EP1196089A2

EP1196089A2 - Apparatus and methods for medical diagnostic and for medical guided interventions and therapy

Info

Publication number: EP1196089A2
Application number: EP00914346A
Authority: EP
Inventors: Victor Segalescu; Yoav Paltieli
Original assignee: Ultraguide Ltd
Current assignee: Ultraguide Ltd
Priority date: 1999-03-31
Filing date: 2000-03-30
Publication date: 2002-04-17
Also published as: AU3573900A; WO2000057767A3; JP2003527880A; WO2000057767A2

Abstract

The apparatus, and methods introduced in the present invention are enabled to measure the relative position between different medical imaging devices (18)(152), betweeen the image planes, and/or image volumes produced by them by means of using a position measuring system based with attachable position measuring components (28)(30). This facilitates image fusing when images of the same plane/volume are available from different medical imaging systems. Additionally/alternately it enables to position a second medical imaging device over a desire area/volume according to information received from the image produced by the first medical imaging device.

Description

APPARATUS AND METHODS FOR MEDICAL DIAGNOSTIC AND FOR

MEDICAL GUIDED INTERVENTIONS AND THERAPY

CROSS REFERENCES TO RELATED APPLICATIONS

This PCT Patent Application is related to and claims priority from commonly

owned U.S. Provisional Patent Application No. 60/ 127,267 filed on March 31 , 1999

entitled:

APPARATUS AND METHODS FOR MEDICAL DIAGNOSTIC AND FOR

MEDICAL GUIDED INTERVENTIONS USING MULTIPLE IMAGING

SYSTEMS.

This Provisional Patent Application is incorporated by reference in its entirety

herein.

FIELD OF THE INVENTION

The present invention relates to apparatus for performing medical diagnosis,

and to apparatus for planing and performing medical interventions or therapy

procedures. Particularly, the present invention is related to apparatus for performing

guided medical interventions or medical therapy procedures that employ multiple

medical imaging systems for viewing the target in a body or body volume during the

intervention.

BACKGROUND OF THE INVENTION

During recent years fusing images from different medical imaging systems in

order to receive a better diagnostic has become widely used. Additionally, the

cooperative operation of several medical imaging devices can reduce the amount of radiation at which patient is subjected during diagnosis, therapy planning and medical procedures and interventions. While these facts have been already recognized, the

realization of such cooperative operation has been until now generally restricted to

medical imaging devices having a common mechanical platform.

Additionally, various directional therapy procedures (based on directing an

energy field towards a target in a body) are assisted by images of said body and target produced by medical imaging devices like CT, MR, ultrasound, etc.

SUMMARY OF THE INVENTION

During diagnosis during medical interventions or during therapy procedures, it

may be necessary or helpful to operate several medical imaging devices simultaneously or sequentially. This is done upon necessity and compatibility between the devices, in

order to indicate the condition of the patient and/or designate a target in a body or

body volume. For example the same target can be viewed by ultrasound and by some

other medical imaging device such as a CT, X-Ray, or endoscope imaging device.

The present invention comprises methods and apparatus for combining two or

more medical imaging systems (such as an ultrasound and a CT) in medical diagnosis

and procedures without mechanical constrains between the position of the two or more

medical imaging devices. The present invention is particularly useful in guided medical interventions into a body or body volume, where a target is sought to be evaluated. The apparatus disclosed in the present invention comprises at least two medical

imaging devices for example, an ultrasound, CT, X-Ray, endoscope, at least a display,

a data processor, and a position measuring system comprising position controlling and

position measuring components. At least part of the position measuring components

are located at determined positions with respect to the medical imaging devices and

calibrated with respect to the image\beam produced by the imaging devices. The position measuring system enables the establishment of the relative positions between

the at least two medical imaging devices. The data processor receiving the information

from the position measuring system, is also able to establish the position between the image planes/volumes produced by the at least two imaging devices and using it for at

least one of the following; a) maneuvering one or more imaging devices in order to scan the interest

target within the body according to information available from another medical

imaging device, or

b) facilitating image fusing when images of same plane/volume are available from two or more imaging devices.

The term position measuring components defines any of the following group:

transmitter or receiver or reflector or transceiver or optical indicia or inertial sensor or

any combination of the above, suitable to be part of a position measuring system. This

position measuring system may be magnetic, acoustic, optic, inertial or a combination of the above.

The resultant apparatus enables free-hand manipulation of all or part of the

medical imaging devices used in the same intervention or diagnosis.

