Multifrequency Impedance Tomography System for Research on Environmental and Thermal Processes

The possibility for spatial and temporal monitoring of environmental, chemical or thermal processes is of high importance for their better understanding thus control and optimization. Therefore, measurement methods that enable such opportunities might be especially valuable for researchers and process engineers. For this reason, in this paper the novel Electrical Impedance Tomography system is proposed that enables the visualization of the processes in which the electrical conductivity of material is changing. The proposed EIT system is based mostly on general purpose equipment. It consists of three laboratory-grade devices: a signal generator, a switching device and a data acquisition card for voltage measurement. In addition to those devices, the current source was constructed to complete the system. The EIT system was designed to have the ability of sourcing the current of frequency up to 250 kHz. A set of validation experiments were carried out to verify the EIT system accuracy. The validation tests consisted of object detection, distinguishing between objects of different conductivity, multifrequency imaging and visualization of slow-changing processes. The obtained results were also compared with the numerical simulations. The proposed system was proven to have the ability of correct imaging of irregularity inside the area of the sensor.

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Study of Voltage Control Current Source in Electrical Impedance Tomography System

2010 4th International Conference on Bioinformatics and Biomedical Engineering ◽

10.1109/icbbe.2010.5515066 ◽

2010 ◽

Cited By ~ 7

Author(s):

Zhangyong Li ◽

Zhui Xu ◽

Chaoshi Ren ◽

Wei Wang ◽

Dechun Zhao ◽

...

Keyword(s):

Electrical Impedance Tomography ◽

Electrical Impedance ◽

Current Source ◽

Voltage Control ◽

Impedance Tomography ◽

Tomography System ◽

Control Current

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A design of programmable wide bandwidth current source for an impedance tomography system

Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society ◽

10.1109/iembs.1996.651983 ◽

2002 ◽

Author(s):

W. Wang ◽

Z. Cheng ◽

M. McCormick

Keyword(s):

Current Source ◽

Wide Bandwidth ◽

Impedance Tomography ◽

Tomography System

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System introduction and evaluation of the first Chinese chest EIT device for ICU applications

Scientific Reports ◽

10.1038/s41598-021-98793-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Shuo-Yao Qu ◽

Meng Dai ◽

Shuo Wu ◽

Zhi-Rang Lv ◽

Xin-Yu Ti ◽

...

Keyword(s):

Signal To Noise Ratio ◽

Human Subjects ◽

Current Source ◽

Impedance Measurement ◽

Measurement Unit ◽

Voltage Measurement ◽

Impedance Tomography ◽

Promising Application ◽

One Machine ◽

Ventilation And Perfusion

AbstractChest electrical impedance tomography (EIT) is a promising application which is used to monitor the ventilation and perfusion of the lung at the bedside dynamically. The aim of the study was to introduce the first Chinese made chest EIT device for ICU application (Pulmo EIT-100). The system design of the hardware and software was briefly introduced. The performance of the system was compared to PulmoVista 500 (Dräger Medical) in healthy volunteers. The EIT system Pulmo EIT-100 consists of impedance measurement module, power supply module, PC all-in-one machine, medical cart and accessories. The performance of the system current source and voltage measurement unit was tested. A total of 50 healthy lung volunteers were prospectively examined. Subjects were asked to perform repetitive slow vital capacity (SVC) maneuvers with a spirometer. EIT measurements were performed in the following sequence during each SVC with: (1) Pulmo EIT-100, (2) PulmonVista500, (3) Pulmo EIT-100 and (4) PulmonVista500. Linearity and regional ventilation distribution of the reconstructed images from two devices were compared. The output frequency stability of the current source was 2 ppm. The amplitude error within one hour was less than 0.32‰. The output impedance of the current source was about 50kΩ. The signal-to-noise ratio of each measurement channel was ≥ 60 dB. For fixed resistance measurements, the measured values drifted about 0.08% within one hour. For human subjects, the correlations between the spirometry volume and EIT impedance from two devices were both 0.99 ± 0.01. No statistical significances were found in the parameters investigated. The repeatability (variability) of measures from the same device was comparable. Our EIT device delivers reliable data and might be used for patient measurement in a clinical setting.

