title: (68)Ga-labeled superparamagnetic iron oxide nanoparticles (SPIONs) for multi-modality PET/MR/Cherenkov luminescence imaging of sentinel lymph nodes.
abstract: The aim of this study was to develop (68)Ga-SPIONs for use as a single contrast agent for dynamic, quantitative and high resolution PET/MR imaging of Sentinel Lymph Node (SLN). In addition (68)Ga enables Cherenkov light emission which can be used for optical guidance during resection of SLN. SPIONs were labeled with (68)Ga in ammonium acetate buffer, pH 5.5. The labeling yield and stability in human serum were determined using instant thin layer chromatography. An amount of 0.07-0.1 mL (~5-10 MBq, 0.13 mg Fe) of (68)Ga-SPIONs was subcutaneously injected in the hind paw of rats. The animals were imaged at 0-3 h and 25 h post injection with PET/CT, 9.4 T MR and CCDbased Cherenkov optical systems. A biodistribution study was performed by dissecting and measuring the radioactivity in lymph nodes, kidneys, spleen, liver and the injection site. The labeling yield was 97.3 ± 0.05% after 15 min and the (68)Ga-SPIONs were stable in human serum. PET, MR and Cherenkov luminescence imaging clearly visualized the SLN. Biodistribution confirmed a high uptake of the (68)Ga-SPIONs within the SLN. We conclude that generator produced (68)Ga can be labeled to SPIONs. Subcutaneously injected (68)Ga-SPIONs can enhance the identification of the SLNs by combining sensitive PET and high resolution MR imaging. Clinically, hybrid PET/MR cameras are already in use and (68)Ga-SPIONs have a great potential as a single-dose, tri-modality agent for diagnostic imaging and potential Cherenkov luminescent guided resection of SLN.
authors.affiliation: Department of Medical Radiation Physics, Lund University Lund, Sweden.
authors.forename: Renata
authors.initials: R
authors.lastname: Madru
authors.affiliation: Department of Medical Radiation Physics, Lund University Lund, Sweden ; Lund University Bioimaging Center, Lund University Lund, Sweden.
authors.forename: Thuy A
authors.initials: TA
authors.lastname: Tran
authors.affiliation: Department of Physics, Lund University Lund, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Axelsson
authors.affiliation: Department of Surgery, Skane University Hospital Lund, Sweden.
authors.forename: Christian
authors.initials: C
authors.lastname: Ingvar
authors.affiliation: Department of Medical Radiation Physics, Lund University Lund, Sweden.
authors.forename: Adnan
authors.initials: A
authors.lastname: Bibic
authors.affiliation: Department of Medical Radiation Physics, Lund University Lund, Sweden ; Lund University Bioimaging Center, Lund University Lund, Sweden ; Department of Diagnostic Radiology, Lund University Lund, Sweden.
authors.forename: Freddy
authors.initials: F
authors.lastname: Ståhlberg
authors.affiliation: Department of Medical Radiation Physics, Lund University Lund, Sweden.
authors.forename: Linda
authors.initials: L
authors.lastname: Knutsson
authors.affiliation: Department of Medical Radiation Physics, Lund University Lund, Sweden ; Lund University Bioimaging Center, Lund University Lund, Sweden.
authors.forename: Sven-Erik
authors.initials: SE
authors.lastname: Strand
keywords: 68Ga; Cherenkov imaging; PET/MR imaging; lymphatics; sentinel lymph node (SLN); superparamagnetic iron oxide nanoparticle (SPION)