37 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.

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.

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.

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 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.