|Publication number||US4572201 A|
|Application number||US 06/659,672|
|Publication date||Feb 25, 1986|
|Filing date||Oct 11, 1984|
|Priority date||Oct 11, 1983|
|Publication number||06659672, 659672, US 4572201 A, US 4572201A, US-A-4572201, US4572201 A, US4572201A|
|Inventors||Shinichi Kondo, Chitose Nakaya, Shizuo Ishikawa|
|Original Assignee||Hitachi, Ltd.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (3), Referenced by (60), Classifications (11), Legal Events (4)|
|External Links: USPTO, USPTO Assignment, Espacenet|
1. Field of the Invention
This invention relates to a probe for an intraluminal ultrasonic scanner, and more particularly to a probe which is inserted into a lumen of a patient so that a transducer therein can scan to provide an ultrasonic tomography of the patient.
2. Description of the Prior Art
Most conventional ultrasonic tomographs are obtained by rediating ultrasonic pulses into the body from the body surface, and by receiving the reflected waves therefrom to obtain information on the inside of the body. Recently, intraluminal tomography in which an ultrasonic probe is inserted into a body cavity and ultrasonic pulses are transmitted to and received from near the organs in a living body has been drawing increasing attention. This method of intraluminal tomography is characterized in that a higher resolution with high frequencies can be obtained because there is less damping of sound waves due to subcutaneous fat layers between the target organ and the probe.
Transrectal tomography is particularly effective for diagnosis related to the prostate, and various apparatuses for this tomography have been proposed in the past. On the other hand, various proposals have also been made for an apparatus for diagnosis concerning the walls of the stomach, the pancreas, and the like, that is, a so-called "echo endoscope". Japanese Patent Laid-Open No. 1984/1979, for example, discloses an apparatus in which a fiber scope and a ultrasonic transducer are assembled into a single probe, and which enables both observation of the surfaces of internal walls and tomography within those walls.
The most ordinary type of this intraluminal ultrasonic scanner is one in which a transducer is mechanically rotated within a probe to obtain a radial tomogram. A problem encountered in this mechanical scanning transducer concerns the size and shape of the transducer. In the prior art in the Japanese Patent Laid-Open document quoted above, a round transducer is used, but there is a limit on the inner diameter of the probe. The lateral resolution in ultrasonic tomography is inversely proportional to the diameter of the transducer, and hence the resolution drops if the diameter of the round transducer is reduced, such as in the prior art described above. In addition, since the sensitivity of the probe is substantially proportional to the sound-wave transmission and reception area of the transducer, the sensitivity drops and the depth that can be observed is less if the diameter of the round transducer is reduced.
With the background described above, the present invention is directed to providing a probe which can eliminate the problems in the prior art, and which can improve the resolution in the thickness direction of the sectional surface, that is, in the direction parallel to the axis of rotation thereof, as well as the sensitivity.
In a probe element constituted in such a manner that it is rotated mechanically within a probe inserted into a lumen of a patient, the object of the present invention can be accomplished by a probe which is characterized in that the length of a transducer surface in the direction parallel to the axis of rotation thereof is made greater than its length in directions perpendicular to the axis of rotation, so that the resolution in the direction parallel to the axis of rotation is improved, as well as the sensitivity, by the consequent increase in area.
FIG. 1 is a section through a probe in accordance with one embodiment of the present invention;
FIGS. 2A and 2B are a plan view and a sectioned view of the principal portions of the probe of FIG. 1, respectively;
FIG. 3 is a plan view of the probe in accordance with another embodiment of the present invention; and
FIG. 4 is a graph of the lateral resolution of each embodibent.
FIG. 1 is a section through the probe tip of a so-called "echo endoscope" used for diagnosis related to the walls of the stomach, the pancreas, and so forth. In this embodiment, both the echo endoscope and a fiber scope are provided in a probe which is inserted into the body through the gullet. In the drawing, reference numeral 12 denotes a light guide for guiding the illumination light, 13 denotes a rectangular prism, 14 an imaging lens, and 15 an image guide. In this optical system, the rectangular prism 13 and the imaging lens 14, which are arranged adjacent to each other in the proximity of a radiating end 12A of the light guide 12, constitute an image formation system which forms an image on the end surface of the image guide 15, and the image thus formed is observed by an external optical system provided for image observation.
