Z-tech (canada) Inc.

Other

University of Toronto

Impedimed Limited

Ztech, Inc.

Kenneth Carless Smith

Frank Zhang

Joel Steven Ironstone

Chung Shing Fan

Reza Safaee-Rad

Milan Graovac

George Peter Darmos

Ilya Gavrilov

Leslie W Organ

Morrie Altmejd

David Wang

Chu P Chong

Zvonko G Vranesic

Apparatus for electrically connecting measurement apparatus to a biological subject, the apparatus including a signal delivery circuit including a current buffer having a current buffer input for receiving a signal from a signal source and a current buffer output for supplying a current to an electrode attached to the biological subject, and a voltage buffer having a voltage buffer input coupled to the current buffer output and a voltage buffer output for providing a voltage signal indicative of a voltage at the electrode, to a sensor.

Signal distribution for patient-electrode measurements

In various embodiments, applicants' teachings are related to an active guarding circuit and method for reducing parasitic impedance signal loading on a signal-transmission channel that is shunted by a parasitic impedance. The presence of an electrical signal on the signal-transmission channel causes a leakage current to flow through the parasitic impedance. In various embodiments, the circuit comprises an amplifier and an impedance, one terminal of the impedance is coupled to the signal-transmission channel. The input of the amplifier is coupled to the signal-transmission channel and the output is coupled to the other terminal of the impedance so as to cause a compensation current to flow through the impedance. The gain of the amplifier and the value of the impedance are selected so that the compensation current has a magnitude substantially equal to the leakage current magnitude.

Active guarding for reduction of resistive and capacitive signal loading with adjustable control of compensation level

A system for diagnosing the possibility of disease in one of a first body part and a second substantially similar body part by impedance measurements is described. The system includes an impedance module for calculating impedances of corresponding segments of the first and second body parts from current and voltage signals. The measured impedances are corrected to account for the effect of stray impedances arising from non-body part sources.

Eliminating interface artifact errors in bioimpedance measurements

A system and method for measuring a voltage in a body part are described. The system includes a multiplexing unit, and N body leads for electrically connecting the multiplexing unit to the body part. The system also includes a controller switching unit for allowing a current to flow through the body part between two body leads, nand nof the N body leads, and a resultant voltage to be measured between two body leads, nand nof the N body leads, where n&#x2260;nand n&#x2260;n, but where nnnand nneed not otherwise be distinct.

Bioimpedance measurement using controller-switched current injection and multiplexer selected electrode connection

The present invention relates to an improved method and apparatus for detecting and diagnosing disease states in a living organism by using a plurality of electrical impedance measurements. In particular, the invention provides for an improved electrode array for diagnosing the presence of a disease state in the human breast, and discloses a method of application of the array to the breast that ensures that the multiplicity of impedance measurements obtained from a first body part correspond as precisely and reproducibly as possible to the multiplicity of impedance measurements that are obtained from another, homologous, second body part. A number of diagnostic methods based on homologous electrical difference analysis are disclosed, including the calculation of a number of metrics used to indicate disease states by comparison with pre-established threshold values, and the construction of a number of graphical displays for indicating the location of disease to a body part sector.

Electrical impedance method and apparatus for detecting and diagnosing diseases

An operational amplifier is provided and includes at least two input terminals of one polarity and another input terminal of the opposite polarity. The amplifier includes an amplifying portion which comprises a differential section for receiving input signals applied to the input terminals. The differential section includes at least two differential amplifiers which form difference signals from the input signals. A summing section receives the difference signals and forms a sum result therefrom. A multiplying section provides an amplification gain to the sum result to form an output signal of desired gain. The amplifier is also provided with a feedback for applying an input signal to one of the input terminals, the output signal. The amplifier can be configured to provide amplification gains of 2, 1/2, -1 and 1. In view of the amplification gains equal to 2 and 1/2 respectively, there is also provided an analog to digital converter and a digital to analog converter both of which comprise a cascaded series of operational amplifiers.

Analog to digital converter, a digital to analog converter and an

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Toronto, Canada

Kenneth Carless Smith