CA1163013A - Endoscopic method and apparatus including ultrasonic b-scan imaging - Google Patents

Abstract

¦ ABSTRACT OF THE DISCLOSURE
Endoscopic method and apparatus are provided for the simul-taneous visual and ultrasonic imaging of internal body parts through use of a probe insertable into a body cavity. The probe includes a rectilinear transducer array acoustically coupled to the body through a cylindrical focusing lens having an outer face which conforms to the probe contour. The transducer array is included in a pulsed ultrasonic imaging system of the B-scan type, A tube, which includes a flexible portion adjacent the probe, connects the probe to a control housing containing man-ually operated control mechanism for bending the flexible tube portion. A control handle extends from the side of the housing for control of bending by the operator. The pulsed ultrasonic imaging system includes pulse generator and pulse receiver means connoted to individual elements of the transducer array by co-axial cables extending through the tube. Electronic beam focus-ing and scanning means for rectilinear B-scan operation are pro-vided for imaging of objects at close distances adjacent the probe. Visual display means are provided for visual display of the ultrasonic image from the B-scan receiver. An optical illuminating and viewing system is provided for optically viewing internal body parts through the probe, which system includes an objective lens and illuminating means adjacent the distal ends of the probe and transducer array. A removable eyepiece at the housing is used for direct viewing by the operator while guiding the probe into desired position in the body cavity. Means also are provided for viewing the optical image by a video camera having an output connected to a monitor adjacent the ultrasonic image display. Consequently, both the optical and ultrasonic images are simultaneously displayable and viewable by the oper-ator.

Description

O~L3 1 I ORIGIN OF THE~INVENTION

3 The invention described herein was made in the course of 4 work under a contract with the Department of Health, Education 5 and Welfare.

Endoscopes for the visual inspection of internal organs of living ~odies are well known. They include either a flexible or 11 rigid tube extending between a control hous;ng at the proximal 12 end and a tip or probe at the dieta1 end thereof~ A ~lexible 13 tube pQrtion is included adjacent the probe which is bent under 14 operatd~ control by use o~ control mechanism at the control .
housing. Optical illuminating and viewing means are provided 16 which include an objective lens at the probe and an eyepiece at 17 the control housing ~or use in viewing the cavity surface.
18 While endoscopes provide the operator with in~ormation con-19 cerning interior surface conditions, the need for ultrasonic imaging of underlying surfaces has been recognized. I~ an article 21 entitled A New Trans-d gestive;tract scanner with a gastro-~ib~r-22 scope, by K. Hisanaga and A. Hisanaga~ in the Proceedings of the 23 23rd Annual Meeting of the American Institute o~ Ultrasound in 24 Medicine/ 1978, page 108, an optic-fiber endoscope i~ sho~m fitted with a movable transducer for obtaining B-sector-scan images of 26 underlying tissues. However, as noted in .~he ar~icle, the images 27 obtained are of no diagnostic value. Probes containing linear 28 transducer arrays also are ~nown as shown in U.S. Patent 29 3,938,502 and German Patent 2,305,501. ~here, cîrcular and rec- .
tilinear transducer arrays, respect~vely arè shown. ~hese probes, 32 1~ however, 1 k optioal viewing means which permit the operator to ¦

., 1 1~i3~

l~cate the probe at desired locations within the body part. With-

2 out such knowledge of transducer location and ~rientation, any

3 ultrasonic images obtained would be of minimum diagnostic use.

4 Additionally, optical ~iewing means generally are required ~or ~ safely guiding the pr~be during insertion thereof into the body 6 organ to avoid damage and pain to the patient. These probes also 7 lack acoustical cylindrical lens focusing means ~or beam focusing.
8 ~inear array ultrasonic transducers with a cylindrical lens for 9 focusing in one plane normal to electronic beam ~ocusing in a second plane are known as shown in U~S~ Patent 3,936,7910 There~
11 however, the lens is formed with a concave outer free sur~ace 12 which would not be suitable for use in an endoscopic probe.

14 SUMMARY OF_THE_INVENTION AND_OBJECTS
It is a general object o~ this invention to pro~ide an 16 improved !` '/~ ~ .' probe insertable into a body cavity for use ir 17 rectilinear ultrasonie B-scan imaging of internal body parts~
18 It is another general object o~ this invention to provide a 19 combinati~n pulsed ultrasonic B-scan ima~ing system and endoscopi instrument which overcomes the above-m~ntioned shortcomings and 21 difficulties of the prior art devices.
22 Another object o~ this invention is the provision of an 23 ultrasonic imaging system and endoscopic instrument which include 24 a probe which is readily optically ~uided to desired locations within ~ody o~gans, and by means o~ which high-resolution, real-26 time, images of underlying tissue are obtained which are useful 27 ~or diagnostic purposes.
28 The above and ~ther objectæ and ad~antages are achieved by 29 use of an endoscopic instrument having a probe connected by a tube to a control housing. The instrument ma~ inclu~e an ~ptical 31 ;lluminating and ~iewing system including an objecti~e lens at th 32 l ¦ probe and eyepiece at the housing for optiaally viewing ~in- ¦

