摘要:
A feed circuit accepts a stream of digital payload data and inserts it at predetermined first positions into a stream of digital transmission data. The feed circuit generates supplementary digital data using the stream of digital payload data and inserts it at predetermined second positions into a stream of digital transmission data. The feed circuit feeds the digital transmission data into a transmission medium. Said circuit determines the supplementary digital data in such a way that at least one frequency's portion of a frequency spectrum of the stream of digital transmission data will be minimized.
摘要:
A coil arrangement for a magnetic resonance apparatus has a number of coil elements that are capable of being operated independently of one another and are situated around a common central area. Each coil element of the coil arrangement is capacitively or inductively decoupled from the coil elements of the coil arrangement that are immediately adjacent to this coil element. In the central area, there is situated a capacitor network that connects the coil elements of the coil arrangement to one another. The capacitor network is fashioned and dimensioned such that it at least reduces the coupling of each coil element of the coil arrangement to at least one additional coil element of the coil arrangement that is not immediately adjacent to the respective coil element.
摘要:
A method for determining positron emission measurement information in the context of positron emission tomography is disclosed. The method includes using a marker substance to carry out a positron emission measurement, in a body area of a subject to be examined, to determine positron emission measurement information, and at the same time, generating images of the body area to be examined by way of a second medical method with a time resolution suitable for determining perfusion and/or diffusion information. The method further includes using the images from the second method to determine perfusion and/or diffusion information for at least a part of the measurement period, and evaluating the positron emission measurement information as a function of the perfusion and/or diffusion information.
摘要:
Combined positron emission tomography and magnetic resonance tomography unit for imaging an examination object in an examination space, comprising a positron emission tomography unit that has a unit part assigned to the examination space, and a first evaluation unit for evaluating the electric signals for a positron emission tomography image of the examination object. The unit part in this case comprises a gamma ray detector with an assigned electronics unit. Furthermore, the combined unit comprises a magnetic resonance tomography unit and a second evaluation unit for evaluating the magnetic resonance signals for a magnetic resonance image of the examination object. The magnetic resonance unit in this case has a high frequency antenna device as well as a gradient coil system, the high frequency antenna device being arranged nearer to the examination space than the gradient coil system, as well as a high frequency shield arranged between the gradient coil system and the high frequency antenna device. The positron emission tomography unit part is arranged in this case between the high frequency shield and the high frequency antenna device, and is provided, at least on the side facing the high frequency antenna device, with a shielding cover that is caused by the high frequency antenna device and is opaque to high frequency radiation.
摘要:
A magnetic resonance apparatus has an RF antenna unit, a gradient coil unit and an RF shield, the conductor structures of which are independent of one another. The RF shield is arranged between the RF antenna unit and the gradient coil unit, a first RF field return volume is arranged between RF the antenna unit (1, 29, 55A, and the gradient coil unit, the RF field return volume closes RF magnetic field lines of the RF antenna unit and is bordered by the RF shield on the side of the gradient coil unit. The conductor structure of the gradient coil unit occupies a first region. A second conductor-free region is within the first region, on the side facing the RF antenna unit, between a primary gradient coil unit and a secondary shim gradient coil unit of the gradient coil unit. The second conductor-free region is at least partially surrounded by the conductor structure of the gradient coil unit and is fashioned as a second RF field return volume in connection with the first RF field return volume. The RF shield proceeds between the RF field return volumes and the conductor structure of the gradient coil unit. The RF antenna unit is closer to the data acquisition region of the magnetic resonance apparatus than the gradient coil unit.
摘要:
A time-variable magnetic fields generator for a magnetic resonance apparatus has at least one gradient coil with conductors extending essentially in the region of a subject-receiving hollow opening of the magnetic resonance apparatus, and that is free of conductors in a middle axial region of the hollow opening, a first radio-frequency shield that encloses the conductors disposed on the one side of the middle region, a second radio-frequency shield that encloses the conductors disposed on the other side of the middle region, a radio-frequency antenna element that emits a radio-frequency field, disposed between the first and second radio-frequency shield in the middle region, a third radio-frequency shield proceeding radially, externally around the antenna element, such that the radio-frequency shields delimit a field return space within the generator and that is designed for a return of the radio-frequency field.
摘要:
A generator (13A, . . . 13C) of a time-variable magnetic field (B1) of a magnetic resonance device (1) which has an examination space (9,9A) for accommodating at least one area to be examined of an examination subject (7), in which examination area the time-variable magnetic field (B1) is generated by means of a current through a conductor (15, 19, 31). The magnetic field lines (23) of the magnetic field (B1) close with the aid of a field flux return space (17), in which there is arranged at least one sub-assembly (27) which has magnetizable material. A reduction of a magnetic energy density in the field flux return space (17) is produced by this means. This increases e.g. the efficiency i n the generation of high-frequency magnetic fields (B1) or of gradient fields with the aid of the conductor (15,19,31).
摘要:
A device for amplifying an input signal comprising a semiconductor unit having at least one semiconductor component, and circuit for setting an operating point of the semiconductor unit. The circuit is designed such that during amplification of the input signal, an operating point of the semiconductor unit can be varied automatically and independently for a measured value, in accordance with a predetermined profile of a maximum possible signal amplitude of the input signal between a distortion-optimized setting, for high maximum possible signal amplitude and a noise-optimized setting for a low maximum possible signal amplitude.
摘要:
A magnetic resonance apparatus with a hollow interior and with a gradient coil system disposed in the hollow interior, wherein the hollow interior exhibits a barrel-like bulge, the gradient coil system is essentially enclosed by a radio-frequency shield, and he radio-frequency shield is fashioned free of a slotting in regions in which it, with regard to a boundary of the hollow interior is at a shorter distance compared with a middle region of the bulge.
摘要:
A radio-frequency antenna has two end rings and a number of antenna rods that form a birdcage resonator. A coupling element couples high-frequency electromagnetic energy into the resonator in the transmission mode and out therefrom in the reception mode. The coupling element is fashioned as a conductor system tangentially surrounding the resonator and into which a high-frequency systems of currents can be fed in the transmission mode or from which a high-frequency system of currents can be fed out in the reception case. The coupling element is coupled only inductively to the resonator.