33 results about "Rf excitation" patented technology

A method for acquiring a magnetic resonance image dataset of a field-of-view using a gradient-echo imaging protocol includes acquiring additional k-space lines within a central region of k-space at intervals throughout the imaging protocol, wherein the additional k-space lines are used for estimating motion parameters of the field-of-view. The imaging protocol has been amended by inserting additional gradient blips after at least some of the RF excitations, such that at least one additional gradient echo is generated, allowing the acquisition of at least one additional k-space line during one echo time.

The invention discloses a special high-frequency low-level control system, which is characterized by comprising a digital signal processing board card and a radio frequency front-end board card, the digital signal processing board card mainly comprises a clock distribution unit, an ADC digital-to-analog conversion unit, a DAC analog-to-digital conversion unit, an FPGA and a cavity frequency tuning driving unit. The ADC digital-to-analog conversion unit is used for converting an intermediate frequency acquisition analog signal output by the radio frequency front-end board card into a digital intermediate frequency signal and sending the digital intermediate frequency signal to the FPGA; the DAC analog-to-digital conversion unit is used for converting the DDS excitation signal output by the FPGA into an intermediate frequency excitation analog signal and sending the intermediate frequency excitation analog signal to the radio frequency front-end The radio frequency front-end board card performs up-conversion on the intermediate-frequency excitation analog signal to obtain an RF excitation signal, sends the RF excitation signal to a high-frequency cavity for field construction, and performs down-conversion on a cavity field recovery signal to obtain an intermediate-frequency acquisition analog signal; the cavity frequency tuning drive unit comprises a motor slow tuning drive and a piezoelectric ceramic fast tuning drive; and the FPGA is used for data acquisition and loop control.

This invention discloses a multi-level collaborative SAW exhaled breath detection system and method based on a large language model, belonging to the field of SAW detection technology. The system includes a precision RF excitation control layer, an IoT gateway layer, and a cloud-based AI analysis layer. Data interaction between the three layers is achieved through a heterogeneous communication protocol stack. The precision RF excitation control layer includes a microcontroller, a DDS frequency synthesizer, and an SAW resonator; the microcontroller has a built-in pre-verification module. The IoT gateway layer includes a dual-core processor, a wireless communication module, and an I / O interface. 2 The system features an S-channel audio interface and a dual-core processor with a heterogeneous architecture. The cloud-based AI analysis layer includes speech recognition services, large language model inference services, a utility function definition library submodule, and a command string generation submodule. The system has an end-to-end device-level mapping channel from user speech to the DDS frequency synthesizer's frequency tuning word register. This invention lowers the operational threshold for precision SAW inspection and adapts to on-site inspection scenarios.

The invention relates to a method of MR imaging of an object (10) positioned in an examination volume of a MR device (1). It is an object of the invention to enable efficient spiral MR imaging without blurring artefacts, even in situations of strong B0 inhomogeneity. The method of the invention comprises the following steps: —subjecting the object (10) to an imaging sequence comprising at least one RF excitation pulse and modulated magnetic field gradients, —acquiring MR signals along two or more planar spiral k-space trajectories (31, 32, 33), wherein the radial k-space speed, i.e. the rate of variation of the radial distance from the spiral origin is essentially constant along each planar spiral k-space trajectory, and wherein the two or more k-space trajectories (31, 32, 33) are offset in-plane from each other, and—reconstructing an MR image from the acquired MR signals. Moreover, the invention relates to a MR device (1) and to a computer program for a MR device (1).

In a method for improving the recording of measurement data of an object under inspection, the method includes loading desired imaging parameters and a desired flip angle for recording the measurement data by means of a recording method, wherein the gradient to be switched for position encoding of the measurement data has its full intensity during the incident RF excitation pulse. A quantization value of a desired interference for the recording method is determined based on the desired imaging parameters, and a check on the feasibility of correcting for the interference is performed based on the quantization value and the desired flip angle.