~ 0~3 1 ternal surfaces of body parts. At least a portion of the tube 2 adjacent the probe is flexible, and a control handle at the contr~
3 housing provides means under operator control for bending the 4 same in a desired direction to facilitate guiding the probe into the body part and to locate the same at ~ desired location there-6 within. Ultrasonic imaging o~ underlying tissue at optically-7 identified areas is provided by means o~ a pulsed ultrasonic 8 imaging system of the rectilinear B~scan type. A transducer array 9 is located within the probe adjacent the distal end thereof~ and coaxial cables connect individual transducer elements of the array 11 to pulæe generator and pulse receiver means of the B-scan system, 12 Means are proYided for transmitting and receiving ultrasonic 13 energy using groups of transducer elements in a manner to provide 14 ~or beam focusing and scanning in the longitudinal plane o~ the array. Solid focusing lens means of low-veloci-ty material is 16 attached to the face of the array, which lens means has an outer 17 face which conforms essentially to the contour of the outer 18 surface of the probe, for beam focusing in a direction normal to 1~ the longitudinal plane of the transducer array. With this arrange ment high resolution ultrasonic images are obtained oYer a range 21 of depths beneath the surface of the body part. The rèal-t;me 22 images are displayed at disp~ay means readily viewable by the 23 operator~ Where the instr~ment includes an optical viewing ~ys-~4 tem, a closed circuit TV æystem also is provided which includes.a 2~ camera responsive to optical images from the probe, and a TV
26 monitor adjacent the B-scan display means~ As a result, the 27 op-tical and ultrasonic images are simultaneously displayed for 28 simultaneous viewing by the operator.
29 The nature o~ the present invention will be more fully apparent and understood from a consideration of the following 31 description in light o~ the drawings wherein like reference 32 characters refer to the æame items in the several ~iews~
.

1~3~

1 B~IEF DESCRIPTION_OF THE DRAWINGS
2 In the drawings:
3 Fig. l is a combination ele~ational and perspectiYe ~iew of 4 an endoscopic instrument and ultrasonic imaging system which ~ em~odie~ the present invention;
6 Fig~ 2 is an elevational view of an eyepiece which may be 7 used with the present system;
8 Fig. 3 is an enlarged ~ra~mentary elevational ~iew of the 9 probe/ with parts thereof being shown broken away for clarity;
~0 Fîg. 4 is a sectional ~iew taken along lines 4-4 of Fig. 3;
11 Fig. 5 is a simplified block diagram of the system shown in 12 Fig. l, including details sf an ultrasonic imaging system o~ the 13 type which is suitable for use in the system;
14 Fig, 6 is a diagrammatic YieW showing the probe positioned within a stomach for ultrasonic examination of the adjacent 16 pancreas; and ~7 Fig. 7 i~ a ~ectional view of a composite ~ylindrical acous-18 tical focusing lens of the type which may be used in the probe o~
19 this invention.
As noted above D ultrasonic imaging of internal body parts is 21 well known. Al~o, it is known-;that not only is the ultrasonic ~2 energy attenuated in travel through organs and tissues, but that 23 the attenuation increases with frequency. That is,high ~requency 24 signals are attenuated more se~erely than low ~requency signals, o~ signal components. Consequently, where imaging from the 26 patient'~ skin o~ body parts deep within the body is desired, 27 relatively low frequency energy is employed to minimize attenua-28 tion. Resolution obtainable, however, is dependent upon the 29 frequency of the energy waves. Consequently, i~ transmission of ultrasonic energy through substantial amounts of body material is 31 required ~or ;maging the desired body part, it will be apparent 32 that use of relati~ely low f~equency energy is required, thereby limiting resolutiGn. ~y~includin~ the transducer array in ~n r- ~Q _ ~

