System for treating a lesion using mechanical waves

Abstract

A device for treating a lesion, the device comprising: an elongated structure between a first proximal end and a first distal end and defining a cavity extending from the first proximal end, the elongated structure comprising a photoacoustic transducer portion, the cavity being configured for receiving therein an optical waveguide extending along a second longitudinal axis between a second proximal end for receiving light and a second distal end, the optical waveguide comprising a light scattering section configured for scattering at least part of the light in at least one direction other than the second longitudinal axis, the photoacoustic transducer portion being configured for receiving the light scattered by the light scattering section when the optical waveguide is inserted into the cavity and generating mechanical waves in order to treat the lesion.

Description

SYSTEM FOR TREATING A LESION USING MECHANICAL WAVESCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority on U.S. Provisional Patent Application No. 63 / 564,236 filed on March 12, 2024, the content of which is incorporated herein by reference.FIELD

[0002] The present invention relates to the field of medical devices and methods for treating a lesion, and more specifically methods and systems for generating mechanical waves for treating lesions.BACKGROUND

[0003] Calcified lesions within the body may be harmful. Calcified lesions such as a calcified artery of a calcified heart valve may involve difficult surgical interventions for treatment. Current surgical interventions such as those using balloon devices comprising a photoacoustic transducer therein, may experience a loss of intensity of the photoacoustic waves produced as the photoacoustic waves must propagate through the balloon material before arriving at the target calcified structure, and cross various interfaces between media of different acoustic impedances that originate acoustic reflections and further loss of intensity.

[0004] Therefore, there is a need for an improved method and system for treating a lesion using mechanical waves.SUMMARY

[0005] According to a first broad aspect, there is provided a device for treating a lesion of a subject, the device comprising: an elongated structure extending along a first longitudinal axis between a first proximal end and a first distal end and defining a waveguide-receiving cavity extending from the first proximal end along the first longitudinal axis, the elongated structure comprising a photoacoustic transducer portion, the waveguide -receiving cavity being configured for receiving therein at least a distal section of an optical waveguide extending along a second longitudinal axis between a second proximal end for receiving light and a second distal end, the optical waveguide comprising a light scattering section configured for scattering at least part of the light in at least one direction other than the second longitudinal axis, the photoacoustic transducer portion of the elongated structure being configured for receiving at least some of light scattered by the light scattering section of the optical waveguide when the optical waveguide is inserted into the waveguide-receiving cavity and generating mechanical waves in order to treat the lesion.

[0006] In some embodiments, the elongated structure comprises an elongated body extending along a third longitudinal axis between a first end and a second end and defining the waveguide-receiving cavity extending from the first end along the third longitudinal axis, the elongated body comprising a section made of a photoacoustic transducer material for receiving the at least some of the light scattered by the light scattering section of the optical waveguide and generating the mechanical waves, the section made of a photoacoustic transducer material corresponding to the photoacoustic transducer portion.

[0007] In other embodiments, the elongated structure comprises: an elongated body extending along a third longitudinal axis between a first end and a second end and defining the waveguide-receiving cavity extending from the first end along the third longitudinal axis; and a photoacoustic transducer mounted on the elongated body, the photoacoustic transducer being positioned so as to receive the at least some of the light scattered by the light scattering section of the optical waveguide and generate the mechanical waves, the photoacoustic transducer corresponding to the photoacoustic transducer portion.

[0008] In some embodiments, the photoacoustic transducer is mounted on an external face of the elongated body.

[0009] In some embodiments, the external face of the elongated body is provided with a recess, the photoacoustic transducer being inserted into the recess.

[0010] In some embodiments, a thickness of the recess is equal to a thickness of the photoacoustic transducer.

[0011] In other embodiments, the photoacoustic transducer is mounted on an internal face of the elongated body.

[0012] In some embodiments, the internal face of the elongated body is provided with a recess, the photoacoustic transducer being inserted into the recess.

[0013] In some embodiments, a thickness of the recess is equal to a thickness of the photoacoustic transducer.

[0014] In some embodiments, the photoacoustic transducer comprises a coating of photoacoustic transducer material.

[0015] In some embodiments, a length of the photoacoustic transducer portion is at least equal to a length of the light scattering section of the optical waveguide.

[0016] In some embodiments, a portion of the light scattering section is configured for reflecting at least part of the scattered light.

[0017] In some embodiments, the portion of the light scattering section is coated with a light reflecting material.

[0018] In some embodiments, the waveguide-receiving cavity extends between the first proximal end and the first distal end of the elongated structure as to form an opening extending along the elongated structure.

[0001] In some embodiments, a cross-sectional size of the opening varies along the first longitudinal axis.

[0020] In some embodiments, the light scattering section is located adjacent to the second distal end of the optical waveguide.

[0021] In some embodiments, the second distal end of the optical waveguide is configured for at least partially reflecting the light.

[0022] In some embodiments, the photoacoustic transducer portion is radiopaque.

[0023] In other embodiments, the device further comprises a radiopaque marker mounted to one of the optical waveguide and the elongated body.

[0024] In some embodiments, the device further comprises an anchoring device mounted to the elongated structure for anchoring the device to the subject at a desired position relative to the lesion.

[0025] In some embodiments, the anchoring device is movable between a rest position and an extended position, the anchoring device being adjacent to the elongated structure when in the rest position and away from the elongated structure when in the extended position.

[0026] In some embodiments, the device further comprises the optical waveguide.

[0027] In some embodiments, the optical waveguide comprises an optical fiber and the elongated structure comprises a catheter.

[0028] According to another broad aspect, there is provided an assembly for treating a lesion of a subject, the device comprising: an optical waveguide extending along a first longitudinal axis between a first proximal end connectable to a light source for receiving light therefrom and a first distal end, the optical waveguide comprising a light scattering section configured for scattering at least part of the light in at least one direction other than the first longitudinal axis; and an elongated structure extending along a second longitudinal axis between a second proximal end and a second distal end and defining a waveguidereceiving cavity extending from the second proximal end along the second longitudinal axis, the waveguide -receiving cavity being configured for receiving at least a section of the optical waveguide comprising the first distal end thereof, the elongated structurecomprising a photoacoustic transducer portion configured for converting the light into mechanical waves, the photoacoustic transducer portion of the elongated structure being configured for receiving at least some of light scattered by the light scattering section of the optical waveguide when the optical waveguide is inserted into the waveguide -receiving cavity and generating the mechanical waves in order to treat the lesion.

