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"Purpose: To describe the design and construction of an 8 Tesla/80 cm whole body MRI system operating at 340 MHz.
Methods: The 8 Tesla/80 cm magnet was constructed from 414 km of Niobium Titanium super conducting wire. The winding of this wire on four aluminum formers resulted in a total inductance of 4155 Henries. Gradient subsystems included either a body gradient or a head gradient along with a removable shim insert. The magnet and gradient subsystems were interfaced to two spectrometers. These provided the control for the gradient amplifiers and the two sets of 4 RF power amplifiers. The latter provide in excess of 8 kWatts of RF power from 10-140 MHz and 10 kWatts of RF power from 245-345 MHz. A dedicated computer controlled patient table was designed and assembled. The entire system is located in a clinical setting facilitating patient based studies.
Results: The 8 Tesla/80 cm magnet was energized without complication and achieved persistent operation using 198.9 Amps of current thereby storing 81.5 Mjoules of magnetic energy. Exceptional performance was observed for nearly all components both in isolation and when combined within the complete system.
Discussion: An 8 Tesla/80 cm MRI system has been assembled. The magnet subsystem is extremely stable and is characterized by good homogeneity and acceptable boil-off rates."
P.-M. L. Robitaille et. al., J. Comp. Assist. Tomog. 23:808-820 (1999).