1630i3 1 lendoscopic probe, high resolution ultrasonic images of internal 2 body parts ~ar removed from the skin may be obtained by operating ~ at high ~requencies, on the order of, say, lOMHz~ With the 4 present system, high resolution images o~, for example, the ~ pancreas are possible, intragastricall~, through the stomach and 6 duodenum walls~
Reference now is made to ~ig. 1 wherein the novel endoscopic 8 and ultrasonic imaging system is shown comprising a novel probe 10 9 connected to housing 12 through a tube 14, at least a portion of which tube adjacent the probe is flexible. The system comprises 11 an endoscope Pf substantially conventional design and, for pur-12 poses of illustration, a flexible endoscope is æhown. The probe 13 10 includes a rigi~ distal end member9 or support block, 16, of 14 generall~ cylindrical shape at the distal end. The end member is formed~ or provided, with a generally semi-cylindrical shape 16 rearwardly extending portion,or member 16A~ used for suppDrt o~
17 portions of an optical illuminat.ion and viewing system, and of a 18 transducer array, a~ described below~
19 The optical illumination and ~iewing system is shown comprising light-transmitting fiber bundles 18~ 18 which extend .
~1 axially through the long portion of the upporting block 16 and 22 terminate at the front face thereof. The bundles, which are con-23 tained in a protective sheathing, pass rear~ardly through the tube 24 14, into housing 12, and terminate at optical coupling means 19 at one wall o~ the housing 12. A fiber-optic cable 20 connects 26 the bundles to a suitable source of illumination, not shown, at 27 an endoscopic control unit 22. A light switch and intensity con-28 trol 24 i~ provided at the panel o~ the control unit 22 for illum~
29 ination control. The illustrated unit 22 also provides a source of $1ulds such as pressurized air and water, which may be connect-31 ed to the endoscope. In ~ig. 1, only a water source is ~hown 32 which is connected to the endoscope, for ~urp~ses descrîbed below.
_~ _ ~6~3 1 ~he optical viewing system includes an objective lens com- .
2 prising e~g. lens elements 28 and 30 (see also Fig. 3) conta.ined 3 in an axially extending aperture extending through the long por-4 tion of the supporting block 16. The one lens element 28 is suitakly mounted adjacent the front face of the supporting block 6 16 while the other element 30 is att~ched to t~e for~ard end of a 7 bundle 32 of light-tran mitting fibers~ From the probe 10, the 8 bundle 32 passes rear~ardly through the tube 14 and control hous-~ ing 12 to an optical connector 34 at the rear of the housing. In Fig. 1 a fiber-optic oable 36 is diagrammatically shown for con-11 nection o~ the view;ng system to a video camera! not shown, in-12 cluded in a Yideo display and control unit 38, The cam~r in con-13 trol unit 38 comprises an element of a close-circuit TV system , 14 which includes visual display means 40 for ~isual display of 1~ objects within ~iew of the objective lens. ~n-of~, brightness, 16 and contrast controls included in conventional closed circuit TV
17 systems are shown at the front panel of the video display and 18 control unit 38.
19 An eyepiece 42, shown in Fig. 29 may be coupled to the endo-scope viewing system through optical coupler 34 after ~irst dis-21 connecting optic-fiber cable 36 therefrom to allow for direct 22 viewing by the operator, instead of viewing at the screen 400 Use 23 of the eyepiece 42 often is preferred during insertion of the '24 probe into the body ca~ity~
Flexure control means of conventional design may be employed 26 to control bending of the tube 14 adjacent the probe 10. In Fig.
7 1, a de~lector ring 44 is shown in broken lines adjacent the 28 proximal end of the probe lO, which connects through three con-29 trol wires 45 to flexure control mechanism contained in housing 12. The ~lexure control mechanism includes a ~irst rotatable 31 shaft 46 extending from the housing, a second rotata~le sha~t 48 32 extending radially from the ~irst shaft 46 9 and a handle 50 at the free end of the shaft 48. Simultaneous rotation of the i3013 1 I two shafts 46 and 48 by operation of the handle 50 is possible for 2 bend;ng of t~e probe 10 in any desired direction relative to the 3 flexible distal end of tube 14.
4 As noted above, the unit 22 also provides a source of water

5 for the endoscope. Water pressure gauge 52 displays the pressure

6 of water supplied to the endoscope, and control 54 is used ~or

7 ~etting the pressure at the desired le~el. Water i~ supplied o~er

8 conduit 56 to the housing 12 and from there is fed through the

9 tube 14 and probe 10 to a nozzle head 58 pro-truding slightly from the ~ace of the probe. Water from the nozzle flows past the ends 11 of illuminating fiber bundles 18, 18 and over lens element 28 to 12 maintain the same clear of mucus, or the likec In the illustrated 13 arrangement, a guide channel 60 also is provided which extends 14 from the tip o~ the probe 10 to unit 12, opening to the exterior thereof, through which tools of various types, not shown ~ may be 16 passed. It here will be noted that with the novel probe o~ this invention the various endoscopic channels described above extend 18 through the generally semicylindrical portion 16A of the support-19 ing blQck 16, and terminate within approximately a substantia~ly semicircular area of the tip face. The other half, approximatel~, ~1 of the generally cylindrically shaped probe is occupied by a 22 rectilinear ultrasonic transducer array, identified generally by 23 re~erence numeral 70. With the illustrated side-by-side position-24 ing ef the transducer array and endoscopic ¢hannels, and by locat 25 ing the distal end o~ the transducer array adjacent the distal 26 end of the probe; a probe of minimum overall length iæ provided 27 for ease of insertion into a patient.
28 The illustrated transducer array, best seen in Figs. 3 and 4 29 o~ the drawings, i~ shown comprising a rectangular base 72 of conducting material to which piezoelectric transdueer elements 74 31 of the arra~ are aecured. Electrodes 76 and 78 are provided at 32 respective cpposite ~aces of the piezoelectric material 74~