[0029] In some embodiments, the elongated structure comprises an elongated body extending along a third longitudinal axis between a first end and a second end and defining the waveguide -receiving cavity, the elongated body comprising a section made of a photoacoustic transducer material for receiving the at least some of the light scattered by the light scattering section of the optical waveguide and generating the mechanical waves, the section made of a photoacoustic transducer material corresponding to the photoacoustic transducer portion.

[0030] In other embodiments, the elongated structure comprises: an elongated body extending along a third longitudinal axis between a first end and a second end and defining the waveguide-receiving cavity extending from the first end along the third longitudinal axis; and a photoacoustic transducer mounted on the elongated body, the photoacoustic transducer being positioned so as to receive the at least some of the light scattered by the light scattering section of the optical waveguide and generate the mechanical waves, the photoacoustic transducer corresponding to the photoacoustic transducer portion.

[0031] In some embodiments, the photoacoustic transducer is mounted on an external face of the elongated body.

[0032] In some embodiments, the external face of the elongated body is provided with a recess, the photoacoustic transducer being inserted into the recess.

[0033] In some embodiments, a thickness of the recess is equal to a thickness of the photoacoustic transducer.

[0034] In other embodiments, the photoacoustic transducer is mounted on an internal face of the elongated body.

[0035] In some embodiments, the internal face of the elongated body is provided with a recess, the photoacoustic transducer being inserted into the recess.

[0036] In some embodiments, a thickness of the recess is equal to a thickness of the photoacoustic transducer.

[0037] In some embodiments, the photoacoustic transducer comprises a coating of photoacoustic transducer material.

[0038] In some embodiments, a length of the photoacoustic transducer portion is at least equal to a length of the light scattering section of the optical waveguide.

[0039] In some embodiments, a portion of the light scattering section is configured for reflecting at least part of the scattered light.

[0040] In some embodiments, the portion of the light scattering section is coated with a light reflecting material.

[0041] In some embodiments, the waveguide -receiving cavity extends between the second proximal end and the second distal end of the elongated structure as to form an opening extending along the elongated structure.

[0042] In some embodiments, a cross-sectional size of the opening varies along the first longitudinal axis.

[0043] In some embodiments, the light scattering section is located adjacent to the first distal end of the optical waveguide.

[0044] In some embodiments, the first distal end of the optical waveguide is configured for at least partially reflecting the light.

[0045] In some embodiments, the photoacoustic transducer portion is radiopaque.

[0046] In other embodiments, comprising a radiopaque marker mounted to one of the optical waveguide and the elongated body.

[0047] In some embodiments, the assembly further comprises an anchoring device mounted to the elongated structure for anchoring the elongated structure to the subject at a desired position relative to the lesion.

[0048] In some embodiments, the anchoring device is movable between a rest position and an extended position, the anchoring device being adjacent to the elongated structure when in the rest position and away from the elongated structure when in the extended position.

[0049] In some embodiments, the optical waveguide comprises an optical fiber and the elongated structure comprises a catheter.

[0050] Implementations of the present technology each have at least one of the above- mentioned objects and / or aspects, but do not necessarily have all of them. It should be understood that some aspects of the present technology that have resulted from attempting to attain the above-mentioned object may not satisfy this object and / or may satisfy other objects not specifically recited herein.

[0051] Additional and / or alternative features, aspects and advantages of implementations of the present technology will become apparent from the following description, the accompanying drawings and the appended claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0052] For a better understanding of the present technology, as well as other aspects and further features thereof, reference is made to the following description which is to be used in conjunction with the accompanying drawings, where:

[0053] FIG. 1 is a block diagram illustrating a system for treating a lesion, in accordance with an embodiment;

[0054] FIG. 2A illustrates an assembly comprising a catheter device and an optical fiber, wherein a photoacoustic transducer is secured to the external surface of the catheter device, in accordance with an embodiment;

[0055] FIG. 2B illustrates a cross-sectional view of the catheter device of FIG. 2A;

[0056] FIG. 2C illustrates a longitudinal cross-sectional view of the optical fiber of FIG. 2A inserted into the catheter device of FIG. 2A;

[0057] FIG. 2D illustrates an assembly comprising a catheter device and an optical fiber, wherein a photoacoustic transducer is secured to a recess present on the external surface of the catheter device, in accordance with an embodiment;

[0058] FIG. 3 A illustrates an assembly comprising the optical fiber of FIG. 2A and a catheter device, wherein a photoacoustic transducer is secured to the internal surface the catheter device, in accordance with an embodiment;

[0059] FIG. 3B illustrates an assembly comprising the optical fiber of FIG. 2A and a catheter device provided with an integral photoacoustic transducer, in accordance with an embodiment;

[0060] FIG. 4 illustrates a catheter device comprising a handle portion, a catheter, a photoacoustic transducer and a tube, in accordance with an embodiment;

[0061] FIG. 5 illustrates an optical fiber device comprising an optical fiber, a light scattering section and a mirror, in accordance with an embodiment;

[0062] FIG. 6A is a cross-sectional view of the tip of catheter device comprising an aperture, in accordance with a first embodiment;

[0063] FIG. 6B is a cross-sectional view of the tip of catheter device comprising an aperture, in accordance with a second embodiment;

[0064] FIG. 7A illustrates a catheter device comprising a handle portion, a catheter, a tube, a photoacoustic transducer and an anchoring mechanism, in accordance with an embodiment;

[0065] FIG. 7B illustrates the tip of the catheter device of FIG. 8A;

[0066] FIG. 8A illustrates the insertion of the distal end of the catheter device of FIG. 7 A into a cardiac vessel comprising cardiac valve leaflets around a guide wire, the anchoring mechanism being in a rest position, in accordance with an embodiment;

[0067] FIG. 8B illustrates the distal end of the catheter device of FIG. 7A being positioned between the cardiac valve leaflets, in accordance with an embodiment;

[0068] FIG. 8C illustrates the distal end of the catheter device of FIG. 7A being positioned between the cardiac valve leaflets with the anchoring mechanism being in an extended position, in accordance with an embodiment; and

[0069] FIG. 8D illustrates the distal end of the catheter device of FIG. 7A being positioned between the cardiac valve leaflets with the anchoring mechanism being in an extended position and the guidewire removed, in accordance with an embodiment.DETAILED DESCRIPTION

[0070] The examples and conditional language recited herein are principally intended to aid the reader in understanding the principles of the present technology and not to limit its scope to such specifically recited examples and conditions. It will be appreciated that those skilled in the art may devise various arrangements which, although not explicitly described or shown herein, nonetheless embody the principles of the present technology and are included within its spirit and scope.

