41 results about "Electric impedance tomography" patented technology

Tumors can be treated with an alternating electric field. The size of cells in the tumor is determined prior to the start of treatment by, for example, biopsy or by inverse electric impedance tomography. A treatment frequency is chosen based on the determined cell size. The cell size can be determined during the course of treatment and the treatment frequency is adjusted to reflect changes in the cell size. A suitable apparatus for this purpose includes a device for measuring the tumor impedance, an AC signal generator with a controllable output frequency, a processor for estimating the size of tumor cells and setting the frequency of the AC signal generator based thereon, and at least one pair of electrodes operatively connected to the AC signal generator such that an alternating electric field is applied to the tumor.

Tumors can be treated with an alternating electric field. The size of cells in the tumor is determined prior to the start of treatment by, for example, biopsy or by inverse electric impedance tomography. A treatment frequency is chosen based on the determined cell size. The cell size can be determined during the course of treatment and the treatment frequency is adjusted to reflect changes in the cell size. A suitable apparatus for this purpose includes a device for measuring the tumor impedance, an AC signal generator with a controllable output frequency, a processor for estimating the size of tumor cells and setting the frequency of the AC signal generator based thereon, and at least one pair of electrodes operatively connected to the AC signal generator such that an alternating electric field is applied to the tumor.

Voltage sources produce desired current patterns in an ACT-type Electrical Impedance Tomography (EIT) system. An iterative adaptive algorithm generates the necessary voltage pattern that will result in the desired current pattern. The convergence of the algorithm is shown under the condition that the estimation error of the linear mapping from voltage to current is small. The simulation results are presented along with the implication of the convergence condition.

A method is provided for taking electrical impedance tomography measurements using multiple electrodes located at selected positions external to a volume of a subject body. Multiple orthogonal or near-orthogonal signals are introduced simultaneously by way of selected different electrodes and resultant predetermined responses (if any) at receiving electrodes are recorded or determined. The signals are encoded using the technique of code division multiplexing and received signals at each receiving electrode are cross-correlated with original signals to determine the contribution of each original signal to a composite received signal. The invention also relates to apparatus suitable for use in applying a method.

An electroimpedance tomograph is provided with a plurality of electrodes (1), which can be placed on the body of a patient and are connected to a control and evaluating unit (20) via a selector switch (60). The control and evaluating unit (20) cooperates with the selector switch (60) such that two electrodes each are supplied with alternating current from an AC power source (22). The detected analog voltage signals of the other electrodes are sent into the control and evaluating unit (20) via a measuring amplifier (62) and AD converter (64) and are processed there in order to reconstruct the impedance distribution of the body in the plane of the electrodes therefrom. A symmetrical AC power source (22) is used to reduce common-mode signals. To make it possible to suppress errors due to common-mode signals, provisions are made for the control and evaluating unit (20) to be set up for making available an additional common-mode signal at an output during an adjusting mode of operation and to send it to the body via common-mode signal electrodes (4, 90) that can be placed on the body. The control and evaluating unit (20) is prepared, furthermore, to adjust the measuring amplifier (62) according to value and phase for each electrode pair connected by the selector switch (60) such that the common-mode signal at the output of the measuring amplifier (62) is minimized, and the adjusted parameters are stored for each electrode pair.

The invention discloses a calibration device for an electric impedance tomography system. The calibration device comprises basic impedance units for simulating impedance distribution or the disturbance of the impedance distribution and electrode / skin contact units for simulating electrode / skin contact characteristics, wherein the basic impedance units are distributed to form a calibration network with a known conductivity; at least four layers of basic impedance units are arranged from the central point to the edges of the calibration network; and the electrode / skin contact units are formed by electrode / skin contact impedance modules and electrode polarization potential simulation modules, distributed around the calibration network at equal interval and connected with the basic impedance units on the outermost layer of the calibration network. The device provided by the invention can meet the evaluating requirements of performance and an image reconstruction effect of an electric impedance tomography data acquisition system.