~ 31D~

1 For purposes of illustration only, and no-t by way of limitation, 2 the aIray ~ay be constructed from say, a 3cm. by 0.5 cm. body of 3 piezoelectric ~aterial having electrodes disposed at opposite 4 faces thereof, which piezoelectric body is uniformly polarized ~ normal to said opposite, parallel, electrode-covered ~aces. The 6 piezoelectric body, with electrodes disposed thereon, is attached 7 to the base 72 by use of an electrical conducting cement for elec-8 trical connection thereto. The base 72 is made of an acoustic 9 damping material for lowering the acoustic Q-~actor of the array o that short acoustic pulses may be generated and recei~ed, a 11 requirem~nt for good range resolution. After bo~ding to the base 12 72, the piezoelectric material is diced into, ~ay 64 closely 13 spaced elements to form the illustrated rectilinear array. Wîth 14 the above-dimensions, and su;table thickness dimension, the trans-ducer elements may be made to operate at a frequency in the range 16 o~, say, 8-12 MXzo The distal end o~ the base 72 of the trans-ducer array is attached, as by bonding,.to the end member 16~ and 18 means,not shown,support the proximal end Qf the transducer array 19 within the probeO It will be seen that the longitudinal plane 80 of the transducer array extends longitudinally of the probe.
21 The illustrated transducer means is provided with focusing means 82 ~or focusing of the beam 84 in a plane normal to the 23 longitudinal plane 80. The illustrated focusing means 82 com~
24 prises a cyli~lrical lens having one ~ace attached to the face o~
the transducer array, and an outer face which conforms, essen-tial-26 ly, to the cylindrical contour o~ the outer sur~ace o~ the probe.
27 Here, the outer face is of generally, convex shape to no-t only 28 conform to the probe curvature, but also to provide ~or good con-29 tact with the internal body part. Where the probe is used intra-gastricall~, for example, the contour provides good contact with 31 the stomach and intestinal ~ucosa~ As seen in Figs. 1 and 4, . 1~

3b~
I
¦ the probe includes a generally ~e~i-cylindrical shaped tubular 2 I housing section 85A at the optieal portion there9~ Potting 3 I material B5B fills ~r~ids in the housing ~ection 85A and i8 molded 4 ¦ about the transducer array 70 t9 house the same. By way of ex-~ ¦ ample, the housing pQrtion 85B mar be formed of an electrical 6 potting resin which may be applied by use o~ a ~uitable mold, ~ a~d cured in place. ~gether, ~lement~ ~5A and 85B comprise a 8 gener~lly cylindrical-shaped hou6ing ~or the probe, through 9 which the cylindrical ~o~using len~ means 82 e~:tends. In Fig. 3,

10 potting material 85B i~ shown r~mo~ed from the b~oken away portion

11 o~ the probe to clearly illustrate other internal probe elements.

12 As is understood, the velocity of propagation of acoustic

13 waves in 80:ft body ti~sue i8 approximately the ~ame as in water.
To provide for the illustrated ~ocllsing by the cyllndri~al lens 1~ meas~s 82, the lens i6 made of a material ha~ring a velocity o~
16 propagation o~ acoustic wa~e~ which i8 substantially lesæ than-17 the ~elocity in the soft tis~ue~ and in water. One ~uch ma~eri~l X8 which may be used in the ~abrication o~ the lens include~ ~
19 "Sylgard" (Trad~ELk) 184 manufact~ by Do~ CDn~ng o*~ration. o~er low-velocity material~ which are suitable ~or use may be u~ed, 21 In the illustrated embodiment, the focusing means oomprises a 22 single lens element~ Ob~iously, a composite lens made up o~ a 23 plurality of lens elements may be used, ~uch as ~ho~n in ~ig. 7 24 and de~cribed below. A' BO, the lens surface may be ooated with 25 an antireflection material, not shown, to m;nimiz~ internal re-26 flectians of acoustic waves. Focusing o~ the beam!84 by the lens 27 82 in a plane normal to the longitudinal plane 80 o~ the trans-28 ducer array i~ illus~rated in Fig~ 4 o~ the drawing. Ob~iously, 29 the ~uter ~ur~ace c~ the lens 82, as well as the remainder of the probe lO and tube 14 surfaces which, in use, will be in con-31 tact with body æecretion~, ~UBt be f~rmed of 6table material 32 whîch i8 non-~eacti~e with sulh body secretions~ .

