WO1999024967A1 - Sonde a ultrasons blindee - Google Patents

Sonde a ultrasons blindee Download PDF

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Publication number
WO1999024967A1
WO1999024967A1 PCT/US1998/024152 US9824152W WO9924967A1 WO 1999024967 A1 WO1999024967 A1 WO 1999024967A1 US 9824152 W US9824152 W US 9824152W WO 9924967 A1 WO9924967 A1 WO 9924967A1
Authority
WO
WIPO (PCT)
Prior art keywords
ultrasound
conductive shield
conductive
acoustic
shield layer
Prior art date
Application number
PCT/US1998/024152
Other languages
English (en)
Inventor
Han Wen
Eric B. Bennett
Original Assignee
The Government Of The United States Of America As Represented By The Secretary, Department Of Health And Human Services
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by The Government Of The United States Of America As Represented By The Secretary, Department Of Health And Human Services filed Critical The Government Of The United States Of America As Represented By The Secretary, Department Of Health And Human Services
Priority to EP98957883A priority Critical patent/EP1031135A1/fr
Priority to AU14032/99A priority patent/AU1403299A/en
Publication of WO1999024967A1 publication Critical patent/WO1999024967A1/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
    • G01V3/08—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
    • G01V3/082—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices operating with fields produced by spontaneous potentials, e.g. electrochemical or produced by telluric currents
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/004—Mounting transducers, e.g. provided with mechanical moving or orienting device
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/18—Methods or devices for transmitting, conducting or directing sound
    • G10K11/20—Reflecting arrangements
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
    • A61B8/44—Constructional features of the ultrasonic, sonic or infrasonic diagnostic device
    • A61B8/4444—Constructional features of the ultrasonic, sonic or infrasonic diagnostic device related to the probe

