摘要:
An antenna system for the reception of magnetic resonance signals has at least two resonant individual antennas. The individual antennas are connected to a pre-amplifier via a combination circuit. The combination circuit is fashioned such that signal contributions that can be emitted by the individual antennas exhibit a phase difference of 0° or 180° at the pre-amplifier.
摘要:
A combined positron emission tomography/magnetic resonance imaging apparatus including a positron emission tomography apparatus having at least one radiation detector, and a magnetic resonance imaging apparatus having at least one gradient coil and a radio-frequency antenna device. At least one embodiment of the combined position emission tomography/magnetic resonance imaging apparatus is developed further in that a first molding is provided, whose surface coincides with the inner shell of the at least one gradient coil, and a second molding is provided, whose surface coincides with the outer shell of the radiation detector, the distance between the two shells being virtually constant over the circumference of the shells, and a vacuum seal being arranged in each case along at least a first and a second circumferential line such that a closed cavity is formed between the vacuum seals.
摘要:
A combined positron emission tomography/magnetic resonance imaging apparatus for imaging organs of an examination object in an examination space is disclosed, including a positron emission tomography apparatus having at least one radiation detector, and a magnetic resonance imaging apparatus having at least one gradient coil and a radio-frequency antenna device. In order to prevent mechanical oscillations being induced in the PET gantry by the gradient coil, at least one embodiment of the combined position emission tomography/magnetic resonance imaging apparatus is developed further in that a first molding is provided, whose surface coincides with the inner shell of the at least one gradient coil, and a second molding is provided, whose surface coincides with the outer shell of the radiation detector, the distance between the two shells being virtually constant over the circumference of the shells, and a vacuum seal being arranged in each case along at least a first and a second circumferential line such that a closed cavity is formed between the vacuum seals.
摘要:
An arrangement for controlling an antenna arrangement in a magnetic resonance device has an antenna arrangement that surrounds an examination region and that has at least one antenna element for emitting an amplified transmit signal. At least one amplifier is provided, at the input of which a high-frequency transmit signal is connected, which is present on the output side of the amplifier as an amplified transmit signal. The amplifier is connected to a feed point of the antenna arrangement on the output side, in order to emit the amplified transmit signal. Coil windings of a primary gradient coil are also provided, which at least partially include the antenna arrangement and the examination region. Coil windings of a secondary gradient coil at least partially include the coil windings of the primary gradient coil, the antenna arrangement (and the examination region). The coil windings of the secondary gradient coil and the coil windings of the primary gradient coil are at a distance from one another, in which the at least one amplifier is arranged.
摘要:
APD-based PET modules are provided for use in combined PET/MR imaging. Each module includes a number of independent, optically isolated detectors. Each detector includes an array of scintillator (e.g. LSO) crystals read out by an array of APDs. The modules are positioned in the tunnel of a MR scanner. Simultaneous, artifact-free images can be acquired with the APD-based PET and MR system resulting in a high-resolution and cost-effective integrated PET/MR system.
摘要:
The embodiments relate to a method, a MRI device, and a circuit for an imaging magnetic resonance imaging device that includes at least one transmission coil for transmitting a magnetic field, where the circuit includes a hybrid coupler and at least one phase shifter that may be or are arranged in the transmission path between an amplifier and at least one transmission coil of the magnetic resonance imaging device.
摘要:
A control device for a magnetic resonance system activates the coils of a transmission array and a gradient magnet system of the magnetic resonance system by causing an excitation pulse to be supplied to each coil. A magnetization that exhibits a first actual inhomogeneity thereby is generated in an excitation volume of the magnetic resonance system. The control device determines the excitation pulse for each coil using a start pulse and a maximum allowable inhomogeneity. The respective start pulse has a total time duration. When the control device activates the coils of the transmission array and of the gradient magnet system corresponding to the start pulse, a magnetization that exhibits a second actual inhomogeneity that is smaller than the maximum permissible inhomogeneity is generated in the excitation volume. The control device determines an intermediate point of the start pulse so that the respective start pulse is divided into a first pulse part and a second pulse part that is complementary to the first pulse part. The first pulse part corresponds to a respective low-energy portion of the start pulse, the second pulse part with a high-energy portion of the respective start pulse. The control device temporally extends the second pulse part and correspondingly compresses the second pulse part in terms of amplitude. The temporally extended and amplitude-compressed pulse part is used as the excitation pulse. The control device determines the intermediate point such that the first inhomogeneity is still smaller than the maximum allowable inhomogeneity.
摘要:
An arrangement configured for controlling an antenna arrangement in a magnetic resonance device has an antenna arrangement that surrounds an examination region and that has at least one antenna element configured for emitting an amplified transmit signal. At least one amplifier is provided, at the input of which a high-frequency transmit signal is connected, which is present on the output side of the amplifier as an amplified transmit signal. The amplifier is connected to a feed point of the antenna arrangement on the output side, in order to emit the amplified transmit signal. Coil windings of a primary gradient coil are also provided, which at least partially include the antenna arrangement and the examination region. Coil windings of a secondary gradient coil at least partially include the coil windings of the primary gradient coil, the antenna arrangement (and the examination region). The coil windings of the secondary gradient coil and the coil windings of the primary gradient coil are at a distance from one another, and within that distance the at least one amplifier is arranged.
摘要:
A positron emission tomography unit (PET), having a unit part assigned to an examination space and a first evaluation unit, is combined with a magnetic resonance tomography unit (MRT). The unit part of the PRT includes at least two gamma ray detector units with in each case an assigned electronics unit. The MRT includes a second evaluation unit, a gradient coil system and a high frequency antenna device formed as a stripline antenna device having at least two conductors. The high frequency antenna device is arranged nearer to the examination space than the gradient coil system with a high frequency shield between the gradient coil system and the high frequency antenna device. Each conductor of the stripline antenna device respectively includes a gamma ray detector unit with an assigned electronics unit. The conductors of the stripline antenna device are configured for the respective gamma ray detector units and their assigned electronics units as shielding covers that are caused by the high frequency antenna device and are opaque to high frequency radiation. An examination object in the examination space can be imaged by the combined positron emission tomography and magnetic resonance tomography unit.
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.