o~

1 ! The r0ctilinear transducer array 70 is included in a pulsed ~ ultrasonic B-scan imaging system operating in a rectilinear beam 3 scanning mode as opposed, say, tn sector scanning. Although 4 sector scan systems have the advantage that a small transducer array can provide a large field of view far from the array, the 6 field of view is small and the resolution is poor close to the 7 array. By using a rectilinear scan, all lines of the image are 8 parallel, and tissue near the transducer array is readily imaged, 9 Reference now also is made to Fig. 5 which includes a block diagram showing of a B-scan system of conventional design and 11 which may be used in the present arrangement~ As noted above~ a 12 64 element ~ransd~cer array 70 may be used, in which case 64 13 mi^rominiature coaxia] cables 86 are used to connect the trans-; 14 ducer elements to the B~scan transmitter/receiver identified generally by reference numeral 90. ~he 64 coaxial cables 86 are 16 1008ely bound within shaath 92, seen in Fig~ 1, to allow for re-17 peated bending without damage thereto. In the illustrated arrange 18 ment, the bundle of cables simply extends through the interior of 13 the control housing 12, and the individual cables thereof are 1 20 attached by connector 94 (Figo 1) to the B-scan transmitter/
21 receîver 90. To avoid unnecessary deleterious effects on signals 22 carried by the cables~ no connectors 9 or ter~inals, are included 23 at the housing 12. Obviously, the bundle of cables 92 may be 24 extended from the ~ide of the fl;xible tube 14 adjacent the housing 12 for direct ooupling thereof to the transmitter~
26 receiver 90 without passage through the housing 12, if desired.

22z79 ~

31 .
32 .

.~L~3~

1 ~ As seen in Fig. 5, the transducer elements are connected to 2 a switching matrix 96 by means of which selected groups of ad-3 jacent transducer elements are connected to delay means 98~
4 or pulse generating means 100. For purposes of illustration only, groups Df five transducer elements are employed, and each 6 delay means 98 and pulse generating means 100 comprise fi~e such 7 individual devices. A timing and control unit 102 is connected 8 to the switching matrix ~or selecting groups of transducer 9 elements to be activatedO The timing and control unit also con-trols the timing of the operation of the fi~e pulse generators 11 100 for excitation o~ the elements of the selected group in 12 phased relation for $ocusing 9f the beam 84 in the longitudinal 1~ plane of the transducer array. In Figs. 3 and 5, such focusin~

14 by proper excitation of the first five transducer elements in the array is illustrated. The energized ~roup is shifted along 16 the array for beam scanning in the direction of arrow 104.

.
~9 .22 . 13 1 ~63~

1 ~efledted ultrasonic si~nals from discontinuities within the 2 puls~-insonified body par~ are received by the sa~e grou~ o~
3 transducer elements and su~pli~d throu~h switching matriY~ 96 and 4 delay means 98 to pre-am~lifier mean3 106. The five preampliliers of prea~.pli~ier means 106 are o~ the low-noi5e, broad-~and, hi~h 6 dyn~mic range type having ~ood lir.ear gain characteristics over 7 a wide input signal strength range. The delays are selected to 8 provide focusing of the beam patter~ in the longitudinal plane 80 cf the transducer array during receiver operation. It will be seen, then, that phased array operation of the transducer arra~
11 is provided during both tra.nsmitting and recei~ing operation for 12 beam focusing. Shifting of the selected groups of active trans-13 ducer elements follows the pulse-echo ~eceiving period to provide 14 for the above-mentioned rectilinear beam scanning operation~ By shifting in increments of one transducer ele~ent, a total of 60 16 scan lines are provided. Obviously, the system may be operated 17 with groups us~n~ di~.~erent number~ of transducer elements. Also, 18 groups o~ both odd and even numbers of tr~nsducer elements may be 19 employed ~or shiftin~ in increments of one-half a ~ransducer 2n element width, as is well understood.
21 The preamplifier outputs are fed to a summing amplifier 22 108 having an output related to a weighted sum of the inputs.
23 The summing amplifier output is supplied to a time variable gain 24 amplifi~r 110 ~a~rin~ a gain charact~ristic whi^h v~ries as a function of tim~ to co~pensate for the loss of signal a~plitude 26 as it t~a~erses the tissue. In the illustrated ar~angement, the 27 gain o~ the amplifier 110 is ~aried in accordance with the output 28 from a gain function generator 112. A synchronizing signal is 29 ~upplied to the gain function ~enerator 112 from ~h~ timing and control uni.t 102 for initiatin~ operation ther~o~ a predetermined 31 time period following ~peration o~ the pulse generators 100.

. ~4 630,~ 1 1 The ~ain function gen~ra~or 112 simply may comprise a ram~ genera-¦
2 ¦tor with ~n output si~nal ~hich funetions to incre~sQ the gain o~
3 the amplifier 110 in pro~orti~n to r3nge in a m~J~er to of~set the 4 loss o~ signal caused by acoustic absorption within the subject, 5 In the present arr~ngement, an adjustable func tion genQ~ator 112 S is used having a plurality of con~rol~ 114 accessible at the front of the B~scan unit 90 (see Fig, 1) for control of the shape 8 of the generator output. The setting o~ each of the five CQntrois 9 114 determin~s the amplifier 112 gain during one-fifth of the 10 echo signal duration thereby permittin~ the opera-tor to tailor 11 the B-scan display as desired. Adjustable gain function ge~erator-12 for control o~ variable gain amplifie~s are ~ell known and require 13 no detailed description.
14 The ou~put from the time gain control amplifier 110 is 1~ supplied to a broad band co~pression amplifier 116 comprisin~, 16 f~r example, a DC coupled log amplifier. The compression ampli-17 ~ier 116 is followed by a ~ariab~.e gain amplifier 118 having 18 a galn control 120 for setting the gain thereof~
19 ~he variable gain ampli~ie~ 118 output is d~tected by an envelope det.ector 122 compr-ising, for example, a full wave recti-21 fiex followed by a low pass filter, the deteetor output signal 22 being related to t~e en~elope of the broad band hi~h ~requency 23 signal output from the amplifier 118. The en~elope detecto~
24 output is supplied to the ultrasonic image dis~lay device 1~4 comprising a cathode ray tube. Gener-ally, a compression amplifier ~6 not shown~ is included in the connection.of the detector output 27 signal to the cathode ray tube 124 for matchin~ the detected 28 signal with characteristics of the cathode r~y tube 124 ~or 29 proper display o~ the entire si~nal range. The detector output 30 is app~ ied as an input to the con~rol ~rid o~ the cathode ra;V
31 tube for intensity, Z-axis, control of the electron beam.

