Multi-laser energy emitter device and associated heat treatment assembly

Abstract

A multi-emitting laser device (1) for treating a target region of biological tissue, comprising: - at least one sheath (150) including; - at least two optical fibers (123, 124, 125, 126, 127) extending within the sheath to guide a thermal laser beam to the target region and deposit laser energy in the target region; - a laser source system (19) configured to generate at least two laser beams having different or identical wavelengths with adjustable light power; - a laser beam control unit (31) configured to control the laser source system so as to select the wavelength, light power, laser energy deposition time, and emission timing of each of the laser beams guided and emitted by the optical fibers toward the target region. Abstract figure: Figure 1

Description

Title of the invention: Device with multiple laser energy emitters and associated heat treatment assembly Technical field

[0001] The present invention relates to the field of treatment of biological tissue using localized temperature variation under intraoperative imaging guidance.

[0002] More specifically, the invention relates to a device with multiple laser energy emitters capable of emitting a plurality of laser beams to induce in a biological tissue a 3D temperature variation corresponding to a predefined target region of any shape and potentially asymmetrical.

[0003] The invention also relates to a thermal treatment assembly comprising such a device with multiple laser energy emitters coupled to an MRI imaging device. Prior art

[0004] It is known to locally treat pathological biological tissues by targeted administration of an increase in temperature (hyperthermia) or a decrease in temperature (hypothermia) by means of an energy source. The energy can be provided, for example, by a laser, microwaves, radiofrequency waves, focused ultrasound or by cryotherapy.

[0005] Among these techniques, a first category of thermal treatment is distinguished which consists of depositing a dose of energy in a target region of a biological tissue via remotely positioned energy generating means (focused ultrasound or induction radiofrequencies) and a second category of thermal treatment which consists of depositing a dose of energy in the target area percutaneously or vascularly (radiofrequencies, laser, microwaves, cryotherapy). The thermal treatment system of the present invention belongs to the second category.

[0006] Prior to the heat treatment, a phase called the “preoperative planning phase” aims to evaluate the 3D extension of the target region using suitable imaging techniques, for example by computed tomography (which may be referred to as “CT”) or by Magnetic Resonance Imaging (which may be referred to as “MRI”), capable of determining the size, number, location and shape of the target region(s).

[0007] During this preoperative planning phase, summary indicators of the dimensions of the target region, their number and their relative location in relation to identifiable anatomical landmarks are generally defined.

[0008] The planning phase also aims to prepare the treatment which consists of defining the treatment instructions, namely the dose of thermal energy to be delivered in a volume according to the functional characteristics of the biological tissue to be treated, the size of the target region and the severity of the pathological tissue.

[0009] For a treatment to be effective, a target region is defined which includes the pathological tissue visible in imaging and possibly a minimum safety margin to be respected, defined by the practitioner around the pathological tissue. This target region must undergo a suitable temperature variation in order to treat the pathological tissue.

[0010] The target region is generally surrounded by a region whose tissue is healthy and should ideally not undergo a deleterious thermal variation during the heat treatment. In this region which surrounds the target region, one or more critical regions to be preserved (organs and / or vital structures) can be distinguished.

[0011] In the region where the tissue is healthy and does not include critical regions, the tissues should ideally not undergo a temperature variation during the heat treatment. However, a possible temperature variation is not considered critical for the patient.

[0012] Although the heat treatment technique is much less invasive than surgery, it does have some drawbacks.

[0013] One of the main limitations of the effectiveness of this technique is due to the arbitrary shape of the target region to be treated. Indeed, in known hyperthermic treatment devices, the deposited energy generally aims to heat a spherical or ellipsoidal volume around the point of application. However, the proposed devices do not allow the shape of the lesion generated by the applicator to be adjusted to the shape of the target region to be treated. On the other hand, the distribution of heat in the tissues depends on their intrinsic thermal characteristics (absorption, thermal diffusivity, perfusion) and often leads to a modification of the spatial distribution of the temperature compared to the thermal distribution planned by the practitioner. Consequently, the deposited energy does not allow for a complete treatment of all target regions.

[0014] The lack of adaptability between the shape of the effective temperature distribution and the shape of the target region may result in insufficient energy deposition in certain areas of the target region and / or possible unwanted energy deposition in a critical region to be preserved. One of the consequences of this lack of adaptability of the lesion shape is the increase in the number of incomplete treatments and the associated risks of local recurrence. Similarly, the risks of altering healthy biological tissues are accentuated, increasing the risks of potentially serious side effects.

[0015] It is known to use an optical fiber or a set of optical fibers to deposit a dose of laser energy in contact with the target region. Indeed, the use of optical fibers makes it possible to bring its distal end into direct contact with the target region and to deposit the required thermal energy there by absorption of light energy emitted using a laser source.