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An Experimental Measurement and Control of Human Body Stomach Using Electrical Impedance Tomography

Journal of Circuits System and Computers ◽

10.1142/s0218126621501036 ◽

2020 ◽

pp. 2150103

Author(s):

Ramesh Kumar ◽

Rajesh Mahadeva

Keyword(s):

Electrical Impedance Tomography ◽

Human Body ◽

Electrical Impedance ◽

Imaging Modality ◽

Current Source ◽

Voltage Measurement ◽

Impedance Tomography ◽

Cross Sectional ◽

Non Invasive ◽

The Cross

A newly proven technique is non-invasive bio-impedance, and also known as Electrical Impedance Tomography (EIT), which is used for medical or non-medical applications. EIT images are based on the internal distributions of the conductivity or resistivity from the boundary data, which depend on the voltage measurement of the stomach attached electrodes of the human body. An experimental study of the EIT system presented here has been used 8/16 surface electrodes configurations for the human body’s stomach. Then, according to the data acquisition methods of the EIT, the surface potentials of the stomach through the current injection were measured. For current pulses, a voltage-controlled current source has been created, and the created current source is a combination of voltage to current converter and current signal generator. Current positions and measuring voltages have been calculated using the designed control unit. However, the imaging algorithm requires sufficient data through the experimental work, which defines the cross-sectional image of resistivity. The cross-sectional image has been based on the Finite Element Method (FEM). It produces 2D/3D images, impedance distribution graphs and Mesh models. The proposed EIT system has been used for non-medical and industrial applications, which have non-invasive, inexpensive, radiation-free and a high potential for imaging modality.

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The first Chinese chest EIT device for ICU applications: system introduction and evaluation

10.21203/rs.3.rs-359754/v1 ◽

2021 ◽

Author(s):

Shuo-yao Qu ◽

Meng Dai ◽

Shuo Wu ◽

Zhi-rang Lv ◽

Xin-yu Ti ◽

...

Keyword(s):

Signal To Noise Ratio ◽

Human Subjects ◽

Current Source ◽

Impedance Measurement ◽

Measurement Unit ◽

Voltage Measurement ◽

Impedance Tomography ◽

Promising Application ◽

One Machine ◽

Ventilation And Perfusion

Abstract Background Chest electrical impedance tomography (EIT) is a promising application which is used to monitor the ventilation and perfusion of the lung at the bedside dynamically. The aim of the study was to introduce the first Chinese made chest EIT device for ICU application (Pulmo EIT-100). The system design of the hardware and software was briefly introduced. The performance of the system was compared to PulmoVista 500 (Dräger Medical) in healthy volunteers. Methods The EIT system Pulmo EIT-100 consists of impedance measurement module, power supply module, PC all-in-one machine, medical cart and accessories. The performance of the system current source and voltage measurement unit was tested. A total of 50 healthy lung volunteers were prospectively examined. Subjects were asked to perform repetitive slow vital capacity (SVC) maneuvers with a spirometer. EIT measurements were performed in the following sequence during each SVC with: (1) Pulmo EIT-100, (2) PulmonVista500, (3) Pulmo EIT-100 and (4) PulmonVista500. Linearity and regional ventilation distribution of the reconstructed images from two devices were compared. Results The output frequency stability of the current source was 2ppm. The amplitude error within one hour was less than 0.32‰. The output impedance of the current source was about 50 KΩ. The signal-to-noise ratio of each measurement channel was ≥ 60 dB. For fixed resistance measurements, the measured values drifted about 0.08% within one hour. For human subjects, the correlations between the spirometry volume and EIT impedance from two devices were both 0.99 ± 0.01. No statistical significances were found in the parameters investigated. The repeatability (variability) of measures from the same device was comparable. Conclusion Our EIT device delivers reliable data and might be used for patient measurement in a clinical setting.

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A PXI-Based Biomedical Electrical Impedance Tomography System

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.670-671.1205 ◽

2014 ◽

Vol 670-671 ◽

pp. 1205-1209

Author(s):

Xiao Yan Chen ◽

Tao Yang ◽

Yong Zheng Yang

Keyword(s):

Electrical Impedance Tomography ◽

Electrical Impedance ◽

System Structure ◽

Impedance Tomography ◽

Tomography System ◽

Imaging Results ◽

Data Acquisition Card ◽

Programmable Gain ◽

The Stability ◽

Stability And Accuracy

This paper presents a PXI-based biomedical electrical impedance tomography (BEIT) system and interprets how to build up a practical BEIT system quickly. The hardware platform of the system is composed of signal source module, switch module, signal conditioner module and PXI-6251 data acquisition card supplied by National Instruments (NI), which simplify the system structure as well as improving the stability and accuracy of the system. Different from the traditional BEIT systems, the electrodes selection, the switch pattern, the programmable gain amplifier (PGA) gain selection are realized by code programming in LabVIEW instead of electrical components design. The composition of the proposed system and the specialized software package developed in LabVIEW are introduced in detail in the paper, and experiments are undertaken to verify the feasibility of the system. The imaging results verify that the PXI-based BEIT system has prominent performance in flexibility, reliability and scalability.

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