title: Biodistribution and radiation dosimetry for the chemokine receptor CXCR4-targeting probe 68Ga-pentixafor.
abstract: (68)Ga-pentixafor is a promising PET tracer for imaging the expression of the human chemokine receptor 4 (CXCR4) in vivo. The whole-body distribution and radiation dosimetry of (68)Ga-pentixafor were evaluated.
  
  
  METHODS
  Five multiple-myeloma patients were injected intravenously with 90-158 MBq of (68)Ga-pentixafor (mean ± SD, 134 ± 25 MBq), and a series of 3 rapid multiple-bed-position whole-body scans were acquired immediately afterward. Subsequently, 4 static whole-body scans followed at 30 min, 1 h, 2 h, and 4 h after administration of the radiopharmaceutical. Venous blood samples were obtained. Time-integrated activity coefficients were determined from multiexponential regression of organ region-of-interest data normalized to the administered activity, for example, the time-dependent percentages of the injected activity per organ. Mean organ-absorbed doses and effective doses were calculated using OLINDA/EXM.
  
  
  RESULTS
  The effective dose based on 150 MBq of (68)Ga-pentixafor was 2.3 mSv. The highest organ-absorbed doses (for 150 MBq injected) were found in the urinary bladder wall (12.2 mGy), spleen (8.1 mGy), kidneys (5.3 mGy), and heart wall (4.0 mGy). Other organ mean absorbed doses were as follows: 2.7 mGy, liver; 2.1 mGy, red marrow; 1.7 mGy, testes; and 1.9 mGy, ovaries.
  
  
  CONCLUSIONS
  (68)Ga-pentixafor exhibits a favorable dosimetry, delivering absorbed doses to organs that are lower than those delivered by (18)F-FDG- or (68)Ga-labeled somatostatin receptor ligands.
authors.affiliation: Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, California Herrmann_K1@ukw.de.
authors.forename: Ken
authors.initials: K
authors.lastname: Herrmann
authors.affiliation: Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany.
authors.forename: Constantin
authors.initials: C
authors.lastname: Lapa
authors.affiliation: Pharmaceutical Radiochemistry, Technische Universität München, Munich, Germany Scintomics GmbH, Fürstenfeldbruck, Germany.
authors.forename: Hans-Juergen
authors.initials: HJ
authors.lastname: Wester
authors.affiliation: Pharmaceutical Radiochemistry, Technische Universität München, Munich, Germany.
authors.forename: Margret
authors.initials: M
authors.lastname: Schottelius
authors.affiliation: Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, California.
authors.forename: Christiaan
authors.initials: C
authors.lastname: Schiepers
authors.affiliation: Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany.
authors.forename: Uta
authors.initials: U
authors.lastname: Eberlein
authors.affiliation: Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Bluemel
authors.affiliation: III. Medical Department of Hematology and Medical Oncology, Technische Universität München, Munich, Germany; and.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Keller
authors.affiliation: Division of Hematology and Medical Oncology, Department of Internal Medicine II, Universitätsklinikum Würzburg, Würzburg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Knop
authors.affiliation: Scintomics GmbH, Fürstenfeldbruck, Germany.
authors.forename: Saskia
authors.initials: S
authors.lastname: Kropf
authors.affiliation: Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schirbel
authors.affiliation: Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany.
authors.forename: Andreas K
authors.initials: AK
authors.lastname: Buck
authors.affiliation: Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Lassmann
mesh_terms: D000368:Aged; D001853:Bone Marrow / Q000000981:diagnostic imaging; D056831:Coordination Complexes / Q000737:chemistry; D005260:Female; D005708:Gallium / Q000737:chemistry*; D005710:Gallium Radioisotopes; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000000981:diagnostic imaging*; D010455:Peptides / Q000737:chemistry; D010456:Peptides, Cyclic / Q000737:chemistry; D049268:Positron-Emission Tomography; D011874:Radiometry / Q000379:methods*; D019275:Radiopharmaceuticals; D019718:Receptors, CXCR4 / Q000378:metabolism*; D013997:Time Factors; D014018:Tissue Distribution
chemical_list: C000597686:68Ga-pentixafor; C527276:CXCR4 protein, human; D056831:Coordination Complexes; D005710:Gallium Radioisotopes; D010455:Peptides; D010456:Peptides, Cyclic; D019275:Radiopharmaceuticals; D019718:Receptors, CXCR4; D005708:Gallium
keywords: 68Ga; CXCR4; PET; dosimetry