[0016] A known embodiment is a device which comprises a main sheath incorporating an optical fiber or a set of optical fibers. The distal end of the sheath comprises an opening through which the end of the optical fiber or the set of optical fibers emits irradiation light energy intended to locally treat the target area. This solution makes it possible to bring the optical fiber as close as possible to the target area. However, it does not make it possible to meet all the technical constraints indicated above.

[0017] One of the aims of the present invention is therefore to provide an emission device having a plurality of optical fibers whose emission direction can be different for each fiber and adjustable, in order to be able to create a treatment in accordance with the therapeutic objective.

[0018] Another object of the present invention is to be able to propose a device which is capable of controlling and modulating the light power and the wavelength of each emitted laser fiber independently. Adjusting the wavelength makes it possible to modulate the depth of induced heating, since biological tissues absorb light differently depending on their wavelengths.

[0019] Another object of the present invention is to provide a device for measuring the temperature at the distal end of the device in real time, thus providing a temperature measurement means complementary to the thermometric imaging system.

[0020] Other aims and advantages of the present invention will appear during the following description which is however given only for information and which is not intended to limit it. Statement of the invention

[0021] A laser device with multiple laser energy emitters is provided for treating a target region of biological tissue, comprising: - at least one sheath having a longitudinal axis (AA') and comprising a proximal end and a distal end intended to be placed opposite the target region; - at least two optical fibers extending in the sheath between the proximal end and the distal end, each of the optical fibers being adapted to guide a beam heat treatment laser to the target region and depositing laser energy in the target region; - the distal ends of at least two optical fibers being configured to each emit a laser beam in a different emission direction relative to the longitudinal axis of the sheath; - a laser source system configured to generate at least two laser beams, said at least two laser beams having different or identical wavelengths with adjustable light power; - a laser beam control unit configured to control the laser source system so as to select the wavelength, light power, duration of laser energy deposition and time of emission of each of the laser beams guided and emitted by the optical fibers towards the target region.

[0022] The features set forth in the following paragraphs may optionally be implemented. They may be implemented independently of one another or in combination with one another:

[0023] The distal end of at least two optical fibers is positioned at a different distance from a surface of the distal end of the sheath.

[0024] The distal end of the optical fibers is configured to emit a laser beam in an emission direction oriented at an angle α between 0 and 180° relative to the longitudinal axis of the sheath.

[0025] The laser source system comprises a plurality of monochromatic laser sources.

[0026] The laser source system is adapted to generate at least two laser beams of different wavelengths per optical fiber.

[0027] According to one embodiment of the invention, the device further comprises a plurality of transmission optical fibers capable of transmitting the laser beams generated by the laser source system to the optical fibers of the sheath.

[0028] Preferably, the device further comprises a temperature sensor.

[0029] According to an exemplary embodiment, the temperature sensor is an optical detection fiber capable of detecting a temperature variation in the target region.

[0030] According to an exemplary embodiment, said plurality of thermal treatment optical fibers is distributed according to radial symmetry around the detection optical fiber.

[0031] Advantageously, the device further comprises connection means capable of connecting the optical fibers of the sheath with the optical transmission fibers of the laser source system.

[0032] According to a particularly advantageous embodiment, the sheath comprises at least one lumen adapted for the injection of a therapeutic substance under pressure intended to be ejected towards the target region.

[0033] According to another exemplary embodiment, the sheath comprises a closed cooling circuit adapted for transporting a cooling liquid intended to cool a portion of the distal end of the sheath.

[0034] According to one variant, the closed cooling circuit is formed by at least two ports provided in the sheath.

[0035] Preferably, the cooling circuit is formed by a cooling sheath surrounding the sheath comprising the optical fibers and a lumen provided in the sheath.

[0036] According to another aspect, there is provided an assembly for heat treatment of a target region of a biological tissue comprising: - a laser device with multiple laser energy emitters as defined above for treating the target region; - a magnetic resonance imaging system configured to generate anatomical images and thermometric images of the target region. Brief description of the drawings

[0037] Other characteristics, details and advantages of the invention will appear on reading the detailed description below, and on analyzing the appended drawings, in which: Fig.l

[0038] [Fig.l] [Fig.l] shows a laser device with multiple laser energy emitters according to one embodiment of the invention; Fig. 2

[0039] [Fig.2] [Fig.2] shows a laser device with multiple laser energy emitters according to another embodiment; Fig. 3

[0040] [Fig.3] [Fig.3] schematically shows a perspective view of a sheath comprising a set of optical fibers; Fig. 4

