WO1993004379A1 - Process and device for determining the exact position of a target (c) by aligning the locating means with the target and use thereof in an apparatus for treatment of said target, preferably by pressure waves - Google Patents

Abstract

Process and device for determining the exact position of a target (C). The apparatus comprises an emission device comprising a radiation source for forming an image of at least the target, a device disposed on the other side of the target for receiving said radiation, a mask forming device (40, 50) positioned between the receiving device (30) and the radiation source (20), comprising at least one locating means for forming an image of known position in relation to a reference point (0), means for displacing the locating means in a given plane in relation to the device for treating the patient, and means for recording the position coordinates of each image of the target and of the locating means coinciding with the position of the target image.

Description

_ /

Method and device for determining the exact position of a target (C) by aligning locating means with the target and use within the framework of an apparatus for processing said target, preferably by pressure waves. ^{, f}

The present invention essentially relates to a method and device for determining the exact position of a target (C) by aligning locating means with the target and use within the framework of an apparatus for processing said target, preferably pressure waves. According to a preferred embodiment, it is an apparatus for pressure wave treatment of a target chosen from the group consisting of a lithiasis, for example a renal or biliary lithiasis; tissue, for example benign or malignant tumors; bones, for example a fracture or a bone area to be treated, in particular an osteoporosis area.

Until now, various methods and apparatuses are known for determining the exact position of a target, comprising the use of a radiation source emitting radiation capable of being received by a device for receiving this radiation, said source and said receiving device being arranged on either side of said target (see EP-A-0 240 565 or EP-A-0 260 550.

We also know from document US-A-4 764 944 (Finlayson) a method and a device for positioning a calculus located inside a kidney of a patient using two sources of convergent penetrating radiation crossing at focal point F2 constituting the external focus of an ellipsoid where shock waves are generated. Here, the initial position of the sources is not arbitrary, but on the contrary must be very precise to cross at the focal point. In addition, the technical solution proposed by Finlayson requires a calibration step to determine the value of the angle a between the coordinates in the observation plane and to determine the angle between the observation plane and the hori¬ zontal. A rod terminating in a ball is used, which is observed until the radiation observed by the fluoroscopes is centered on the point of intersection of each of the screens. This procedure is therefore extremely complicated and requires in all cases the use of two sources and two reception devices, in particular fluoroscopes, the initial position of which must be well determined for each of them by its second focus, which requires that these sources be permanently linked to the treatment device, here an ellipsoid. In addition, calibration is necessary using the device comprising the ball to bring the image of the ball to the center of the fluoroscopic screens.

Furthermore, the applicant has also described in document W0-A-91/07913 a method and an apparatus for determining the position of a target using a masking device combined with a film sensitive to X-rays. This solution which is safe and reliable, however, requires a minimum film development time which is not always compatible with industrial and medical requirements.

The main object of the present invention is therefore to solve the new technical problem consisting in providing a solution making it possible to determine the exact position of a target in a relatively short time while being very reliable and reproducible.

The main object of the present invention is also to solve the new technical problem consisting in providing a solution making it possible to determine the exact position of a target without having to carry out any movement of the patient and / or patient treatment device. .

The main object of the present invention is also to solve the new technical problem consisting in providing a method and an apparatus for determining the exact position of a target without having to bring this target into a determined position relative to the detection device. treatment and / or without having to bring it into a determined position relative to the device for receiving radiation.

The present invention also aims to solve the technical problems stated above with a minimum of manipulations, in particular a minimum of steps, or of shots or of displacements, thereby also limiting the dose of exposure to radiation emitted by the radiation source, which is particularly important when the radiation source emits X-rays. The present invention also aims to solve the new technical problems set out above in a manner permitting to use the method and the apparatus of the invention in the context of a target treatment apparatus, preferably by pressure waves, more preferably this target being chosen from the group consisting of a lithiasis, for example renal or biliary; tissue, for example benign or malignant tumors; and bone, for example a bone area, for example a fracture or an osteoporosis area.

The present invention enables these technical problems to be solved for the first time simultaneously, particularly simple, inexpensive and usable on an industrial and medical scale.