The apparatus and methods described in the present invention facilitate the combination of a number of medical imaging devices to perform various medical

diagnostic, therapy procedures and intervention tasks more safely and efficiently than those of the conventional systems. Particularly, the apparatus of the present invention

enabling viewing of a target with one medical imaging device and guiding a medical

intervention tool or a medical therapeutic tool, or alternatively inserting a medical device when using a second medical imaging device. This can be particularly useful

when employing image guided medical intervention systems such as those introduced

by the assignees in commonly assigned U.S. Patent No. 5,647,373, entitled:

Articulated Needle Guide For Ultrasound Imaging And Method Of Using Same, and patent applications, PCT/IL96/00050 (WO 97/03609), entitled: Free-Hand Aiming Of A Needle Guide; PCT/IL98/00578, entitled: System And Method For Guiding The

Movements Of A Device To A Target Particularly For Medical Applications; and

PCT/IL98/00631, entitled: Calibration Method And Apparatus For Calibrating

Position Sensors On Scanning Transducers, all four of these documents incorporated

by reference in their entirety herein.

The apparatus described in the present invention may also reduce the amount of

radiation applied on a patient during diagnostic and medical interventions and/or

therapy, for example when using ultrasound and CT in the same intervention.

The present invention also comprises methods and apparatus for guiding a directional

therapy procedure without mechanical constrains between the position of the medical

imaging device or devices used to assist the therapy procedure and the directional

therapeutic device. The apparatus therefore, enables free-hand manipulation of part or

all of the medical imaging devices used to assist the therapy procedure and/or of the

therapeutic head. The term directional therapy procedure will define any procedure

during which an energy field is directed towards a target or area in the body of the

patient. This energy field can be ultrasonic or Shockwaves (lithotripsy) , or

electromagnetic (radiotherapy, laser, etc) or particle beam (proton beam for example).

The data processor receives the information from the position measuring system and

uses it for directing the therapy device head\beam towards a desired target in the body.

The method and apparatus are beneficial in that they have add-on capabilities;

can define dynamic architectures, and enable free-hand maneuvering of all or part of

the devices employed therein. BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described by way of the accompanying

drawings, wherein like reference numerals and/or characters indicate corresponding or

like components. In the drawings:

FIG. la pictorially illustrates one form of a system constructed according in

accordance with the present invention for cooperative operation of an ultrasound and a

computerized topography (CT) apparatus;

FIG. lb pictorially illustrates the relative position between the scanning beams

of the CT and ultrasound in FIG. la;

FIG. 2a is a vector diagram which pictorially illustrates the vectors used in

calculating the relative position between the scanning beams of the ultrasound and the

CT in FIG la;

FIG. 2b is a block diagram illustrating the steps involved in calculating the

relative position between the scanning beams of the ultrasound and the CT in FIG la. ;

FIG. 3 pictorially illustrates display functions enabled according to the present

invention in relation to FIG. la;

FIG. 4 is a simplified flowchart illustrating the steps of using in a cooperative

mode two medical scanning devices in accordance to the present invention;

FIG. 5a pictorially illustrates one possible position measuring system to be used

in accordance to the present invention;

FIG. 5b pictorially illustrates another possible position measuring system to be

used in accordance to the present invention; and FIG. 6 pictorially illustrates one form of a system constructed according in

X-Ray:

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. la illustrates a first embodiment, exemplary of the present invention. The

first embodiment utilizes at least two compatible medical imaging devices that produce

medical images. Here, the medical imaging devices include an ultrasound apparatus 2,

and a computerized tomography (CT) apparatus 4, employed in a cooperative

operation. Alternately, the medical imaging devices could be the same or different

devices, or combinations thereof, provided they operate cooperatively with respect to

each other and are compatible. For example, these devices may be devices that

produce images by ultrasound, computerized tomography (CT), X-ray, endoscopy etc.

In the set-up illustrated in Fig. 1, for example, images produced by CT 4 of a

body 6 (or body volume) of a target 8 in the body 6 (body volume) may be utilized to position ultrasound transducer 18 at known position with respect with respect to target

8, even if target 8 cannot be imaged as accurately by ultrasound. This is particularly

useful in CT assisted medical interventions enabling to use ultrasound images for

real-time monitoring of the invasive tool while using the CT images for primary

location of the target. Additionally, images produced by the two medical imaging

devices may be combined in real-time or off-line to produce the detail required in the

area of the image required. This may also be used for monitoring anatomic changes

due to breathing or internal movements between the CT images and the situation of the

body 6 at the time of the procedure. The system can be fitted to existing and deployed

medical imaging devices without major modifications or adaptations.

Ultrasound 2 and/or CT 4 are connected to a display 10 via an image processor

12 (optional) contained in data processor 14, for displaying on display 10 at least the images produced by ultrasound 2 and CT 4. Ultrasound 2 and/or CT 4 can also be

connected directly to display 10 via the necessary connections and hardware. Image

processor 12 can be part of the data processor 14 or can be connected to it.

Ultrasound 2 comprises a main unit 17 connected to a scanning head 18 further

referred to as the ultrasound transducer as is known in the art. CT 4 comprises a main

unit (CT computer) 20 connected to a scanning head 22, further referred as a CT

scanning head. CT scanning head 22 includes X-ray emitter and detector(s) (not

shown) as is known in the art. The term scanning head will be used to define the

detector and/or emitter component of the medical imaging or scanning device, such as

the transducer of an ultrasound, or the X-ray emitter and detector(s) of a CT or an

X-ray or the CCD of an optical endoscope.