[0041] [Fig.4] [Fig.4] schematically shows a side and sectional view of a set of three optical processing fibers in a sheath according to an exemplary embodiment; Fig. 5

[0042] [Fig.5] [Fig.5] schematically shows a perspective view of an exemplary embodiment in which the device comprises three sheaths, each of the sheaths comprises a set of five optical fibers; Fig. 6A

[0043] [Fig.6A] [Fig.6A] shows a cross-sectional and front view of an exemplary embodiment of a sheath provided with five lumens intended to receive optical treatment fibers and a sixth central lumen intended to receive a temperature sensor or for the injection of a cooling liquid or a therapeutic substance; Fig.6B

[0044] [Fig.6B] [Fig.6B] shows a cross-sectional and front view of an exemplary embodiment of a sheath of [Fig.6A] provided with two additional ports to form a closed cooling circuit; Fig.6C

[0045] [Fig.6C] [Fig.6C] shows a cross-sectional and front view of an exemplary embodiment of an optical sheath of [Fig.6A] surrounded by a cooling sheath to form a closed cooling circuit with the central lumen; Fig. 7

[0046] [Fig.7] [Fig.7] shows a heat treatment assembly according to a method of embodiment of the invention comprising a multi-emitter laser device coupled to an MRI imaging device; Fig. 8A

[0047] [Fig.8A] [Fig.8A] schematically shows a sheath comprising six optical processing fibers capable of emitting six light energies. Fig. 8B

[0048] [Fig.8B] [Fig.8B] shows six temperature images obtained by MRI thermometry with the sheath of [Fig.8A], each temperature image being obtained simultaneously with the activation of a single optical fiber and each optical fiber being activated sequentially one after the other; Fig. 8C

[0049] [Fig.8C] [Fig.8C] shows a temperature image obtained with the sheath of [Fig.8A], during the simultaneous activation of the six optical fibers with the same power; Fig. 9

[0050] [Fig.9] [Fig.9] schematically shows an example of use with two sheaths whose distal ends are positioned on either side of a target region; Fig. 10

[0051] [Fig. 10] [Fig. 10] shows schematically an example of the embodiment of a laser source system that can generate two laser beams of different wavelengths per processing optical fiber.

[0052] Definitions

[0053] In the context of the present invention, the term "target region" means a region comprising the pathological tissue to be treated visible in imaging and a region which surrounds the pathological tissue. The extent of the vicinity around the pathological tissue is defined by the practitioner. The target region must undergo a temperature variation in order to treat the pathological tissue. The region is designated by Rc in [Fig.7].

[0054] In the context of the present invention, a 3D anatomical image is a reconstructed image representing the anatomy of the target region and its environment. This 3D anatomical image can be obtained by different imaging techniques.

[0055] In the context of the present invention, a 3D temperature image is a 3D image representative of a spatial distribution of the temperature of the target region and the region surrounding it. The 3D temperature image is obtained by a magnetic resonance imaging (MRI) device, using a temperature-sensitive imaging sequence and a real-time image processing device which calculates and displays the temperature variations in the target region and the region surrounding it.

[0056] For the purposes of this disclosure, "proximal" means a part or portion of the device that is located near the operator or practitioner when the operator or practitioner is using the device, while "distal" means a part or portion of the device that is remote from the operator during such use. Description of the embodiments

[0057] The drawings and the description below contain, for the most part, elements of a certain character. They may therefore not only serve to better understand the present invention, but also contribute to its definition, if necessary.

[0058] In the following, the invention will be described more particularly in the case of a heat treatment of a target region and a detection of temperature variation during the heat treatment. This is not, however, limiting, insofar as the system can be used in conjunction with the injection of a treatment solution or other types of fluids, introduced into a lumen of the sheath provided for this purpose.

[0059] [Fig.l] schematically represents a device with multiple laser energy emitters 1 according to an embodiment of the invention.

[0060] The device 1 comprises a plurality of optical fibers 123, 124, 125, 126, 127, 128 intended to transport a plurality of laser beams to a target region of a biological tissue, a laser source system 19 and a main control unit 10. The laser source system 19 is configured to generate a plurality of laser beams intended to be injected into the optical fibers and guided by the optical fibers towards the target region. A portion of the plurality of laser beams is intended to irradiate the target region so as to induce a temperature variation and / or to activate molecules present in a solution previously deposited in the target region. The main control unit 10 is configured to control the laser source system 19 so as to select the wavelength, the light power, the duration of the laser energy deposition and the time of emission of each of the treatment laser beams for each of the optical fibers.

[0061] The device also comprises one or more temperature sensors having the function of measuring the temperature of the target region in contact with the sheath.

