99mTc-Labeled Superparamagnetic Iron Oxide Nanoparticles for Multimodality SPECT/MRI of Sentinel Lymph Nodes

• DOI: 10.2967/jnumed.111.092437
• Publication Date: 2012-02-11T01:34:33Z
• Authors: Renata Madru; Pontus Kjellman; Fredrik Olsson; Karin Wingårdh; Christian Ingvar; Freddy Ståhlberg; Johan Olsrud; Jimmy Lätt; Sarah Fredriksson; Linda Knutsson; Sven-Erik Strand
• Keywords: Biodistribution; Technetium-99m; Ex vivo; Spect imaging

The purpose of this study was to develop multimodality SPECT/ MRI contrast agents for sentinel lymph node (SLN) mapping in vivo.Methods: Nanoparticles with a solid iron oxide core and polyethylene glycol coating were labeled 99m Tc.The labeling efficiency determined instant thin-layer chromatography magnetic separation.The stability the radiolabeled superparamagnetic nanoparticles (SPIONs) verified both sterile water human serum at room temperature 6 24 h after labeling.Five Wistar rats injected subcutaneously right hind paw Tc-SPIONs (25-50 MBq, ;0.2 mg Fe) sacrificed 4 injection.Two animals imaged SPECT/MRI.All 5 dissected; nodes, liver, kidneys, spleen, containing injection site removed weighed; activity samples measured.The microdistribution within nodes studied digital autoradiography.Results: SPIONs 99% serum.The yield 98% 97% labeling.The SLN could be identified vivo SPECT/MRI.The accumulation (as percentage dose/g [%ID/g]) 100 % ID/g, whereas liver spleen it less than 2 %ID/g.Digital autoradiography images revealed nonhomogeneous distribution nodes; found cortical, subcapsular, medullary sinuses.Conclusion: This feasibility subcutaneous animals, by SPECT/MRI, is encouraging applications breast cancer malignant melanoma.