The invention provides a multi-depth layer electrical impedance tomography imaging system which detects a plurality of subcutaneous tomograms paralleling to different depth layers on the surface of the skin by the measurement of voltage amplitudes of a plurality of different electrodes. When in practical medical inspection, the subcutaneous practical impedance information of a human body is reconstructed by the measurement of the voltage amplitudes of the plurality of different electrodes. Firstly, a plurality of tomograms paralleling to the contact surface of the skin and an electrode disk and under the electrodes are set. The depth of each tomogram can be preset according to detection demands, and then all tomograms are respectively dissected, i.e. all tomograms are dissected into a plurality of small areas. The detection purpose for obtaining the corresponding impedance value of all small areas in all set tomograms can be achieved, and the impedance values are showed by a picture so as to obtain the tomography information of a plurality of subcutaneous tomograms paralleling to different depth layers on the surface of the skin.

Electrical impedance tomography (EIT) data processing system, for acquiring and processing data from two-phase flows, comprising a dual-plane sensor, a plurality of digital signal processing modules configured in a data pipeline processing arrangement and a plurality of data acquisition subsystems in communication with a first one of said digital signal processing modules.

Electrical impedance tomography (EII) data processing system, for acquiring and processing data from two-phase flows, comprising a dual-plane sensor, a plurality of digital signal processing modules configured in a data pipeline processing arrangement and a plurality of data acquisition subsystems in communication with a first one of said digital signal processing modules.

There is suggested a system for automated adjustment of a pressure set by a respiration device, in particular a positive end-expiratory pressure and / or a maximum airway pressure, comprising: an arrangement for electrical impedance tomography for detecting an electrical impedance distribution along at least a two-dimensional cross-section through the human thorax at least at the end of an inspiration phase and at the end of an associated expiration phase; a device for dividing the detected electrical impedance distribution at the end of the inspiration phase and at the end of the expiration phase into a plurality of EIT pixels and for determining a value of the electrical impedance at the end of the inspiration phase and at the end of the expiration phase, as associated with a respective EIT pixel; and a device for automated adjustment of the pressure set by the respiration device on the basis of a comparison (i) of a deviation between the value of the electrical impedance at the end of the inspiration phase associated with an individual EIT pixel and the value of the electrical impedance at the end of the expiration phase associated with the respective individual EIT pixel (ii) with a deviation between the value of the electrical impedance at the end of the inspiration phase and the value of the electrical impedance at the end of the expiration phase, as determined on the basis of the entirety of EIT pixels.

There is disclosed a system of electrodes used for transdermal conduction of electric signals and a method of use thereof, the said system comprising a plurality of electrode parts (17, 58, 58′) connected by means of electrical conductors (17′, 68) to electric impedance tomography apparatuses, as well as other devices, the said parts being secured to the outer side (15a, 54a, 54′a) of a flexible and porous blade (15, 54c, 51′) coated on both sides thereof by layers of electrically conductive and adhesive materials, such electrically conductive materials being in mutual contact through the pores (74) of the said blade, the inner face of the latter being removably secured, by means of adhesion, to the skin of the patient (65). The invention comprises means for positioning the said electrode parts, as well as means for external protection thereof and of their respective conductors.

The invention discloses an electric impedance tomography method of a brain based on layered reconstruction, which comprises the steps as follows: layering a head model; layering the head model as a scalp layer omega scalp, a skull layer omega skull and a brain layer omega brain according to space distribution prior information; introducing a constraint matrix D to further layer and reconstruct so as to reduce artificial images of the skull layer; and layering and reconstructing the reconstructed head model in a second step to further reduce the interference of the scalp layer and highlight the target in the brain. By means of concept of layered image reconstruction, the method has the benefits of reducing the skull artificial images, lowering the interference of the scalp layer and improving the imaging quality.

The invention provides a focused type electric impedance tomography signal detection system. Focused electrode arrays (1) are evenly distributed around a three-dimensional research object, and the output end of an excitation current source module, the output end of a focusing current source module and the input end of a signal detection processing module are connected with the focused electrode arrays (1). The output end of a control module is connected with the focused electrode arrays (1), the input end of the excitation current source module, the input end of the focusing current source module and the input end of the signal detection processing module. The input end of an electric impedance tomography algorithm module is connected with the output end of the signal detection processing module. By means of focused electrode bodies (5 and 6) distributed at the two ends of a focused electrode, current is injected into the three-dimensional research object, a current shielding face is formed in the object, three-dimensional divergency of current injected into main electrodes (2) is limited, and conductivity distribution of the whole three-dimensional research object is inverted by solving section conductivity information of a circulation interface S where the main electrodes (2) inject current.