[0071] Furthermore, as an aid to understanding, the following description may describe relatively simplified implementations of the present technology. As persons skilled in the art would understand, various implementations of the present technology may be of a greater complexity.

[0072] In some cases, what are believed to be helpful examples of modifications to the present technology may also be set forth. This is done merely as an aid to understanding, and, again, not to define the scope or set forth the bounds of the present technology. These modifications are not an exhaustive list, and a person skilled in the art may make other modifications while nonetheless remaining within the scope of the present technology.Further, where no examples of modifications have been set forth, it should not be interpreted that no modifications are possible and / or that what is described is the sole manner of implementing that element of the present technology.

[0073] In the context of the present disclosure, the words "first", "second", "third", etc. have been used as adjectives only for the purpose of allowing for distinction between the nouns that they modify from one another, and not for the purpose of describing any particular relationship between those nouns. Thus, for example, it should be understood that the use of the terms "system" and "third system" is not intended to imply any particular order, type, chronology, hierarchy or ranking (for example) of / between the system, nor is their use (by itself) intended imply that any "second system" must necessarily exist in any given situation. Further, as is discussed herein in other contexts, reference to a "first" element and a "second" element does not preclude the two elements from being the same actual real-world element. Thus, for example, in some instances, a "first" system and a "second" system may be the same software and / or hardware, in other cases they may be different software and / or hardware.

[0074] Moreover, all statements herein reciting principles, aspects, and implementations of the present technology, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof, whether they are currently known or developed in the future. Thus, for example, it will be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative circuitry embodying the principles of the present technology. Similarly, it will be appreciated that any flowcharts, flow diagrams, state transition diagrams, pseudo-code, and the like represent various processes which may be substantially represented in computer-readable media and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.

[0075] In the following, there is described a device or assembly for treating a lesion of a subject. The device or assembly comprises at least an elongated structure extending along a longitudinal axis between a proximal end and a distal. The elongated structure further defines a waveguide-receiving cavity or aperture which extends from its proximal endtowards its distal end along the longitudinal axis. The elongated structure comprises at least one photoacoustic transducer portion which is configured for converting light incident thereon into mechanical waves.

[0076] The waveguide -receiving cavity is configured for receiving therein at least a distal section of an optical waveguide such as an optical fiber. The optical waveguide extends along a longitudinal axis between a proximal end for receiving light and a second end and comprises a light scattering section configured for scattering at least part of the light propagating into the optical waveguide in at least one direction other than the longitudinal axis of the optical waveguide.

[0077] When the optical waveguide is inserted into the waveguide -receiving cavity of the elongated structure and light such as pulsed light is coupled into the optical waveguide at its proximal end, at least some of the light propagating into the optical waveguide is scattered by the light scattering section and at least part of the scattered light propagates up to the photoacoustic transducer portion which converts this incident light into mechanical waves in order to treat the lesion.

[0078] In some embodiments, the elongated structure comprises an elongated body, such as a catheter, designed for receiving the optical waveguide therein and the photoacoustic transducer portion is integral with the elongated body, i.e., at least one section of the elongated body is made of a photoacoustic transducer material.

[0079] In other embodiments, the elongated structure comprises an elongated body, such as a catheter, designed for receiving the optical waveguide therein and a separate or independent photoacoustic transducer mounted on the elongated body.

[0080] In some embodiments, the device or assembly further comprises the optical waveguide.

[0081] Fig. 1 illustrates one embodiment of a system 10 for treating a lesion 12. The system 10 comprises a light source 14, an optical waveguide 16, a catheter device 18, and a photoacoustic transducer 20.

[0082] In at least some embodiments, a lesion such as lesion 12 should be understood as any tissue with injury or irregular change. In the context of the present disclosure, examples will be made to lesions located within the cardiovascular system that have been hardened by the presence of calcification. Such lesions in a cardiovascular system may be located on cardiac valve leaflets, a blood vessel, an artery, any cardiac structure, and / or any structure of the circulatory system. For example, a lesion may correspond to a calcium deposit, a calcified body, a lipid deposit, plaque and / or the like. It will be understood that the location of a lesion is not limited to the circulatory system. For example, a lesion may be located in a structure of the urological system. For example, a lesion may be a stone in a kidney. It will be understood that treating a lesion may correspond to destroying, weakening, ablating and / or interfering with the lesion.

[0083] The catheter device 18 is configured to be inserted partially into a vessel of a subject adjacent to the lesion to be treated and to receive therein at least a portion of the optical waveguide 16. The optical waveguide 16 is configured for receiving the light emitted by the light source 14 and transversally radiates the light. The photoacoustic transducer 20 is configured to collect at least part of the transversally radiated light and convert the collected light into a mechanical wave for treating the lesion 12.

[0084] The light source 14 is configured to emit light having a given wavelength. It should be understood that the optical waveguide 16 is configured for propagating light having the given wavelength and the photoacoustic transducer 20 is configured for converting light having the given wavelength into a mechanical wave. It should also be understood that the light source may be configured for emitting light having more than one wavelength, i.e., the wavelength of the light emitted by the light source 14 may be comprised within a given range of wavelengths.

[0085] In some embodiment, the light source 14 is configured for emitting pulses of light. In some embodiments, the characteristics of the light pulses are chosen so that the photoacoustic transducer generate mechanical shock waves. In some embodiments, the light source 14 comprises at least one pulsed laser.

[0086] In other embodiments, the light source 14 is configured for emitted a modulated continuous-wave (CW) light.

[0087] The optical waveguide 16 is connectable to the light source 14 so that the light emitted by the light source 14 be coupled at one end of the optical waveguide 16 to propagate along the longitudinal axis of the optical waveguide 16. The optical waveguide 16 comprises a section 22 that allows at least a portion of the light propagating into the optical waveguide to radiate or propagate outside of the optical waveguide 16 transversally, i.e., in a direction other than along the longitudinal axis of the optical waveguide 16. For example, the section 22 may allow light to radiate in a direction orthogonal to the longitudinal axis of the optical waveguide 16. In another example, the section 22 may be partially mirrored (a circumferential or radial side or portion of the section 22 is mirrored, e.g., is coated with a light reflecting material, to reflect light towards the non-mirrored portion of the section 22) to allow for the reflection of part of the light arriving at the mirrored side and the propagation outside with higher intensity through the non-mirrored (i.e., transmissive) side and increase light fluence on the photoacoustic transducer. The ability to treat a lesion depends on the peak pressure of the mechanical waves and, for pulsed lasers, this therefore depends on the fluence (i.e., radiance energy received by the surface per unit area) on the surface of the photoacoustic transducer. The higher the fluence, the higher the peak pressure. However, optical fibers usually do not withstand high fluences from pulsed lasers which may limit how much radiant energy could be transmitted to the photoacoustic transducer. The partially mirrored section 22 allows to concentrate the light transmitted on a smaller area of the photoacoustic transducer, which will increase the intensity of the generated mechanical waves.