A position measuring system comprising at least a position sensing controller

26 and position measuring components (PMCS) 28, 30, 32 and 34 is used to measure

the relative position between ultrasound transducer 18 and the CT scanning head 22.

The term position measuring components will define any of the following group:

any combination of the above, suitable to be part of a magnetic (for example, in

accordance with the systems detailed in U.S. Patents Nos. 4,314,251, 4,054,881) or

acoustic (for example, in accordance with the system detailed in U.S. Patent No.

4,124,838) or optic (for example, in accordance with the system detailed in U.S.

Patent No. 4,649,504) or inertial (for example, IS900 manufactured by InterSense

Inc.) position measuring system or any combination of the above, all of the above listed U.S. Patents incorporated by reference herein. Also, position levers in accordance with U.S. Patent No. 5, 647, 373 and PCTs PCT/IL96/ 00050, PCT/IL98/ 00578, PCT/IL98/ 00578 and PCT/IL98/ 00631, listed above, are also

suitable. Position sensing controller 26 can be part of the data processor 14.

In order to perform the task of measuring the relative position between

ultrasound transducer 18 and CT scanning head 22, position measuring component 28

is attached at a known and fixed position with respect to the ultrasound transducer 18.

The attachment can be either directly to the transducer 18 or by means of an extension

27. Position measuring component 28 is calibrated to ultrasound transducer 18 such

that the ultrasound beam 36 is at a known and fixed position with respect to position

measuring component 28. Such calibration can be achieved by operating according to PCT application PCT/IL98/00631.

Position measuring component 30 is attached at a known and fixed position

from CT scanning head (gantry) 22. The attachment can be either directly to the CT

scanning head (gantry) 22 or by means of an extension 29. The term position defines

location and/or orientation.

Position sensing controller 26 measures the relative position between position

measuring component 28 and position measuring component 30, enabling to calculate

the relative position between ultrasound transducer 18 and CT scanning head 22.

Position measuring component 30 is calibrated to scanning head 22 such that the CT

scanning beam 34 is at a known and fixed position with respect to position measuring component 30. Such calibration can be achieved by operating according to the

co-assigned PCT application PCT/IL98/00631. Reference is now made to FIG. lb that shows a detailed view of ultrasound

transducer 18, CT scanning head 22 and position measuring components 28 and 30.

Items referred to in previous figures are numbered similarly and will not be further described.

Alternately /additionally position measuring component 32 may be attached to

CT bed 15. The attachment can be either directly to the CT bed 15 or by means of an

extension 31. In this case position measuring component 34 is attached at a fixed

position with respect to a reference position of the CT scanning head 22 (for example

the default perpendicular position), and movements of the gantry 22 are compensated

according to information available from the CT computer 20.

An additional position measuring component 34 may be attached at a fixed

position from CT scanning head attached from the ceiling of the CT room by arm 33.

In this case position measuring component 34 is attached at a fixed position with

respect to a reference position of the CT (for example the default position), and

movements of the gantry 22 are compensated according to information available from

the CT 20.

It is not necessary to use position measuring components 30, 32 34 together. Rather, it is sufficient to use at least one of them. In order to operate the apparatus

properly it is sufficient to implement only one of the above position measuring

components 30, 32 and 34 in combination with position measuring component 28.

Position measuring components 32 and 34, if used, are calibrated to CT scanning head

22 similar to the calibration of position measuring component 30, if used. Since position measuring component 28 is calibrated to transducer 18 and at

least one of the position measuring components 30, 32 and 34 is calibrated to CT

scanning head 22 it is possible to calculate the relative position between ultrasound

scanning beam 36 and CT scanning beam 38. This is calculated based on measuring

the relative position between position measuring components 28 and at least one of the

following: one of position measuring components30, 32 and 34, and based on the

calibration values defined above. The vector diagram of FIG. 2a and flowchart of FIG.

2b illustrate one possible algorithm to be used for calculating the relative position

between the beams of the two medical imaging devices.

Reference to flowchart of FIG. 2b, block 40 shows the result of the calibrating

position measuring component 28 to ultrasound transducer 18. Block 42 shows the

result of the calibrating position measuring component 28 to ultrasound transducer 18.

Blocks 40 and 42 are generally performed off-line. Block 44 shows the measurement

of the relative position of position sensor 28 with respect to position sensor 30. Block

46 shows one possible set of equations (Equations 1 and 2 described below) for

calculating the relative position between ultrasound scanning beam 32 and CT scanning

beam 34. These equations are:

* [M]y&g * ( [ ]_u-_s ^Mό²⁸)^{τ (}Eq- D

~? US .J3 _ r_M-, P_M_C_28 * r_M1 P_M_^C_„28 , T * ~1 P_M_C_30 ^u CT_S_B ^— L^1V1J US_S_B V L^1V1J P_M_C_30 ) ^u CT S_B ^

20 (Eq. 2) r λ_/fl ^P-^M-^C-²⁸ * H P_ _C_28 ~ P M_C_28 ^•,

1^1V11 US_S_B I ^U P_M_C_30 ^{" U} US_S_B .

