Resonators for magnetic resonance imaging

摘要

Single-turn loop-gap solenoidal resonators for establishing RF fields (B1) transverse to the static B0 field of a magnetic resonance imaging system. Tubular forms of dielectric (plastic) material have conductive foil bands attached to their outside walls with one or more gaps between the ends of the bands and provide solenoidal single-turn coils. A circuit resonant at radio frequencies is defined by the inductance of the solenoidal coils formed by the bands and the capacitance across the gap. The resistors and/or capacitors spaced along the axis of the tubular bodies tune the circuit and provide RF magnetic field homogeneity within the structure. Holes in the sides of the forms through the bands provide for the entrance of the analytical sample or body mass of a subject (the head, shoulder, hand, foot, knee or elbow). The forms and bands are two part assemblies, each having part of the opening therein so as to facilitate the entry of the body mass to be studied into the tubular body of the resonator. A pair of canted cylindrical forms assembled together with a plate and having bands of conductive material extending around the forms and across the opposite sides of the plate define a resonator suitable for imaging of the breasts of the subject.