[0088] The catheter device 18 corresponds to an elongated body which extends longitudinally between a proximal end and a distal end and defines a cavity or an aperture that extends longitudinally from the proximal end towards the distal end thereof for receiving therein at least a portion of the optical waveguide 16. It should be understood that when the optical waveguide 16 is inserted into the catheter device 18, the transversally radiating section 22 of the optical waveguide 16 is positioned within the catheter device 18.

[0089] The photoacoustic transducer 20 is positioned within the system 10 so as to receive at least of portion of the light transversally propagating from the section 22 of the optical waveguide 16 so as to convert the light incoming thereon into a mechanical wave.

[0090] In some embodiments, the photoacoustic transducer 20 is mounted on the catheter device 18. For example, the photoacoustic transducer 20 may be mounted on the external surface of the catheter device 18. In another example, the photoacoustic transducer 20 may be mounted within the cavity or aperture onto the internal surface of the catheter device 18. In some embodiment, the photoacoustic transducer 20 is positioned onto the catheter device so as to substantially face the section 22 of the optical waveguide 16 when the optical waveguide 16 is inserted into the catheter device 18.

[0091] In some embodiments, the catheter device 18 comprises a single elongated body made of a flexible material.

[0092] In other embodiments, the catheter device 18 comprises at least one first portion made of a flexible material and a second portion made of a rigid material such as glass and on which photoacoustic transducer 20 is mounted. For example, when the photoacoustic transducer 20 is mounted adjacent to the distal end of the catheter device 18, the catheter device 18 may comprise a flexible portion which extends from the proximal end thereof and a rigid portion which extends from the flexible portion up to the distal end of the catheter device 18, and the photoacoustic transducer 20 is mounted on the rigid portion of the catheter device 18.

[0093] In operation, the optical waveguide 16 is connected to the light source 14 and inserted into the catheter device 18 so that the section 22 of the optical waveguide 16 be positioned into the catheter device 18. The assembly formed of the catheter device 18 and the optical waveguide 16 is inserted into a vessel of the subject so that the photoacoustic transducer 20 be adjacent to the lesion 12 to be treated and the number of interfaces between different sound propagation media is minimized. The light source 14 is activated to emit light that is coupled into the optical waveguide 16. The coupled light propagates along the optical waveguide 16 up to the section 22 of the optical waveguide 16. At least part of the light reaching the section 22 is transversally emitted outside of the opticalwaveguide 16. The photoacoustic transducer 20 collects at least part of the transversally emitted light and generates a mechanical wave that propagates up to the lesion 12 in order to treat the lesion 12.

[0094] In some embodiments in which the photoacoustic transducer 20 is mounted on the catheter device 18, the photoacoustic transducer 20 may correspond to a coating deposed on the internal face or the external face of the catheter device 18.

[0095] Exemplary photoacoustic transducers 20 may include at least one of:

[0096] - a carbon-based coating such as a carbon black coating, a graphene oxide coating, a carbon nanotubes (CNT) coating, or the like;

[0097] - a metal-based coating such as a gold nanoparticles coating, a titanium nitride coating, a copper oxide coating or the like;

[0098] - a polymer-based coating such as polydopamine coating, a polypyrrole coating, or the like;

[0099] - a dye-based coating such as a nigrosine coating, a metallic organic dye coating, or the like;

[0100] - a polymer coating such as a polydimethylsiloxane (PDMS) coating, a polyurethane coating, a polyvinylidene fluoride (PVDF) coating, or the like;

[0101] - a ceramic coating such as an alumina coating, a zirconia coating, a silicon carbide coating, a titanium nitride coating or the like;

[0102] - an oxide coating such as a silica aerogel coating, a zirconia coating, or the like; and

[0103] - a hybrid materials coating such as a carbon-polymer composite coating, a metal-polymer laminate coating, an aerogel-graphene composite coating, or the like.

[0104] In some embodiments, the coating material is chosen so as to exhibit a high optical absorption, a good thermal conductivity and / or a strong adhesion to the catheter device.

[0105] In embodiments in which the photoacoustic transducer corresponds a coating deposited on the catheter device, it should be understood that any adequate method for depositing the coating may be used. For example, at least one of the following deposition methods may be used: spray coating, dip coating, spin coating, sputtering, physical vapor deposition, chemical vapor deposition, electrodeposition, and the like.

[0106] In some embodiments in which the photoacoustic transducer is integral with he catheter device, at least some of the above-mentioned materials for a coating may be used for the section of the catheter device that exhibits the photoacoustic transducer properties.

[0107] In some embodiments, the photoacoustic transducer 20 is a thin film of a lightabsorbing species embedded in a material with a large Griineisen parameter, and this film may be attached to a transparent section of the catheter device 18. In operation, the light transmitted through section 22 of the optical waveguide 16 traverses the transparent section of catheter device 18 and is at least partially absorbed by the thin film photoacoustic transducer 20. In this case, the transparent section strongly confines one side of the photoacoustic transducer 20 and assists in launching the mechanical wave generated by light absorption predominantly outwards, in the direction of the lesion. Moreover, the property of being thin increases the density of energy deposited in the photoacoustic transducer 20 when it absorbs pulsed light, the temperature transiently increases to higher values, a stronger thermoelastic expansion is produced and a higher intensity mechanical wave is launched. In some embodiments, the thickness of the thin film is less than that of the outside wall of catheter device 18. In some embodiments, the thickness of the thin film is less than 100 pm. In some embodiments, the thickness of the thin film is less than 50 pm.

[0108] In some embodiments, the photoacoustic transducer 20 is configured to convert light into at least one acoustic or mechanical wave. In other embodiments, the photoacoustic transducer 20 is configured to convert light into at least one ultrasound wave.

[0109] In embodiments in which the light source 14 is configured for emitting light pulses, the photoacoustic transducer 20 is configured for generating mechanical pulses such as acoustic pulses or ultrasound pulses.

[0110] In embodiments in which the light source 14 is configured for emitting modulated CW light, the photoacoustic transducer 20 is configured for generating modulated CW mechanical waves such as modulated CW acoustic waves or modulated CW ultrasound waves.