The indexes and parameters in the above equations are according to vector

diagram of FIG. 2a and flowchart of FIG. 2b. It is therefore possible to calculate the relative position of transducer 18 and ultrasound beam\image 36 with respect to a CT

image or CT set of images.

Necessary correction due to moving the CT stretcher 16 outside the gantry can

be performed according to information available from the CT system (the displacement

of stretcher 16 can be measured with an accuracy of less than 1

0.25mm to 0.5 mm). The movement of the bed stretcher 16 can be at a predetermined

value bringing the desired target 6 or CT slice of interest at the same position from CT

scanning head (gantry) 22. Alternately, the CT stretcher 16 can be moved at any

desired position.

Necessary correction due to tilt of the scanning head of the CT 22 may be

performed according to information available from the CT system 4.

Necessary correction due to swivel of bed stretcher 16 can be performed

according to information available from the CT system.

Necessary correction due to using oblique or perpendicular CT images can be

performed according to information available from the CT system.

All the above mentioned correction values can be manually inputted to the data

processor 14 or transferred through communication links from CT main unit 20 or data

processor 14 can identify them automatically for example according to information

generally available in the CT image (video or DICOM form).

Similar or alternate algorithms can be implemented in connection to position

measuring components 32 and 34.

Referring to FIG. 3, the relative position of ultrasound image (scanning beam

34) with respect to a set of CT images is indicated to the operator on the apparatus display 10. The indications are in 2-D and/or 3-D fashion for example in the form of

boxes 60, 62, 64, 66. and 68.

The amount of deviation of ultrasound scanning beam 36 from a reference CT

scanning image 38 can be displayed to the operator, for example in the from of angles and distances, as in box 60, and in the form of side-view illustration box 62, and

top-view illustration, box 64. This enables the operator to first scan body 6 by CT,

identify at least one target 8 in body 6, and then position ultrasound transducer 18 such

as to view a desired CT slice\image.

Additionally, target 8 can be marked in a CT image and it is possible to

maneuver ultrasound transducer 18 such as to view the target 8. The indications can be

in the form of box 66 comprising arrows indicating how to maneuver transducer 18

and numbers indicating the distance of target 8 from ultrasound scanning beam 36. It is

then possible, for example, to guide an invasive tool towards target 8 based on CT images in combination with real-time imaging of the invasive tool by ultrasound. .

Boxes 68 and 70 provide information regarding the position transducer beam 36

with respect to a volume of CT images. Box 68 shows the CT slice (reconstruction)

aligned with the current position of transducer 18. Box 70 illustrates the relative

position of transducer 18 with respect to the scanned volume in a sagital view.

While Fig. 3 illustrated specific display modalities for enabling the user to

cooperatively use ultrasound 2 and CT 4 information additional or alternate displays

may be used. In applications requiring very high accuracy it may be necessary to constrain

body 6 in order to avoid small movements between scanning body 6 by ultrasound 2

and scanning body 6 by CT 4. In most applications this requirement is not necessary.

Reference is now made to FIG. 4 which is a flow-chart illustration of the steps

required in order to operate ultrasound 2 and CT 4 in operative cooperation as

illustrated in Fig. l and in accordance to the present invention. At step 90, it is

measured the relative position between position measuring components (PMC) 28 and

30 (FIG. 4). It is possible to use position measuring components 32 or 34 or both

instead or in addition to position measuring component 30 (as explained above). At

step 92 it is calculated the relative position between ultrasound scanning

plane/volume/image 36 and CT scanning plane/volume/image 38. The calculation at step 92 is based on the calibration of position measuring component 28 and 30 (32, 34)

with respect to ultrasound transducer 18 and CT scanner 22 (step 94). The calculation

in step 94 may also be used in other medical procedures (step 96) that is optional, but

preferred, for example in image guided interventions, such as described in commonly

assigned U.S. Patent No. 5,647,373. The calculation in step 92 may also be used in order to instruct the maneuvering ultrasound transducer 18 in a required position.

Once the relative position between the scanning planes/volume is calculated the images

from CT system 4 and ultrasound system 2 may be correlated and or fused in optional,

but highly preferred step 98. This can be performed according to conventional image processing algorithms and techniques. By correlating or fusing these images (from the

ultrasound and CT scanning beams, respectively), the displayed ultrasound image may

be enhanced. The superimposed image/information resulting of step 98 may be optionally used to improve calculation at step 92 in an iterative mode. The

superimposed image/information resulting of step 98 may also be used in other medical

procedures (step 96) or in order to instruct maneuvering of ultrasound transducer 18

(step 120).