Reference numerals 2 and 16 through 25 denote the principal constituents of the echo endoscope. A concave ultrasonic transducer 2 is fixed to a rotary shaft 20 together with a damper member 17 which absorbs sound waves, and is connected to an external motor by a flexible shaft 16. Reference numeral 18 denotes an acoustic case of cylindrical shape which acoustically couples an ultrasonic-wave transmission medium 19 such as olive oil with the patient's body, 21 denotes a support, 22 a bearing, 23 a signal line on the rotational side, 24 a signal line on the fixed side, and 25 a slip ring.
The ultrasonic transducer 2 is driven by pulses from a driving circuit, not shown, through the signal line 24, the slip ring 25, and the signal line 23. The reflected waves generated by this are detected by the transducer, and a detection signal is supplied to a reception circuit back along the route described above. This operation above is repeated as the transducer 2 is rotated by the motor, not shown, centered on the Z-axis, and a tomogram perpendicular to the Z-axis can be obtained thereby.
FIG. 2A is a plan view of just the transducer 2 portion of the probe shown in FIG. 1. As shown in this drawing, the transducer 2 is elliptical. When compared with a conventional transducer 13, represented by dashed line for reference, the transducer 2 of the present invention has the same dimension (D1) perpendicular to the axis of rotation (Z-axis), but has a much larger dimension (D2) parallel to the Z-axis than that of the conventional transducer.
FIG. 2B is a section taken along the line X--X of FIG. 2A. As illustrated in the drawing, the surface of the transducer 2 forms part of a spherical surface of a radius f.
According to Rayleigh, both the lateral resolution (hereinafter called simply "resolution") in the X-axis direction at a distance y and the Z-axis resolution are given by:
where D is the diameter of the transducer.
In this embodiment:
D=D1 in the X-axis direction,
D=D2 in the Z-axis direction, and
Therefore, the following relationships hold, where Δ1 and Δ2 are the resolutions in the X-axis direction and the Z-axis direction, respectively:
Δ1 =1.22 (λ/D1)y
Δ2 =1.22 (λ/D2)y
In the conventional transducer, the diameter D is D=D1 in both the X- and Z-axis directions, and hence the resolution is Δ1 in both directions. Therefore, compared with that of the conventional transducer, the resolution of the transducer of this embodiment in the X-axis direction is unchanged, but the resolution in the Z-axis direction can be improved.
As described above, the transducer of this embodiment is provided with a spherical cross-sectional shape in order to utilize the space within the inner surface of the cylindrical acoustic case as effectively as possible. The best shape for this purpose is as follows. The major axis D2 of the ellipse should satisfy the following relationship: ##EQU1## where f is the focal distance of the concave transducer, r=R-δr where R is the inner radius of the acoustic case, and δr is the clearance which enables the transducer to rotate smoothly within the acoustic case, with the proviso that ##EQU2## The formulae given above determine the common portion of the sphere of radius f and the cylinder of radius r, and a corresponds to the distance between the axis of rotation and the focal point with respect to the minor diameter D1 of the concave transducer.
Although the transducer of the embodiment described above is elliptical, the shape is not particularly limited thereto. For instance, the same results can be obtained using a rectangular transducer which is elongated along the axis of rotation. It is also obvious that a planar transducer can be used in combination with an acoustic lens instead of the concave transducer. When a planar transducer is used, the shape of the transducer is most preferably rectangular, to provide the most effective utilization of the internal space of the cylindrical acoustic case.