Definitions

  • the present invention relates generally to ultrasound transducers or probes, and more particularly to an ultrasound probe which is shielded from electrical interference and from ultrasonic interference or noise induced by electrical interference (e.g., pulses) or by the interaction of electrical pulses with a magnetic field.
  • electrical interference e.g., pulses
  • HEI Hall Effect Imaging
  • a static magnetic field is applied to an object or subject, an electrical pulse is propagated into the object, and an ultrasound signal is detected which is related to the interaction of the electrical pulse generated in the conductive object and the magnetic field.
  • the acquired ultrasound signal which is dependent on local conductivity as well as local acoustic properties, is then processed to provide an image of the object.
  • the direction of the propagation of the ultrasound signal is in a plane perpendicular to the orientation of the magnetic field, and particularly the ultrasound signal direction is mutually perpendicular to the electric pulse field direction and the magnetic field direction which are preferably orthogonally oriented (i.e., the ultrasound propagation direction is perpendicular to the plane formed by the electric pulse field direction and magnetic field direction).
  • the electrical excitation pulse used in HEI may not only cause direct electrical interference in the ultrasound sensor, but also the electrical voltage picked up by the piezoelectric material in the ultrasound probe may cause excessive noise and instability in the preamplifier electronics and also cause the piezoelectric material to vibrate and send out unwanted (e.g., uncontrolled, unintended, unknown power spectrum) ultrasonic pulses, the echoes of which are later received by the ultrasound transducer as noise.
  • the present invention overcomes the above mentioned problems and other limitations, by providing a shielded ultrasound transducer which includes an ultrasound probe having an acoustic aperture and enclosed by a conductive member.
  • the transducer includes an ultrasound reflector which redirects acoustic signals from a first direction into a second direction incident on the acoustic aperture of the ultrasound probe.
  • the portion of the conductive member that encloses the acoustic aperture is substantially planar, and is oriented substantially perpendicular to a magnetic field direction present during use of the ultrasound transducer.
  • the conductive member includes a first conductive shield layer and a second conductive shield layer which surrounds the first conductive shield region except in a portion of the first conductive shield region that encloses the acoustic aperture of the ultrasound probe.
  • FIG. 1 shows a schematic cross-sectional side view of an embodiment of a shielded ultrasound transducer 10 in accordance with the present invention.
  • the present invention provides a shielded ultrasound transducer or probe, and is particularly well suited for adapting or modifying a conventional, commercial ultrasound transducer such as, for example, the Panametrics V314
  • MHZ/0.75 diameter transducer and the hereinbelow described embodiment of the present invention is representative of such a modification of these probes. It will be appreciated, however, that the present invention is not limited to embodiments which represent modifications of commercial probes, and that one skilled in the art may design and/or manufacture a custom shielded ultrasound transducer (not constrained by practicalities of adapting a commercial probe) in accordance with the present invention.
  • Ultrasound transducer 10 includes preamplifier 12, coaxial coupling 14, ultrasound probe 16, first conductive shield layer 18 having continuous surface portions 18a, 18b, and 18c, second conductive shield layer 20, ultrasound prism 22 having reflective surface 32, probe encasement 26, and acoustic coupling medium 28.
  • an ultrasound (acoustic) signal 30 (generated by some means, e.g., HEI) propagates from the sample into the ultrasound prism 22, which reflects ultrasound signal 30 into the acoustic aperture of ultrasound probe 16.
  • Ultrasound probe 16 transduces the acoustic signal to provide an electrical signal to preamplifier 12 via coaxial coupling 14.
  • Preamplifier 12 amplifies the electrical signal, providing an amplified signal via a coaxial signal line (not shown) to additional electronics (not shown) for further acquiring and processing the amplified signal representative of the ultrasound (acoustic) signal.
  • Preamplifier 12, ultrasound probe 16, and coaxial coupling 14 may be conventional elements present in conventional, commercial ultrasound transducers such as those described above.
  • the outer housing of preamplifier 12 is preferably conductive to shield the enclosed preamplifier circuitry, and is also preferably grounded.
  • preamplifier 12 is electrically coupled via coaxial (shielded) coupling 14 to receive electrical signals generated (transduced from acoustic vibrations) by ultrasound probe 16.
  • Ultrasound probe 16 generally includes a piezoelectric material and two opposing substantially planar conductive electrodes, one of which provides the acoustic aperture (i.e., the surface area of ultrasound probe 16 onto which acoustic signals impinge).
  • the electrode surface of ultrasound probe 16 which provides the acoustic aperture surface is electrically grounded.
  • commercial ultrasound probes may have a slightly curved acoustic aperture surface, with possibly an array of piezoelectric elements either sharing a common ground electrode or having individual ground electrodes, and either of these ultrasound probes may be used for practicing the present invention. Either of these probes can be used to focus or orient the direction of acoustic responsivity, and can be used in this manner to practice the present invention.
  • conventional single-element ultrasound probes may be used.
  • the typical commercial single-element probe is cylindrical in shape, and may be packaged or otherwise encased in a plastic-like or metallic housing, with the conductive electrodes available for electrical connection (e.g., to coaxial coupling 14).
  • probe encasement 26 is used in the present embodiment in order to facilitate shielding of a cylindrically shaped ultrasound probe 16, based on the shielding techique (copper foil) used in an experimental probe constructed by the inventors by adapting a conventional commercial ultrasound probe.
  • Probe encasement 26 is generally rectilinear (e.g., cubic) in shape, and includes a cylindrical bore completely through probe encasement 26, the cylindrical axis of the bore normally intersecting opposite faces of probe encasement 26.
  • Ultrasound probe 16 tightly fits into the bore (and may include a surrounding O-ring coaxial with the bore and ultrasound probe cylindrical axes, and which is not shown), and a recessed set screw (not shown) through probe encasement 26, transverse to the cylindrical axis, engages and affixes ultrasound probe 16, such that the acoustic aperture of ultrasound probe 16 is substantially parallel to and preferably substantially flush with the adjacent surface of probe encasement 26. It may be appreciated, however, that probe encasement 26 is not necessary for practicing the present invention, and may not be desirable in alternative embodiments.
