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

Summary, in English

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

• Författare: Renata Madru; Pontus Kjellman; Fredrik Olsson; Karin Wingårdh; Christian Ingvar; Freddy Ståhlberg; Johan Olsrud; Jimmy Lätt; Sarah Fredriksson; Linda Knutsson; Sven-Erik Strand
• Avdelning/ar: MultiPark: Multidisciplinary research focused on Parkinson´s disease; eSSENCE: The e-Science Collaboration; Medicinsk strålningsfysik, Lund; Kirurgi, Lund; Diagnostisk radiologi, Lund; MR Physics
• Publiceringsår: 2012
• Språk: Engelska
• Sidor: 459-463
• Publikation/Tidskrift/Serie: Journal of Nuclear Medicine
• Volym: 53
• Issue: 3
• Länkar: http://www.ncbi.nlm.nih.gov/pubmed/22323777?dopt=Abstract; http://dx.doi.org/10.2967/jnumed.111.092437
• Dokumenttyp: Artikel i tidskrift
• Förlag: Society of Nuclear Medicine
• Ämne: Radiology, Nuclear Medicine and Medical Imaging
• Nyckelord: Tc-99m; lymph nodes; SPECT/MRI; nanoparticles; iron oxide; SPIONs
• Status: Published
• Forskningsgrupp: MR Physics
• ISBN/ISSN/Övrigt: ISSN: 0161-5505