Akihisa Adachi

Bio: Akihisa Adachi is an academic researcher from Panasonic. The author has contributed to research in topics: Ultrasonic sensor & Ultrasonic flow meter. The author has an hindex of 10, co-authored 73 publications receiving 578 citations.

Ultrasonic probe for transmission and reception of ultrasonic wave and ultrasonic diagnostic apparatus including ultrasonic probe

Abstract: An ultrasonic probe to be used for an ultrasonic diagnostic apparatus for obtaining an ultrasonic image. The ultrasonic probe comprises a catheter having a hollow tubing structure, a joint having a tubing structure and arranged to be at its one end portion connected to a tip portion of said catheter, a bearing connected to the other end portion of the joint, a rotating shaft inserted into the bearing to be rotatable and arranged so that a portion of the rotating shaft contacts with one end portion of the bearing, and a rotator connected to the rotating shaft and arranged so that one end portion of the rotator contacts with the other end portion of the bearing so that the bearing is interposed and supported between the portion of the rotating shaft and the rotator. An ultrasonic transducer is inserted into the rotator for transmitting and receiving an ultrasonic wave, a torque transmission shaft having a hollow structure is at its one end portion connected to the rotating shaft, and a guide wire is inserted into the hollow of the torque transmission shaft. A rotating force generated by a drive section is applied through the torque transmission shaft to the ultrasonic transducer whereby the ultrasonic transducer rotationally driven to perform a radial scanning operation. This arrangement allows a free movement of the guidewire within the catheter so that the catheter can easily be lead along the guidewire up to a target portion within a blood vessel.

Ultrasonic transducer and ultrasonic flowmeter

Abstract: The present invention provides an ultrasonic transducer having uniform characteristics. Because the characteristics of a pair of ultrasonic transducer are equalized with each other, measuring accuracy of an ultrasonic flowmeter can be improved. Electrical connection from an electrode surface 13 of a piezoelectric body 11 to an external electrode is achieved not by soldering but by an electroconductive elastic body 16. As a result, variations of the frequency characteristics due to thermal load on the piezoelectric body 11 can be reduced, and this makes it possible to obtain an ultrasonic transducer with uniform characteristics, and measuring accuracy of an ultrasonic flowmeter using a pair of the ultrasonic transducer can be improved.

Ultrasonic diagnostic system

Abstract: An ultrasonic probe has an elongated form with an end. A transducer element array is disposed in the probe for emitting ultrasonic wave frontward with respect to the end of the probe and receiving echo ultrasonic waves. The transducer element array converts the received echo ultrasonic waves into corresponding electric echo signals. The electric echo signals are processed according to a predetermined aperture synthesis technique, and thereby an image signal is generated on the basis of the electric echo signals. An image of a region in front of the end of the probe is reproduced in response to the image signal.

Ultrasonic flowmeter and ultrasonic generator/detector

Abstract: An ultrasonic flowmeter includes a flow passage and an ultrasonic generator/detector for measuring the flow rate in the flow passage wherein the ultrasonic generator/detector is equipped with a piezoelectric body having electrodes on the opposed surfaces thereof, one of which is used as an ultrasonic wave generating/detecting surface and faces the flow passage. The lengths of the sides of the generating/detecting surface is so determined that the vibration in the electrode direction is the main mode, preferably that the ratio of the lengths of the sides of the transmission/reception surface to the thickness is not greater than 0.8. Consequently, because the flow meter uses the thickness longitudinal vibration of the piezoelectric body as the main mode, the ultrasonic generator/detector has a high sensitivity, a high speed response and a small size and the ultrasonic flow meter has a high accuracy and is compact.