It is also possible to employ a multi-ring transducer consisting of a plurality of transducers split in a ring-shaped manner to provide phase differences, so as to synthesize an ultrasonic beam and form a focus. Such an embodiment is illustrated in FIG. 3. The elliptical transducer is divided in a ring-shaped manner into a plurality of elements 2-1, 2-2, 2-3, 2-4, 2-2', 2-3' and 2-4'. The elements are arranged in such a fashion that the elements corresponding to one another vertically, that is, elements 2-2 and 2-2', 2-3 and 2-3', or 2-4 and 2-4', have the same phase. Ultrasonic waves are transmitted and received by controlling the phase of each element pair by changing the focus and the depth direction (y direction). In other words, this arrangement makes it possible to obtain multi-stage focusing, and improve the resolution over a wider range than that of the embodiment of FIGS. 2A and 2B.
FIG. 4 is a graph of lateral direction parallel to the Z-axis with respect to distance y from the transducer in each of the embodiments described above, and in the conventional transducer. Δ1 denotes the resolution when the conventional round transducer is used, Δ2 that when the elliptical transducer of FIGS. 2A and 2B is used, and Δ3 that when multi-stage focusing is provided using the multi-ring elliptical transducer of FIG. 3. As can be seen clearly from this graph, the resolution can be improved near the focus by the use of an elliptical transducer. Furthermore, the transducer of FIG. 3 provides an improved resolution over the entire zone. This means that the thickness of a tomograph section is reduced.
Although the invention has been described with reference to preferred embodiments thereof applied to a side-viewing echo endoscope which is inserted through the gullet, the invention can obviously be applied to the probe for transrectal tomography.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US4248090 *||Mar 27, 1978||Feb 3, 1981||New York Institute Of Technology||Apparatus for ultrasonically imaging a body|
|US4398422 *||Mar 11, 1981||Aug 16, 1983||Siemens Aktiengesellschaft||Ultrasonic-image device|
|US4431006 *||Jan 7, 1982||Feb 14, 1984||Technicare Corporation||Passive ultrasound needle probe locator|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US4732156 *||Jun 6, 1986||Mar 22, 1988||Olympus Optical Co., Ltd.||Ultrasonic endoscope|
|US4856337 *||Jul 30, 1987||Aug 15, 1989||Westinghouse Electric Corp.||Apparatus and method for providing a combined ultrasonic and eddy current inspection of a tube|
|US4911170 *||Aug 22, 1988||Mar 27, 1990||General Electric Company||High frequency focused ultrasonic transducer for invasive tissue characterization|
|US4928699 *||May 11, 1988||May 29, 1990||Olympus Optical Co., Ltd.||Ultrasonic diagnosis device|
|US4951677 *||Mar 21, 1988||Aug 28, 1990||Prutech Research And Development Partnership Ii||Acoustic imaging catheter and the like|
|US4955235 *||Jun 23, 1989||Sep 11, 1990||Westinghouse Electric Corp.||Apparatus and method for providing a combined ultrasonic and eddy current inspection of a metallic body|
|US5020539 *||Mar 8, 1989||Jun 4, 1991||Olympus Optical Co., Ltd.||Ultrasonic endoscope apparatus|
|US5115814 *||Aug 18, 1989||May 26, 1992||Intertherapy, Inc.||Intravascular ultrasonic imaging probe and methods of using same|
|US5201731 *||Jun 26, 1991||Apr 13, 1993||Hakky Said I||Laser resectoscope with ultransonic imaging means|