` 15 03.3 1 ~ Fo~ B-scan operation, cathode ray tube beam deflect;on in 2 the X, or horizontal, direction is proportional to the position 3 of the beam 84 along the scanning path. X-axis generator 126, 4 triggered by a synchronizing signal from the timing and control unit 102, provides a stepped signal output which is supplied to 6 the horizontal de~lection system o~ the cathode ray tube 124 for shifting the trace on the cathode ray tube in accordance with 8 the position of the ultrasonic beam 84.
9 Vertical, or Y-axis, deflection of the cathode ray tube beam ;s provided by a ramp generator 128 which is tr~ggered by an 11 output from the timing and control unit 102 a predetermined time 12 period ~ollowing transmitter operation. The ramp generator 128 13 output is supplied to the vertical deflection system of the 14 cathode ray tube 124 for vertical scanning of the trace. It will be apparent, then, that a rectilinear B-scan ultrasonic image of 16 the body part lying within the longitudinal plane 80 of the 17 transducer array 70 contained in the probe 10 is provided at the 18 $ace of the cathode ray tube 124. As seen in Fi~. 1, thP ultra-~9 sonic image displa~ means 124 is located adja~ent the TV monitor, or display means, 40. The simultaneous displa~s of the optical 21 and ultrasonic images are readily ~iewable by the operator to aid 2~ the operator in properly positio~ing the probe wi~hin the body 23 cav;ty for obtaining the desired ultrascnic images. Obviously, 24 recording means, not shown, may be included for recording of the 2~ r~al-time ultrasonic images provided by the B-scan system to 26 preserve the same for subsequent examination. Similarly, a re-27 cording of the optical images may be made, if desired, from~
28 say, the video camera si~nal outputs. Also, i~ desired, the sg B-scan receiver output may be supplied to a scan converter, not shown, for conv~rsion of the ultrasonic imag~ signals to signals 31 ha~ing a conventional television ~ormat, in which case the scan I il63~113 1 converter output may be supplied to a conventional television ¦ monitor, not shown, for,display. In this case, a recording of 3 the scan converter output may be made and used with conventional 4 TV play-back and monitor means for subsequent display of the ultrasonic images.
Although the operation o~ the endoscopic system o~ this 7 invention is believed to be apparent ~rom the above description, 8 a brief description thereo~ with reference also to Fig. 6 now will be gi~en. For purposes o~ illustration, and not by way of limitation, the present endoscopic apparatus is shown, in Fig. 6, 11 employed in the gastrointestinal system of a patientO The de-12 tection of malignancy outside the tubular ~astrointestinal tract ; 13 ~s difficult, and the diagnosis of cancer involving the pancreas 14 and pancreatic bed, peritonsal cavity, and mesentery is particu-larly di~icult. However, the proximit~ of the pancreas to the 16 stomach and duodenum make it and its surrounding structures ideal 17 ~or high-resolution ultrasonic visualization with the ultrasonic 18 probe of the present invention.
19 In Fig. 6 the endoscopic ultrasonic probe lO is shown in-2~ 8@rted into the patient ~ s stomach 1300 Conventionally~ op-tical 21 guidance is relied upon to guide the probe through the esophagus 22 and into desired placement within the gastrointestinal tract.
23 Many endoscopists prefer using the eyepiece 42 ~Fig. 2) when 24 guiding the probe into desired position, in whic~ case the light .
transmitting fiber cable 36 ~Fig. l) is removed and the eyepiece ~6 42 is attached to the endoscope by use o~ the co~nector assembly 27 34. With the eyepisce 42 in place, the endoscopic ultrasonic 28 probe lO is guidad into desired position for ultrasonic imaging ~9 o~ underlying soft tissue. In Fig. 6, the probe lO is shown advanced tc the greater cur~ature of the stomach 130 adjacent the 31 pancreas 132. Through manipulation of the probe~ ~irm contact 1~63013 1 of the cylindrical lens 82 of the transducer array with the mu-2 cosa is effected enabling ultrasonic scanning to proceed. At 3 this time, the eyepiece 42 may be removed ~rom the endoscope 4 and replaced b~ optical fiber cable 36 ~or connection of the optical system to the closed circuit television for display of 6 the optical image at the screen 40 of the ~V monitor. Both the 7 optical image and ultrasonic image are simultaneously displayed, 8 and viewable, by the operator. In Fig. 6 the ultrasonic imaging 9 plane 80 is identified, together with the optical viewing angle 134. By proper manipulation of the probe lOt ultrasonic scanning 11 of the pancreas may be provided from the tail area thereof to 12 the pancreatic head through the stomach wall. By maneuvering the 13 p~obe into the duodenum 136, addltional ultrasonic imaging of the 14 head of the pancreas 132 from different locations is possible.
High resolution ultrasonic images which extend from a position 16 close to the surface of the probe to a depth of approximately 17 4 cm. are possible. With a transducer array 70 having a:length lB of 3 cm,, ~or example, a 3 cm. wide X 4 cm. deep ~ield of view is 19 possible. Also, by operating at, say lOMHz, good lateral resolu-tion o~ approximately 0.5 mm., average, and good ran~e resolu-~1 tion of approximately 0.5 mm., are possible.
22 As noted above, composite ~ocusing lens means may be used 23 in place of lens means 82 shown in Figs, 1~ 3 and 4 and described 24 above~ Reference now iæ made to Fig~ 7 wherein a composite cylindrical lens 140 for ùse herein is shown~ which includes 26 first and ~econd lens elements 142 and 144. The first lens 27 element 142 has a planar face bonded to the face of the trans-~8 ducer array 70, and an opposite concave face~ The ~econd lens 29 element 144 has opposite convex surfaces, one o~ which is bonded to the concave ~ace o~ the first element 142. The outer convex 31 face o~ the outer lens element con~orms generally to a curved _ _ _ . . ~ . .