[0111] It should be understood that the characteristics of the light emitted by the light source 14, such as wavelength, amplitude, and / or the like, may be chosen based on properties of the photoacoustic transducer 20 and desired characteristics for the mechanical waves. For example, when the light source is configured for generating light pulses, the characteristics of the light pulses, such as their wavelength, repetition rate, pulse duration, peak amplitude, fluence, fluence rate, etc., may be chosen based on the properties of the photoacoustic transducer 20 and desired characteristics for the mechanical pulses. In some embodiments, the system 10 further comprises a controller (not shown) to control the light source and thereby control the characteristics of the emitted light.

[0112] Fig. 2A illustrates one embodiment of an assembly comprising a catheter device 24 and an optical fiber 26. Fig. 2B illustrates a cross-sectional view of the catheter device 24 and Fig. 2C illustrates a cross-sectional view of the catheter device 24 having the optical fiber 26 inserted therein.

[0113] Referring to Fig. 2A, the optical fiber 26 extends longitudinally from a proximal end 36 to a distal end 38. The optical fiber 26 comprises a light scattering section 40 extending longitudinally along a given section of the optical fiber 26. The light scattering section 40 is configured for allowing at least some of the light propagating within the optical fiber 26 to radiate or propagate transversally outside of the optical fiber 26. While in the illustrated embodiment, the light scattering section 40 is located adjacent to the distal end 38 of the optical fiber 26, it should be understood that the light scattering section 40 may have any adequate position along the optical fiber 26 as long as at least some of thelight emitted by the light scattering section 40 may reach a photoacoustic transducer 28 when the optical fiber 26 is inserted into the catheter device 24.

[0114] Referring to Figs. 2A and 2B, the catheter device 24 comprises an elongated body 27, i.e., a catheter, and a photoacoustic transducer 28 mounted on the elongated body 27. The elongated body 27 extends longitudinally from a proximal end 30 to a distal end 32 and defines a cavity 33 that extends longitudinally from the proximal end 30 up to a cavity end 35 along a given longitudinal section of the elongated body 27. The cross- sectional size and shape of the cavity 33 are chosen so that at least the distal portion of the optical fiber 26 comprising the light scattering section 40 may be inserted therein. For example, the cavity 33 may have a circular cross-section of which the diameter is slightly greater than the diameter of the optical fiber 26.

[0115] The elongated body 27 further comprises a translucent or transparent section or window 34 extending longitudinally along a given section thereof. In the illustrated embodiment, the section 34 extends along the whole circumference of the elongated body 27 and is located adjacent to the distal end 32 of elongated body 27. It should be understood that the section 34 is transparent or translucent for light having the same wavelength as that of the light propagating in the optical fiber 26 so that at least part of the light radially emitted by the optical fiber 26 may propagate transversely through the section 34.

[0116] The catheter device 24 further comprises the photoacoustic transducer 28 which is mounted onto the external face of the elongated body 27, and more precisely on the section 34 of the elongated body 27 so at least part of light propagating through the section 34 may reach the photoacoustic transducer 28. In the illustrated embodiment, the photoacoustic transducer 28 is a tubular element mounted around the elongated body 27, i.e., the photoacoustic transducer 28 extends around the whole circumference of the elongated body 27. In the illustrated embodiment, the length of the photoacoustic transducer 28 is slightly shorter than that of the section 34 for illustrative purposes. However, the person skilled in the art will understand that other configurations are possible and may be preferred. For example, the photoacoustic transducer 28 and the section 34 may have the same length. In another example, the length of the photoacoustic transducer 28may be longer than that of the section 34, e.g., the length of the photoacoustic transducer 28 is chosen to be long enough in comparison to that of the section 34 so as to prevent any light from reaching any surrounding tissue. Similarly, while the photoacoustic transducer 28 is substantially centered along the length of the section 34, it should be understood that the relative position between the photoacoustic transducer 28 and the section 34 may vary as long as part of the light propagating through the section 24 can reach the photoacoustic transducer 28. For example, only a section of the photoacoustic transducer 28 could face the section 34 of the elongated body 27.

[0117] Referring to Fig. 2C, when the optical fiber 26 is inserted into the catheter device 24, the distal end 38 of the optical fiber 26 abuts against the cavity end 35 and the light scattering section 40 faces the transparent section 34 so that at least some of the light radially propagating from the light scattering section 40 the optical fiber 26 may reach the transducer 28. It should be understood that the length of the transparent section 34, the photoacoustic transducer 28 and / or the light scattering section 40 may vary. For example, the light scattering section 40 may be longer than the transparent section 34 and the photoacoustic transducer 28, or vice versa.

[0118] Referring again to Fig. 2C, it should be understood that the shape and size of the transparent section 34, the photoacoustic transducer 28, the cavity 33 and the light scattering section 40 and the relative positions between the transparent section 34, the photoacoustic transducer 28 and the light scattering section 40, when the optical fiber 26 is inserted into the catheter device 24, are chosen so that, at least a distal portion of the optical fiber 26 is insertable into the cavity 33 of the elongated body 27 and, when the optical fiber 26 is inserted into the cavity 33, at least part of the light radially emitted by the light scattering section 40 of the optical fiber may reach the photoacoustic transducer 28. For example, while the light scattering section 40 extends radially along the whole circumference of the optical fiber 26, and the transparent section 34 and the photoacoustic transducer 28 each radially extend along the whole circumference of the elongated body 27 of the catheter device 24, the light scattering section 40 may extend radially along a given section of the circumference of the optical fiber 26 only, the transparent section 34 may extend radially along a given first section of the circumference of the elongated body27 and the photoacoustic transducer 28 may extend radially along a given second section of the circumference of the elongated body 27. In this case, the first and second circumferential sections at least overlap and the optical fiber 26 is inserted into the catheter device 24 so that its light scattering section 40 at least overlaps the first circumferential section in order for at least part of the light radially emitted by the light scattering section 40 of the optical fiber 26 to reach the photoacoustic transducer 28. As mentioned above, a circumferential portion of the light scattering section 40 may be coated with a light reflecting material so as to reflect light towards the portion of the light scattering section 40 that is not coated in order to increase the fluence of the light on the photoacoustic transducer 28.

