title: A gelatin liver phantom of suspended 90Y resin microspheres to simulate the physiologic microsphere biodistribution of a postradioembolization liver.
abstract: For phantom studies involving (90)Y PET/CT, homogeneous solutions of (90)Y, for example, (90)Y citrate, are commonly used. However, the microsphere biodistribution of a postradioembolization liver is never homogeneous; therefore, such phantoms are physiologically unrealistic for simulating clinical scenarios. The aim of this work was to develop a safe and practical phantom capable of simulating the heterogeneous microsphere biodistribution of a postradioembolization liver.
  
  
  METHODS
  Gelatin (5%) was used to suspend (90)Y resin microspheres, poured into plastic containers to simulate a liver with 2 tumors. Microspheres were added while the gelatin was maintained in a liquid state on a hot plate and continuously stirred with magnetic stir bars. The liquid microsphere mixture was then rapidly cooled in an ice bath while being stirred, resulting in a heterogeneous suspension of microspheres. The completed phantom was serially scanned by (90)Y PET/CT over 2 wk.
  
  
  RESULTS
  All scans demonstrated a heterogeneous microsphere distribution throughout the liver and tumor inserts. Serendipitously, magnetic stir bars left inside the phantom produced CT artifacts similar to those caused by embolization coils, whereas pockets of air trapped within the gelatin during its preparation mimicked gas within hollow viscus. The microspheres and tumor inserts remained fixed and suspended within the gelatin, with no evidence of breakdown or leakage.
  
  
  CONCLUSIONS
  A gelatin phantom realistically simulating the physiologic microsphere biodistribution of a postradioembolization liver is feasible to construct in a radiopharmacy.
authors.affiliation: Department of Nuclear Medicine, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia Department of Nuclear Medicine, Austin Hospital, Melbourne, Victoria, Australia; and yung.h.kao@gmail.com.
authors.forename: Yung Hsiang
authors.initials: YH
authors.lastname: Kao
authors.affiliation: Department of Nuclear Medicine, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia.
authors.forename: Oliver S
authors.initials: OS
authors.lastname: Luddington
authors.affiliation: Department of Nuclear Medicine, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia.
authors.forename: Simone R
authors.initials: SR
authors.lastname: Culleton
authors.affiliation: Department of Nuclear Medicine, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia School of Medicine and Pharmacology, University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Roslyn J
authors.initials: RJ
authors.lastname: Francis
authors.affiliation: Department of Nuclear Medicine, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia.
authors.forename: Jan A
authors.initials: JA
authors.lastname: Boucek
mesh_terms: D004621:Embolization, Therapeutic; D005780:Gelatin / Q000737:chemistry* / Q000493:pharmacokinetics*; D008099:Liver / Q000000981:diagnostic imaging / Q000378:metabolism*; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism / Q000628:therapy; D008863:Microspheres; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography; D012449:Safety; D013535:Suspensions; D014018:Tissue Distribution; D014057:Tomography, X-Ray Computed; D015021:Yttrium Radioisotopes
chemical_list: D013535:Suspensions; D015021:Yttrium Radioisotopes; D005780:Gelatin
keywords: 90Y PET/CT; 90Y radioembolization; phantom; radiopharmacy; selective internal radiation therapy