  • First conductive shield layer 18 extends beyond the back surface of probe encasement 26 and is electrically coupled to the grounded, conductive package of preamplifier 12 along the entire edge (in all dimensions) of the back surface of probe encasement 26. Accordingly, ultrasound probe 16 is substantially enclosed or encompassed by a contiguous layer of conductive material (i.e, conductive shield layer 18, and conductive package of preamplifier 12), which preferably is of high conductivity.
  • the conductive shield layer 18 needs to be thick enough to shield out the electromagnetic fields, and the portion in front of the acoustic aperture of ultrasound probe 16 needs to be thin enough to allow ultrasonic signal to pass without noticeable attenuation and reflection (which is generally satisfied if the thickness is much less than an acoustic wavelength).
  • 0.001 inch (i.e., 1 mil) thick copper foils were found to be sufficient. These foils included an adhesive backing which facilitated mounting on probe encasement 26.
  • a thin layer of silicone rubber type compound (e.g., RTV) may be inserted between the front surface portion 18a of conductive shield layer 18 and ultrasound transducer 16 in the region of the acoustic aperture.
  • RTV silicone rubber type compound
  • various other conductive materials, thicknesses, and mechanisms for providing the conductive material e.g., electroplating, evaporation, sputtering, etc.
  • conductive shield 18 it is not strictly necessary for conductive shield 18 to lack any apertures; for instance, conductive shield layer 18 may include small apertures provided they still render conductive shield layer 18 "opaque" to the electromagnetic radiation present and conductive shield 18 remains electrically contiguous in surrounding ultrasound probe 16.
  • ultrasound transducer 10 is shown oriented such that the substantially planar front surface portion 18a of first conductive shield layer 18 which covers, and is preferably parallel to, the acoustic aperture of ultrasound probe 16 is oriented perpendicular to the magnetic field B 0 (e.g., used in HEI). More particularly, as may be appreciated, when the probe is used in the presence of electromagnetic radiation (e.g., pulses) and strong magnetic fields (e.g., if the probe is used in HEI, there is a very strong magnetic field on the order of 1 tesla or more), when the high voltage impulse occurs, the induced currents in the shield layer experience Lorentz forces, which cause the layer to vibrate.
  • electromagnetic radiation e.g., pulses
  • strong magnetic fields e.g., if the probe is used in HEI, there is a very strong magnetic field on the order of 1 tesla or more
  • the induced currents in the shield layer experience Lorentz forces, which cause the layer to vibrate.
  • first conductive shield layer 18 bends back to encase the probe (i.e., planar surface portion 18b and 18c), and therefore it loses its perpendicular direction relative to the magnetic field. If these portions of the shield are not precisely parallel to the magnetic field, then they may vibrate such that the vibrations propagate to the acoustic aperture as noise.
  • a second conductive shield layer 20 encompasses the first conductive shield layer 18 except within the acoustic aperture region, with a small air gap in between the two layers to prevent the acoustic vibrations of the second conductive shield layer 20 from reaching the first conductive shield layer 18.
  • Second conductive shield layer 20 is also electrically connected to the conductive package of preamplifier 12.
  • the only portion of the first conductive shield layer 18 exposed to the electromagnetic field is the acoustic aperture, which, as described above, does not produce acoustic noise. It is appreciated, however, that in the embodiment shown in FIG. 1 with first conductive shield layer 20 encompassing ultrasound transducer 16 and having front surface 18a oriented as described with respect to the magnetic field, second conductive shield layer 20 is not essential for practicing the present invention.
  • first conductive shield layer 18 surrounds the first conductive shield layer 16 in all but the acoustic aperture area, it is not necessary that the inner shield include portions which are not parallel to the magnetic field direction.
  • inner first conductive shield layer 18 would include only a planar portion perpendicular to the magnetic field and covering the acoustic aperture of ultrasound probe 16 (e.g., planar portion 18a of first conductive shield layer 18, exclusive of planar portions 18b and 18c).
  • Such an alternative first conductive shield layer may be grounded by using the grounded electrode surface of ultrasound probe 16 as the acoustic aperture and connecting the shield thereto, or by extending a small portion of (or attaching a small wire from) the inner first conductive shield layer to the second conductive shield layer 20, or by leaving it floating but strongly capacitively coupled to the outer shield by ensuring a very small gap and significant areal overlap therebetween.
  • the metallic electrode of the ultrasound probe 16 itself may be used as a first (inner) conductive shield layer, with additional conductive material deposited thereon if necessary to provide sufficient shielding, and possibly including a planar conductive member (in order to enlarge the area) having an aperture, with the periphery of the aperture electrically contacting the outer periphery of the metallic electrode of ultrasound probe 16.
  • the plastic housing of the ultrasound probe itself may be covered (e.g., evaporated or sputtered) with a conductive layer to replace and provide all or part of first conductive shield 18.
  • encasement 26 may be made of a conductive material in order to effectively replace portions 18a and 18b of first conductive shield layer 18.
  • ultrasonic signal 30 is redirected into the aperture by ultrasound prism 22, which is mounted in a fixed (and preferably finely adjustable) orientation with respect to o acoustic aperture of ultrasound transducer 16.
  • acoustic coupling is facilitated by including acoustic coupling medium 28, such as a silicone rubber compound (e.g., RTV) between ultrasound prism 22 and planar front surface portion 18a of first conductive 5 shield layer 18.
  • Ultrasound prism 22 employs a reflection surface 32 of large acoustic impedance mismatch to reflect the acoustic beam into the desired direction.
  • the reflection surface can be flat, or can be curved to realize specific focusing into the sample or a desired ultrasonic field of view, much like the techniques used in curved- , ⁇ surface mirrors.
  • ultrasound prism 22 was made by machining a hollow plastic frame structure which included apertures for receiving and transmitting the ultrasound signal. The frame was covered with a cellophane-like material and filled with a silicone oil (e.g., dimethyl silicone fluid). The silicon oil was selected because it is electrically inert and has an acoustic impedance close to