|US5271402 *||Jun 2, 1992||Dec 21, 1993||Hewlett-Packard Company||Turbine drive mechanism for steering ultrasound signals|
|US5313949 *||Feb 1, 1993||May 24, 1994||Cardiovascular Imaging Systems Incorporated||Method and apparatus for intravascular two-dimensional ultrasonography|
|US5368035 *||Sep 17, 1992||Nov 29, 1994||Boston Scientific Corporation||Ultrasound imaging guidewire|
|US5372138 *||Dec 9, 1992||Dec 13, 1994||Boston Scientific Corporation||Acousting imaging catheters and the like|
|US5421338 *||Jun 3, 1994||Jun 6, 1995||Boston Scientific Corporation||Acoustic imaging catheter and the like|
|US5465724 *||May 28, 1993||Nov 14, 1995||Acuson Corporation||Compact rotationally steerable ultrasound transducer|
|US5524630 *||May 17, 1995||Jun 11, 1996||Crowley; Robert J.||Acoustic imaging catheter and the like|
|US5546948 *||Nov 28, 1994||Aug 20, 1996||Boston Scientific Corporation||Ultrasound imaging guidewire|
|US5554100 *||Mar 24, 1994||Sep 10, 1996||United States Surgical Corporation||Arthroscope with shim for angularly orienting illumination fibers|
|US5562096 *||Jun 28, 1994||Oct 8, 1996||Acuson Corporation||Ultrasonic transducer probe with axisymmetric lens|
|US5582178 *||Jun 6, 1995||Dec 10, 1996||Cardiovascular Imaging Systems, Inc.||Method and apparatus for intravascular ultrasonography|
|US5626138 *||Jun 7, 1995||May 6, 1997||Acuson Corporation||Ultrasonic transducer probe with axisymmetric lens|
|US5640961 *||Sep 25, 1995||Jun 24, 1997||Hewlett-Packard Company||Device with aspherical compensation for focusing ultrasound|
|US5651364 *||Jun 6, 1995||Jul 29, 1997||Cardiovascular Imaging Systems, Inc.||Method and apparatus for intravascular|
|US5651759 *||Jun 6, 1995||Jul 29, 1997||United States Surgical Corporation||Method of making arthroscope having a shim for angularly orienting illumination fibers|
|US5676151 *||Dec 3, 1993||Oct 14, 1997||Cardiovascular Imaging Systems, Inc.||Method and apparatus for intravascular ultrasonography|
|US5707389 *||Jun 7, 1995||Jan 13, 1998||Baxter International Inc.||Side branch occlusion catheter device having integrated endoscope for performing endoscopically visualized occlusion of the side branches of an anatomical passageway|
|US5715825 *||Jun 10, 1996||Feb 10, 1998||Boston Scientific Corporation||Acoustic imaging catheter and the like|
|US5718664 *||Jun 6, 1995||Feb 17, 1998||United States Surgical Corporation||Light guide connection port for a disposable arthroscope|
|US5770800 *||Aug 6, 1996||Jun 23, 1998||The United States Of America As Represented By The United States Department Of Energy||Flexible ultrasonic pipe inspection apparatus|
|US5865178 *||Jun 6, 1995||Feb 2, 1999||Cardiovascular Imaging System, Inc.||Method and apparatus for intravascular ultrasonography|
|US5902245 *||Aug 15, 1997||May 11, 1999||Cardiovascular Imaging Systems, Inc.||Method and apparatus for intravascular ultrasonography|
|US6152872 *||Jun 6, 1995||Nov 28, 2000||United States Surgical Coporation||Relay lens assembly for a disposable arthroscope|
|US6165127 *||Sep 26, 1997||Dec 26, 2000||Boston Scientific Corporation||Acoustic imaging catheter and the like|
|US6221015||Apr 27, 1999||Apr 24, 2001||Cardiovascular Imaging Systems, Inc.||Method and apparatus for intravascular two-dimensional ultrasonography|
|US6228039 *||Nov 3, 1999||May 8, 2001||Kenneth F. Binmoeller||Biopsy device|
|US6287261 *||Jul 21, 1999||Sep 11, 2001||Scimed Life Systems, Inc.||Focused ultrasound transducers and systems|
