scispace - formally typeset
Search or ask a question
Author

Tadamitsu Iritani

Bio: Tadamitsu Iritani is an academic researcher from University of Tokushima. The author has contributed to research in topics: Standing wave & Phase-locked loop. The author has an hindex of 14, co-authored 48 publications receiving 663 citations. Previous affiliations of Tadamitsu Iritani include NEC & College of Industrial Technology.

Papers
More filters
Journal ArticleDOI
TL;DR: The results showed that these parameters (Re, Ri, and Cm) exhibit significant differences among various tissues and tumors, suggesting possible applications in tumor diagnosis.
Abstract: A new system of impedance measurement over a frequency range of 0 to 200 kHz was developed by a three-electrode method. In this study, the electrical impedances of various tumors were measured in vivo in 54 patients with breast disease (31 breast cancers, 13 fibroadenomas, and 10 fibrocystic diseases) and 57 patients with pulmonary disease (44 lung cancers, 5 metastatic pulmonary tumors, 4 pulmonary tuberculoses, and 4 organized pneumonias). On the basis of those impedance measurements and the equivalent circuits in vivo, we calculated the extracellular resistance (Re), intracellular fluid resistance (Ri), and cell membrane capacitance (Cm) in tissues, all of which were compared among the various diseases. It was found that Re and Ri were significantly higher in breast cancers than in benign tumors and normal breast tissues and that Cm was significantly lower in breast cancers than in other tissues. On the other hand, Re and Ri were significantly higher, and Cm was significantly lower, in normal lung tissues than in pulmonary masses. Re and Ri were significantly higher, and Cm was significantly lower, in malignant tumors than in organized pneumonias. The results showed that these parameters (Re, Ri, and Cm) exhibit significant differences among various tissues and tumors, suggesting possible applications in tumor diagnosis.

140 citations

Journal ArticleDOI
TL;DR: Measurement of the electrical bio-impedance of breast tumors may have value in the differential diagnosis of breast lesions and the curve-fitting technique using a computer program.
Abstract: A new impedance analytical system was developed, and measurements were performed over a frequency range of 0–200 kHz by the three-electrode method. The three electrodes consist of a coaxial needle ele

103 citations

Journal ArticleDOI
01 Jun 1994-Chest
TL;DR: The rapid measurement of the electrical impedance of a lung mass, preoperatively, may be of value in the clinical evaluation of a pulmonary mass both by facilitating needle guidance and by permitting diagnosis based on electrical impedance.

65 citations

Journal ArticleDOI
TL;DR: An in vivo, fast method of measurement of local tissue bio-impedance in the beta dispersion region (0–200 kHz) is shown, and the electrical representations are discussed and compared using it.
Abstract: The objective of the research is to show an in vivo, fast method of measurement of local tissue bio-impedance in the beta dispersion region (0-200 kHz). A needle electrode is used for the purpose. The performances with respect to circuits, electrodes, measurement area and electrical representations are evaluated. A measurement example is shown, and the electrical representations are discussed and compared using it. The method discussed, although invasive, is considered to be useful for local tissue diagnoses concerning structures and physiological functions.

46 citations

Journal Article
TL;DR: The results suggest that differential diagnosis of breast tumors is possible by measuring the mammary electrical bioimpedance using noninvasive electrodes on the skin and by examining the relationship between the tissue structure of the breast and electrical bioIMpedance.
Abstract: The purpose of this study was to evaluate the possibility of differential diagnosis of tumors, such as breast cancer, by measuring the mammary electrical bioimpedance via the skin surface noninvasively and by examining the relationship between the tissue structure of the breast and electrical bioimpedance. The mammary electrical bioimpedance was measured in 24 patients with breast cancer. Taking into account the measurement results and the distribution of the mammary glands and fatty tissue, a breast model with tumors was proposed. Based on this model, the distributions of the electric potential and electric field in the tissue were theoretically analyzed by the three-dimensional finite element method. In clinical cases, the Re values of the diseased breast were significantly larger than those of the contralateral healthy breast. In theoretical analysis based on the breast model, the Re value of mammary electrical bioimpedance varied due to the structure of the breast, that is, the ratio of fatty tissue to mammary gland and the presence of mammary tumors. The results of the measurement agreed with the theoretical analyses. These results suggest that differential diagnosis of breast tumors is possible by measuring the mammary electrical bioimpedance using noninvasive electrodes on the skin.

