Abstract: A direct-current high voltage obtained by rippling, stepping-up and rectification of a direct-current low voltage is regulated in such a manner as to ensure that the maximum value of direct-current high voltage attains a predetermined peak value at each ripple pulse of the inverter. To this end, a following pulse of the inverter is produced as soon as the high voltage of the direct-current high-voltage signal has become lower than the predetermined peak value reduced by the measurement of a variation in said direct-current high voltage during a preceding pulse.
Abstract: The invention relates to an X-ray tube with a rotating anode which is driven by a magnetic bearings motor. The anodic current is outflowed by a friction-type contact device which is located inside the shaft supporting the rotor of the motor. The friction contact device is actuated so as to cut off or establish an electrical contact between an inner wall of the rotor and the friction contact device.
Type:
Grant
Filed:
January 17, 1989
Date of Patent:
October 16, 1990
Assignee:
General Electric CGR SA
Inventors:
Michel Laurent, Pierre Noualhagnet, Claude Mathieu
Abstract: The invention concerns an X-ray stand permitting isocentric movements and intended particularly for radio diagnosis. Stand includes a base supporting a binding clip having a first and second arm supporting respectively an X-ray source and receiver. According to a feature of the invention, binding clip includes a foot by which it is supported by the base by means of devices to move foot in a circular movement centered on an isocenter point.
Abstract: A rotating anode for X-ray tube including a base body on which target is formed by the deposit of at least one layer of target material wherein said base body includes a first central section comprising at least to some extent a carbon-carbon composite material and a second part of monolithic graphite supporting target arranged at least partly at the periphery of the former with the two parts bound mechanically to one another by a means of interconnection, such as brazing at the junction point of the two parts.
Type:
Grant
Filed:
December 22, 1988
Date of Patent:
September 18, 1990
Assignee:
General Electric CGR SA
Inventors:
Christine Guerin, Jean-Marie Penato, Yves Debrouwer
Abstract: An examination bed, notably for RMN or tomodensitometry, which includes a chassis, an examination plateau, and a mechanism for driving movement of the plateau with respect to the chassis and with respect to the apparatus wherein the moving mechanism includes a moving assembly with respect to the plateau and the chassis, elongated in its shape with one end being movable with respect to the chassis and whose other end is movable with respect to the plateau.
Abstract: In order to optimize the determination of radio-frequency energization in an NMR experiment, the Schrodinger equation is written relative to the amplitude of probability of the wave function of spins resonating at a given resonance frequency wherein the Hamiltonian depends on the frequency and on the radio-frequency energization to which they are subjected. Analytical polynominal expressions are deduced for the probability amplitudes at the end of the energization as a function of the resonance frequency. The coefficients are optimized by means of calculation algorithms, from which the characteristics of the energization are deduced.
Abstract: A device for monitoring a patient in a medical examination apparatus has a support on which are mounted a television camera and a mirror sending on an image of a part of the patient to the camera, said support being movable with respect to the frame of the apparatus but fixed with respect to the patient.
Type:
Grant
Filed:
December 7, 1988
Date of Patent:
May 8, 1990
Assignee:
General Electric CGR SA
Inventors:
Jacques Sireul, Jacob Herve, Gauthier Rene
Abstract: In an x-ray equipment stand designed to perform isocentric scanning movements and having three axes of rotation concurrent to the isocenter O, the isocenter can be caused to rotate about a fourth axis (Axis 4) perpendicular to the second axis (Axis 2) and parallel to the third axis (Axis 3). This permits displacement of the isocenter in the horizontal plane, especially along straight lines which are secant with the third axis.
Abstract: An X-ray emitting device of the X-ray unit type is disclosed, the arrangement of which simplifies maintenance problems. The emitting device has a metallic casing containing an X-ray tube and supply means. According to a feature of the invention, the X-ray tube and the supply means are contained in a first and second imperviously sealed chamber, filled with oil.
Abstract: An antenna for nuclear magnetic resonance imaging devices has two electromagnetic circuits connected to each other so as to produce mutual opposition of their electromotive force when they are placed in a uniform electromagnetic induction field. It is considered that a localized transmitter does not produce a uniform field. This antenna therefore makes it possible to detect this field if it comes close to this latter. On the other hand, this antenna does not present any reactive field to a transmitter in which it may be considered that the field opposite to said antenna is uniform.
Abstract: Gradient pulses are applied during the common periods and with homothetic shapes on each of three imaging axes of an NMR machine in order to form oblique images. This results in a simplification of programming of the supplies of the gradient pulse application device.