title: Improved radiation protection of the thyroid gland with thyroxine, methimazole, and potassium iodide during diagnostic and therapeutic use of radiolabeled metaiodobenzylguanidine in children with neuroblastoma.
abstract: BACKGROUND
  During radiolabeled metaiodobenzylguanidine (MIBG) administration in children with neuroblastoma, the thyroid is protected from (123/131)I uptake by potassium iodide. Despite this protection, up to 64% of patients develop thyroid dysfunction. The authors introduce a new method of radiation protection for the thyroid gland.
  
  
  METHODS
  In a prospective cohort study, 34 children with neuroblastoma who received MIBG were given thyroxine, methimazole, and potassium iodide for protection of the thyroid gland. Protection started 1 day before the start of diagnostic 123I-MIBG and was continued until 4 weeks after the last therapeutic 131I-MIBG dose. Follow-up measurements were performed every 3 months after the protection was stopped. Visualization of the thyroid on MIBG images was reviewed by three nuclear medicine physicians. Results were compared with a historic control group of children who had received potassium iodide for thyroid protection during MIBG administration.
  
  
  RESULTS
  After a mean follow-up of 19 months, there were 23 evaluable patients. Thyroid function was normal in 86% of survivors compared with 44% of children in the historic control group (P=0.011; Pearson chi-square test). Scintigraphic visualization of the thyroid diminished substantially after the new protection (21.5% vs. 5.3%, respectively; P=0.000).
  
  
  CONCLUSIONS
  The results of the current study indicate that compared with potassium iodide alone, combined thyroxine, methimazole, and potassium iodide protect the thyroid more effectively against radiation damage from (123/131)I during diagnostic and therapeutic MIBG administration in children with neuroblastoma.
authors.affiliation: Department of Pediatric Endocrinology, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. h.m.vansanten@amc.uva.nl
authors.forename: Hanneke M
authors.initials: HM
authors.lastname: van Santen
authors.forename: Jan
authors.initials: J
authors.lastname: de Kraker
authors.forename: Berthe L F
authors.initials: BL
authors.lastname: van Eck
authors.forename: Jan J M
authors.initials: JJ
authors.lastname: de Vijlder
authors.forename: Thomas
authors.initials: T
authors.lastname: Vulsma
mesh_terms: D019797:3-Iodobenzylguanidine / Q000009:adverse effects* / Q000627:therapeutic use; D000970:Antineoplastic Agents / Q000009:adverse effects* / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008713:Methimazole / Q000627:therapeutic use*; D009447:Neuroblastoma / Q000532:radiotherapy*; D011193:Potassium Iodide / Q000627:therapeutic use*; D011837:Radiation-Protective Agents / Q000627:therapeutic use*; D013959:Thyroid Diseases / Q000209:etiology / Q000517:prevention & control*; D013960:Thyroid Function Tests; D013974:Thyroxine / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D011837:Radiation-Protective Agents; D011193:Potassium Iodide; D019797:3-Iodobenzylguanidine; D008713:Methimazole; D013974:Thyroxine