The imaging options 100 are non-exhaustively, listed as follows. The image from CT system 4 and ultrasound system 2 may be displayed individually (steps 102

and 104), the relative position between CT and ultrasound scanning beams may be

displayed (step 106, illustrated in Fig. 3) and the result of image fusing, at step 98 may

also be displayed (step 108). Target and image correlation information can also be available to the operator indicating for example internal anatomic movements as

explained herein below.

In addition to and interacting with display functions 100, there are various

ancillary functions such as optionally marking a target 8 (step 112) on the image

produced by one of the imaging devices as appearing on display 10. Then the position of target 8 may be calculated within the scanning beam of the medical imaging device,

(step 114). Additionally /alternately a reference plane/volume may be marked or

signaled according to the image produced by one of the imaging device (step 116). The

position of the reference plane/volume may then be calculated (step 118). The data in steps 114 and/or 118 may be optionally used in order to instruct the positioning of CT

scanning head 22 and ultrasound transducer 18 with respect to each other (step 120).

A specific implementation to be used in connection to the present invention

regards the use of image correlation in applications where internal organs may

significantly move between the time the CT scan was performed and the time of performing a procedure. Body volume 6 is scanned by the CT system 4 producing high

resolution image/ information. The operator defines at least one target on CT image as

displayed on display 10. The same target is then scanned with ultrasound transducer

18. The position of the ultrasound scanning beam\image 36 is determined (as detailed

above) with respect to position of the CT scanning beam 38. Additionally, by

comparing the relative position of target 8 in the ultrasound image with the position

calculated from the CT image, it is possible to monitor and compensate for internal

movements or for respiratory changes in body 8 between taking the CT scan and the

time of performing an intervention. For this implementation it is preferred (but not

necessary) to mark more than one target/points in the CT image and then locate them

by ultrasound. This enables to calculate internal anatomic displacements inside body 8,

between the images produced by the CT and the situation during the time of an

intervention. The operation defined above can also be performed automatically

provided enough distinctive targets\points\clusters may be found in the CT and

ultrasound images.

Reference is now made to FIG. 5a that illustrates a magnetic position

measuring system to be used in accordance with an exemplary embodiment of the

present invention. Similar items in previous figures have similar numbers and will not

be further described.

In this exemplary embodiment position measuring component 28 is a receiver

28' being attached to ultrasound transducer 18 and position measuring component 30 is

a transmitter 30' being attached to CT scanning head 22 by an arm 80' . Transmitter

30' is transmitting AC or DC magnetic/electromagnetic signals to receiver 28' . The output of receiver 28' is transmitted by wire or wireless connections to position

sensing controller 26 enabling to calculate the relative position of receiver 28' with

respect to transmitter 30' . Alternately, position measuring component 28 could be a

transmitter and position measuring component 30 could be a receiver.

Reference is now made to FIG. 5b wherein an optical position measuring

system is employed in accordance with another exemplary embodiment of the present

invention. Similar items in previous figures have similar numbers and will not be

further described. A stereo vision charge coupled device (CCD) camera 84' is

positioned on an arm 86' at a first reference location. Position measuring component

28 includes a cluster of LED's 28" being attached to ultrasound transducer 18 by an

arm 88' and position measuring component 30 includes a cluster of LED's 30" being

attached to CT scanning head 22 by an arm 80" . The relative position of cluster of LED's 28" is measured with respect to the CCD camera 84' (first reference location),

and also the relative position of cluster of LED's 30" is measured with respect to CCD

camera 84' (first reference location). It is therefore possible to calculate from the

above measurements the relative position of cluster of LED's 30' ' with respect to cluster of LED's 28" and hence, the relative position between ultrasound scanning

beam 32 and CT scanning beam 34.

The above detailed position measuring systems enable measurement of the

relative position between ultrasound transducer scanning beam 32 and CT scanning

beam 34 can be optical, acoustic, magnetic or inertial or a combination of the above. The relative position between position measuring components 28 and 30 can be

measured directly, for example, when one of the components is a receiver and the other one is a transmitter as illustrated in the exemplary embodiment in FIG. 5a.

Alternately, the relative position between position measuring components 28 and 30

can be calculated indirectly, for example, by measuring the position of each with

respect to a reference location as illustrated in the exemplary embodiment in FIG. 5b. When making these indirect calculations, a third position measuring component

84 (illustrated in FIG. 5b by a stereo Charge Coupled Device (CCD) 84') is in

operative communication with position measuring components 28 and 30, this CCD 84

is positioned at a first reference location. The first reference location may be fixed and

known. Alternately, the first reference position can be movable and unknown.

Optionally, the first reference position can be attached to the bed 24.

Position measuring components 28, 30 and 84 (if part of the system) may be

any of the following group: transmitter or receiver or reflector or transceiver or optical

indicia or any combination of the above. Position measuring components 28, 30 and 84 (if part of the system) may be part of a magnetic or acoustic or optic or inertial

position measuring system or a combination of the above.

