The fabrication of cylindrical MRI magnetic and RF shields

Conference · Wed May 01 00:00:00 EDT 1985 · J. Nucl. Med.; (United States)

OSTI ID:7135980

Flynn, M J; Froelich, J W; Ewing, J R; Tomasik, M; Windham, J P; Hearshen, D O

The authors have designed magnetic resonance shields for two magnetic resonance systems: 1) A 1.9 tesla, 60 cm bore superconducting magnet with a bruker biospec spectrometry system used for medical research, and 2) A 1.5 tesla, 100 cm bore superconducting magnet with a General Electric imaging system used for clinical diagnosis. The research system is enclosed by an iron cylindrical shield having a weight of 49,000 pounds. The diagnostic imaging system shield is a tapered thickness iron cylinder with conic ends having a weight of 100,000 pounds. The later shield was fabricated to control RF penetration and coupled to a coper RF end shield. Both shield designs were developed using finite element magnetic field computation methods using computed design facilities of the magnetic resonance system suppliers. The shields were constructed from cold rolled steel sections which were welded in place at the magnet site. The finished shields are supported by four saddle supports located in a concrete pit. The low carbon, specially annealed steel employed has particularly desirable properties of induced magnetism. The magnetic resonance system is supported on an aluminum support frame and floor such that the magnet center line is on the shield center line. Both shields restrict the 5 gauss field to within 4 meters from the magnet center line and produce minimal perturbations of the magnet homogeneity. The fabrication cost for each system is approximately $75,000 plus $1.55 per pound of installed iron.

• Research Organization: Henry Ford Hospital, Detroit, MI
• OSTI ID: 7135980
• Report Number(s): CONF-850611-
• Journal Information: J. Nucl. Med.; (United States), Vol. 26:5; Conference: 32. annual meeting of the Society of Nuclear Medicine, Houston, TX, USA, 2 Jun 1985
• Country of Publication: United States
• Language: English

Related Subjects

47 OTHER INSTRUMENTATION
62 RADIOLOGY AND NUCLEAR MEDICINE
MAGNETIC SHIELDING
DESIGN
FABRICATION
NMR IMAGING
SUPERCONDUCTING MAGNETS
COMPUTER CALCULATIONS
COST
MAGNETIC FIELDS
MAGNETIC INSULATION
RF SYSTEMS
STEELS
ALLOYS
DIAGNOSTIC TECHNIQUES
ELECTRICAL EQUIPMENT
ELECTROMAGNETS
EQUIPMENT
IRON ALLOYS
IRON BASE ALLOYS
MAGNETS
SHIELDING
SUPERCONDUCTING DEVICES
440300* - Miscellaneous Instruments- (-1989)
550600 - Medicine