Design of Intravascular Ultrasound-enhanced Thrombolysis Excitation System Based on FPGA / 中国医疗器械杂志

An intravascular ultrasound-enhanced thrombolysis excitation system with adjustable frequency, amplitude and duty cycle was designed based on FPGA (ZYNQ-7Z020). Firstly, the FPGA generated waveform amplitude binary data based on direct digital frequency synthesis (DDS) technology, and then the data was converted into burst signal through an external daughter card, which included D/A conversion circuit, active low-pass filter, power amplifier circuit and impedance matching circuit. The test results demonstrated that the output waveform reached the target with advantages of simple implementation and flexible control, the peak negative pressure generated from ultrasound transducer was doubled by means of an electrical impedance matching network. In vitro thrombus models were applied to verify the excitation system, it turned out that ultrasound cavitation effect generated could accelerate the penetration of urokinase and increase the thrombolysis rate by about 20%.

Modeling and FPGA-based implementation of an efficient and simple envelope detector using a Hilbert Transform FIR filter for ultrasound imaging applications

Abstract Introduction Although the envelope detection is a widely used method in medical ultrasound (US) imaging to demodulate the amplitude of the received echo signal before any back-end processing, novel hardware-based approaches have been proposed for reducing its computational cost and complexity. In this paper, we present the modeling and FPGA implementation of an efficient envelope detector based on a Hilbert Transform (HT) approximation for US imaging applications. Method The proposed model exploits both the symmetry and the alternating zero-valued coefficients of a HT finite impulse response (FIR) filter to generate the in-phase and quadrature components that are necessary for the envelope computation. The hardware design was synthesized for a Stratix IV FPGA, by using the Simulink and the integrated DSP Builder toolbox, and implemented on a Terasic DE4-230 board. The accuracy of our algorithm was evaluated by the normalized root mean square error (NRMSE) cost function in comparison with the conventional method based on the absolute value of the discrete-time analytic signal via FFT. Results An excellent agreement was achieved between the theoretical simulations with the experimental result. The NRMSE was 0.42% and the overall FPGA utilization was less than 1.5%. Additionally, the proposed envelope detector is capable of generating envelope data at every FPGA clock cycle after 19 (0.48 µs) cycles of latency. Conclusion The presented results corroborate the simplicity, flexibility and efficiency of our model for generating US envelope data in real-time, while reducing the hardware cost by up to 75%.

FPGA-Based Interface of Digital DAQ System for Double-Scattering Compton Camera / 대한핵의학회잡지

PURPOSE: The double-scattering Compton camera (DSCC) is a radiation imaging system that can provide both unknown source energy spectra and 3D spatial source distributions. The energies and detection locations measured in coincidence with three CdZnTe (CZT) detectors contribute to reconstructing emission energies and a spatial image based on conical surface integrals. In this study, we developed a digital data acquisition (DAQ) board to support our research into coincidence detection in the DSCC.METHODS: The main components of the digital DAQ board were 12 ADCs and one field programmable gate array (FPGA). The ADCs digitized the analog 96-channel CZTsignals at a sampling rate of 50MHz and transferred the serialized ADC samples and the bit and frame clocks to the FPGA. In order to correctly capture the ADC sample bits in the FPGA, we conducted individual sync calibrations for all the ADC channels to align the bit and frame clocks to the right positions of the ADC sample bits. The FPGA logic design was composed of IDELAYand IDDR components, six shift registers, and bit slip buffer resources.RESULTS: Using a Deskew test pattern, the delay value of the IDELAY component was determined to align the bit clock to the center of each sample bit.We determined the bit slip in the 12-bit ADC sample using an MSB test pattern by checking where the MSB value of one is located in the captured parallel data.CONCLUSION: After sync calibration, we tested the interface between the ADCs and the FPGA with a synthetic analog Gaussian signal. The 96 ADC channels yielded a mean R2 goodness-of-fit value of 0.95 between the Gaussian curve and the captured 12-bit parallel data.