Thus, according to a first aspect, the present invention provides a method for determining the exact position of a target ⁽ C) relative to a reference point (0) determined for example by a device for processing the target (C), comprising the use of an emission device comprising a source of radiation emitting at least one imaging radiation from the target (C) capable of being received by a device for receiving this radiation, said source and said receiving device being arranged on either side of said target, characterized in that between the receiving device and the radiation source is interposed a mask device comprising at least means for locating known positions relative to the point of reference (0), said locating means being able to form an image by said imaging radiation, as well as means for moving the locating means in a determined relative plane the treatment device,

- an image forming radiation is made to emit a first position of the source (S ,.) simultaneously encompassing the target and the receiving device, in order to obtain a pre- first image (I ,,) of the target (C) on the receiving device, and the first position coordinates of the image of the target are noted, respectively x .. ,, y- _* * '

the emission of the image-forming radiation by the source (S.) is permanently maintained and the locating means are moved until the image of the locating means coincides with the position of the first image ( I ..) of the target (C), on the receiving device, and the first position coordinates of the locating means are noted, - the radiation device is moved into a difference angular position (S .,) from the previous one (S.), this angular position making it possible to simultaneously encompass the reception device and the target (C),

- We emit a second radiation by said source (S _? ) to obtain a second image (I_) of the target (C) on the receiving device, and note the second position coordinates of said second image (I _? ) , respectively x. _? , Y - -, *

- the emission of said second radiation by said source (S _? ) is permanently maintained and the means of locating known position is moved until the image of said means of locating on the receiving device coincides with the second image (I _? ) of the target (C) on the reception device, and the second position coordinates of the locating means are noted,

- The coordinates of the target (C) are calculated from the first known position coordinates of the locating means respectively, the second known position coordinates of the locating means, and either at least certain position coordinates known to the source of transmission, or certain position coordinates of the receiving device. According to an advantageous embodiment, at least two procedures are provided for aligning the aforementioned locating means with the image of the target at two different distances from the device forming a mask for the same position of the emission source. . According to a particular variant embodiment, the locating means are defined by the intersection of two non-son parallel absorbing the radiation, said fi Ls then being displaced by the aforementioned displacement means.

According to an advantageous alternative embodiment, the displacement means comprise means for coding the position coordinates of the locating means during its displacement.

According to a particularly advantageous embodiment, two mask devices are provided, each comprising at least one aforementioned locating means arranged in two separate planes of the receiving device, in the case where the position of the emission source, or of the receiving device, is unknown. According to a particular variant embodiment, the reception device comprises a fluoroscopy screen connected to a video image forming device, and means of pointing on this screen, manual or automatic, of the position of the image of The target for each position of the source.

According to an advantageous embodiment, a control unit is provided comprising means for calculating the position coordinates of the image of the target for each position of the source, and means for controlling the manual or automatic movement of the means to bring it into coincidence with the image of the target.

According to a second aspect, the present invention provides an apparatus for determining the exact position of a target (C) relative to a reference point (0) determined for example by a target processing device (C), comprising a emission device comprising a source of radiation emitting at least one image-forming ray from the target (C), capable of being received by a device for receiving this radiation, said source and said reception device being arranged on either side of said target, characterized in that it comprises a device forming a mask interposed between the receiving device and the radiation source, comprising at least one locating means of known position relative to the point of reference (0), said locating means being able to form an image by said imaging radiation, as well as means for moving the locating means in a determined relative plane- ment to the processing device, means for noting The cooi— position data of each image of the target as well as coor¬ position data of the locating means when during its displacement by the displacement means, the locating means is moved to coincide with the target image position.

According to an advantageous alternative embodiment, this device comprises means for positioning locating means in two separate planes of the mask device, for the same position of the emission source, at least in the case where the position of the source of emission, or receiving device, is unknown.

According to another advantageous embodiment, the above-mentioned locating means is defined by the intersection of two non-parallel wires absorbing the radiation, said wires then being displaced by the above-mentioned displacement means.

According to another advantageous embodiment, the displacement means comprise means for coding the position coordinates of the locating means during its displacement.

According to another advantageous embodiment, two mask devices are provided, each comprising at least one aforementioned locating means arranged in two separate planes of the receiving device, at least in the case where the position of the emission source, or the receiving device, is unknown.

According to a particular variant embodiment, the reception device comprises a fluoroscopy screen connected to a video image forming device, and means of pointing on this screen, manual or automatic, of the position of the image of The target for each position of the source.