[0062] According to an exemplary embodiment, the temperature sensor is formed by one of the optical fibers and at least one laser beam among the plurality of laser beams emitted by the optical fibers is intended to detect a variation in the temperature of the target region during the heat treatment. The laser beam control unit 10 is also configured to receive a detection laser beam coming from this optical fiber dedicated to measuring the temperature.

[0063] According to a variant, the temperature sensor may be, for example, a thermocouple inserted into one of the lumens of the sheath. The thermocouple is connected to the laser beam control unit 10.

[0064] With reference to [Fig. 3], the optical fibers 123, 124, 125, 126, 127, 128 are held in a sheath 150 which has the function of holding the optical fibers together. The sheath 150 is in the form of a flexible or rigid body, depending on the intended therapeutic application, of substantially cylindrical shape having a longitudinal axis AA'. The sheath comprises a proximal end 151 and a distal end 152 intended to be placed opposite the target region. The sheath 150 is made of a material compatible with a surgical intervention and adapted to allow the light beams emitted by the optical fibers to pass through. The sheath is provided with lumens and each of the lumens contains an optical fiber which extends between the distal end 152 and the proximal end 151 of the sheath 150.

[0065] According to a particularly advantageous form, the sheath is in the form of an end piece capable of being detachably connected to the laser source system 19. The sheath has, for example, an external diameter of 1.8 mm and an internal diameter of 1.2 mm. The sheath can be covered with a protective surface which can become blackened due to the absorption of the light beam; it will be possible to change the protective surface without changing the set of optical fibers.

[0066] According to an exemplary embodiment, the processing and detection optical fibers have a diameter of between 50 μm and 1000 μm, preferably between 100 and 400 microns.

[0067] In Figures 1, 2 and 3, the five optical fibers 123, 124, 125, 126, 127 are for example treatment optical fibers each adapted to transmit a light beam having a wavelength adapted to treat the target region, and the sixth optical fiber 128 is a detection fiber and has the function of measuring a temperature variation of the target region. For the remainder of the description, the optical fibers intended to transmit a light beam dedicated to the thermal treatment are designated by the term “treatment fiber” or “emitter” and the optical fiber dedicated to the detection of a temperature variation by the term “detection fiber”.

[0068] The five light beams emitted by the five emitters or processing fibers can each cover, for example, an angular sector with an angle of 72°, so as to emit according to a complete revolution of 360°. According to another variant, the sheath 150 can comprise ten optical emitters which can each cover an angular sector of 36°. The number of emitters is not limiting. The example arrangement shown in FIGS. 1, 2, 3 and 4 is not limiting and can vary according to requirements.

[0069] According to an exemplary embodiment, the distal end of each of the treatment fibers can be positioned at different distances L relative to the distal end of the sheath, making it possible to modulate the relative position of each of the optical fibers in the direction of the length of the sheath.

[0070] According to an exemplary embodiment, the distal end of each of the emitters is configured so as to emit a light beam oriented in a different direction. The distal end of each of the optical fibers is for example polished so as to emit a laser beam whose emission direction is oriented at an angle a defined relative to the main axis AA' of the optical fiber. This angle can be between 0° and 180°. It is thus possible to obtain a set of optical fibers capable of emitting a set of light beams which each illuminate a predefined angular sector.

[0071] The combination of the different light beams emitted by the distal end of each of the emitters with a different emission direction and at different distal positions along the sheath makes it possible to generate lesions of dimensions and geometries adapted to the shape of the target region.

[0072] [Fig. 4] shows an example of a sheath 150 comprising three treatment fibers or emitters 123, 124, 125. The distal end of each of the treatment emitters 123, 124, 125 is positioned respectively at a different distance L1, L2, L3 relative to the distal end 152 of the sheath. Each of the emitters emits a beam light in a different direction, thus covering a different angular sector. Each of the three directions is defined here by a different angle a1, a2, a3 between the axis of symmetry of the beam and the main axis AA' of the optical fiber. The angle a can be between 0° and 180°.

[0073] According to another exemplary embodiment, the device may also comprise a plurality of optical sheaths.

[0074] With reference to [Fig. 5], the device may comprise, for example, three optical sheaths 210, 220, 230. Each of the optical sheaths 210, 220, 230 here comprises, for example, respectively five processing optical fibers 211, 212, 213, 214, 215, 221, 222, 223, 224, 225, 231, 232, 233, 234, 235 and a central detection optical fiber 216, 226, 236. The light beams transported by the fibers of the same assembly may, for example, have different wavelengths, different powers, different emission durations and different emission times. Depending on the shape of the distal end of the optical fibers and their distal position relative to the distal end of the cladding, they can have different emission directions and different distal emission positions along the cladding.

