title: Histological Comparison of Kidney Tissue Following Radioembolization with Yttrium-90 Resin Microspheres and Embolization with Bland Microspheres.
abstract: BACKGROUND
  Intra-arterial brachytherapy with yttrium-90 (90Y) resin microspheres (radioembolization) is a procedure to selectively deliver high-dose radiation to tumors. The purpose of this research was to compare the radioembolic effect of90Y-radioembolization versus the embolic effect of bland microspheres in the porcine kidney model.
  
  
  METHODS
  In each of six pigs, ~25-33 % of the kidney volume was embolized with90Y resin microspheres and an equivalent number of bland microspheres in the contralateral kidney. Kidney volume was estimated visually from contrast-enhanced fluoroscopy imaging. Morphologic and histologic analysis was performed 8-9 weeks after the procedure to assess the locations of the microspheres and extent of tissue necrosis from90Y-radioembolization and bland embolization. A semi-quantified evaluation of the non-acute peri-particle and perivascular tissue reaction was conducted. All guidelines for the care and use of animals were followed.
  
  
  RESULTS
  Kidneys embolized with90Y-radioembolization decreased in mass by 30-70 % versus the contralateral kidney embolized with bland microspheres. These kidneys showed significant necrosis/fibrosis, avascularization, and glomerular atrophy in the immediate vicinity of the90Y resin microspheres. By contrast, glomerular changes were not observed, even with clusters of bland microspheres in afferent arterioles. Evidence of a foreign body reaction was recorded in some kidneys with bland microspheres, and subcapsular scarring/infarction only with the highest load (4.96 × 106) of bland microspheres.
  
  
  CONCLUSIONS
  This study showed that radioembolization with90Y resin microspheres produces localized necrosis/fibrosis and loss of kidney mass in a porcine kidney model. This result supports the study of90Y resin microspheres for the localized treatment of kidney tumors.
authors.affiliation: Radiology Department Sutherland Hospital, Southern Radiology Group, The Kingsway Caringbah, Sydney, NSW, 2229, Australia. suresh.desilva@unsw.edu.au.
authors.forename: Suresh
authors.initials: S
authors.lastname: de Silva
authors.affiliation: Department of Urology, Western General Hospital, Crewe Road, Edinburgh, Scotland, EH42XU, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Mackie
authors.affiliation: Department of Urology, St George Hospital, South Street, Kogarah, NSW, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Aslan
authors.affiliation: Sirtex Technology Pty Ltd, Level 33, 101 Miller Street, North Sydney, NSW, 2060, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Cade
authors.affiliation: Douglass Hanly Moir Pathology, 14 Giffnock Ave, Macquarie Park, NSW, 2113, Australia.
authors.forename: Warick
authors.initials: W
authors.lastname: Delprado
mesh_terms: D000818:Animals; D001918:Brachytherapy / Q000379:methods*; D004195:Disease Models, Animal; D005471:Fluoroscopy; D007668:Kidney / Q000473:pathology* / Q000528:radiation effects*; D008863:Microspheres; D009336:Necrosis; D009929:Organ Size; D013552:Swine; D015021:Yttrium Radioisotopes / Q000008:administration & dosage*
chemical_list: D015021:Yttrium Radioisotopes
keywords: Embolization; Porcine kidney; Radioembolization; Selective internal radiation therapy; Yttrium-90 resin microspheres