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Remote Sensing (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Electromagnetism (AREA)
  • Electrochemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Environmental & Geological Engineering (AREA)
  • Geology (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Geophysics (AREA)
  • Ultra Sonic Daignosis Equipment (AREA)

Abstract

L'invention concerne un transducteur (10) à ultrasons blindé comprenant une sonde (16) à ultrasons présentant une ouverture acoustique et contenue dans un élément conducteur (18). Le transducteur comprend un réflecteur (32) à ultrasons lequel renvoie les signaux acoustiques d'une première direction dans une seconde direction incidente sur l'ouverture acoustique de la sonde à ultrasons. La partie (18a) de l'élément conducteur renfermant l'ouverture acoustique est sensiblement plane, elle est orientée sensiblement perpendiculaire à la direction d'un champ magnétique présent pendant l'utilisation du transducteur (10) à ultrasons. L'élément conducteur peut comprendre une première couche (18) de blindage conducteur ainsi qu'une seconde couche (20) de blindage conducteur entourant la première région (18) de blindage conducteur excepté dans une partie de la région (18) du premier blindage conducteur renfermant l'ouverture acoustique de la sonde à ultrasons. La sonde (10) à ultrasons blindée est bien adaptée à une utilisation en imagerie à effet Hall et à une mise en oeuvre par modification ou adaptation d'une sonde commerciale classique de tomodensitomètre ou d'un réseau à ultrasons.
PCT/US1998/024152 1997-11-12 1998-11-12 Sonde a ultrasons blindee WO1999024967A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP98957883A EP1031135A1 (fr) 1997-11-12 1998-11-12 Sonde a ultrasons blindee
AU14032/99A AU1403299A (en) 1997-11-12 1998-11-12 Shielded ultrasound probe

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US6511197P 1997-11-12 1997-11-12
US60/065,111 1997-11-12

Publications (1)

Publication Number Publication Date
WO1999024967A1 true WO1999024967A1 (fr) 1999-05-20

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1998/024152 WO1999024967A1 (fr) 1997-11-12 1998-11-12 Sonde a ultrasons blindee

Country Status (3)