[0075] According to one embodiment of the invention and with reference to [Fig.6A], the sheath comprises five lumens 153, 154, 155, 156, 157 arranged according to radial symmetry around a central lumen 158. The peripheral lumens 153, 154, 155, 156, 157 are intended, for example, each to receive a treatment optical fiber. The central lumen 158 of the sheath is intended to pass the temperature sensor, for example a detection optical fiber 128 or a thermocouple having the function of measuring the temperature. This temperature measurement makes it possible to control a possible deviation between the temperature measured at the end of the optical fiber and the temperature measured by a Magnetic Resonance Imaging (MRI) device. A known technique consists of using an optical fiber provided with a Bragg grating inscribed in the core of the fiber.The Bragg grating consists of a periodic and longitudinal modulation of the refractive index of the core of the single-mode fiber. The Bragg grating reflects light at the Bragg wavelength. When the optical fiber is subjected to a temperature variation, the fiber undergoes a relative elongation as well as a variation in refractive index, which results in a variation in the reflected wavelength. Thus, it is possible to measure the temperature by measuring the variation in the wavelength of the reflected light.

[0076] According to another exemplary embodiment of the invention, the sheath comprises an additional lumen which makes it possible to convey, for example, a therapeutic solution intended to be deposited in the target region. The injected solution is a solution comprising, for example, molecules activatable by temperature, for example anticancer agents encapsulated in a thermosensitive nanovehicle. According to this exemplary embodiment, when the solution is deposited, the emitters or treatment fibers each emit a light beam towards the target region to thermally activate the molecules of the solution.

[0077] According to yet another exemplary embodiment and with reference to [Fig.6B], the sheath 150 may comprise two ports 159, 160 intended for the circulation of a cooling liquid by forming a closed circuit and another port 158 ​​intended to convey a therapeutic substance. The port 160 is intended for the arrival of cooling fluid and the port 159 for the return of cooling fluid.

[0078] According to a variant, the central port 158 ​​can be used as a cooling fluid inlet and the other two ports 159, 160 as a cooling fluid return. All three ports form a closed circuit.

[0079] According to yet another exemplary embodiment and with reference to [Fig.6C], the optical sheath 150 which comprises the set of optical fibers is surrounded by a cooling sheath 161. The cooling fluid arrives via the central lumen 158 and is returned via the cooling sheath 161. This configuration of the cooling circuit makes it possible to have more homogeneous cooling over the entire distal part of the sheath.

[0080] In the context of an injection of therapeutic substance, the lumen comprises an inlet orifice located on a proximal end surface of the sheath and an outlet or injection orifice on the distal end surface of the sheath. The inlet orifice is connected to a piston intended to inject the therapeutic substance into the lumen provided for this purpose. The injection rate of the solution circulating in the lumen is controlled so that the therapeutic substance can be directed and ejected towards the target region. Other embodiments are conceivable in order to eject the substance into the target region.

[0081] With reference to Figures 1 and 2, the laser source system 19 and the main control unit 10 are described below.

[0082] The laser source system 19 is adapted to generate a plurality of laser beams for the thermal treatment of the target region and possibly the detection of a temperature variation in the case where the temperature sensor is an optical fiber.

[0083] The number of laser beams generated by the laser source system 19 is not limiting. According to an exemplary embodiment and with reference to [Fig. 10], the laser source system 19 can generate, for example, two laser beams of different wavelength per treatment optical fiber 123, 124, 125, 126, 127. Thus, for the device of [Fig. 1] which comprises five treatment optical fibers and one detection optical fiber 128, the laser source system is configured to generate ten treatment laser beams and one detection laser beam.

[0084] Preferably, the laser beams generated for each optical fiber may have identical or different wavelengths and light powers. In the exemplary embodiment where the laser source system 19 generates two laser beams for each treatment optical fiber, it is therefore possible to select one of the two wavelengths XI or / .2 and one of the two light powers of the treatment light beam transported and emitted by the treatment optical fiber.

[0085] According to an exemplary embodiment, the laser beams are generated by means of a plurality of monochromatic laser sources. Each of the monochromatic laser sources generates a light beam at a given wavelength. The use of a plurality of treatment wavelengths makes it possible to adjust the penetration depth of the beam into the tissue of the target region.

[0086] In the examples of Figures 1 and 2, the source system comprises six laser diodes 23, 24, 25, 26, 27, 28 for generating five treatment laser beams and one detection laser beam, each of the beams being able to have its own wavelength and its own light power. The source system may also comprise, for example, three diodes which emit at 976 nm and three diodes which emit at 793 nm. Each of the diodes is associated with its own power supply unit 13, 14, 15, 16, 17, 18 and can be individually controlled by an electronic control unit 12.