Techniques are described for acquiring data of an examination object and imaging parameters for an acquisition of measured data via an acquisition method in which gradients to be switched for position encoding of the measured data have their full strength during an irradiation of the RF excitation pulses, and a desired flip angle are loaded. The feasibility of the correction, the acquisition method is selectively performed with the loaded imaging parameters and the loaded flip angle. If a feasibility check is negative, a pulse duration of the RF excitation pulses to be irradiated in the acquisition method and / or of the desired flip angle are adjusted into an adjusted flip angle and / or at least one of the desired imaging parameters into an adjusted imaging parameter, and the acquisition method is performed with an adjusted pulse duration and / or with an adjusted flip angle and / or with an adjusted imaging parameter.

A system for RF based frequency encoding utilizing a Bloch-Siegert shift, includes a controller, an RF encoding system, and an injection transformer simultaneous transmit and receive filter. The controller generates RF excitation pulses, RF based frequency encoding pulses, and a cancellation signal. The RF encoding system includes one or more RF coils configured to transmit the RF excitation pulses and RF based frequency encoding pulses, and to receive an MR signal from the subject where the MR signal includes a leakage signal induced by the RF based frequency encoding pulses. The injection transformer simultaneous transmit and receive filter is in signal communication with the controller and the RF encoding system. The injection transformer simultaneous transmit receive filter is configured to receive the cancellation signal, the MR signal including the leakage signal, and to cancel the leakage signal from the received MR signal to generate a filtered MR signal.

An apparatus for multiphoton parallel transmission for magnetic resonance imaging (MRI) of a subject, includes a radio frequency (RF) transmit coil, a single-channel universal excitation coil positioned outside of the RF transmit coil, and a processor device coupled to the RF transmit coil and the single-channel universal excitation coil. The RF transmit coil is configured to perform at least one RF excitation pulse of a multiphoton parallel transmit excitation comprising a multiphoton excitation pulse configured to correct spatial inhomogeneities and the single-channel universal excitation coil is configured to perform a low-frequency excitation pulse of the multiphoton excitation pulse. The processor device is configured to control current waveforms provided to the RF transmit coil to perform the at least one RF excitation pulse and to control current waveforms provided to the single-channel universal coil to perform the low frequency excitation pulse of the multiphoton excitation pulse.

In a method for measuring brain free water content, in response to an RF excitation field generated on the basis of a magnetic resonance fingerprinting sequence and applied to the brain, an equilibrium magnetization mixed term (M0) signal is acquired from radiation emitted by each excited voxel of the brain, to obtain an M0 value of each voxel of the brain; a receive coil sensitivity (RP) value of each voxel of the brain is acquired; the M0 value of each voxel of the brain is divided by the RP value of the corresponding voxel to obtain a proton density (PD) value of each voxel of the brain; a PD value of cerebrospinal fluid is taken to be a reference PD value; and the PD value of each voxel of the brain is divided by the reference PD value to obtain the free water content of each voxel of the brain. The method advantageously increases the speed and accuracy of measurement of brain free water content.

A method according to the invention for acquiring T2*-weighted measurement data of a test object using a magnetic resonance system comprises the steps: - irradiating a first RF excitation pulse to excite spins in a first layer in the test object, - switching gradients to generate at least one gradient echo signal, - after an echo time following the irradiation of the first RF excitation pulse, acquiring a first gradient echo signal from the first layer, - after the irradiation of the first RF excitation pulse and before the elapsed echo time following the first RF excitation pulse, irradiating at least one further RF excitation pulse to excite spins in a further layer,wherein, before the application of a further RF excitation pulse and after each RF excitation pulse preceding the further RF excitation pulse, a pre-rephasing gradient of a moment corresponding to the further RF excitation pulse following the pre-rephasing gradient is switched, - recording generated further gradient echo signals from further layers. By switching the pre-rephasing gradients according to the invention, gradient echo signals of the spins of different layers excited by the first RF excitation pulse and the at least one further RF excitation pulse can be separated. Thus, the echo time TE, which elapses until a first gradient echo signal is measured after the first RF excitation pulse, can be used to generate and measure further gradient echo signals in further layers after the first gradient echo signal, which increases the readout efficiency.

