Magnetic shielding from professionals
As physicians require ever improved images, so too the development of the MRI-Systems has to keep pace if it is meet this demand. A few years ago a 1.0 Tesla (T) MRI System would be considered a very high magnetic field strength, today; this has more than doubled with 3.0T systems operating in the high end of the market. In the field of human medicine research, MRI-Systems with 4.0T or 9.4T are in use. Additionally, in the physical, chemical and biomedical research areas MRI-Systems of 21.0T are employed.
In practice this means that the critical field lines (e.g., 0.5 mT) move away from the ISO-center of the magnet and can often be outside of the RF Room; this phenomenon must be considered for each installation. Primarily, the Magnetic field from the MRI Scanner must not be disturbed, while at the same time ensuring that any residual Magnetic field outside the RF Room, will not have an affect on other persons or equipment. Expert advice, perfect processing
For the magnetic field to be properly attenuated, the shielding materials will have Magnetic properties and the installation method must ensure that the interface between the shielding materials on all surfaces have overlapping joints. The Albatross Projects shielding designs will attenuate the Magnetic field such that it is adequately contained within the desired perimeter.
Several materials are available for achieving a proper magnetic shielding; the choice of the most appropriate type depends either from the prescriptions of the MRI System supplier and/or from the technical feasibility study. In the overall responsibility for the RF shielded room Albatross Projects, will consider together with its customer, a design to meet the most suitable price vs. performance ratio. The following materials are used:
• Construction steel St 37
• Dynamo sheet (STABOLEC)
• ARMCO Pure Iron (American Rolling Mill Company)
The quantity of materials to be installed depends on the calculated material which is dependent on the permeability (μr.). The higher the permeability, the higher is the shielding effect of the material.