[0087] According to another exemplary embodiment not illustrated, the system may comprise a plurality of monochromatic laser sources, for example laser diodes, associated with each optical fiber. In this way, it is possible to select a given wavelength from a plurality of wavelengths for the laser beam intended to be transported and emitted by the optical fiber.

[0088] The central control unit 10 is connected to the electronic control unit 12 in order to transmit control signals to the control unit 12 to drive the diodes individually and independently of each other. The central control unit 10 comprises a laser beam control unit 31 and a display unit 32. The beam control unit 31 is configured to send the control signals to the electronic control unit 12 to adjust the heat treatment parameters for each of the laser beams which are the wavelength, the duration of the emission of the laser beam, the time of emission of the laser beam and the light power of the laser beam.

[0089] The laser beam control unit 31 also receives data from a temperature measurement acquisition unit measured by a temperature sensor, for example by the distal end of a detection fiber or by a thermocouple. The temperature measurement acquisition unit is housed in the source system 19. The display unit 32 makes it possible to display this temperature data from the temperature sensor.

[0090] The beam control unit 31 is configured to select the light power of the laser beam transmitted to each of the transmitters. In the case where there are, for example, two laser beams generated by optical fiber, it is possible to select, for example, one of the two light powers for each optical fiber.

[0091] The laser beam control unit 31 is configured to select the wavelength of the light beam conducted and emitted by each of the emitters in order to be able to modulate the penetration depth of the laser beam into the tissue of the target region. In the case where there are for example two laser beams generated by optical fiber, it is possible to select for example one of the two wavelengths for each optical fiber.

[0092] The beam control unit 31 is configured to select the emission duration of each treatment fiber and the emission time of each treatment fiber. According to an exemplary embodiment, it is possible to activate the treatment optical fibers sequentially or simultaneously for a portion of the treatment optical fibers. Two possible examples of use are illustrated in FIGS. 8A-8C.

[0093] Thus in the case of the sheath of [Fig.4], each of the three optical processing fibers conducts and emits a light beam having its own light power PI, P2, P3, its own wavelength XI, X2, X3, and its own emission duration t1, t2, t3. It is also possible to envisage three different emission moments and three different emission durations for the three optical processing fibers.

[0094] The optical fibers are each adapted to transport a laser beam from the proximal end of the sheath to the distal end of the sheath. For this, the proximal end of the optical fibers of the sheath is connected to the laser source system 19 by connections provided for this purpose in the proximal zone of the sheath and which will be detailed below.

[0095] [Fig. 1] schematically represents an example of connection connectors intended to connect the optical fibers and the laser source system 19. In [Fig. 1], the connection connectors are shown detached from each other. The sheath 150 comprises at its proximal end a single connector 130 intended to engage in a connection connector 30 of the laser source system 19.

[0096] Advantageously, the light beams generated by the laser source system 19 are guided by a plurality of transmission optical fibers 43, 44, 45, 46, 47, 48 to the optical connector 30. The transmission optical fibers are fibers equivalent to the optical fibers in the sheath, and may be of the same structure. The use of these transmission optical fibers makes it possible to install the laser source system 19 and the main control unit 10 in a remote room of the room containing the MRI imaging device. Once the sheath is positioned in the patient's body by the practitioner, the latter can use the central control unit 10 to adjust the various parameters of the laser beam during the treatment phase.

[0097] The use of transmission fibers makes it possible to route the light beams from the control part to a distance close to the patient, thus making it possible to use the multi-laser energy emitter device of the present invention in conjunction with an MRI device without creating interference between the MRI device and the electronic components of the laser source system 19. According to an exemplary embodiment, the length of the transmission optical fibers is between 10 meters and 15 meters. The transmission optical fibers are protected by a plastic sheath in order to protect them against any possible external disturbance.

[0098] According to an exemplary embodiment not illustrated, the connector 130 of the sheath 150 comprises connection tabs on a planar connection surface. The connector 30 of the source system comprises connection orifices on a connection surface. The connection tabs are adapted to be inserted into the orifices to engage the two connection connectors. Furthermore, when the connection tabs are inserted into the orifices, the two connection surfaces are in contact such that the ends of the optical fibers of the sheath come into contact respectively with the ends of the transmission optical fibers to connect the optical fibers together. The optical connectors are adapted to be mutually engaged to optically couple the plurality of optical fibers of the sheath to the plurality of transmission optical fibers of the laser source system 19.

[0099] The sheath 150 is thus detachably connected to the laser source system 19 via the optical connectors 30, 130 which allow easy manual connection and disconnection. Preferably, the connectors are made to be compatible with MRI.

