title: Feasibility of carbidopa premedication in pediatric patients: a pilot study.
abstract: OBJECTIVE
  To verify the potential role and feasibility of carbidopa premedication in pediatric patients undergoing ¹⁸F-DOPA (Fluorine-18 fluorodihydroxyphenylalanine) PET scanning.
  
  
  METHODS
  For this limited study, 5 patients (M:F=3:2; mean age 4.8 years) with a positive history for neuroblastoma who had been referred to our institution for instrumental monitoring during clinical follow-up were enrolled. In all cases, two consecutive ¹⁸F-DOPA PET scans, the first without carbidopa and the second with carbidopa premedication, were scheduled: patients received 4 MBq/kg of radiotracer and a dose of 2 mg/kg of carbidopa. Dedicated VOIs were drawn on the basal ganglia, pancreas, liver, and renal cortex. These regions were semiquantitatively analyzed at both the first and at the second ¹⁸F-DOPA scan, and mean SUV(max) values were compared using the t-test.
  
  
  RESULTS
  On a visual basis, a clear reduction in the abdominal accumulation of (18)F-DOPA was observed in all cases after carbidopa premedication. This reduction related both to the biliary structures and the excretory system, and was accompanied by a generalized increase in soft tissue uptake. The semiquantitative analysis documented an absolute increase in SUV(max) after carbidopa premedication in the basal ganglia (3.4±1.3 vs. 2.1±0.8) and liver parenchyma (2.2±0.5 vs. 1.5±0.5), whereas SUV(max) decreased in the renal cortex (1.7±0.8 vs. 3.7±1.0) and the pancreas (2.3±0.6 vs. 3.5±0.5). The changes in SUV(max) were statistically significant for the pancreas and liver parenchyma (p=0.022 and 0.045, respectively), but not for the basal ganglia and renal cortex (p=0.143 and 0.15, respectively).
  
  
  CONCLUSIONS
  Carbidopa premedication in the pediatric population appears feasible and seems to influence ¹⁸F-DOPA distribution in the liver and pancreas in a manner similar to that reported in adults. Larger series are however needed to properly define the clinical role of carbidopa premedication in children.
authors.affiliation: Department of Nuclear Medicine, Alma Mater Studiorum, University of Bologna, Bologna, Italy. egesta.lopci@cancercenter.humanitas.it
authors.forename: Egesta
authors.initials: E
authors.lastname: Lopci
authors.forename: Daniela
authors.initials: D
authors.lastname: D'Ambrosio
authors.forename: Cristina
authors.initials: C
authors.lastname: Nanni
authors.forename: Arturo
authors.initials: A
authors.lastname: Chiti
authors.forename: Andrea
authors.initials: A
authors.lastname: Pession
authors.forename: Mario
authors.initials: M
authors.lastname: Marengo
authors.forename: Stefano
authors.initials: S
authors.lastname: Fanti
mesh_terms: D002230:Carbidopa / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D004295:Dihydroxyphenylalanine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D004347:Drug Interactions; D005260:Female; D005462:Fluorine Radioisotopes; D006801:Humans; D008297:Male; D009447:Neuroblastoma / Q000000981:diagnostic imaging / Q000378:metabolism; D010865:Pilot Projects; D011292:Premedication / Q000379:methods*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000008:administration & dosage / Q000493:pharmacokinetics*
chemical_list: D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals; C043437:fluorodopa F 18; D004295:Dihydroxyphenylalanine; D002230:Carbidopa