According to a preferred embodiment, a control center is provided comprising means for calculating the position coordinates of the image of the target for each position of the source, and control means for manual or automatic movement. locating means to bring it into coincidence with the image of the target. The invention also covers, according to a third aspect,

The use of the process and / or the apparatus to determine the exact position of the aforementioned target (C), in the context of an apparatus for processing a target, preferably by pressure waves. This treatment apparatus is in particular an apparatus for treating a target chosen from the group consisting of a lithiasis, for example a renal or biliary lithiasis; tissue, for example benign or malignant tumors; bone, for example a fracture or an osteoporosis area. A preferred treatment device is characterized in that it comprises a truncated ellip¬ soidal reflector filled with a coupling liquid comprising an internal focal point immersed in said liquid and an external focal point intended to be placed in coincidence with the target to be treated, as well as at least two electrodes arranged symmetrically on either side of the internal focal point for generating said pressure waves by electrical discharge in said coupling liquid. It is thus understood that the invention makes it possible to solve the new technical problem previously stated, to lead to the determining technical advantages also previously stated, as well as those which will appear clearly to those skilled in the art from the following description. which will be made of the invention with reference to a currently preferred embodiment given simply by way of illustration and which therefore cannot in any way limit the scope of the invention. In the drawings:

- Figure 1 is a schematic view, in principle, of an apparatus according to the present invention for treating a target (C), by pressure waves, incorporating the method and the apparatus for determining the exact position of La target (C), the latter comprising two mask-forming devices arranged at two separate distances from the receiving device;

FIG. 2 represents a schematic view of two positions of the radiation source, the two mask-forming devices being arranged with their locating means formed by the intersection of two non-parallel wires aligned with the target for a first position (S, .) of the radiation source.

With reference to FIGS. 1 and 2, and more particularly to FIG. 1, a processing device according to the present invention is represented by the general reference number 10. This processing device is preferably a processing device emitting pressure waves, better still pressure waves focused at a focal point F2, intended to be placed in coincidence with the target C to be processed. Thus, this device includes a device 12 for generating pressure waves. According to a preferred embodiment, as shown, this pressure wave generation device 12 comprises a truncated ellipsoidal reflector 14 filled with a Liquid 16, which is well known to those skilled in the art and by example described in US patent RIEBER 2,559,227 or in previous documents of the applicant such as US-A-4,730,614; US-A-4,866,330; US-A-4,915,094; US-A-4,962,753 to which those skilled in the art may refer. This truncated ellipsoidal reflector 14 includes an inner focus _F. , and an external focal point F_ intended to be placed in coincidence with the target C to be treated. This reflector 14 is provided with at least two electrodes 13, 15 arranged symmetrically relative to the internal focus F. and generating by electric discharge, using a high voltage generator, pressure waves at the focus F ., which are focused on the external focal point F_ by being transmitted by the coupling liquid 16, as is well known to those skilled in the art. The device 12 is usually mounted movable in space in three directions, for example here symbolized U, V, W, by means of control 34, for example with motors 36.

The target C is for example an internal target in the body of a patient P. This target C can be chosen from the group consisting of a lithiasis, for example renal or biliary, of tissues, such as malignant or benign tumors; bone, in particular a fracture or a bone area, for example an osteoporosis area. The apparatus according to the invention 10 comprises a device 20 for emitting radiation comprising a radiation source 22 emitting imaging radiation at least from the target C capable of being received by a receiving device 30 of this radiation. The source 22 and the reception device 30 are arranged on either side of the target C. The source 22 is usually of unknown position relative to a reference point 0. In the context of a preferred reali sati on example, the reference point 0 is const i killed by the external foye F_ of the reader ref el l ipsoïda lt ronqué 14. We can also use r equivalently as a reference point 0 The internal foy F. then there is a direct relationship between the internal f ₁ and the external f

^F 2 "

According to the present invention, the apparatus comprises at least one mask device 40, 50 comprising at least one locating means 42, 44; 52, 54, respectively of known position relative to the reference point 0. The locating means 42, 44; 52, 54 is able to form an image by the image forming radiation. In addition, displacement means such as 34, 36 are provided for carrying out a displacement of the locating means 40, 50 in a determined plane relative to the processing device 12. The apparatus also comprises a control unit 60 comprising means of computation such as a computer, computer or microcomputer, constituting on the one hand means for noting the position coordinates of each image of the target for each position of the source S, as well as the position coordinates of each means of location R-, R_, in particular when the location means coincides with an image of the target C on the reception device 30.

