title: Biodistribution of post-therapeutic versus diagnostic (131)I-MIBG scans in children with neuroblastoma.
abstract: BACKGROUND
  To evaluate the biodistribution of therapeutic (131)I-metaiodobenzylguanidine (MIBG) and assess the sensitivity of diagnostic versus therapeutic (131)I-MIBG scans to detect metastatic disease.
  
  
  METHODS
  This retrospective study included 44 diagnostic and post-therapy scans (PTS) in 18 children with neuroblastoma treated with (131)I-MIBG (2.0-33.1 GBq). The findings of diagnostic scans (DS) (2.6-44.4 MBq) were compared to those of corresponding PTS.
  
  
  RESULTS
  In terms of biodistribution, the PTS identified (131)I-MIBG activity in one or more patients in the following regions not detected on the DS: nasal mucosa, cerebellum, central brain, adrenals, spleen, kidneys, thyroid, salivary glands, lower halves of the lungs, bladder, bowel, and an incisional scar. Conversely, the DS identified activity in the thorax, heart, kidneys, and bladder each in one patient without being visualized on the PTS. In terms of sensitivity to detect metastatic disease, 210 lesions were seen on the PTS compared to 151 on the DS. The PTS demonstrated sites of disease not evident in the DS in 16 cases.
  
  
  CONCLUSIONS
  The biodistribution of (131)I-MIBG is different using therapeutic doses as compared to pre-therapy doses. (131)I-MIBG imaging following high therapeutic doses often reveals sites of occult metastatic disease that may be clinically relevant.
authors.affiliation: The Children's Hospital of Philadelphia, 34th and Civic Center Boulevard, Philadelphia, PA 19104, USA.
authors.forename: Marc P
authors.initials: MP
authors.lastname: Hickeson
authors.forename: Martin
authors.initials: M
authors.lastname: Charron
authors.forename: John M
authors.initials: JM
authors.lastname: Maris
authors.forename: Patricia
authors.initials: P
authors.lastname: Brophy
authors.forename: Tammy I
authors.initials: TI
authors.lastname: Kang
authors.forename: Hongming
authors.initials: H
authors.lastname: Zhuang
authors.forename: Jehanzeb
authors.initials: J
authors.lastname: Khan
authors.forename: Teresa
authors.initials: T
authors.lastname: Nevrotski
mesh_terms: D019797:3-Iodobenzylguanidine / Q000493:pharmacokinetics* / Q000627:therapeutic use; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D002910:Chronology as Topic; D005260:Female; D006801:Humans; D007223:Infant; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics* / Q000627:therapeutic use; D008297:Male; D009362:Neoplasm Metastasis / Q000000981:diagnostic imaging / Q000532:radiotherapy; D009447:Neuroblastoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy*; D011829:Radiation Dosage; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014018:Tissue Distribution
chemical_list: D007457:Iodine Radioisotopes; D019797:3-Iodobenzylguanidine