Flow meter device

Abstract: A flow meter device includes: an inlet portion, into which a fluid flows; an outlet portion, from which the fluid flows out; a plurality of measurement passage portions provided parallel to each other between the inlet portion and the outlet portion; and at least one flow rate measurement unit, each flow rate measurement unit being configured to measure a flow rate of the fluid that flows through a passage in a corresponding one of the measurement passage portions Shapes of passages in the respective measurement passage portions coincide with each other The plurality of measurement passage portions include: the one measurement passage portion(s), which is/are each provided with the flow rate measurement unit; and the other measurement passage portion(s), which is/are not provided with the flow rate measurement unit

Multiple ultrasound image registration system, method and transducer

Abstract: An ultrasonic imaging system includes an ultrasonic transducer having an image data array and a tracking array at each end of the image data array. The tracking arrays are oriented transversely to the image data array. Images from the image data array are used to reconstruct a three-dimensional representation of the target. The relative movement between respective frames of the image data is automatically estimated by a motion estimator, based on frames of data from the tracking arrays. As the transducer is rotated about the azimuthal axis of the image data array, features of the target remain within the image planes of the tracking arrays. Movements of these features in the image planes of the tracking arrays are used to estimate motion as required for the three-dimensional reconstruction. Similar techniques estimate motion within the plane of an image to create an extended field of view.

Organic Electroluminescent Materials and Devices

Abstract: Novel tricarbazole compounds are provided. By appropriately selecting the nature of the tricarbazole substituents, compounds with appropriate HOMO and LUMO energies can be obtained for use as materials in a secondary hole transport layer.

Volumetric image ultrasound transducer underfluid catheter system

Abstract: An underfluid ultrasound imaging catheter system includes a catheter having a distal end inserted into an underfluid structure, an ultrasonic transducer array mounted proximate the distal end of the catheter wherein the array has a row of individual transducer crystals, a lens mounted on the array for defocusing ultrasound beams in a direction perpendicular to an axis of the array so as to provide a volumetric field of view within which the underfluid features are imaged. Alternatively, the single row of transducer crystals is replaced by multiple rows of transducer crystals so as to provide a volumetric field of view. This imaging catheter system helps an operator see 3-dimensional images of an underfluid environment, such as the 3-dimensional images of fluid-filled cavities of heart, blood vessel, urinary bladder, etc. Features in such wide volumetric field of view can be imaged, measured, or intervened by an underfluid therapeutic device with an aid of the real-time image.

Apparatus and method for noninvasive doppler ultrasound-guided real-time control of tissue damage in thermal therapy

Abstract: A method and apparatus for noninvasive and real-time monitoring and feedback control of the extent and geometry of tissue damage induced by various thermal modalities (laser, electromagnetic wave, ultrasound and thermistor) in different thermal therapies (hyperthermia, thermal coagulation and ablation) is provided. Unlike the existing ultrasound configurations, which use non-Doppler ultrasound techniques, the single-beam configuration in this invention employs a multiple-range-gate pulsed Doppler technique. The configuration may be operated in A-mode, M-mode, or multi-dimensional image mode to monitor tissue thermal response in the tissue being treated at multiple tissue depths along the sound beam. By measuring changes in phase (i.e., motion) and amplitude (i.e., echogenicity) of the echoes returned from the tissue under treatment, the Doppler system can determine temporal and spatial profiles of tissue temperature and the extent and geometry of tissue thermal damage. The system can also differentiate tissue responses corresponding to coagulation of tissue (in hyperthermia or coagulation treatment) versus ablation of tissue. Further, the Doppler detection provides feedback signals using fuzzy logic technology to automatically and in real-time regulate thermal output of various thermal modalities so that optimal thermal treatment can be obtained. The control of thermal output is achieved by adjusting treatment parameters such as pulse rate, exposure time and output power in the case of lasers. The Doppler detection results can also be shown on a suitable display device to allow manual feedback control of a thermal modality by a human operator.

Ultrasonic probe, system and method for two-dimensional imaging or three-dimensional reconstruction

Abstract: An ultrasonic probe that includes at least two ultrasonic arrays and allows three dimensional images to be constructed of the region examined by the probe in a precise and facile manner.