The apparatus also comprises means 18 for angular displacement of the source 22. In general, the assembly formed by the source 22 and the receiving device 30 is mounted on a mobile surgical table available in any hospital. In general, the receiving device is permanently aligned with the axis of the source whatever the orientation position of the radiation source, and the radiation source 22 is a source of X radiation.

The locating means R ,. or R-, is advantageously arranged successively in two separate planes of the receiving device 30 for the same position of the emission source 22. Therefore, it is preferred to provide two devices forming a mask 40, 50, as shown, each comprising at least one means of marking R., R- ,, arranged at two separate distances from the reception device 30, at least in the case where the position of the emission source 22, or of the reception device 30, is unknown as is generally the case . According to an advantageous embodiment, the locating means R .., R _? is defined by the intersection of two non-parallel wires 42, 44; 52, 54, respectively, absorbing the radiation, said wires then being displaced by the above-mentioned displacement means 34, 36. In practice, the wires 42, 44; 52, 54 are mounted on a frame 46, 56, the two frames being integral with a common support 70, mounted in displacement by the displacement means 34, 36 at least in one plane, such as The UV plane shown in Figure 1.

According to an advantageous embodiment, the displacement means 34, 36 comprise means for coding the position coordinates of the locating means R,., R _? while moving. Such coding means are well known to those skilled in the art.

According to a particular variant embodiment as shown, the reception device 30 comprises a fluoroscopy screen 80 connected to a device 82 for forming a video image which can be displayed on display means 84 connected to the control unit 60 , and pointing means 86 on the display means 84, manual or automatic, of the position of the image of the target C for each position of the source 22. In FIG. 2 two positions are shown respectively. S ,, and S_ of the source 22, these two positions being angularly offset by a few degrees, for example from approximately 5 to 10.

Thanks to the structure defined above, the method for determining the exact position of the target C relative to the reference point 0 can be implemented, here for example defined by the external focus F_ of the processing device 12.

According to this method, and with reference to FIGS. 1 and 2, the transmitter is first of all transmitted, for example by the control center

60, an image forming radiation for a first position S. of the source 22 simultaneously encompassing the target C and the dispo- reception device 30, to obtain a first image I .. of the target C on the reception device, and the first position coordinates of the image of the target are noted, respectively x.,., y. , in the plane defined by the fluoroscopy screen 80, or in an equivalent plane which can be the plane of the display means 84.

The emission of the imaging radiation from the source is permanently maintained in its first position and. we move the locating means R., R _? until the image of the locating means coincides with the position of the first image I .. of the target C on the receiving device 30, and the first position coordinates of the locating means R, are then noted. , R- ,, respectively XR1. „, YR1 ..; XR2 ._-, YR2. . he 'he' ι2 'ι2

Then the radiation device is moved to a different angular position, for example the position S_, this angular position S _? making it possible to simultaneously include the reception device 30 and the target C, which is generally the case when the angular displacement is a few degrees, such as for example from 5 to 10.

A second radiation is made to emit by the source 22 in this second position S_, in order to obtain a second image I_ of the target C on the receiving device, and the second position coordinates of said second image I are noted, respectively x . , y. _? in the plane of the fluoroscopy screen or in the equivalent plane in which the coordinates of the first image I have been noted _. ..

The emission of the second radiation by the source 22 is still permanently maintained in this second position S_, and the locating means R are moved _. ., R_, of known position until the image of the locating means on the receiving device 30 coincides with the second image I-, of the target C on the receiving device 30, and the second coordinates are noted. position of the locating means R .., R_, respectively XR1 - ₂ , YRI. _. - XR2. _? ,

YR2 ..,. ι2

The coordinates of the target (C) are calculated from the first coordinates XR1.-, Y RI respectively. *, X- ^ ' ^YR2 - * ^ciu locating means R,., R_, of the second coordinates XR1._, YR1._, XR2. _? , YR2._, of the locating means R., R ,, and either at least certain known position coordinates of the emission source 22, or certain position coordinates of the reception device 30. When the coordinates position of the source 22 or of the reception device 30 are unknown, when there is only one locating means R., the latter is moved in two distinct planes of the mask device, as shown in FIG. 1, but it is naturally preferred at this time to use two mask-forming devices as shown, 40, 50, arranged at two separate distances from the receiving device, this distance being known.