[0100] [Fig. 2] illustrates another example of optical connection between the optical sheath 150 and the source system 19. The processing and detection optical fibers are each provided at their proximal end with an individual optical connector 133, 134, 135, 136, 137, 138, and the transmission optical fibers are also provided at their distal end with an individual optical connector 33, 34, 35, 36, 37, 38. The connectors allow easy manual connection and disconnection between the optical sheath and the source system 19.

[0101] The multi-laser energy emitter device of the present invention can be integrated into a thermal processing assembly.

[0102] According to one embodiment of the invention and with reference to [Fig.7], such a heat treatment assembly comprises: - a multi-transmitter device as illustrated in Figures 1 and 2, - an MRI imaging device 50 configured to provide 3D anatomical images of the target region as well as temperature images of the target region throughout the treatment.

[0103] The assembly also comprises an image construction unit 51 configured to provide 3D anatomical images and 3D temperature images from the data acquired by the MRI device. According to an exemplary embodiment, the central control unit 10 of the multi-emitter device and the image construction unit 51 can be integrated into a single entity.

[0104] The display unit 32 of the central control unit 10 is connected to the image construction unit 51 and also allows the temperature images to be displayed in real time during the treatment and the temperature measurements transmitted by the temperature sensor of the multi-emitter device 1. The display unit 32 comprises a data entry interface, thus allowing the practitioner to enter the data to adjust the wavelength, the light power, the emission duration and the emission time of each of the light beams generated by the laser source system and intended to be transported and emitted by the optical fibers.

[0105] The target region is a region in which the biological tissue must undergo a temperature variation. This region must have an appropriate size to ensure the destruction of all the pathological tissue while preserving the tissues in the vicinity of the target region. The evaluation of the spatial extension of the target region is carried out by the practitioner in a phase called the “preoperative planning phase” from data relating to anatomical images of the target region. This phase also makes it possible to determine the complex geometric shape and the location of the target region.

[0106] As an example, in [Fig.7], an organ comprising a target region, named Rc, surrounded by healthy regions is schematically represented.

[0107] During the preoperative planning phase, based on the anatomical image of the target region, the practitioner defines an intervention strategy which consists of defining: - a position of the distal end of the optical sheath relative to the target region; - the angular sector covered by each of the emitters; - the distal position of each of the transmitters; - a wavelength for each of the treatment laser beams; - a light power for each of the treatment laser beams; - a duration of laser energy deposition in the target region for each of the emitters, this duration being able to be different for each emitter; - potentially different emission times for each of the transmitters.

[0108] During the thermal treatment phase, the practitioner can individually adjust the light power, wavelength, emission duration and emission time of the beams emitted by the emitters or optical fibers according to the temperature images transmitted by the MRI imaging device 50.

[0109] With reference to Figures 8A, 8B and 8C, two examples of possible use of the same optical sheath are described. [Fig. 8A] schematically illustrates an optical sheath 150 with a radial distribution of six optical fibers positioned at the distal end of the sheath. Each of the optical fibers is capable of emitting a laser beam numerically referenced F1, F2, F3, F4, F5 and F6. [Fig. 8B] shows six temperature images obtained by the MRI imaging device. Each temperature image is obtained simultaneously with the activation of a single optical fiber, each optical fiber being activated sequentially one after the other. The temperature images clearly show six heated zones in distinct angular sectors. On the other hand, the temperature distributions around the optical sheath are more or less extensive, due to a different power delivered to each optical fiber. [Fig.8C] shows a temperature image obtained during simultaneous activation of the six optical fibers with the same power. The temperature image shows a substantially circular temperature rise around the optical cladding 150. .

[0110] With reference to [Fig.9], an example of possible use of two sheaths 240, 250 whose distal ends are positioned on either side of a target region Rc. Each of the sheaths 240, 250 here comprises for example respectively three optical fibers 241, 242, 243, 251, 252, 253. Thanks to the technical solution of the present invention, it is thus possible to activate only the two optical fibers 241, 242, 251, 252 whose laser beams are emitted in the direction of the target region, and to leave inactive the third optical fiber whose emitted laser beam covers an angular sector located in a healthy region to be preserved from the biological tissue. In addition, it is also possible to select a different wavelength, light power and laser energy deposition time for each of the four emitted laser beams so that a 3D thermal distribution can be generated that matches the 3D geometric shape of the target region. Industrial application

[0111] The use of a plurality of laser energy emitters, each covering a different angular sector and at different positions along the sheath, makes it possible to generate a 3D temperature distribution adjustable with respect to any geometric shape of the target region. Due to this flexibility on the geometry of the thermal lesion created, the invention is particularly suitable for treatment of cardiac fibrillations, to treat tumors in various organs, such as the abdomen and pathological brain regions.