[0119] While in the illustrated embodiment, the photoacoustic transducer 28 is mounted on the external face of the elongated body 27, the external face of the elongated body 27 may comprise a circumferential recess 29 in which the photoacoustic transducer 28 is located, as illustrated in Fig. 2D. It should be understood that the circumferential recess 29 is shaped and sized for receiving the photoacoustic transducer 28 therein. In some embodiments, the thickness of the circumferential recess 29 is chosen to be substantially equal to the thickness of the photoacoustic transducer 28 so that when the photoacoustic transducer 28 is inserted into the circumferential recess 29, the external or outer face of the photoacoustic transducer 28 is aligned or flush with the external face of the elongated body 27 adjacent to the recess 29, i.e., the photoacoustic transducer 28 does not radially project from the external face of the elongated body 27. In other embodiments, the thickness of the circumferential recess 29 is chosen to be greater than the thickness of the photoacoustic transducer 28. In further embodiments, the thickness of the circumferential recess 29 is chosen to be less than the thickness of the photoacoustic transducer 28. While in the illustrated embodiment, it extends along the whole circumference of the external face of the elongated body 27, the recess 29 may extend only along a section of the circumference of the external face of the elongated body 27. In this case, the photoacoustic transducer 28 is shaped and sized to fit into the recess 29, and when inserted therein, also extend only along a section of the circumference of the elongated body 27.

[0120] While in the illustrated embodiment, the catheter device 24 comprises a single transparent section 34 and a single photoacoustic transducer 28, it should be understood that the catheter device 24 may be provided with a plurality of transparent sections positioned at different locations along the length of the elongated body 27, and a plurality of photoacoustic transducers each mounted on a respective transparent section. In this case, the optical fiber 26 may comprise a single light scattering section which is positioned to face a given one of the plurality of transparent sections when the optical fiber 26 is inserted into the catheter device 24. In other embodiments, the optical fiber 26 may be provided with a plurality of light scattering sections which are located at different given locations along the length of the optical fiber 26 so that each light scattering section substantially faces a respective transparent section of the elongated body 27 when the optical fiber 26 is inserted into the catheter device 24.

[0121] Fig. 3 A illustrates one embodiment of an assembly comprising a catheter device41 and the optical fiber 26. The catheter device 41 comprises a catheter or elongated body42 and a photoacoustic transducer 44. It should be understood that the illustration of catheter device 41 in Fig. 3 A is a cross-sectional view thereof.

[0122] The elongated body 42 is a tubular body which extends longitudinally between a proximal end 46 and a distal end 48 and radially between an internal face and an external face, thereby defining an aperture 50 extending longitudinally between the proximal end 46 and the distal end 48. The internal face of the elongated body 42 is provided with a recess 51 which extends circumferentially from the internal face towards the external face of the elongated body 42. While in the illustrated embodiment, the recess 51 is located adjacent to the distal end 48 of the elongated body 42, it should be understood that the recess 51 may be located at any other adequate location along the length of the elongated body 42.

[0123] It should be understood that the shape and size of the aperture 50 are chosen so that the optical fiber 26 may be inserted therein.

[0124] As mentioned above, the catheter device 41 further comprises the photoacoustic transducer 44 which is mounted into the internal recess 51 of the elongated body 42. In thisembodiment, the photoacoustic transducer 44 has a tubular shape, i.e., the photoacoustic transducer 44 consists in a circular device having an aperture that extends along its length and is shaped and sized to receive the optical fiber 26 therein. In the illustrated embodiment, the outer diameter of the photoacoustic transducer 44 is substantially equal to the diameter of the recess 51 and the internal diameter of the photoacoustic transducer 44 is substantially equal to the diameter of the aperture 50 so that the thickness of the photoacoustic transducer 44 is substantially equal to the thickness or transversal depth of the recess 51 of the elongated body 42 and the aperture within the photoacoustic transducer 44 is substantially identical to the aperture 50 (i.e., both apertures have substantially the same shape and size). As a result, when the photoacoustic transducer 44 is inserted into the recess 51 , the internal face of the photoacoustic transducer 44 is substantially flush with the internal face of the elongated body 42 surrounding the recess 51 and the optical fiber 26 may be inserted thought the aperture 50 and the photoacoustic transducer 44. While in the illustrated embodiment, the shape and size of the photoacoustic transducer 44 substantially match those of the recess 51 , it will be understood that other configurations may be possible. For example, the thickness of the photoacoustic transducer 44 may be less than the thickness or transversal depth of the recess 51. In another example, the thickness of the photoacoustic transducer 44 may be greater than the thickness or transversal depth of the recess 51.

[0125] It should be understood that the aperture 50 extending along the elongated body 42 is also configured for receiving therein a guidewire.

[0126] In operation, after a guidewire is installed within a blood vessel, the proximal end of the guide wire is inserted into the distal end 48 of the catheter device 41 and the catheter device 41 is inserted over the guide wire and into the blood vessel until the photoacoustic transducer 44 faces the lesion to be treated. The guidewire is then removed and the distal end 38 of the optical fiber 26 is inserted into the proximal end 46 of the catheter device 41. The optical fiber 26 is then inserted into the catheter device 41 until the light scattering section 40 of the optical fiber 26 has a desired position relative to the photoacoustic transducer 44 so that at least a portion of the light emitted by the light scattering section 40 can reach the photoacoustic transducer 44, such as until the lightscattering section 40 faces the photoacoustic transducer 44. At this point, the treatment of the lesion starts by propagating light pulses into the optical fiber 26.

[0127] In some embodiments, the catheter device 41 is provided with securing means (not shown) such as a clamp for securing the optical fiber 26 to catheter 42. In this case, once the optical fiber 26 has been inserted into the catheter device 41 so that the light scattering section 40 has the desired position relative to the photoacoustic transducer 44, the securing means is activated to fix the relative position between the optical fiber 26 and the catheter 42.

[0128] Referring to Fig. 3 A, it should be understood that the length of the photoacoustic transducer 44, the recess 51 and the light scattering section 40 may vary. For example, light scattering section 40 may be shorter than the photoacoustic transducer 44 and the recess 51 , or vice versa.

[0129] Referring to Fig. 3 A, it should be understood that the shape and size of the recess 51, the photoacoustic transducer 44 and the light scattering section 40 and the relative position between the recess 51 (and therefore the photoacoustic transducer 44) and the light scattering section 40 are chosen so that, at least a distal portion of the optical fiber 26 is insertable into the aperture 50 of the elongated body 42 and, when the optical fiber 26 is inserted into the aperture 50, at least part of the light radially emitted by the light scattering section 40 of the optical fiber 26 may reach the photoacoustic transducer 44. For example, while the light scattering section 40 extends radially along the whole circumference of the optical fiber 26 and the recess 51 and the photoacoustic transducer 44 radially extends along the whole circumference of the recess 51 of the catheter device 41, the light scattering section 40 may extend radially along a first circumferential section of the optical fiber 26 and the recess 51 may extend radially along a second circumferential section of the elongated body 42. In this case, the optical fiber 26 is inserted into the catheter device 41 so that its first circumferential section at least overlaps the second circumferential section so that at least part of the light radially emitted by the light scattering section 40 of the optical fiber 26 may reach the photoacoustic transducer 44.