Design of high-frequency ultrasound grayscale blood flow imaging system based on field programmable gate array / 医疗卫生装备

Objective To develop a set of high-frequency ultrasound grayscale blood flow imaging system based on field programmable gate array (FPGA) to execute simultaneous imaging of superficial blood flow and tissues.Methods This system was mainly composed of an ultrasonic transducer,an ultrasonic transmission and receiving modules,imaging software in host computer and peripheral equipment.A PVDF transducer with the frequency between 20 and 50 MHz was used for the ultrasonic transducer.In transmission and receiving modules,the radio frequency echo signals were digitized by high-speed A/D.Then the digital signals were transmitted,added,filtered,demodulated,log amplified,double sampled,and lastly transferred to the host computer by USB interface for real-time display.Results A vascular 1 mm far form the surface of the hand skin was examined by this system.Four blood flow images were obtained in corresponding with four transmission frequencies.Conclusion Real-time superficial organ blood flow imaging is realized by this system.The solution has the architecture concise and clear,and lays an experimental foundationfor high-frequency ultrasound gray-scale blood flow imaging.

Design of high-speed data acquisition system for very high frequency medical ultrasonic echo signals / 医疗卫生装备

Objective To develop a high-speed data acquisition system for very high frequency medical ultrasonic echo signals. Methods The chip LTC2285 with two integrated ADC channels was adopted to realize analog-to-digital conversion of ultrasonic echo signals. The sampling rate was 120 MHz. The converted digital signals were then input to the FPGA to realize parallel to serial conversion, and high-speed digital signals with a sampling rate of 240 MHz were obtained. Finally, the data were transferred through USB interface to the computer terminal to display. Results A timing simulation experiment, a resolution detection experiment, and an in vivo experiment of normal human eyes were carried out in this system. A preferable simulation result and real-time image were obtained. Conclusion The multi-channel and FPGA technology are used in the design of the system. Lastly, this technology simplifies the overall design of the system and improves the speed and reliability of the high speed data acquisition system.

Design of a high speed data acquisition system for biological mass spectrometers / 军事医学

Objective To develop a high-speed data acquisition system with sampling frequency of 2 GHz to meet the requirement of accurate measurement of flight time.Methods The ALTERA STRATIX Ⅲ series FPGA was used as the main control chip, matching with high-performance ADC chip with sampling frequency up to 2 GHz and sampling accuracy up to 12 bit, while extending 512 MB DDR3 SDRAM for data cache and exchanging data with the host computer through Gigabit Ethernet.In addition, a variety of PCB wiring methods were used to effectively ensure the signal integrity.Results The 250 MHz sine signal was input into the data acquisition board with 2 GHz sampling frequency,by analyzing and calculating the sampling data,acquired the following performance index of SNR=44.6639 and ENOB=7.1.Conclusion This high-speed data acquisition system based on ADC technology is a fast and reliable path and method for the measurement and analysis of biological mass spectrometry data.

Design of endoscope image acquisition system based on CCD and FPGA / 医疗卫生装备

Objective To design an endoscopic image acquisition system.Methods High resolution CCD image sensor was used as the image acquisition equipment to converse the optical signals into electrical ones. Data were stored with FPGA controller after ADC, and then transmitted to the computer with PCI bus,Results Trials proved that the system could acquire clear and stable image with simple structure and easy operation.Conclusion The system can acquire high-quality images for the diagnosis and treatment of endoscope.

An algorithm of real-time peak detection for pulse signals based on FPGA / 军事医学

Objective To present a new algorithm of real-time peak detection for pulse signals based on FPGA , which is known as the dynamic threshold with half peak detection method ( DT-HP ) .Methods With Gaussian-shaped pulse signals as the target , the method was improved from conventional methods .The FPGA detection process of the algorithm required no more than three detection parameters: the starting point , the maximum value and the pulse width .Results The algorithm solved the floating baseline and repeating detection that occur in traditional methods .Compared with the results of polynomial fitting method and flow cytometry , the difference was only 3.2% and 9.3%.Conclusion The algorithm takes less time ,RAM, and cache while allowing floating baseline detection , which can be used as an effective method for rapid detection in FPGA .

