title: Pre-therapeutic dosimetry and biodistribution of 86Y-DOTA-Phe1-Tyr3-octreotide versus 111In-pentetreotide in patients with advanced neuroendocrine tumours.
abstract: OBJECTIVE
  For the internal radiotherapy of neuroendocrine tumours, the somatostatin analogue DOTATOC labelled with 90Y is frequently used [90Y-DOTA-Phe1-Tyr3)-octreotide (SMT487-OctreoTher)]. Radiation exposure to the kidneys is critical in this therapy as it may result in renal failure. The aim of this study was to compare cumulative organ and tumour doses based upon dosimetric data acquired with the chemically identical 86Y-DOTA-Phe1-Tyr3-octreotide (considered as the gold standard) and the commercially available 111In-pentetreotide.
  
  
  METHODS
  The cumulative organ and tumour doses for the therapeutic administration of 13.32 GBq 90Y-DOTA-Phe1-Tyr3-octreotide (three cycles, each of 4.44 GBq) were estimated based on the MIRD concept (MIRDOSE 3.1 and IMEDOSE). Patients with a cumulative kidney dose exceeding 27 Gy had to be excluded from subsequent therapy with 90Y-DOTA-Phe1-Tyr3-octreotide, in accordance with the directives of the German radiation protection authorities.
  
  
  RESULTS
  The range of doses (mGy/MBq 90Y-DOTA-Phe1-Tyr3-octreotide) for kidneys, spleen, liver and tumour masses was 0.6-2.8, 1.5-4.2, 0.3-1.3 and 2.1-29.5 (86Y-DOTA-Phe1-Tyr3-octreotide), respectively, versus 1.3-3.0, 1.8-4.4, 0.2-0.8 and 1.4-19.7 (111In-pentetreotide), with wide inter-subject variability. Despite renal protection with amino acid infusions, estimated cumulative kidney doses in two patients exceeded 27 Gy.
  
  
  CONCLUSIONS
  Compared with 86Y-DOTA-Phe1-Tyr3-octreotide, dosimetry with 111In-pentetreotide overestimated doses to kidneys and spleen, whereas the radiation dose to the tumour-free liver was underestimated. However, both dosimetric approaches detected the two patients with an exceptionally high radiation burden to the kidneys that carried a potential risk of renal failure following radionuclide therapy.
authors.affiliation: Department of Nuclear Medicine, University of Mainz, Mainz, Germany. helisch@nuklear.klinik.uni-mainz.de
authors.forename: Andreas
authors.initials: A
authors.lastname: Helisch
authors.forename: Gregor J
authors.initials: GJ
authors.lastname: Förster
authors.forename: Helmut
authors.initials: H
authors.lastname: Reber
authors.forename: Hans-Georg
authors.initials: HG
authors.lastname: Buchholz
authors.forename: Rudolf
authors.initials: R
authors.lastname: Arnold
authors.forename: Burkhard
authors.initials: B
authors.lastname: Göke
authors.forename: Matthias M
authors.initials: MM
authors.lastname: Weber
authors.forename: Bertram
authors.initials: B
authors.lastname: Wiedenmann
authors.forename: Stanislas
authors.initials: S
authors.lastname: Pauwels
authors.forename: Ulrike
authors.initials: U
authors.lastname: Haus
authors.forename: Hakim
authors.initials: H
authors.lastname: Bouterfa
authors.forename: Peter
authors.initials: P
authors.lastname: Bartenstein
mesh_terms: D001822:Body Burden; D005260:Female; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000532:radiotherapy; D015282:Octreotide / Q000031:analogs & derivatives* / Q000493:pharmacokinetics* / Q000627:therapeutic use; D009928:Organ Specificity; D011832:Radiation Injuries / Q000517:prevention & control; D011835:Radiation Protection / Q000379:methods; D011874:Radiometry / Q000379:methods*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics / Q000627:therapeutic use; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D012062:Relative Biological Effectiveness; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000493:pharmacokinetics* / Q000627:therapeutic use; D014018:Tissue Distribution; D015021:Yttrium Radioisotopes / Q000493:pharmacokinetics* / Q000627:therapeutic use
chemical_list: D019275:Radiopharmaceuticals; D015021:Yttrium Radioisotopes; D013004:Somatostatin; C081788:pentetreotide; D015282:Octreotide; C106246:Edotreotide