title: [Radiation exposure of patients during 68Ga-DOTATOC PET/CT examinations].
abstract: OBJECTIVE
  Investigation of the biodistribution and calculation of dosimetry of Ga-68-DOTATOC- for patients imaged in the routine clinical setting for diagnosis or exclusion of neuroendocrine tumours.
  
  
  METHODS
  Dynamic PET/CT-imaging (Biograph 16) was performed over 20 min in 14 patients (8 men, 6 women) after injection of (112+/-22) MBq 68Ga-DOTATOC followed by whole body 3D-acquisition (8 bed positions, 3 or 4 min each) 30 min p.i. and 120 min p.i.. Urinary tracer elimination was measured and blood activity was derived non-invasively from the blood pool of the heart. The relevant organs for dosimetry were spleen, kidneys, liver, adrenals, urinary bladder and pituitary gland. Dosimetry was performed using OLINDA/EXM 1.0 software and specific organ uptake was expressed as standardized uptake values (SUVs).
  
  
  RESULTS
  Rapid physiological uptake of the radiotracer could be demonstrated in liver, spleen and kidneys, adrenals and pituitary gland (mean SUVs were 6, 20, 16, 10, and 4, respectively). Radiotracer elimination was exclusively via urine (16% of injected dose within 2h); no redistribution could be observed. The spleen and the kidneys received the highest radiation exposure (0.24 mSv/MBq, 0.22 mSv/MBq resp.), mean effective dose yielded 0.023 mSv/MBq.
  
  
  CONCLUSIONS
  68Ga-DOTATOC is used extensively for diagnosis of somatostatin receptor positive tumours because it has several advantages over the 111In-labelled ligand. The derived dosimetric values are lower than first approximations from the biological data of OctreoScan. The use of CT for transmission correction of the PET data delivers radiation exposure up to 1 mSv (low dose).
authors.affiliation: Klinik und Poliklinik für Nuklearmedizin, Universitätsklinikum Dresden, Fetscherstr. 74, 01307 Dresden, Germany. Holger.Hartmann@uniklinikum-dresden.de
authors.forename: H
authors.initials: H
authors.lastname: Hartmann
authors.forename: K
authors.initials: K
authors.lastname: Zöphel
authors.forename: R
authors.initials: R
authors.lastname: Freudenberg
authors.forename: L
authors.initials: L
authors.lastname: Oehme
authors.forename: M
authors.initials: M
authors.lastname: Andreeff
authors.forename: G
authors.initials: G
authors.lastname: Wunderlich
authors.forename: G
authors.initials: G
authors.lastname: Eisenhofer
authors.forename: J
authors.initials: J
authors.lastname: Kotzerke
mesh_terms: D000328:Adult; D000368:Aged; D001842:Bone and Bones / Q000528:radiation effects; D004781:Environmental Exposure; D005260:Female; D005710:Gallium Radioisotopes / Q000493:pharmacokinetics; D006801:Humans; D007668:Kidney / Q000528:radiation effects; D008099:Liver / Q000528:radiation effects; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D015282:Octreotide / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D049268:Positron-Emission Tomography / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D005710:Gallium Radioisotopes; D015282:Octreotide; C106246:Edotreotide