~ 3iC~3 po~tion of the contour of the outer surface of the probe~ not 2 shown in Fig. 70 The first lens element 142 is ~o~med of a 3 material having a-velocity of propagation of acoustic waves 4 which i~ substantially greater than the velocity Df propagation 5 of acoustic waves in soft body tissue, and in water. The ~econd 6 lens element 144 is formed of a material having a velocity of 7 propagatlon of acoustic waves which is no greater, but pre~erably 8 is substantially less, than the ~elocity of propagation in soft 9 body tissue. It will be apparent that by using a low ~elocity material ~or the outer lens 144, focusing action at both the 11 soft tissue-lens 144 interface, ænd lens 144-lens 142 interface, 12 is provided. Also D as with the len~ means 82V good contaot be-13 tween the outer convex face of lens élement 144 and 60~t body 14 tissue is possible because of the convex lens face.
The invention having been described in detail in accord-~
16 ance with requirements o~ the Patent Statutes, various other 17 changes and modifications will suggest themselves to those skill-18 ed in the art. For example, instead of the illustrated ~orward 19 looking optical system, the probe may be proYided with a side, 2~ or with partially for~ard and side looking optical viewing means.
21 Also, for use in different body cavities, a rigid tube endoscope~
22 rather than the ~lexible tube 14 endoscopic instrument may be 23 used, in which case, simple optical telescope and illumination 24 means, without the need ~or the light transmitting ~iber cables may be employed in the construction. Als~, as noted above, 26 although electronic rectilinear B-scan imaging is required for 27 satisfactory ultrasonic real-time imaging, numerous apparatii for 28 implementing the ~ame are kn~wn, and the apparatus shown in ~9 Fig. 5 ~imply i5 ~or purposes of illus~ration only, and not by way o~ lîmitation. Use of the illustrated sequenced5 dyn~mically 32 . 19 .

1163U~L3 ~ focused, rectilinear array requires a s~gnificant amount o~
2 preprocessing electronics. To maximize dynamic range~ the~e 3 circuits should be located as close to the transducer array as 4 possible. The present invention contemplates locating such circuitry in the probe lO itself, using integrated circuit chips.
6 Present, commercially available,chips are not well suited to 7 such use, and custom fabricated electronicq which are suitable 8 would be very expensive. Nevertheless, the use of suitable 9 preprocessing microelectronic circuitry within the probe i8 ~0 entirely feasible, and is contemplated by the present invention. .
11 It is intended that the above and other such changes and 12 modifications shall fall within the spirit and scope of the 13 invention as def~ned in the appended claimsO

~3 . `

Claims (12)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR PRIVILEGE
IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An endoscopic probe for use in a system for visually examining and for ultrasonically imaging internal body parts, said probe comprising, a substantially cylindrical shaped elongated housing having forward and rear ends at the respective distal and proxi-mal ends thereof and a longitudinal axis, said housing including a distal end member at the forward end thereof, means forming a plurality of longitudinally extending apertures through said distal end member at a first substantially semicylindrical portion of said housing for use in optically imaging internal body parts, and a longitudinally extending rectilinear ultrasonic transducer array including a plurality of adjacent transducer elements within the probe housing, said transducer array being positioned rearwardly the forward end of said distal end member at a second substantially semicylindrical portion of said housing substantially opposite said first semicylindrical portion for use in ultrasonically imaging internal body parts.