Country Link
EP (1) EP1031135A1 (fr)
AU (1) AU1403299A (fr)
WO (1) WO1999024967A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000019243A1 (fr) * 1998-09-30 2000-04-06 The Government Of The United States Of America As Represented By The Secretary, Department Of Health And Human Services Sondes ultrasonores protegees du bruit par un guide d'ondes et par un element conducteur assurant la compensation active
WO2010107637A3 (fr) * 2009-03-18 2010-11-25 Bp Corporation North America Inc. Réseau linéaire de capteurs ultrasoniques, installé de manière permanente et couplé à sec
CN103108594A (zh) * 2011-05-13 2013-05-15 奥林巴斯医疗株式会社 超声波振子单元、超声波内窥镜
US9078593B2 (en) 2008-02-05 2015-07-14 Fujitsu Limited Ultrasound probe device and method of operation

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60188805A (ja) * 1984-03-09 1985-09-26 Sumitomo Metal Ind Ltd 電磁超音波計測装置
US4656870A (en) * 1984-07-30 1987-04-14 Kraftwerk Union Aktiengesellschaft Ultrasonic testing device
US4887606A (en) * 1986-09-18 1989-12-19 Yock Paul G Apparatus for use in cannulation of blood vessels
JPH0965477A (ja) * 1995-08-24 1997-03-07 Olympus Optical Co Ltd 超音波トランスデューサ
WO1998000732A1 (fr) * 1996-07-03 1998-01-08 The Government Of The United States Of America Represented By The Secretary, Department Of Health And Human Services Systeme et procede d'imagerie par effet hall a ultrasons

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60188805A (ja) * 1984-03-09 1985-09-26 Sumitomo Metal Ind Ltd 電磁超音波計測装置
US4656870A (en) * 1984-07-30 1987-04-14 Kraftwerk Union Aktiengesellschaft Ultrasonic testing device
US4887606A (en) * 1986-09-18 1989-12-19 Yock Paul G Apparatus for use in cannulation of blood vessels
JPH0965477A (ja) * 1995-08-24 1997-03-07 Olympus Optical Co Ltd 超音波トランスデューサ
WO1998000732A1 (fr) * 1996-07-03 1998-01-08 The Government Of The United States Of America Represented By The Secretary, Department Of Health And Human Services Systeme et procede d'imagerie par effet hall a ultrasons

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 010, no. 041 (P - 429) 18 February 1986 (1986-02-18) *
PATENT ABSTRACTS OF JAPAN vol. 097, no. 007 31 July 1997 (1997-07-31) *

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000019243A1 (fr) * 1998-09-30 2000-04-06 The Government Of The United States Of America As Represented By The Secretary, Department Of Health And Human Services Sondes ultrasonores protegees du bruit par un guide d'ondes et par un element conducteur assurant la compensation active
US9078593B2 (en) 2008-02-05 2015-07-14 Fujitsu Limited Ultrasound probe device and method of operation
WO2010107637A3 (fr) * 2009-03-18 2010-11-25 Bp Corporation North America Inc. Réseau linéaire de capteurs ultrasoniques, installé de manière permanente et couplé à sec
CN102356311A (zh) * 2009-03-18 2012-02-15 Bp北美公司 干耦合永久性安装的超声波传感器的线性阵列
US8408065B2 (en) 2009-03-18 2013-04-02 Bp Corporation North America Inc. Dry-coupled permanently installed ultrasonic sensor linear array
AU2010226178B2 (en) * 2009-03-18 2014-07-10 Bp Corporation North America Inc. Dry-coupled permanently installed ultrasonic sensor linear array
CN103108594A (zh) * 2011-05-13 2013-05-15 奥林巴斯医疗株式会社 超声波振子单元、超声波内窥镜
EP2591731A1 (fr) * 2011-05-13 2013-05-15 Olympus Medical Systems Corp. Unité de transducteur à ultrasons, endoscope à ultrasons
EP2591731A4 (fr) * 2011-05-13 2013-07-17 Olympus Medical Systems Corp Unité de transducteur à ultrasons, endoscope à ultrasons
US8517949B2 (en) 2011-05-13 2013-08-27 Olympus Medical Systems Corp. Ultrasound transducer unit and ultrasound endoscope

Also Published As

Publication number Publication date
EP1031135A1 (fr) 2000-08-30
AU1403299A (en) 1999-05-31

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