Abstract: In nuclear magnetic resonance experiments, Cartesian electronic feedback is used to reduce substantially in transmission and/or reception the deleterious effects of sample-mediated and direct interactions between coils in an array of transmitting and/or receiving coils. The feedback is also used with single or multiple coils to maintain at essentially constant values the relationship between an input transmitter voltage and the magnetic resonance flip angle, and the relationship between transverse nuclear magnetisation and the strength of the free induction decay signal presented by a receiver for analysis, regardless of factors such as sample electrical conductivity.

Abstract: An apparatus for detecting a potentially dangerous ferromagnetic object carried inadvertently by a person approaching the magnet of a magnetic resonance imaging system (14) uses the fringe field (16) of the magnet and provides guide members (11) defining a path along which the person is prescribed to pass. The path (11) is generally or approximately parallel to the field at the path. At least one sense coil and generally two sets of sense coils (12, 13) are located on respective sides of the path (11) so that the movement of the ferromagnetic object in the field of the magnet causes a voltage to be generated in the sense coil.

Abstract: There is described a quadrature radio frequency (RF) coil design to be used with appropriate magnetic resonance imaging (MRI) hardware to obtain images of the human body. The design provides good RF field homogeneity over a volume suitable for thoracic diagnostic imaging, and operates in quadrature mode as a transmit and/or receive coil. The design is for use with a 0.33 tesla permanent, C shaped magnet with a vertical main field but is of general applicability. The coil includes two parallel annular coils connected at top and bottom by two plate conductors. The plates are split longitudinally and transversely and connected across the splits by capacitors to define two modes of resonant oscillation which can be tuned separately and independently to the same frequency, where the modes define fields which are mutually orthogonal. The fields are at right angles to the magnetic field and to the plate conductors so that the sample can be inserted through the openings at right angles to the plates.

Abstract: There is described a quadrature radio frequency (RF) coil design to be used with appropriate magnetic resonance imaging (MRI) hardware to obtain images of the human body. The design provides good RF field homogeneity over a volume suitable for thoracic diagnostic imaging, and operates in quadrature mode as a transmit and/or receive coil. The design is for use with a 0.33 tesla permanent, C shaped magnet with a vertical main field but is of general applicability. The coil includes two parallel annular coils connected at top and bottom by two plate conductors. The plates are split longitudinally and transversely and connected across the splits by capacitors to define two modes of resonant oscillation which can be tuned separately and independently to the same frequency, where the modes define fields which are mutually orthogonal. The fields are at right angles to the magnetic field and to the plate conductors so that the sample can be inserted through the openings at right angles to the plates.

Abstract: Apparatus is provided for use in surgical procedures comprising an operating table for receiving a patient for surgery and a magnetic resonance imaging system for obtaining images of a part of the patient at a series of times through the surgical procedure for analysis by the surgical team to allow the surgical team to monitor the progress of the surgery. The high field magnet and the operating table are shaped and arranged for positioning of the part of the patient into the magnetic field while the patient remains in place on the table and the magnet is mounted for movement between a first position spaced from the table and the patient thereon to allow the surgical team to carry out the surgical procedure and a second position for applying the magnetic field to the part of the patient.