarboxylase. This study aims to assess the impact of residual (18)F-fluoride on (18)F-FDOPA PET in NB and to implement a method to maintain low (18)F-fluoride content in future studies.
  
  
  METHODS
  Automatic synthesis of (18)F-FDOPA was based on the electrophilic method using TRACERlab FXFE module. Radio-TLC was employed to determine residual (18)F-fluoride levels. We analyzed the impact of residual (18)F-fluoride on the images of 35 patients undergoing (18)F-FDOPA PET at initial diagnosis and/or follow-ups of NB.
  
  
  RESULTS
  In 35 batches of (18)F-FDOPA products from 9/28/2010 to 07/27/2011, the mean residual (18)F-fluoride level was 4.4 % (range 0.2-19.1 %). Residual (18)F-fluoride level ≥4.0 % was associated with dense uptake in the growth plates, skull, and pelvis on PET scans, which may interfere with the interpretation of (18)F-FDOPA imaging in NB. By applying stringent restraints in (18)F-FDOPA production, including regular renewal of reagents, exclusive use  of NH4OH, and timely replacement of HPLC column, the incidence of (18)F-FDOPA batches with residual (18)F-fluoride level ≥4.0 % was reduced from 33 to 4 % (P < 0.0001) during 7/30/2011-4/29/2013.
  
  
  CONCLUSIONS
  By monitoring residual (18)F-fluoride levels and keeping stringent restraint procedures, low (18)F-fluoride content was achieved in most batches of (18)F-FDOPA, which diminished false-positive skeletal uptake. An appropriate upper limit of (18)F-fluoride level is suggested to be included in the criteria of routine quality control of (18)F-FDOPA productions.
authors: PET Center, Department of Nuclear Medicine, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan.
authors: Ya-Yao
authors: YY
authors: Huang
authors: Kai-Yuan
authors: KY
authors: Tzen
authors: Yen-Lin
authors: YL
authors: Liu
authors: Ching-Hong
authors: CH
authors: Chiu
authors: Chia-Ling
authors: CL
authors: Tsai
authors: Hsiang-Ping
authors: HP
authors: Wen
authors: Kuang-Hua
authors: KH
authors: Tang
authors: Chien-Chu
authors: CC
authors: Liu
authors: Chyng-Yann
authors: CY
authors: Shiue
mesh_terms: D001859:Bone Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000235:genetics / Q000556:secondary; D002648:Child; D002675:Child, Preschool; D002845:Chromatography; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives*; D005260:Female; D005462:Fluorine Radioisotopes; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D064847:Multimodal Imaging; D000071447:N-Myc Proto-Oncogene Protein; D009447:Neuroblastoma / Q000175:diagnosis* / Q000000981:diagnostic imaging* / Q000235:genetics / Q000473:pathology; D009687:Nuclear Proteins / Q000235:genetics; D015513:Oncogene Proteins / Q000235:genetics; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed; D051598:Whole Body Imaging
chemical_list: D005462:Fluorine Radioisotopes; C459801:MYCN protein, human; D000071447:N-Myc Proto-Oncogene Protein; D009687:Nuclear Proteins; D015513:Oncogene Proteins; D019275:Radiopharmaceuticals; C043437:fluorodopa F 18; D004295:Dihydroxyphenylalanine