In a method for slice-specific correction of scan data recorded for at least two slices simultaneously of an examination object using an EPI-SMS technique, navigator signals encoded in a slice selection direction using a bipolar readout gradient for the at least two slices temporally after a RF excitation pulse radiated into the examination object and temporally before the recording of scan data to be corrected may be simultaneously recorded. Mean navigator signal(s) from at least two of the recorded navigator signals of a same polarity may be determined. Single-slice navigator signals may be determined based on the mean navigator signal and a navigator signal having been recorded with the same polarity as the mean navigator signal(s), but with a different slice selection encoding. Slice-specific correction data from the single-slice navigator signals may be determined, and scan data may be corrected based on the slice-specific correction data.

The invention relates to a method of MR imaging of an object (10) placed in an examination volume of an MR system (1). It is an object of the invention to provide a method that enables improved MR imaging using partial echo acquisition. The method of the invention comprises the steps of: subjecting the object (10) to an imaging sequence comprising a series of RF excitations, wherein an echo signal is generated in the presence of a readout magnetic field gradient in each repetition time interval between successive RF excitations, wherein phase-encoding magnetic field gradients (P, S) are switched in each repetition time interval to sample a pre-defined region of k-space; acquiring the echo signals from the object (10) as partial echoes with different readout polarities, each echo signal being associated with either a first direction of the readout magnetic field gradient or a second direction of the readout magnetic field gradient which is opposite to the first direction, wherein the echo signals associated with the first and / or the second direction sample k-space sparsely in at least one phase-encoding direction (P, S); and reconstructing an MR image from the acquired echo signals. Furthermore, the invention proposes to apply a shift in k-space in the readout direction to the acquired echo signal data and to reconstruct an intermediate MR image for each of a number of different shift values, wherein a final MR image is computed from these intermediate MR images by selecting, for each voxel of the final MR image, the voxel value with the maximum intensity from the set of intermediate MR images at the respective voxel position. Signal loss caused by phase variations of the acquired partial echo signals can be avoided in this way. Moreover, the invention relates to an MR system (1) and to a computer program to be run on an MR system (1).

A computer-implemented method for generating a magnetic resonance (MR) image of an object includes applying, via a processing system comprising one or more processors, a Hadamard encoded radiofrequency (RF) excitation pulse sequence to adjacent slices within a magnetic resonance imaging (MRI) scanner to generate Hadamard encoded adjacent slices; multiplexing, via the processing system, the Hadamard encoded adjacent slices with secondary RF excitation pulses to generate a composite RF pulse; and generating, via the processing system, the MR image of the object using the composite RF pulse.

The invention relates to the technical field of radio frequency, particularly provides a radio frequency excitation source and a radio frequency system, and aims to solve the problems of low frequency resolution and large area power consumption when the radio frequency excitation source is used. In order to achieve the purpose, the radio frequency excitation source comprises a clock management module, a communication module, a frequency adjustment module, a waveform generation module and a waveform output module, the output end of the clock management module is connected with the input ends of the communication module, the frequency adjustment module, the waveform generation module and the waveform output module. The output end of the communication module is connected with the input ends of the frequency adjustment module and the waveform generation module. The output end of the frequency adjustment module is connected with the input end of the waveform generation module; the output end of the waveform generation module is connected with the input end of the waveform output module. Through combination of the frequency adjustment module and the waveform generation module, the problem of phase spurious can be improved under a relatively low reference clock, meanwhile, an excitation signal with a higher frequency resolution is obtained, and the area power consumption is remarkably reduced.

A method for generating a magnetic resonance image of a subject using a magnetic resonance imaging (MRI) system includes receiving, using the MRI system, at least one parameter for a multiphoton parallel transmit excitation comprising a multiphoton excitation pulse configured to correct spatial inhomogeneities and performing, using the MRI system, a pulse sequence comprising the multiphoton parallel transmit excitation to acquire data from the subject. The multi photon excitation pulse of the multi photon parallel transmit excitation is performed using a radio frequency (RF) coil and a set of one or more shim coils of the MRI system. The method further includes generating, using a processor, an image of the subject using the acquired MR data. In some embodiments, the multiphoton excitation pulse includes an off-resonance RF excitation pulse performed using the RF coil and a plurality of low-frequency excitation pulses performed using the set of one or more shim coils. The plurality of low-frequency excitation pulses are performed simultaneously with the off-resonance RF excitation pulse.