2. An endoscopic probe as defined in claim 1 wherein the distal end of said distal end member is of substantially cylindrical shape.

3. An endoscopic probe as defined in claim 2 including a rearwardly extending substantially semicylindrical shaped member integrally formed with said distalend member for support of said transducer array.

4. An endoscopic probe as defined in claim 1 wherein said unitary housing has a substantially cylindrical-shaped outer surface, said probe including cylindrical focusing lens means having one face attached to the transducer elements of the transducer array and having an outer face forming a portion of the outer surface of said probe housing.

5. An endoscopic probe as defined in claim 4 wherein said cylindrical focusing lens means is formed of solid material having a velocity of propagation of acoustic waves which is substantially less than the velocity of propagation of acoustic waves in soft body tissue.

6. An endoscopic probe for insertion into a body cavity for use in a system for visually examining and ultrasonic imaging internal body parts comprising:
a housing having forward and rear ends at the respec-tive distal and proximal ends thereof, said housing having a substantially cylindrical-shaped outer surface with a longitudinal axis, means at the rear end of the housing for attachment thereof to an elongated tube, a rectilinear transducer array inside said housing extending substantially parallel to the longitudinal probe housing axis and having forward and rear ends adjacent the re-spective forward and rear ends of the housing, said array com-prising a plurality of transducer elements for directing pulses of ultrasonic energy along a beam into body parts, cylindrical focusing lens means having one face attached to said transducer face for beam focusing in a plane normal to the longitudinal plane of the transducer array, the outer face of said cylindrical focusing lens means being convex and forming a portion of the outer surface of said housing, and an optical system for use in visually examining internal body parts including objective lens means inside said housing adjacent the forward end of the transducer array at the forward end of the housing.

7. A probe as defined in claim 6 wherein said cylindri-cal focusing lens means is formed of a solid material having a velocity of propagation of acoustic waves which is substantially less than the velocity of propagation of acoustic waves in soft tissue.

8. An endoscopic system for visual and ultrasonic imaging of body parts comprising, an endoscope comprising an elongated tube and probe at the distal end of the tube insertable into a body organ, a television system comprising a camera located at a distance from said endoscope, means for optically coupling said television camera to said endoscope and thence through said elongated tube to said probe for optically viewing the organ from the probe, and a monitor electrically coupled to said camera for visually displaying an image of the viewed organ, and a pulsed rectilinear B-scan ultrasonic imaging system comprising, a rectilinear ultrasonic transducer array inside said probe, pulse transmitter receiver means connected to said transducer array for pulse energization of the transducer array for generating ultrasonic wave pulses and for processing signals received from the transducer array, and visual display means for B-scan display of the pro-cessed signals for the simultaneous display of ultrasonic and video images at said visual display means and monitor, respec-tively.

9. An endoscopic system as defined in claim 8 wherein said visual display means and monitor are adjacent each other for simultaneous viewing.

10. In a combination visual and ultrasonic real-time B-scan imaging method which includes the use of an endoscopic system which includes an endoscopic probe insertable into a body organ, which probe includes a rectilinear ultrasonic trans-ducer array and objective lens of optical telescope means, the steps comprising:
generating by use of said transducer array, recurrent ultrasonic wave pulses to insonify a section of a body part adjacent the body organ into which said probe is inserted, receiving reflected wave pulses and converting the same to corresponding electrical signals by use of said trans-ducer array, displaying a real-time rectilinear B-scan image of an insonified section of the body part, viewing, through said optical telescope means by use of video camera means, optical images of a portion of the interior of the body organ into which the probe is inserted, displaying the output from said video camera means at visual display means, and locating said B-scan image display means and visual display means adjacent each other for substantially simultaneous viewing by the operator of the endoscopic system.

11. In a combination visual and ultrasonic real-time B-scan imaging method as defined in claim 10 which includes locating the video camera a distance from said endoscopic probe and viewing said optical images through optical fiber means included in said optical telescope means and connecting said optical telescope means to the video camera.

12. A probe for use in an endoscopic system for ultra-sonically imaging and optically viewing internal body parts, said probe comprising:
unitary housing means having a substantially cylindrical-shaped outer surface with a longitudinally extending axis, a forward distal end, and a rearward proximal end connected to an elongated tube for use in inserting the housing means into a body organ, ultrasonic transducer means fixedly mounted inside said housing means at one side of the longitudinal axis thereof for use in generating ultrasonic waves and receiving reflected ultrasonic waves for ultrasonic image examination of internal body parts with said transducer inside said housing means, and optical means inside said housing means to a side of the longitudinal axis diametrically opposite said ultrasonic transducer means for use in illuminating and visually examining internal body parts, said optical means including a viewing window adjacent the forward distal end of said housing means forwardly of said ultrasonic transducer means.