title: Optimizing retention of multimodal imaging nanostructures in sentinel lymph nodes by nanoscale size tailoring.
abstract: This study investigates the retention of different sized ultra-small superparamagnetic iron oxide nanoparticles (USPIOs) in lymph nodes of healthy rats, after subcutaneous injection. Three distinct sizes (15, 27 and 58 nm) of USPIOs were synthesized by only varying the thickness of the polymer coating surrounding the 10 nm cores. Particles were injected on the dorsal side of the hind paw of rats and the uptake in the popliteal, inguinal and iliac lymph nodes was monitored. The data reveal that the 15 nm particle accumulates more rapidly and to a higher amount in the first lymph node than the two larger particles. A clear contrast between the first and second lymph nodes could be detected indicating that even the rather small difference in particle size (15-58 nm) tested has significant effects on the retention of USPIOs in the lymph nodes.
  
  
  BACKGROUND
  From the Clinical Editor: In this study, the size-dependence of USPIO particles is studied from the standpoint of their accumulation characteristics in lymph nodes. The authors conclude that the smaller particles accumulated faster and at a higher concentration than the two larger sizes studied.
authors: Medical Radiation Physics, Department of Clinical Sciences, Lund University, Lund, Sweden; GeccoDots AB, Lund, Sweden. Electronic address: pontus.kjellman@genovis.com.
authors: Pontus
authors: P
authors: Kjellman
authors: GeccoDots AB, Lund, Sweden; Lund University Bioimaging Center, Lund University, Lund, Sweden.
authors: René
authors: R
authors: in 't Zandt
authors: GeccoDots AB, Lund, Sweden.
authors: Sarah
authors: S
authors: Fredriksson
authors: Medical Radiation Physics, Department of Clinical Sciences, Lund University, Lund, Sweden; Lund University Bioimaging Center, Lund University, Lund, Sweden.
authors: Sven-Erik
authors: SE
authors: Strand
mesh_terms: D000818:Animals; D001812:Blood-Brain Barrier / Q000473:pathology; D001932:Brain Neoplasms / Q000175:diagnosis; D003287:Contrast Media; D005910:Glioma / Q000175:diagnosis; D008198:Lymph Nodes / Q000473:pathology*; D064847:Multimodal Imaging / Q000379:methods*; D049329:Nanostructures; D051381:Rats; D013059:Spectrum Analysis, Raman / Q000379:methods
chemical_list: D003287:Contrast Media
keywords: MRI; Sentinel lymph node; nanoparticles