title: Magnetic thermal ablation using ferrofluids: influence of administration mode on biological effect in different porcine tissues.
abstract: The purpose of this study was to compare the effects of magnetic thermal ablation in different porcine tissues using either a singular injection or a continuous infusion of superparamagnetic iron oxide nanoparticles. In the first setting samples of three ferrofluids containing different amounts of iron (1:171, 2:192, and 3:214 mg/ml) were singularly interstitially injected into specimens of porcine liver, kidney, and muscle (n = 5). Then the specimens were exposed to an alternating magnetic field (2.86 kA/m, 190 kHz) generated by a circular coil for 5 min. In the second experimental setup ferrofluid samples were continuously interstitially infused into the tissue specimens during the exposure to the magnetic field. To measure the temperature increase two fiber-optic temperature probes with a fixed distance of 0.5 cm were inserted into the specimens along the puncture tract of the injection needle and the temperature was measured every 15 s. Finally, the specimens were dissected, the diameters of the created thermal lesions were measured, and the volumes were calculated and compared. Compared to continuous infusion, a single injection of ferrofluids resulted in smaller coagulation volumes in all tissues. Significant differences regarding coagulation volume were found in kidney and muscle specimens. The continuous infusion technique led to more elliptically shaped coagulation volumes due to larger diameters along the puncture tract. Our data show the feasibility of magnetic thermal ablation using either a single interstitial injection or continuous infusion for therapy of lesions in muscle, kidney, and liver. Continuous infusion of ferrofluids results in larger zones of necrosis compared to a single injection technique.
authors.affiliation: Applied Medical Engineering, Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Pauwelsstrasse 20, 52074 Aachen, Germany. bruners@hia.rwth-aachen.de
authors.forename: Philipp
authors.initials: P
authors.lastname: Bruners
authors.forename: Michael
authors.initials: M
authors.lastname: Hodenius
authors.forename: Martin
authors.initials: M
authors.lastname: Baumann
authors.forename: Jessica
authors.initials: J
authors.lastname: Oversohl
authors.forename: Rolf W
authors.initials: RW
authors.lastname: Günther
authors.forename: Thomas
authors.initials: T
authors.lastname: Schmitz-Rode
authors.forename: Andreas H
authors.initials: AH
authors.lastname: Mahnken
mesh_terms: D000818:Animals; D017115:Catheter Ablation / Q000379:methods*; D003911:Dextrans; D004333:Drug Administration Routes; D052203:Ferrosoferric Oxide; D007501:Iron / Q000008:administration & dosage*; D007668:Kidney / Q000601:surgery*; D008099:Liver / Q000601:surgery*; D008280:Magnetics; D058185:Magnetite Nanoparticles; D018482:Muscle, Skeletal / Q000601:surgery*; D009336:Necrosis; D010087:Oxides / Q000008:administration & dosage*; D013552:Swine
chemical_list: D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; D007501:Iron; C065507:ferumoxides; D052203:Ferrosoferric Oxide