With these coordinates, the calculation means of the control center 60 carry out the exact calculation of the coordinates of the target C, for example a lithiasis inside the kidney of a patient P.

Naturally, to allow correct alignment of the tracking means R. and R _? with the image of Target C, each means of tracking R. and R _? is displaceable independently of the other, that is to say that the perpendicular wires defining, by their crossing, the locating means R,., R _? are mounted displaceable on the frame which supports them, the frame thus defining the plane of movement of the wires. Each wire is controlled in displacement by the aforementioned control means, for example with stepping motors. Thus, the position of the wires is known by the number of steps that the motor takes to position the wire in the correct position from an original position.

The alignment of a wire takes place, for example, in the following way: it is moved until its image appears in the field of vision of the source 22. Then, by a method of zero, the means of calculating the control center moves it again until its image passes through the position of Target C in the image. It is thus understood that for each image, R locating _means. ., R-, are located on a straight line that goes through The target C. Knowledge of the position of the tracking means R., R _? gives the equation of this line.

Thus, during the taking of the second image by modifi¬ cation of the angular position of the source 22, passing for example from the position S ,, to the position S_, again performing the same operations, we obtain L ' equation of a second straight line. The exact position of Target C is obtained by the intersection of these two lines.

The invention therefore makes it possible to achieve the determining technical advantages previously stated. In particular, the radiation source can be constituted by any radioscopy device available in hospitals and which does not need to be referenced with respect to the treatment equipment. It can be used for localization purposes without prior calibration, then be available for other services. The position of the target C is determined in the reference frame in which the reference means R,., R_ moves, this reference point being itself connected to the reference point of the processing equipment, here the pressure wave generating device 12. The duration of the patient's exposure to radiation, in general X-radiation, is short because the alignments are carried out under the control of the control unit, in particular under the control of a computer, microcomputer or computer. ¬ reader. This exposure does not depend on the expertise of the operator. The patient can be moved out of the radiation during the movement of the locating means R,., R- ,.

The position of the target C in space is determined without relative movement either of the target C or of the radiation source. Only the orientation of the source inside the radiation apparatus, generally in the x-ray machine, must be changed between two different positions S ,, and S_.

The invention therefore includes all the means constituting technical equivalents of the means described as well as their various combinations. The invention covers in particular any characteristic which appears to be new with respect to any prior art, in particular resulting from the preceding description incorporating the appended figures which form an integral part of the invention, and therefore of the present description.

