title: Comparative analysis of peptide p5 and serum amyloid P component for imaging AA amyloid in mice using dual-isotope SPECT.
abstract: OBJECTIVE
  I-labeled human serum amyloid P component (SAP) is used clinically only in the UK for imaging visceral amyloidosis to assist with diagnosis, disease staging, and monitoring response to therapy. We compare a new amyloid-reactive probe, peptide p5, with SAP for imaging amyloidosis.
  
  
  METHODS
  Dual-energy SPECT/CT images were acquired of (125)I-labeled SAP and (99m)Tc-labeled p5 in mice with systemic AA amyloidosis (n = 3). Twelve organs and tissues were harvested for radiotracer biodistribution assessment and for micro-autoradiographic analysis.
  
  
  RESULTS
  I-SAP and (99m)Tc-p5 localized equivalently in amyloid deposits in liver (∼10% injected dose (ID)/g) whereas (125)I-SAP was twofold higher in the spleen (∼20% ID/g; (99m)Tc-p5, ∼10% ID/g). In contrast, (99m)Tc-p5 was bound to pancreatic and intestinal amyloid approximately fivefold more efficiently as evidenced in biodistribution data.
  
  
  CONCLUSIONS
  Radiolabeled p5 is an effective amyloid-imaging radiotracer as compared to SAP in the murine model of amyloidosis and may be rapidly translated for imaging patients with visceral amyloidosis in the USA.
authors: Department of Radiology, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920-6999, USA. jwall@utmck.edu
authors: Jonathan S
authors: JS
authors: Wall
authors: Tina
authors: T
authors: Richey
authors: Angela
authors: A
authors: Williams
authors: Alan
authors: A
authors: Stuckey
authors: Dustin
authors: D
authors: Osborne
authors: Emily
authors: E
authors: Martin
authors: Stephen J
authors: SJ
authors: Kennel
mesh_terms: D000682:Amyloid / Q000378:metabolism*; D000686:Amyloidosis / Q000000981:diagnostic imaging*; D000818:Animals; D006801:Humans; D007457:Iodine Radioisotopes; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D010455:Peptides; D000683:Serum Amyloid P-Component; D013667:Technetium; D014018:Tissue Distribution; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014057:Tomography, X-Ray Computed
chemical_list: D000682:Amyloid; D007457:Iodine Radioisotopes; D010455:Peptides; D000683:Serum Amyloid P-Component; D013667:Technetium