title: Design of field-cycled magnetic resonance systems for small animal imaging.
abstract: This paper presents a design study for a field-cycled magnetic resonance imaging (MRI) system directed at small animal imaging applications. A field-cycled MRI system is different from a conventional MRI system in that it uses two separate and dynamically controllable magnetic fields. A strong magnetic field is used to polarize the object, and a relatively weak magnetic field is used during signal acquisition. The potential benefits of field-cycled MRI are described. The theoretical dependences of field-cycled MRI performance on system design are introduced and investigated. Electromagnetic, mechanical and thermal performances of the system were considered in this design study. A system design for imaging 10 cm diameter objects is presented as an example, capable of producing high-duty-cycle polarizing magnetic fields of 0.5 T and readout magnetic fields corresponding to a proton Larmor frequency of 5 MHz. The specifications of the final design are presented along with its expected electromagnetic and thermal performance.
authors.affiliation: Department of Physics and Astronomy, The University of Western Ontario, London, Ontario, N6A 3K7, Canada.
authors.forename: K M
authors.initials: KM
authors.lastname: Gilbert
authors.forename: W B
authors.initials: WB
authors.lastname: Handler
authors.forename: T J
authors.initials: TJ
authors.lastname: Scholl
authors.forename: J W
authors.initials: JW
authors.lastname: Odegaard
authors.forename: B A
authors.initials: BA
authors.lastname: Chronik
mesh_terms: D000465:Algorithms; D000818:Animals; D004574:Electromagnetic Fields; D004867:Equipment Design; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D023421:Models, Animal; D019047:Phantoms, Imaging; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D013696:Temperature; D013997:Time Factors