An electrical impedance tomography (EIT) device (30) with an electrode array (33), with a measured value acquisition and feed unit (40), with a computing / control unit (70) and with a data input unit (50). The computing / control unit (70) coordinates the operation and the data acquisition of EIT data (3) and is configured to identify a heart region.

A process with a corresponding device for lung ventilation involves recording an image of the lung status with an electric impedance tomography (EIT) system (2) and the total area of ventilated lung areas is determined by a computing unit (4) from all image values, subsequently divided into at least two lung areas and the extent of the homogeneity of the ventilated lung areas is determined by comparison of the impedance changes within these areas. In case of a homogeneity rated as being too low, the respiration pressures are increased step by step by means of the respirator (1) and the respiration pressure at which the greatest possible homogeneity is obtained from subsequently determined status images is determined by means of the EIT system (2). The respiration pressure is subsequently lowered again by the respirator (1) until the computing unit (4) detects a reduction in the homogeneity of ventilated lung areas, so that the respiration pressure is subsequently increased again by means of the respirator (1) to the last value at which no reduction in the homogeneity of the ventilated lung areas occurred.

An electric impedance tomography device with chest electrodes, a display and a control and analyzing unit to determine a time series of a global ventilation curve from the sequence of reconstructed matrices as a time series of the mean impedance change or of a measured respiration volume, to divide an inspiration or expiration phase into a number of steps of equal volume change, to determine the times corresponding to these steps, to determine the change in local impedance between these times for each image element, the ratio of this local change in impedance to the global equal volume change to form a local sequence of relative impedance changes of the image element as a function of the steps of equal volume change, to determine a scalar indicator characteristic as a function of the steps of equal volume change and to display each image element based on the respective scalar indicator.

A device (10) processes and visualizes EIT data (3) of at least one region of the lungs to determine and visualize ventilation delays in the lungs of a living being. The EIT data (3) are obtained from an electrical impedance tomography apparatus (30). The device makes it possible to visualize regional ventilation delays of the lungs or of regions of the lungs in which the delay exceeds a predefined duration (76) in a joint image (900).

An EIT device with a plurality of electrodes, which can be arranged about the chest of a patient, with a control and analyzing unit for feeding electrode pairs of a set of electrodes to record a voltage or current signal as a measured signal with electrode pairs acting consecutively as the feeding electrode pair to provide a matrix of image elements. A time series of the impedance change from the sequence of reconstructed matrices over at least one inspiration and one expiration is obtained and compared to a determined time series of the mean impedance change or a time series of a measured respiration volume, by calculating for each image element a scalar value as an indicator of a deviation. The control and analyzing unit assesses and marks the corresponding image element as being non-ventilated if the indicator of the deviation meets a preset threshold value criterion.

A device (10) processes and visualizes EIT data (3) of at least one region of the lungs to determine and visualize ventilation delays in the lungs of a living being. The EIT data (3) are obtained from an electrical impedance tomography apparatus (30). The device makes it possible to visualize regional ventilation delays of the lungs or of regions of the lungs in which the delay exceeds a predefined duration (76) in a joint image (900).

The invention relates to an electric impedance tomography optimization algorithm based on fuzzy clustering, which comprises the following steps: (1) obtaining an image matrix of the electric impedancetomography; (2) extracting a feature representing each pixel information from the image matrix, wherein the feature 1: a mean vector, that is, the mean value of each boundary voltage value corresponding to each pixel point; Feature 2: variance matrix, on the basis of the mean matrix, calculating the variance of each pixel, each pixel 2-dimensional eigenvector to form the eigenmatrix; (3) fuzzy clustering being carried out by using the feature matrix as the input data set of the fuzzy clustering algorithm, and the membership degree value of each pixel point being obtained, and the membership degree value of each pixel point to each class being characterized; according to the degree of membership matrix, the classification being judged.

A system, instrumentality, and method for performing an oral care evaluation of a user via electrical impedance tomography (EIT). For example, a system may include an oral care device having a first member housing a first electrode. The first electrode may be configured to transmit a first signal through a gingiva of a user to cause an altered first signal. The oral care device may have a second member housing a second electrode. The second electrode may be configured to receive the altered first signal. The system may be configured to generate an electrical impedance tomography (EIT) profile of the gingiva of the user, for example, based on data indicative of the first signal and the altered first signal. An oral health characteristic of the user may be determined based on the EIT profile of the gingiva of the user.