The invention relates to a method and system for enhancing acceleration of an MRI scan using Adama excitation. A computer-implemented method for generating a magnetic resonance (MR) image of a subject includes applying, via a processing system comprising one or more processors, a sequence of Hadamard-coded radio frequency (RF) excitation pulses to adjacent slices within a magnetic resonance imaging (MRI) scanner to generate Hadamard-coded adjacent slices; multiplexing, via the processing system, the Adamama-encoded adjacent slices with a secondary RF excitation pulse to generate a composite RF pulse; and generating, via the processing system, the MR image of the subject using the composite RF pulse.

In a method for the improved recording of measurement data of an examination object, a desired imaging parameter and a desired flip angle are loaded for the recording of the measurement data by means of a recording method, the gradient to be switched for the position encoding of the measurement data having its total intensity during the incidence of an RF excitation pulse. A quantized value of an expected disturbance for the recording method is determined based on the desired imaging parameter, and a check of the performability of the correction of the disturbance is performed based on the quantized value and based on the desired flip angle.

Within the scope of a method according to the invention for creating measurement data from an imaging region of a measurement volume of a magnetic resonance system using a PETRA method, a pulse duration of at least one RF excitation pulse radiated during a single-shot acquisition method of the PETRA method is extended compared to a pulse duration of RF excitation pulses radiated during a radial acquisition method of the PETRA method, whereby computational operations for correcting interfering folding can be simplified.

The invention relates to a method for MR imaging of an object (10) positioned in an examination volume of an MR device (1). The object of the invention is to achieve fast spiral MR imaging with a defined T2 contrast. The method of the invention comprises the following steps: generating a plurality of spin echoes by subjecting the object (10) to one or more shots of an imaging sequence, each shot comprising an RF excitation pulse (21) followed by a plurality of RF refocusing pulses (22), wherein a modulated readout magnetic field gradient (23, 24) is applied in each interval between consecutive RF refocusing pulses (22); acquiring MR signal data, wherein each spin echo is recorded in k-space along a spiral trajectory (31-33, 41-43) winding around a k-space origin at a continuously varying radial distance, wherein the trajectory (31, 41) of at least one spin echo has a different rate of change of the radial distance than the trajectories (32, 33, 42, 43) of the other spin echoes, at least in a central k-space region; and reconstructing an MR image based on the acquired MR signal data. The invention also relates to an MR device (1) and a computer program for an MR device (1).

The invention relates to a method for establishing measurement data from an imaging region of a measurement volume of a magnetic resonance system using a PETRA method, a pulse duration of at least one RF excitation pulse incident during a single recording method of a PETRA method is extended with respect to a pulse duration of the RF excitation pulse incident during a radial recording method of the PETRA method, whereby a computational operation for correcting an interfering overlap can be simplified.

The application discloses a special high-frequency low-level control system, characterized by comprising a digital signal processing board and a radio frequency front-end board; the digital signal processing board mainly comprises a clock distribution unit, an ADC digital-analog conversion unit, a DAC analog-digital conversion unit, an FPGA and a cavity frequency tuning driving unit; the ADC digital-analog conversion unit is used for converting intermediate frequency collection analog signals output by the radio frequency front-end board into digital intermediate frequency signals and sending the digital intermediate frequency signals into the FPGA; the DAC analog-digital conversion unit is used for converting DDS excitation signals output by the FPGA into intermediate frequency excitation analog signals and sending the intermediate frequency excitation analog signals into the radio frequency front-end board; the radio frequency front-end board performs frequency up-conversion on the intermediate frequency excitation analog signals to obtain RF excitation signals and sends the RF excitation signals into a high-frequency cavity to build a field, and performs frequency down-conversion on cavity field back collection signals to obtain intermediate frequency collection analog signals; the cavity frequency tuning driving unit comprises a motor slow tuning driving and a piezoelectric ceramic fast tuning driving; and the FPGA is used for data collection and loop control.

