title: Transmission line for improved RF safety of interventional devices.
abstract: A new concept is proposed to improve the safety of transmission lines with respect to heating during RF transmission. It is based on the integration of transformers into the transmission line. The concept was applied to an active tracking device. Miniature transformers were designed, and two types of tracking devices were built based on a standard line and a transformer line. Temperature measurements were performed for both devices during high specific absorption rate (SAR) scanning, and the suppression of RF heating to a physiologically non-relevant level was demonstrated for the transformer device. The transmission properties of the transformer line were examined in simulations and RF measurements. Active tracking with the transformer device performed robustly in the phantom. Because of the favorable signal transmission properties of the tested device, it is expected that the concept can be applied to the construction of clinical devices for tracking and intravascular imaging, which are RF-safe under clinical SAR conditions. Since the transformer line has a large bandwidth, the concept may also be applied for RF-safe transmission of non-MR signals.
authors.affiliation: Department of Technical Systems, Philips Research Laboratories, Hamburg, Germany. Steffen.Weiss@philips.com
authors.forename: Steffen
authors.initials: S
authors.lastname: Weiss
authors.forename: Peter
authors.initials: P
authors.lastname: Vernickel
authors.forename: Tobias
authors.initials: T
authors.lastname: Schaeffter
authors.forename: Volkmar
authors.initials: V
authors.lastname: Schulz
authors.forename: Bernhard
authors.initials: B
authors.lastname: Gleich
mesh_terms: D002404:Catheterization / Q000009:adverse effects* / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008279:Magnetic Resonance Imaging / Q000009:adverse effects* / Q000295:instrumentation*; D019047:Phantoms, Imaging; D011832:Radiation Injuries / Q000209:etiology / Q000517:prevention & control*; D011835:Radiation Protection / Q000295:instrumentation* / Q000379:methods; D011837:Radiation-Protective Agents; D011846:Radio Waves / Q000009:adverse effects*; D025321:Surgery, Computer-Assisted / Q000295:instrumentation* / Q000379:methods
chemical_list: D011837:Radiation-Protective Agents