Claims

1. Method for determining the exact position of a target (C) relative to a reference point (0) determined for example by a device for processing the target (C), comprising the use of a device for emission comprising a radiation source emitting at least one image-forming radiation from the target (C ⁾ capable of being received by a device for receiving this radiation, said source and said receiving device being arranged on the side and other of said target, characterized in that between the receiving device and the radiation source a mask device comprising at least one means of locating known position relative to the reference point (0), said locating means being able to form an image by said imaging beam, as well as means for moving the locating means in a determined plane relative to the processing device (12), - an image-forming radiation is emitted for a first position of the source (S ,.) simultaneously encompassing the target and the receiving device, in order to obtain a first image (I ..) of the target (C) on the receiving device, and note the first position coordinates of the image of the target, respectively x .., y * - * the emission of the image-forming radiation by the source (S.) is permanently maintained and the locating means are moved until the image of the locating means coincides with the position of the first image ( I.) of the target (C), on the receiving device, and the first position coordinates of the locating means are noted, - the radiation device is moved to a different angular position (S_) from the previous one (S ,.), this angular position making it possible to simultaneously encompass the reception device and the target (C), - a second radiation is emitted by said source (S_) to obtain a second image (I_) of the target ⁽ C) on the receiving device, and note the second position coordinates of said second image (I-,), respectively x.- ,, y .->, - the emission of said second radiation by said source (22) is constantly maintained and the means of locating of known position is moved until the image of said means of locating on the reception device coincides with the second image (I_) of the target (C) on the receiving device, and the second position coordinates of the locating means are noted, - The coordinates of the target (C) are calculated from the first known position coordinates of the locating means, the second known position coordinates of the locating means, and either at least certain position coordinates known from the source. of transmission, or certain position coordinates of the receiving device. 2. Method according to claim 1, characterized in that at least two procedures are provided for aligning the aforementioned locating means with the image of the target at two different distances from the mask device for the same position of the source d 'program. 3. Method according to claim 1 or 2, characterized in that the locating means are defined by the intersection of two non-parallel son absorbing radiation, said son then being moved by the aforementioned displacement means. 4. Method according to one of the preceding claims, characterized in that the displacement means comprise means for coding the position coordinates of the locating means during its displacement. 5. Method according to one of the preceding claims, characterized in that two mask devices are provided, each comprising at least one aforementioned locating means arranged in two separate planes of the receiving device, at least in the case where the position of the source of emission, or of the receiving device is unknown. 6. Method according to one of the preceding claims, characterized in that the reception device comprises a fluoroscopy screen connected to a video image forming device, and means for pointing on display means, manual or automatic, of the position of the image of the target for each position of the source. 7. Method according to one of the preceding claims, characterized in that a control unit is provided comprising means for calculating the position coordinates of the image of the target for each position of the source, and control means in manual or automatic movement of the locating means to bring it into coincidence with the image of the target. 8. Apparatus for determining the exact position of a target (C) relative to a reference point (0) determined for example by a target processing device (C), comprising an emission device comprising a source of émet¬ radiation as an image-forming radiation at least of the target ^(C) capable of being received by a receiving device of this rayon ^¬. Said source and said receiver device being disposed on either side of said target, characterized in that it com ^¬ takes a device forming a mask interposed between the receiving device and the radiation source, comprising at least one means of location of known position relative to the reference point (0), said location means being able to form an image by said imaging radiation, as well as means for moving the location means in a determined plane relative to the processing device, means for recording coordinate data of each image position of the target as well as coor ^¬ position data of the sensing means when During its movement by the moving means, the sensing means is moved coincidence with the target image position. 9. Apparatus according to claim 8, characterized in that it comprises means for positioning the aforementioned locating means along two separate planes of the mask device, for the same position of the emission source, at least in the case where The position of the transmitting source, or the receiving device, is unknown. 10. Apparatus according to claim 8 or 9, characterized in that the aforementioned locating means is defined by the inter- section of two non-parallel radiation absorbing wires, said wires then being displaced by the aforementioned displacement means. 11. Apparatus according to one of claims 8 to 10, characterized in that the aforementioned displacement means com¬ take means for coding the position coordinates of the locating means during its displacement. 12. Apparatus according to one of claims 8 to 11, characterized in that it comprises two mask-forming devices (40, 50) each comprising at least one aforementioned locating means arranged in two separate planes of the receiving device, at least in the case where the position of the emission source, or of the reception device, is unknown. 13. Apparatus according to any one of claims 8 to 12, characterized in that the aforementioned reception device (30) comprises a fluoroscopy screen (80) connected to a video image forming device, and pointing means on this screen, manual or automatic, of the position of the target image, for each position of the source. 14. Apparatus according to any one of claims 8 to 13, characterized in that it comprises a control unit comprising means for calculating the position coordinates of the image of the target for each position of the source, and control means for manual or automatic movement of the locating means to bring it into coincidence with the image of the target. 15. Use of the method according to any one of claims 1 to 7, or of the apparatus according to any one of claims 8 to 15, to determine the exact position of a target (C) within the framework of a apparatus for treating a target, preferably by pressure waves. 16. Use according to claim 15, characterized in that the aforementioned treatment apparatus is an apparatus for treating a target chosen from the group consisting of a lithiasis, for example a renal or biliary lithiasis; tissue, for example benign or malignant tumors; bone, for example a fracture or an osteoporosis area. 17. Use according to claim 15 or 16, charac¬ terized in that the aforementioned treatment apparatus comprises a truncated ellipsoidal reflector filled with a coupling liquid com¬ taking an internal focus immersed in said liquid and an external focus intended for be placed in coincidence with the target to be treated, as well as at least two electrodes arranged symmetrically on either side of the internal focal point to generate said pressure waves by electrical discharge in said coupling liquid.