Position sensing controller 26 may communicate with at least one or all of

position measuring components 28, 30 and 84 (if part of the system) by wired or

wireless links.

Reference is now made to FIG. 6, which illustrates an additional embodiment

of the present invention. Similar items to those shown in previous figures have similar

numbers and will not further be described. The second embodiment illustrates an

ultrasound 2, and an X-Ray 138 to be used in cooperative operation according to the present invention. The X-Ray imaging device comprises X-Ray main unit 140 and X-Ray scanning head 142 including emitter 142' and detector 142' . X-Ray scanning head 142 is mounted on a movable and adjustable arm 144. Bed 24 may or may not be

part of X-Ray imaging device 138.

Position measuring component 30 is attached at known and fixed positions from

X-Ray scanning head 142. Additionally, position measuring component 30 is calibrated

to the scanning head 142 such that it is at a known position from the scanning volume

of the X-Ray. Such calibrations can be achieved by operating according to patent

application PCT/IL98/00631. The relative position between ultrasound transducer

scanning beam 36 and the X-ray scanning volume 146 can be calculated as described

in the first embodiment based on direct measurement between position measuring

components 28 and 30.

An additional position measuring component 84 can be placed at a reference

location on an arm 86. This position measuring component 84 (if used) is in

cooperative communication with position measuring components 28 and 30. Thus, the

position of ultrasound transducer 18 and of the X-Ray scanning head 142 are measured

with respect to the reference position similar to the calculation described in relation to

FIG. 5b. Body 6 can be fixed so as to avoid movement during the procedure. X-Ray

scanning head 142 is positioned in order to view target 8 in the body 6 or body volume

at two different positions. The position of X-Ray scanning head 142 is measured with

respect to reference position thus enabling to correlate the two images into stereo

information in order to receive a 3D image of the scanned body 6. Algorithms for creating such 3D image/information from stereo 2D images/information are known to

those skilled in the art. In one exemplary use of present invention, the operator may indicate target 8

on the image received from the X-Ray 138 for example, by marking it with a mouse

on the display 10 (as described herein above with reference to Figs. 1-3). The relative

position of target 8 can be calculated with respect to the reference point. Ultrasound

transducer 18 is then applied to body volume 6 and its position is measured with

respect to the reference position. Thus, it is possible to calculate the position of

ultrasound scanning plane 36 with respect to the image volume received from X-Ray

138 and target 8.

Alternately, the body volume 6 is first imaged by ultrasound in order to

establish a desired reference plane/volume that includes a target 8. The operator selects

a reference plane, in accordance with the procedures detailed above. Alternately, the

operator indicates target 8 for example by marking it on the display 10, using conventional marking software, as described above. Data processor 14 stores the

position of target 8 or of reference plane with respect to the reference location.

Ultrasound transducer 18 is then removed and the position of X-Ray scanning head

142 is calculated with respect to reference plane or target 8. Thus, it is then possible to

position X-Ray scanning head 142 in an optimal way at two different positions so as

two view target 8 and afterwards produce a 3D image/ information.

Additional modalities of employing in operative cooperation ultrasound 2 and

X-Ray 138 are similar to those described for the system illustrated in Figs. la₍4 and

described above.

Reference is now made to FIG. 7a and 7b, which illustrate an additional embodiment of the present invention. Similar items to those shown in previous figures have similar numbers and will not further be described. The second embodiment

illustrates an ultrasound 2, and an optical endoscope 150 to be used in cooperative

operation according to the present invention. Said endoscope 150 comprising an

endoscope head 152 with a CCD 154 (not shown in the drawing) and optical apparatus

156 (not shown in the drawing). Endoscope head 152 can be rigid, or can be flexible. It is still possible to use a rigid endoscope head 152 with a mobile tip enabling to

change the angle of view. It is also possible to use endoscope with changing field of

view.

Position measuring component 30 is attached at a known position with respect

to optical endoscope head 150 and calibrated to the endoscope image 158. Position

measuring component 28 is attached at a known position with respect to transducer 18

and calibrated to transducer beam/image 36 as described above. If endoscope head 152

is rigid position measuring component may be attached internally or externally at any

fixed position with respect to endoscope head 152. If endoscope head 152 is flexible or

has a mobile tip, position measuring component 30 is positioned at the tip of head 150.

An example of such position measuring component is the magnetic sensor

manufactured by Mednetix Inc. Alternately, position component 30 can be a

combination of two different functional sub-components. A first sub-component of positions measuring component 30 measuring the position of the head 152 at a default

situation (default bending or default tip position). A second sub-component of position

measuring component 30 being attached to the flexible part of endoscope head 152

(and preferably also to the tip) and providing indication with respect to the bending or movement of the flexible part with respect to said default situation. An illustrative example for such a second sub-component could be a fiber optic sensor manufactured by Measurand Inc. Still alternately, in the case of a rigid endoscope wit mobile tip it

can be possible to receive from the endoscope information regarding the deviation from the default situation.

