title: Ferrite-enhanced MRI monitoring in hyperthermia.
abstract: In an MRI hyperthermia hybrid system, T1 changes are investigated for monitoring thermal therapy at 0.2 T. The water bolus, which is needed for power transmission and cooling of the skin, limits MR image quality by signal compression and artifacts. Superparamagnetic ferrofluid in different concentration was investigated with MR relaxometry and MRI methods. We found that using ferrofluid in a low concentration of 70-90 ppm magnetite the water signal can be suppressed without susceptibility artifacts. With our method of signal suppression, a significant improvement of spatial and temporal resolution is possible. The ferrofluid is stable and allows RF heating at 100 MHz. This method of signal extinction may also be useful for other experimental setups where suppression of water is necessary.
authors.affiliation: Department of Clinical Radiology, Ludwig-Maximilians-University Munich, Grosshadern, D-81377 Munich, Germany. hreinl@med.uni-muenchen.de
authors.forename: Herbert M
authors.initials: HM
authors.lastname: Reinl
authors.forename: Michael
authors.initials: M
authors.lastname: Peller
authors.forename: Mark
authors.initials: M
authors.lastname: Hagmann
authors.forename: Paul
authors.initials: P
authors.lastname: Turner
authors.forename: Rolf D
authors.initials: RD
authors.lastname: Issels
authors.forename: Maximilian
authors.initials: M
authors.lastname: Reiser
mesh_terms: D016477:Artifacts; D003287:Contrast Media; D005290:Ferric Compounds; D006979:Hyperthermia, Induced; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009369:Neoplasms / Q000628:therapy; D019047:Phantoms, Imaging
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; C001215:ferrite