FPGA-based digital filter used in ultrasound diagnostic device / 国际生物医学工程杂志

A large real-time processing of ultrasonic signals is a very important part in the ultrasound diagnosis system,especially with digital hardware processing.A key part of the signal processing is the filter design which will affect the performance of ultrasound diagnostic equipment.In this paper,the classification of digital filters is introduced briefly,and a number of hardware implementation methods of digital filter in recent years,especially the realization of FIR filters which belongs to the classical filter based on Distributed Algorithms are discussed.Then a number of advantages and problems of digital filter in recent years are analyzed.On this basis,the paper forecasts its developing trends in the future.

Design and Realization of High-speed Fiber Transmission System Based on FPGA / 医疗卫生装备

Objective To design a FPGA(Field-Programmable Gate Array)-based image & voice signal optical transmission system,which can accomplish video & audio frequency long-distance transmission.Methods FPGA was used as the main processing chip.High speed transceiver TLK2501 and SFP optical module were also used to realize high-speed serial fiber transmission.Results A non-compressed digital video optical fiber transmission system based on the TDM technology was designed.Conclusion The system achieves the real-time transmission of video and voice signals,thus greatly improving the accuracy of the examination and providing references for diagnostic experts.

Algorithm of non-standard video transformation based on FPGA / 医疗卫生装备

Objective To study a kind of video transformation algorithm based on FPGA in view of the present situation that the video output of X-ray equipment can not be connected to common video adapter.Methods Through the control of non-standard video signal AD sampling data read-write succession in FIFO,800 digital sampling data was output(output resolution:800?600,refresh rate:60Hz)in the period of every line of effective signal.The output module combined these data with line and field synchronized signal and transform them into standard VGA signal.Results Non-standard medical video signal could be transformed into standard medical video signal by using VHDL in normal FPGA.Conclusion The speed of this algorithm is high,and the transformation effect is clear and smooth.

Design of drive circuit for wireless endoscope capsule / 医疗卫生装备

Medical endoscope capsule is described from its construction principle and drive system.The scheme and function of the drive system,especially the driving velocity and the direction control for that based on FPGA,are introduced in detail.Experiments indicate that the micro-drive system,with a linear speed ranging from 0 to 10 mm/s,can move forward and backward,and turn left and right discretionarily.The availability of programmable logic device makes the system reliable and flexible.

Application of FPGA to the elimination of 50Hz noise in physiological signals / 医疗卫生装备

The application of Field Programmable Gate Array (FPGA) to the elimina tion of 50Hz noise in physiological signal, such as ECG signal, is discussed in this article. The high speed and flexibility are acquired because of FPGA's app lication, which give the system the ability to acquire and process multi bio-par ameters.

Application of Field Programmable Gate Array(FPGA) to medical instruments / 医疗卫生装备

This paper introduces the theory and structure of FPGA.The excellent performance and powerful developing system of FPGA greatly reduce the designing and developing cost,and promote modern medical instruments in the aspects of micromation,multi-function and seriation.Emphasis is put on the application of FPGA to ECG,ultrasonic instruments and endoscope.

Application of FPGA to Doppler measurement system design / 医疗卫生装备

Along with the progressing of micro-electronics technology and the improving of FPGA's performance, it's more and more common to process digital signals using FPGA. In most cases, FPGA is used to do the preprocessing or postprocessing besides processor in order to get a higher processing speed. This article introduces how to construct the signal processing unit of Doppler measurement system with FPGA and universal digital signal processor.

Application of FPGA to medical equipment / 医疗卫生装备

FPGA is a kind of powerful programmable chip used in the development of digital system, and it has such advantages as large capacity, reliability and easy modification. The design of FPGA system is mainly through software method which is easy to grasp. Compared with legacy discrete circuit or ASIC, more and more FPGAs are adopted in digital systems for low cost and fast speed. On the other hand, digital system plays an important role in control system of medical equipments, so FPGA is expected to be widely used in almost all fields of medical equipment.

Transition system for high-resolution non-standard medical video roentgenoscoped by X-ray / 医疗卫生装备

High -resolution non -standard medical video roentgenoscoped by X -ray can't make use of universal video interfaces such as VGA, S - Video. Based on non - standard video feature transition algorithm library, high - speed field integration technology for FPGA digital system and VHDL hardware description language, this paper develops a real-time transition system for high-resolution non-standard medical video roentgenoscoped by X-ray.