[0130] In some embodiments, the elongated body 42 comprises a plurality of recesses along the internal face of the elongated body 42, each positioned at a respective position along the length of the elongated body 42. In this case, the catheter device 41 also comprises a plurality of photoacoustic transducers each inserted into a respective recess. Similarly, in other embodiments, the elongated body 42 comprises a plurality of circumferential recesses along the external face of the elongated body 42, each positioned at a respective position along the length of the elongated body 42. In this case, the catheter device 41 also comprises a plurality of photoacoustic transducers each inserted into a respective circumferential recess.

[0131] While in the above-described embodiments the photoacoustic transducer is separate from the catheter, Fig. 3B illustrates one embodiment of an assembly comprising a catheter device 60 provided with an integral photoacoustic transducer and the optical fiber 26.

[0132] The catheter device 60 comprises a catheter or elongated body 62 having a photoacoustic transducer section 64. It should be understood that the illustration of catheter device 60 in Fig. 3 is a cross-sectional view thereof.

[0133] The elongated body 62 is a tubular body which extends longitudinally between a proximal end 66 and a distal end 68 and radially between an internal face and an external face, thereby defining an aperture 69 extending from the proximal end 46 towards the distal end 48 along the longitudinal axis of the elongated body 62.

[0134] The photoacoustic transducer section 64 is made of a photoacoustic transducer material (i.e., a material that converts light into acoustic wave) and extends along a given section longitudinal portion of the elongated body 62 and circumferentially about the elongated body 62. While in the illustrated embodiment it extends around the whole circumference of the elongated body 62, it will be understood that the photoacoustic transducer section 64 may only extend about a portion of the circumference of the elongated body 62. It will also be understood that the position of the photoacoustic transducer section 64 along the length of the elongated body 62 is chosen so that once theoptical fiber 26 is inserted into the cavity 69, at least some of the light scattered by the light scattering section 40 may propagate up to the photoacoustic transducer section 64.

[0135] It should be understood that the shape and size of the aperture 69 are chosen so that the optical fiber 26 may be inserted therein. It should also be understood that the aperture 69 extending along the elongated body 62 may also be configured for receiving therein a guidewire.

[0136] Referring to Fig. 3B, it should be understood that the length of the photoacoustic transducer section 64 and the light scattering section 40 may vary. For example, the light scattering section 40 may be shorter than the photoacoustic transducer section 44, or vice versa.

[0137] In some embodiments, the whole elongated body 62 is made of a photoacoustic transducer material, i.e., the photoacoustic transducer section 64 extends along the entire length of the elongates body 62.

[0138] In some embodiments, the elongated body 62 comprises a plurality of photoacoustic transducer sections, each positioned at a respective position along the length of the elongated body 62.

[0139] Fig. 4 illustrates one embodiment of a catheter device 72 comprising a handle portion or handle 76. The catheter device 72 further comprises a catheter 78, a photoacoustic transducer 80 and a tube 82.

[0140] The handle portion 76 extends longitudinally between a proximal end 84 to a distal end 86 and comprises an aperture (not shown) that extends longitudinally from the proximal end 84 to the distal end 86. The catheter 78 extends longitudinally between a proximal end 88 and a distal end 90 and comprises an aperture that extends longitudinally between a proximal end 88 and a distal end 90. The proximal end 88 of the catheter 78 is connected to the distal end 86 of the handle portion 76 so that the aperture of the catheter 78 is connected to the aperture in the handle portion 76.

[0141] The catheter 78 is provided with a transparent section (not shown) adjacent to the distal end 90 and the photoacoustic transducer 80 is mounted onto the external face of the catheter 78 around the transparent section.

[0142] In the illustrated embodiment, an optical fiber 74 comprising a light scattering section configured for emitting light radially is inserted into the catheter device 72. The optical fiber 74 is inserted into the catheter device 72 so that the light scattering section of the optical fiber 74 substantially faces the transparent section of the catheter 78 and at least part of the light radially emitted by the light scattering section of the optical fiber 74 can propagate up to the photoacoustic transducer 80 through the transparent section of the catheter 78.

[0143] It should be understood that the cross-sectional size and shape of the aperture in the handle portion 76 and the aperture in the catheter 78 are chosen so that at least the distal portion of the optical fiber 74 may be inserted therein.

[0144] Referring back to Fig. 4, the catheter device 72 optionally further comprises the tube 82. The tube 82 extends through the wall of the handle portion 76 and is fluidly connected to the aperture of handle portion 76. The tube 82 may be used to inject a product into the blood vessel when the catheter 78 is inserted into the blood vessel and / or aspiring a liquid such as blood.

[0145] Fig. 5 illustrates one embodiment of an optical fiber device 92 that may be used with a catheter device such as catheter devices 24, 41 and / or 72 for example. The optical fiber device 92 comprises an optical fiber 94 provided with a light scattering section 96 made of a glass matrix and a mirror 98. The light scattering section 96 is configured for transversally emitting at least a portion of the light propagating along the optical fiber 94.

[0146] The optical fiber device 92 extends longitudinally between a proximal end 100 and a distal end 102. The light scattering section 96 extends longitudinally along a given section of the optical fiber device 92 from the distal end 102 towards the proximal end 100. The optical fiber device 92 further comprises the mirror 98 secured at the distal end 102 of the optical fiber 94. The mirror 98 is configured for reflecting at least part of the lightincoming thereon towards the light scattering section 96 in order to improve the quantity of light that is radially scattered by the light scattering section 96.

[0147] In some embodiments in which the light scattering section 96 is made of a glass matrix, the glass matrix comprises scattering elements such as but not limited to filaments or voids.

[0148] In some embodiments, the mirror 98 comprises a layer or coating made of a reflective material.

[0149] Fig. 6A illustrates the cross-sectional view of the tip of a catheter device that comprises a catheter 104 and a photoacoustic transducer 108 mounted around the catheter 104 adjacent to a distal end 116 thereof. In this embodiment, the whole catheter 104 is made of a transparent material and the catheter 104 is provided with an aperture that extends along its entire length. The aperture comprises two sections, i.e., a first section 110 extending longitudinally from the proximal end of the catheter 104 towards the distal end 116 up to a given position 112 along the length of the catheter 104, and a second section 114 extending longitudinally from the given position 112 up to the distal end 116 of the catheter 104. The first and second sections 110 and 114 of the aperture are connected together.