|US6364840||Sep 27, 2000||Apr 2, 2002||Boston Scientific Corporation||Acoustic imaging catheter and the like|
|US6390978 *||Sep 29, 2000||May 21, 2002||Karl Storz Gmbh & Co. Kg||Imaging method for determining a physical or chemical condition of tissue in human or animal bodies, and system for carrying out the method|
|US6409673||Mar 23, 2001||Jun 25, 2002||Cardiovasular Imaging Systems, Inc.||Method and apparatus for intravascular two-dimensional ultrasonography|
|US6572553||Jan 4, 2002||Jun 3, 2003||Scimed Life Systems, Inc.||Medical imaging device|
|US6572554||Jun 20, 2002||Jun 3, 2003||Scimed Life Systems, Inc.||Method and apparatus for intravascular two-dimensional ultrasonography|
|US6585655||May 31, 2002||Jul 1, 2003||Scimed Life Systems, Inc.||Medical imaging device|
|US6684094||May 12, 2000||Jan 27, 2004||Heinz Lehr||Instrument for medical purposes|
|US6764450||May 13, 2003||Jul 20, 2004||Scimed Life Systems, Inc.||Method and apparatus for intravascular two-dimensional ultrasonography|
|US7037271||May 27, 2003||May 2, 2006||Boston Scientific Corporation||Medical imaging device|
|US7131948||Oct 22, 2003||Nov 7, 2006||Scimed Life Systems, Inc.||Method and apparatus for intravascular two-dimensional ultrasonography|
|US7488289 *||Sep 28, 2001||Feb 10, 2009||Boston Scientific Scimed, Inc.||Imaging catheter and methods of use for ultrasound-guided ablation|
|US20020107447 *||Sep 28, 2001||Aug 8, 2002||Scimed Life Systems, Inc.||Imaging catheter and methods of use for ultrasound-guided ablation|
|US20030208119 *||May 27, 2003||Nov 6, 2003||Crowley Robert J.||Medical imaging device|
|US20040087859 *||Oct 22, 2003||May 6, 2004||Yock Paul G.||Method and apparatus for intravascular two-dimensional ultrasonography|
|US20040133109 *||Jan 7, 2003||Jul 8, 2004||Scimed Life Systems, Inc.||Systems and methods for acoustic thermal imaging|
|US20120108980 *||May 3, 2012||Gore Enterprise Holdings, Inc.||Catheter with shape memory alloy actuator|
|US20120197113 *||Jan 31, 2012||Aug 2, 2012||Sunnybrook Health Sciences Centre||Ultasonic probe with ultrasonic transducers addressable on common electrical channel|
|CN102266237A *||Jul 29, 2011||Dec 7, 2011||深圳市开立科技有限公司||一种超声探头及应用该超声探头的超声仪器|
|CN102266237B||Jul 29, 2011||Jan 23, 2013||深圳市开立科技有限公司||Ultrasonic probe and ultrasonic instrument applying same|
|EP0728444A2 *||Aug 17, 1990||Aug 28, 1996||Intertherapy, Inc.||Ultrasonic imaging system|
|EP1312310A2 *||Aug 17, 1990||May 21, 2003||Boston Scientific Limited||Ultrasonic imaging system|
|EP1723910A2 *||Jul 20, 2000||Nov 22, 2006||Boston Scientific Limited||Focused ultrasound transducers and systems|
|WO2000069341A1 *||May 12, 2000||Nov 23, 2000||Heinz Lehr||Instrument for medical purposes|
|WO2001005305A1 *||Jul 20, 2000||Jan 25, 2001||Boston Scientific Limited||Focused ultrasound transducers and systems|
|U.S. Classification||600/463, 600/104, 73/623, 310/335|
|International Classification||A61B8/12, A61B8/00|
|Cooperative Classification||A61B8/12, A61B8/445, A61B8/4461|
|European Classification||A61B8/44N6, A61B8/12|
|Oct 4, 1985||AS||Assignment|
Owner name: HITACHI, LTD., 6, KANDA SURUGADAI 4-CHOME, CHIYODA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:KONDO, SHINICHI;NAKAYA, CHITOSE;ISHIKAWA, SHIZUO;REEL/FRAME:004468/0226
Effective date: 19850926
|Jun 29, 1989||FPAY||Fee payment|
Year of fee payment: 4
|Jun 26, 1993||FPAY||Fee payment|
Year of fee payment: 8
|Jul 31, 1997||FPAY||Fee payment|
Year of fee payment: 12