39 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: It is revealed that there is a large variation in the dielectric properties of normal breast tissue due to substantial tissue heterogeneity, and there is no statistically significant difference between the within-patient and between-patient variability in the Dielectric Properties.
Abstract: The efficacy of emerging microwave breast cancer detection and treatment techniques will depend, in part, on the dielectric properties of normal breast tissue. However, knowledge of these properties at microwave frequencies has been limited due to gaps and discrepancies in previously reported small-scale studies. To address these issues, we experimentally characterized the wideband microwave-frequency dielectric properties of a large number of normal breast tissue samples obtained from breast reduction surgeries at the University of Wisconsin and University of Calgary hospitals. The dielectric spectroscopy measurements were conducted from 0.5 to 20 GHz using a precision openended coaxial probe. The tissue composition within the probe’s sensing region was quantified in terms of percentages of adipose, fibroconnective and glandular tissues. We fit a one-pole Cole–Cole model to the complex permittivity data set obtained for each sample and determined median Cole–Cole parameters for three groups of normal breast tissues, categorized by adipose tissue content (0–30%, 31–84% and 85–100%). Our analysis of the dielectric properties data for 354 tissue samples reveals that there is a large variation in the dielectric properties of normal breast tissue due to substantial tissue heterogeneity. We observed no statistically significant difference between the within-patient and between-patient variability in the dielectric properties. (Some figures in this article are in colour only in the electronic version)

662 citations

Patent
13 Aug 2001
TL;DR: In this paper, an approach for aiding in the identification of tissue type for an anomalous tissue in an impedance image comprising a first device providing a polychromic immitance map of a portion of the body; a second devise determining a plurality of poly-chromic measures from one or both of the parts of a body.
Abstract: Apparatus for aiding in the identification of tissue type for an anomalous tissue in an impedance image comprising a first device providing a polychromic immitance map of a portion of the body; a second devise determining a plurality of polychromic measures from one or both of a portion of the body; and a display which displays an indication based on the plurality of polychromic measures.

449 citations

Proceedings ArticleDOI
19 May 1999
TL;DR: In this paper, the authors address some of the key design considerations for future microsensor systems including the network protocols required for collaborative sensing and information distribution, system partitioning considering computation and communication costs, low energy electronics, power system design and energy harvesting techniques.
Abstract: Wireless distributed microsensor systems will enable the reliable monitoring and control of a variety of applications that range from medical and home security to machine diagnosis, chemical/biological detection and other military applications. The sensors have to be designed in a highly integrated fashion, optimizing across all levels of system abstraction, with the goal of minimizing energy dissipation. This paper addresses some of the key design considerations for future microsensor systems including the network protocols required for collaborative sensing and information distribution, system partitioning considering computation and communication costs, low energy electronics, power system design and energy harvesting techniques.

376 citations

Journal ArticleDOI
TL;DR: For better breast cancer detection, an invasive impedance technique may be enhanced by combination with other cancer indicators, and EIM using a pair of electrode arrays is a viable method with great potential.

369 citations

Patent
19 Oct 2005
TL;DR: In this paper, localized electrical characteristics are determined over a portion of a body of the subject by using an array of electrodes or electrodes that can be moved over the body, and a controller may implement the process and perform calculations on the measured data to identify tissue types and locations within the measured area, and to present results in graphical form.
Abstract: Systems and methods for discriminating and locating tissues within a body involve applying a waveform signal to tissue between two electrodes and measuring the electrical characteristics of the signal transmitted through the tissue. At least one of the electrodes is constrained in area so that localized electrical characteristics of the tissue are measured. Such localized electrical characteristics are determined over a portion of a body of the subject by using an array of electrodes or electrodes that can be moved over the body. A controller may implement the process and perform calculations on the measured data to identify tissue types and locations within the measured area, and to present results in graphical form. Results may be combined with other tissue imaging technologies and with image-guided systems.

362 citations