title: Estimated background doses of [67Ga]-DTPA-USPIO in normal Balb/c mice as a potential therapeutic agent for liver and spleen cancers.
abstract: BACKGROUND
  The aim of this study was to evaluate the biodistribution of dextran-coated iron oxide nanoparticles labeled with gallium-67 (Ga) in various organs by intravenous injection in Balb/c mice.
  
  
  METHODS
  Ultrasmall superparamagnetic iron oxide (USPIO) was successively labeled with Ga-chloride after chelation with freshly prepared cyclic DTPA-dianhydride. The labeling efficiency of USPIOs labeled with Ga is above 98%. Sixty-five mice were killed at 13 different time points. The percentage of injected dose per gram of each organ was measured by direct counting for 19 harvested organs of the mice. The medical internal radiation dose formula was applied to extrapolate data from mouse to human and to predict the absorbed radiation dose for various organs in the human body.
  
  
  RESULTS
  The biodistribution of Ga-USPIO in Balb/c mice showed that 75% of the injected dose accumulated in the spleen and liver 15 min after injection. These nanoparticles remained in the liver for more than 7 days after injection, whereas their clearance was very fast from other organs. Extrapolating these data to the intravenous injection of Ga-USPIO in humans gave an estimated absorbed dose of 36.38 mSv/MBq for the total body, and the highest effective absorbed dose was seen in the liver (32.9 mSv/MBq).
  
  
  CONCLUSIONS
  High uptakes of USPIO nanoparticles in the liver and spleen and their fast clearance from other tissues suggest that these nanoparticles labeled with a β-emitter radioisotope could be suitable as treatment agents for spleen and liver malignancies only if the organ tolerance dose is not exceeded.
authors.affiliation: Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Iran. sa27sh@gmail.com
authors.forename: Saeed
authors.initials: S
authors.lastname: Shanehsazzadeh
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: Oghabian
authors.forename: Afsaneh
authors.initials: A
authors.lastname: Lahooti
authors.forename: Mohammad
authors.initials: M
authors.lastname: Abdollahi
authors.forename: Seyed
authors.initials: S
authors.lastname: Abolghasem Haeri
authors.forename: Massoud
authors.initials: M
authors.lastname: Amanlou
authors.forename: Fariba J
authors.initials: FJ
authors.lastname: Daha
authors.forename: Barry J
authors.initials: BJ
authors.lastname: Allen
mesh_terms: D000818:Animals; D001417:Background Radiation; D005260:Female; D005290:Ferric Compounds / Q000737:chemistry*; D019786:Gadolinium DTPA / Q000008:administration & dosage / Q000737:chemistry* / Q000493:pharmacokinetics / Q000627:therapeutic use*; D005710:Gallium Radioisotopes / Q000627:therapeutic use; D006801:Humans; D007275:Injections, Intravenous; D008113:Liver Neoplasms / Q000532:radiotherapy*; D059346:Magnets / Q000737:chemistry*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011829:Radiation Dosage; D011879:Radiotherapy Dosage; D013160:Splenic Neoplasms / Q000532:radiotherapy*
chemical_list: D005290:Ferric Compounds; D005710:Gallium Radioisotopes; C000499:ferric oxide; D019786:Gadolinium DTPA