[0112] Furthermore, the control is more precise in terms of the depth of penetration of the light beam into the tissue of the target region by modulating the wavelength of the beams emitted by each of the emitters.

[0113] Finally, when the multi-laser energy emitter device is coupled with an MRI imaging device in a thermal treatment assembly, it is possible to modulate the light power, the emission duration as well as the emission time of each of the emitters in order to adjust the laser energy deposition in time and space from the temperature images obtained by the MRI imaging device.

[0114] The invention is not limited to the embodiments described above as a non-limiting example. It encompasses all variant embodiments that may be envisaged by those skilled in the art. It should be understood in particular that logical modifications may be made. Furthermore, the embodiments presented in the detailed description of the invention should not be interpreted as limiting the order of the steps and sub-steps.

Claims

Claims

1. A multi-laser energy emitter laser device (1) for thermally treating a target region of biological tissue, coupled with an MRI imaging device in a thermal treatment assembly, comprising: - at least one sheath (150) having a longitudinal axis (AA') and comprising a proximal end (151) and a distal end (152) intended to be placed opposite the target region; - at least two optical fibers (123, 124, 125, 126, 127) extending in the sheath between the proximal end and the distal end, each of the optical fibers being adapted to guide a thermal treatment laser beam to the target region and to deposit laser energy in the target region; - the distal ends of at least two optical fibers being configured to each emit a laser beam in a different emission direction relative to the longitudinal axis of the sheath; - a laser source system (19) configured to generate at least two laser beams, said at least two laser beams having different or identical wavelengths with adjustable light power; - a laser beam control unit (31) configured to control the laser source system so as to select the wavelength, the light power, the duration of the laser energy deposition and the moment of emission of each of the laser beams guided and emitted by the optical fibers towards the target region so as to generate a 3D thermal distribution having a geometric shape adapted to the geometric shape of the target region, said laser power system being controlled to modulate the light power, the duration of emission as well as the moment of emission of each of the emitters in order to adjust the deposition of laser energy on the target region in time and in space from temperature images obtained by the MRI imaging device.

2. The device of claim 1, wherein the distal end of at least two optical fibers is positioned at a different distance from a surface of the distal end of the sheath (150).

3. Device according to one of claims 1 or 2, in which the distal end of the optical fibers is configured to emit a laser beam in an emission direction oriented at an angle a between 0 and 180° relative to the longitudinal axis of the sheath (150).

4. Device according to one of claims 1 to 3, wherein said laser source system (19) comprises a plurality of monochromatic laser sources (23, 24, 25, 26, 27, 28).

5. Device according to one of claims 1 to 4, in which the laser source system is adapted to generate at least two laser beams of different wavelengths per optical fiber.

6. Device according to one of claims 1 to 5, further comprising a plurality of transmission optical fibers (43, 44, 45, 46, 47, 48) capable of transmitting the laser beams generated by the laser source system (19) to the optical fibers (123, 124, 125, 126, 127, 128) of the sheath (150).

7. Device according to one of the preceding claims, further comprising a temperature sensor.

8. Device according to claim 7, in which the temperature sensor is an optical sensing fiber (128) capable of detecting a temperature variation in the target region.

9. The device of claim 8, wherein said plurality of thermal processing optical fibers (123, 124, 125, 126, 127) are distributed radially symmetrically around the detection optical fiber (128).

10. Device according to one of the preceding claims and claim 6, further comprising connection means (30, 130) capable of connecting the optical fibers (123, 124, 125, 126, 127, 128) of the sheath (150) with the transmission optical fibers (43, 44, 45, 46, 47, 48) of the laser source system (19).

11. Device according to one of the preceding claims, in which the sheath (150) comprises at least one lumen (158) adapted for the injection of a therapeutic substance under pressure intended to be ejected towards the target region.

12. Device according to one of the preceding claims, in which the sheath (150) comprises a suitable closed cooling circuit for transporting a coolant intended to cool a portion of the distal end (152) of the sheath (150).

13. Device according to claim 12, in which the closed cooling circuit is formed by at least two ports (158, 159, 160) provided in the sheath.

14. A device according to claim 12, wherein the closed cooling circuit is formed by a cooling sheath (161) surrounding the sheath (150) comprising the optical fibers and a lumen (158) provided in the sheath (150).

15. A heat treatment assembly (500) for a target region of a biological tissue comprising: - a laser device with multiple laser energy emitters (1) according to one of claims 1 to 14 for treating the target region; - a magnetic resonance imaging system (50) configured to generate anatomical images and thermometric images of the target region.

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