The invention provides a zero-carbon-emission road and bridge surface acoustic wave wireless displacement monitoring system and a self-calibration method thereof, and relates to the field of traffic infrastructure health monitoring. According to the system, environment energy collection and a low-power-consumption SAW label are integrated, so that a battery-free design is realized, the power supply requirement of equipment is thoroughly eliminated, and zero carbon emission is achieved. The system adopts a self-calibration mechanism, and corrects an environmental drift error in real time by embedding a reference SAW unit and a temperature compensation algorithm, thereby ensuring long-term stability. In addition, the dynamic topology protocol based on LoRaWAN reduces the radio frequency excitation power consumption and prolongs the service life of the system. The system is suitable for displacement monitoring of key parts such as bridges and roads, covers the whole life cycle of the construction period and the operation period, and has the characteristics of high precision, real-time performance, greenness and energy conservation.

The invention relates to a method of MR imaging of an object, namely of at least a part of the female breast. The method of the invention comprises the steps of: a) subjecting the object (10) to an imaging sequence comprising RF excitation pulses and switched magnetic field gradients, wherein multiple echo signals are generated at different echo times (TE1, TE2, TE3) after each RF excitation pulse, b) acquiring the echo signals along a set of radial or spiral k-space trajectories covering a given k-space region, wherein each of the echo signals generated after an RF excitation pulse is assigned a different orientation of the radial or spiral trajectory in k-space; c) reconstructing a single echo image for each echo time (TE1, TE2, TE3) from the echo signals acquired; d) deriving high-resolution water, fat, B0 and / or apparent transverse relaxation time (T2*) maps from the single echo images using a deep learning algorithm; and d) synthesizing a high-resolution mammogram from the water, fat, B0 and / or T2* maps. Moreover, the invention relates to an MR device (1) and to a computer program for an MR device (1).

Techniques are described for acquiring data of an examination object and imaging parameters for an acquisition of measured data via an acquisition method in which gradients to be switched for position encoding of the measured data have their full strength during an irradiation of the RF excitation pulses, and a desired flip angle are loaded. The feasibility of the correction, the acquisition method is selectively performed with the loaded imaging parameters and the loaded flip angle. If a feasibility check is negative, a pulse duration of the RF excitation pulses to be irradiated in the acquisition method and / or of the desired flip angle are adjusted into an adjusted flip angle and / or at least one of the desired imaging parameters into an adjusted imaging parameter, and the acquisition method is performed with an adjusted pulse duration and / or with an adjusted flip angle and / or with an adjusted imaging parameter.

The present invention relates to a multi-channel accelerator power drive system and method, comprising a digital low-level system, a solid-state radio frequency power source, a radio frequency power synthesizer, a directional coupler group, and an input coupler. The digital low-level system is used to generate an RF excitation signal for each solid-state radio frequency power source; receive an extraction signal of radio frequency power in the cavity output by an RFQ cavity sampling antenna; adjust the amplitude and phase of the RF excitation signal of each solid-state radio frequency power source; the solid-state radio frequency power source is used to amplify and output corresponding radio frequency power according to the RF excitation signal; the radio frequency power synthesizer is used to synthesize the radio frequency powers output by two corresponding solid-state radio frequency power sources; the directional coupler group is used to couple and extract the corresponding synthesized radio frequency power, and output the extracted signal to the digital low-level system as a feedback signal; the input coupler is used to couple the radio frequency power to the RFQ cavity and reflect reflected power caused by mismatching. The present invention can be widely applied in the field of particle accelerators.

The invention relates to a method of MR imaging of an object (10) positioned in an examination volume of an MR device (1). It is an object of the invention to enable spiral MR imaging with a reduced level of ringing artefacts close to strong local IC main magnetic field inhomogeneity. The method of the invention comprises the following steps:—generating a spin echo by subjecting the object (10) to an imaging sequence comprising an RF excitation pulse (31) followed by an RF refocusing pulse (32), wherein a modulated readout magnetic field gradient (34) is applied subsequent to the RF refocusing pulse (32),—acquiring MR signal data by recording the spin echo along a spiral trajectory in k-space, wherein the waveform of the readout magnetic field gradient (34) defining the spiral trajectory starts before the spin echo center (33), and—reconstructing an MR image from the acquired MR signal data. Moreover, the invention relates to an MR device (1) and to a computer program for an MR device (1).