According to one aspect of the present invention target 8 is viewed by

ultrasound transducer 18, and endoscope head 152 is maneuvered to view target 8 based on guiding information received from data processor 14 (not shown in Fig. 7)

and displayed on display 10 (not shown in Fig. 7). The guidance can be in accordance

to the methods introduced by the assignees in above cited patent applications

PCT/IL96/00050 or PCT/IL98/00578.

According to another aspect of the present invention target 8 is viewed by

transducer 18 and also by endoscope head 152. It is then possible to mark target 8 in

the ultrasound image and calculate its position with respect to position measuring

component 28. According to the measured relative position between position

measuring components 30 and 28 and based on the calibration of position measuring

component 30 to the endoscope image 158 it is possible to calculate the 3D position of

target 8 with respect to endoscope image 158. This enables to guide an invasive tool

towards target 8 based on endoscope image 158 from any desired angle according to

the method and apparatus described in above cited patent applications PCT/IL96/00050

or PCT/IL98/00578.

According to another aspect of the present invention it is possible to receive

depth information from the endoscope image by alternative methods without the need

to use transducer 18. According to one alternative method a target is viewed by endoscope 150 while moving the endoscope head 150 at several positions on a strait line around the focussed position, at least one position providing a focussed image of

the target. According to the focussing and de-focussing of the target and according to

the measured position of position measuring component 30 it is possible to receive the

depth of the target in the endoscope image from algorithms known as "depth from focus" . According to another method endoscope head 152 is viewing a volume of

body 6 comprising target 8 from at least two different positions enabling to implement

3D stereo imaging. The implementation of the stereo imaging algorithm is based on

knowing the relative position between the two or more positions of the endoscope head 152. According to still another method it is possible to receive the depth of a target 8 from methods known to those skilled in the art as "depth from shading" Such

methods are described in US Patent No. 4,714,319 and US Patent No. 4,695,130

All the above described methods can provide 3D information regarding the

position of target 8 in the image produced by endoscope 150. It is therefore possible to

attach an additional position measuring component to an invasive tool and guide it to target 8 assisted by endoscope imaging in accordance to the methods described in

guidance methods according to above cited patent applications PCT/IL96/00050 or

PCT/IL98/00578.

While the invention has been described with respect to several preferred

embodiments, it will be appreciated that these are set forth merely for purposes of

example, and that many variations, modifications and applications of the invention may

be made. Accordingly, the scope of the invention is defined by the claims, which

follow.

Claims

1. A method enabling free of predefined mechanical constraints cooperative

operation of two or more medical imaging devices useful in medical diagnosis and/or

medical therapy planning and/or medical intervention planning and/or medical therapy

and/or medical intervention and/or medical procedures, the method comprising the

steps of:

imaging a body volume/plane with a first medical imaging device; sensing the position of a second medical imaging device with respect to said first medical imaging device by means of a position measuring system comprising position measuring controller and position measuring components; scanning part or all of said body volume/plane with said second medical imaging device; calculating the relative position of said second medical imaging device and/or relative position of the scanning plane/volume produced by said second medical imaging device with respect to said first medical imaging device and/or with respect to the scanning plane/volume produced by said first medical imaging device: displaying on at least one display screen said calculation in a cooperative way to the medical operator.

2. The method according to claim 1 where said first and said second medical

imaging devices operate sequentially.

3. The method according to claim 1 where said first and said second medical

imaging devices operate simultaneously and/or intermittently.

4. The method of claim 1 where said one first and said one second medical imaging

device are one of the group X-Ray, CT, MRI or ultrasound, endoscope.

5. The method of claim 1 where the position measuring system is from the group:

magnetic, optic, acoustic, inertial, fiber optic or a combination of the above.

6. The method of claim 1 where the step of sensing the position of second medical

imaging device with respect to said first medical imaging device is performed by means of wired or wireless communication.

7. The method according to claim 1 where the position of the scanning

plane/volume/image produced by said second medical imaging device is calculated with respect to the scanning plane/volume/image produced by said first medical

imaging device.

8. The method according to claim 1 where the scanned plane/volume produced by

said first medical imaging device is correlated and/or fused by image processing tools

with the scanned plane/volume/image produced by said second medical imaging

device.

9. The method according to claim 1 further comprising the step of indicating to said

position sensing system the position of a target by marking said target on said at least

one display screen or by automatic recognition of the target in the image.

10. The method according to claim 1 further comprising the step of indicating to said position sensing system the position of a reference plane/volume by marking said

reference plane/volume on said at least one display screen.

11. The method according to any of the claims 9 or 10 , where the position of the said second medical imaging device is calculated with respect to said target and/or said

reference plane/volume/image.

12. The method according to claim 1 where the position of the scanning

plane/volume produced by said one second medical imaging device is calculated with respect to said target and/or said reference plane/ volume.

13. The method according to claim 1 and further comprising the step of indicating

on said at least one display screen the actual progressive motion of said second medical imaging device towards said target and/or reference plane/volume.

