title: Recommended administered activities for (68)Ga-labelled peptides in paediatric nuclear medicine.
abstract: OBJECTIVE
  The aim of this study was to establish a method for determining administered activities for (68)Ga-labelled peptides. Dose calculations were based on the weight-independent effective dose model proposed by the EANM paediatric dosage card for use in paediatric nuclear medicine.
  
  
  METHODS
  Previously published time-integrated activity coefficients for (68)Ga-DOTATATE, (68)Ga-DOTATOC and (68)Ga-pentixafor were used to calculate age-independent effective doses. Consequently, the corresponding weight-dependent effective dose coefficients were rescaled according to the formalism of the EANM dosage card to determine the radiopharmaceutical class of  (68)Ga-labelled peptides ("multiples") and to calculate the baseline activities based on an upper limit for administered activity (185 MBq) in an adult.
  
  
  RESULTS
  All calculated normalization factors suggest that the (68)Ga-labelled peptides are class "B" radiopharmaceuticals. The baseline activity for all compounds is 12.8 MBq. In analogy to (18)F-fluoride, we recommend a minimum activity of 14 MBq.
  
  
  CONCLUSIONS
  For paediatric nuclear medicine applications involving (68)Ga-labelled peptides, we suggest determining administered activities based on the formalism proposed in this work. The corresponding effective doses from these procedures will remain age-independent.
authors.affiliation: Department of Nuclear Medicine, University Hospital Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany. E_Soares_J@ukw.de.
authors.forename: J Soares
authors.initials: JS
authors.lastname: Machado
authors.affiliation: Department of Nuclear Medicine, University Hospital Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Beykan
authors.affiliation: Department of Nuclear Medicine, University Hospital Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany.|Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
authors.forename: K
authors.initials: K
authors.lastname: Herrmann
authors.affiliation: Department of Nuclear Medicine, University Hospital Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Lassmann
mesh_terms: D002648:Child; D005682:Gadolinium / Q000008:administration & dosage* / Q000592:standards; D006801:Humans; D038622:Internationality; D007553:Isotope Labeling / Q000592:standards; D009683:Nuclear Medicine / Q000592:standards*; D010372:Pediatrics / Q000592:standards*; D010455:Peptides / Q000008:administration & dosage / Q000592:standards; D017410:Practice Guidelines as Topic; D011829:Radiation Dosage; D011874:Radiometry / Q000592:standards*; D019275:Radiopharmaceuticals / Q000008:administration & dosage / Q000592:standards
chemical_list: D010455:Peptides; D019275:Radiopharmaceuticals; D005682:Gadolinium
keywords: 68Ga peptide; Administered activity; Dosage card; Dosimetry; Effective dose