The invention relates to a method of MR imaging of at least a portion of a body (10) of a patient placed in an examination volume of an MR system (1). It is an object of the invention to provide an improved fast gradient echo imaging technique with the ability to obtain angiographic information. The method of the invention comprises the steps of subjecting the body portion to a magnetization preparation RF pulse (MP); subjecting the body portion to a gradient echo imaging sequence comprising a series of RF excitations (EP) after a preparation delay (TD), wherein a phase encoding gradient (PE) and a refocusing gradient (RO) and at least one bipolar velocity encoding gradient (VE) pair are applied in repetition time intervals (TR) between successive RF excitations (EP) to sample a predefined region of k-space and generate gradient echoes in each repetition time interval (TR); acquiring echo signals from the body portion; reconstructing a morphological MR image of the body portion from the acquired echo signals; and deriving phase contrast angiographic information from the phase imparted on the echo signals by the velocity encoding gradients (VE). Furthermore, the invention also relates to an MR system (1) and a computer program.

The invention relates to the technical field of application of helium optically pumped magnetometers for high-precision magnetic field measurement, in particular to a compensation method for light intensity matching of a radio frequency excitation light source of a helium optically pumped magnetometer. Applying high-voltage excitation to the helium lamp and the atomic gas chamber, adjusting the radio-frequency excitation frequency to enable the helium lamp and the atomic gas chamber to be in an impedance matching state, and recording a radio-frequency excitation frequency word at the moment; under the impedance matching frequency, adjusting the gain of the driving circuit, adjusting the light intensity of the helium lamp and the atomic gas chamber to a preset empirical value range, and recording a radio frequency excitation gain value at the moment; in a fixed magnetic field environment, the radio frequency excitation frequency and amplitude are adjusted through iteration, the magnetic field test noise level is monitored and reduced to the minimum, and the optimal radio frequency excitation parameter is recorded. According to the method, redundant and complex radio frequency excitation device parameter debugging work of each helium optically pumped magnetometer caused by the individual difference of the helium lamp and the atomic gas chamber can be avoided, and the adaptability of the helium optically pumped magnetometer to the individual difference of the helium lamp and the atomic gas chamber is improved.

This invention discloses an MBE (molecular beam epitaxy) source furnace and its thin film growth method, belonging to the field of semiconductor thin film preparation technology. The source furnace includes a gas mass flow controller, a plasma initiation device, a plasma generation cavity, and a plasma termination device connected sequentially along the beam direction. The outer wall of the plasma generation cavity is surrounded by a cross-distributed RF electrode system for efficient and uniform gas ionization. The plasma termination device is a double-layer batching disk structure used to shape the plasma into a uniform molecular beam. The method for growing thin films using this source furnace includes steps such as substrate heating, introduction of reactive gas, RF excitation to generate plasma, and beam application to the substrate for thin film growth. This invention effectively solves the problems of low ionization efficiency and non-uniform beam flow in traditional plasma sources, and is particularly suitable for the preparation of high-quality nitride and oxide semiconductor single-crystal thin films.

This invention discloses a wireless human body temperature measurement tag based on RFID technology for use in the field of temperature measurement devices. It highly integrates three major functional modules—RF excitation, local data processing, and remote transmission—into a single device—an RF transmitting base station. This enables long-distance, low-power monitoring, solving the pain point of short communication distance in purely passive RFID systems. Furthermore, the RFID temperature tag requires no battery, achieving extremely low maintenance costs throughout the system's lifecycle. Additionally, the introduction of an STM32 microcontroller chip at the base station for data preprocessing enables local data cleaning and verification, effectively filtering out invalid or erroneous data, reducing data redundancy and error rates transmitted to the cloud, and improving the overall system's data quality and transmission efficiency. Finally, a fixing unit is provided for the RFID temperature tag, allowing it to be fixed to clothing, enabling continuous long-term use and reducing the cost of using the RFID temperature tag.