14. The method according to claim 1 and further comprising the step of indicating

on said at least one display screen the deviation of said second medical imaging device or scanning plane/ volume produced by said second medical imaging device from said

target and/or from said reference plane/volume.

15. The method according to claim 1 and further comprising the step of adjusting the position of said second imaging device so as to cause it to include in its scan

plane/volume/image said target or to cause that its scan plane/volume coincide with

said reference plane/volume.

16. The method according to claim 1 and further comprising the step of correlating the calculated position of at least on target or the relative position between several targets/points in order to assess internal anatomic movements between different stages

of a medical procedure.

17. Apparatus enabling free of predefined mechanical constraints cooperative

and/or medical intervention and/or medical procedures, apparatus comprising: one first medical imaging device; one second medical imaging device; a position measuring system comprising at least the following: a position sensing controller and at least one first position measuring component at a known position with respect to said first medical imaging device and second position measuring component at a known position with respect to said second medical imaging device; a data processor for receiving data from the position sensing controller for calculating the relative position of said second medical imaging device and/or relative position of the scanning plane/volume produced by said second medical imaging device with respect to said first medical imaging device and/or with respect to the scanning plane/volume produced by said first medical imaging device, said data processor displaying on at least one display screen said calculation in a cooperative way to the medical operator.

18. Apparatus according to claim 17 where the at least one display screen is one.

19. Apparatus according to claim 17 where said first and said second medical

imaging device operate simultaneously and/or intermittently.

20. Apparatus of claim 17 where said first and said second medical imaging devices are one of the group X-Ray, CT, MRI, ultrasound or endoscope.

21. The apparatus of claim 17 where the position measuring system is from the

group: magnetic, optic, acoustic, inertial, fiber optic or a combination of the above.

22. Apparatus of claim 17 where the step of sensing the position of said second

medical imaging device with respect to said first medical imaging device is performed by means of wired or wireless communication.

23. Apparatus according to claim 17 where said at least one first position measuring component is attached onto said first medical imaging device.

24. Apparatus according to claim 17 where said at least one second position measuring component is attached onto said second medical imaging device.

25. Apparatus according to claim 17 where said at least one first position measuring component and said at least one second position measuring component work

in operative communication.

26. Apparatus according to claim 17 where said calculation is based on the direct

measurement of the relative position between said at least one first position measuring component and said at least one second position measuring component.

27. Apparatus according to claim 17 where said calculation is based on directly

measuring the position of said at least one first position measuring component with to

said at least one second position measuring component.

28. Apparatus according to claim 17 where said position measuring system additionally comprises at least one third reference position measuring component being

placed at a first reference location; said at least one third position measuring component being in operative communication with said at least one first position measuring component and said at least one second position measuring component and enabling to calculate the relative position between them.

29. Apparatus according to claim 37 where the scanned plane/volume produced by

said at least one first medical imaging device is correlated and/or fused by image processing tools with the scanned plane/volume produced by said at least one second

medical imaging device.

30. Apparatus according to claim 17 and further comprising the step of correlating the calculated position of at least on target or the relative position between several targets/points in order to assess internal anatomic movements between different stages

of a medical procedure.

31. Apparatus according to claim 17 further comprising the step of indicating to

said position sensing system the position of a target by marking said target on said at

least one display screen or by automatic recognition from the image..

32. Apparatus according to claim 17 further comprising the step of indicating to said position sensing system the position of said reference plane/volume by marking

said reference plane/volume on said at least one display screen.

33. Apparatus according to any of the claims 31-32, where the position of the said at least one second medical imaging device is calculated with respect to said target and/or said reference plane/ volume.

34. Apparatus according to claim 17 where the position of the scanning

plane/volume produced by the said at least one second medical imaging device is calculated with respect to said target and/or said reference plane/ volume.

35. Apparatus according to claim 17 and further comprising the step of indicating on said at least one display screen the actual progressive motion of said at least one

second medical imaging device towards said target and/or reference plane/volume.

36. Apparatus according to claim 17 and further comprising the step of indicating on said at least one display screen the deviation of said at least one second medical imaging device or scanning plane/volume produced by said at least one second medical imaging device from said target and/or from said reference plane/volume.

37. Apparatus according to claim 17 and further comprising the step of correlating the calculated position of at least on target or the relative position between several targets/points in order to assess internal anatomic movements between different stages

of a medical procedure.

38. Apparatus enabling to guide an invasive tool towards a target visible by

endoscope means, in a free of predefined mechanical constraints cooperative operation

comprising: an endoscopic imaging device; an invasive tool; a position measuring system comprising at least the following: a position sensing controller and at least one first position measuring component at a known position with respect to said endoscope imaging device and second position measuring component at a known position with respect to said invasive tool; a data processor for receiving data from the position sensing controller for calculating the relative position of said invasive tool with respect to the image(s) produced by said first medical imaging device, said data processor displaying on at least one display screen said calculation in a cooperative way to the medical operator.