[0150] The first section 110 has a cylindrical shape and is provided with a first diameter that is constant along a length thereof. The second section 114 has also a cylindrical shape and is provided with a second diameter that is constant along a length thereof and is less than the first diameter. Because of the diameter difference between the first and second sections 110 and 114, an abutting wall is formed at the interface between the first and second sections 110 and 114. The first diameter is chosen so that an optical fiber may be inserted into the first section 110. The second diameter is chosen to be less than the diameter of the optical fiber but at least equal to the diameter of a guidewire so that the optical fiber cannot be inserted into the second section 114 while the guidewire may be inserted into the second section 114.

[0151] In the illustrated embodiment, the position 112 is adjacent to the distal end 116 of the catheter 104. However, it will be understood that the position 112 defining the position of the interface between the first and second sections 110 and 114 may be located at any other adequate position along the length of the catheter 104.

[0152] Fig. 6B illustrates the cross-sectional view of the tip of a catheter device that comprises a catheter 106 and a photoacoustic transducer 108 mounted around the catheter 106 adjacent to a distal end 124 thereof. In this embodiment, the whole catheter 106 is made of a transparent material and the catheter 106 is provided with an aperture that extends along its entire length. The aperture comprises two sections, i.e., a first section 118 extending longitudinally from the proximal end of the catheter 106 towards the distal end 124 up to a given position 120 along the length of the catheter 106, and a second section 122 extending longitudinally from the given position 120 up to the distal end 124 of the catheter 106. The first and second sections 118 and 122 of the aperture are connected together.

[0153] The first section 118 has a cylindrical shape and is provided with a first diameter that is constant along a length thereof. The second section 122 has also a frustoconical shape and is provided with a second diameter that varies along a length thereof, the diameter decreases from the position 120 (where the diameter of the section 122 is maximal and equal to the diameter of the first section 118) to the distal end 124 of the catheter (where the diameter of the section 122 is minimal). The first diameter is chosen so that an optical fiber may be inserted into the first section 118. The minimal diameter of the second section 122 is chosen to be at least equal to the diameter of a guide wire so that the optical fiber cannot be inserted into the second section 122 while the guide wire may be inserted into the second section 122.

[0154] In the illustrated embodiment, the position 120 is adjacent to the distal end 124 of the catheter 106. However, it will be understood that the position 120 defining the position of the interface between the first and second sections 118 and 122 may be located at any other adequate position along the length of the catheter 106.

[0155] In some embodiments, the catheter device comprises an anchoring mechanism or device. The anchoring mechanism is configured to maintain the catheter device, once inserted into the subject, at a chosen position within the anatomy of the subject (e.g., a vessel, a blood vessel, a coronary artery, a peripheral artery, a cardiac valve leaflet, etc.). Consequently, when the catheter is anchored within the subject, the position of the photoacoustic transducer relative to the lesion to be treated is also maintained. In some embodiments, the anchoring mechanism is further configured for centering the elongated body within the anatomy of the subject, e.g., for centering the elongated body within a vessel.

[0156] In some embodiments, the anchoring mechanism comprises at least one anchoring member and an actuator. The anchoring member is mounted to the catheter and provided with a variable geometry so as to be extendable between a rest position / configuration and an extended position / configuration. When in the rest position, the cross-sectional size of the anchoring member is chosen so that the catheter device may be inserted into the subject, such as within a vessel of the subject. For example, when in the rest position, the anchoring member may be collapsed so as to be adjacent to the catheter device or in physical contact with the catheter device. When in the extended position, the cross-sectional size of the anchoring member is greater than that in the rest position so that the anchoring member can be in physical contact with the surrounding anatomy (such as a vessel or tissue) in which it is inserted in order to maintain to removably fix the position of the anchoring member relative to the vessel. The actuator is operatively connected to the anchoring member for moving the anchoring member from the rest position to the extended position, and vice versa.

[0157] It should be understood that the anchoring member may be any adequate device of which the geometry or shape may be changed between a rest position or configuration configured for allowing the catheter device to be inserted into the subject, and an expanded position or configuration in which part of the anchoring member is in physical contact with and experts a pressure force on the anatomy of the subject, such as on the wall of a vessel, to removably fix the position of the catheter device within the subject. For example, the anchoring member may comprise an inflatable balloon, flexible struts, flexible arms, aflexible fishnet structure, a frame, etc. The actuator is then configured for moving the anchoring member between its rest and expanded positions. For example, the actuator may comprise a source of fluid and at least one tube for inflating an inflatable balloon. In another example, the actuator may comprise a mechanical device configured for outwardly bending flexible struts, flexible arms, a flexible fishnet structure, etc. away from the catheter, and vice versa. In this case, the actuator may comprise wires, cables and / or the like to change the shape of the flexible struts, flexible arms, a flexible fishnet structure, and / or the like.

[0158] It should be understood that the anchoring member is mounted to the catheter at any adequate position therealong that allows to maintain a substantially fixed position for the photoacoustic transducer. For example, the anchoring member may be mounted on the catheter adjacent to the photoacoustic transducer. In another example, the anchoring member may be mounted over the photoacoustic transducer.

[0159] In some embodiments, the actuator is connectable to a control device configured for controlling the actuator and thereby controlling the anchoring device. The person skilled in the art will understand that the actuator and controller may be pneumatic, electrical, hydraulic, mechanical etc.

[0160] In some embodiments, the catheter is provided with a lumen extending along at least a section thereof for receiving at least a part of the actuator such as a tube, cables, wires, etc.

[0161] In the following, there is provided an exemplary catheter device provided with an exemplary anchoring member.

[0162] Figs. 7A and 7B illustrate one embodiment of a catheter device 126 provided with a handle or handle portion 128, a catheter 130 provided with a transparent section 136, a photoacoustic transducer 134 mounted around the transparent section 136 and an anchoring mechanism 500. The handle portion 128, the catheter 130 and the photoacoustic transducer 134 are similar to those comprised in the catheter device 72 illustrated in Fig. 4, and the description therefore is not repeated. As described below in further detail, theanchoring mechanism 500 is used for spacing apart cardiac valve leaflets in order to treat a lesion.

[0163] The anchoring mechanism 500 is located adj acent to the distal end of the catheter 130 and comprises a distal ring 140, a proximal ring 142 and a plurality of struts 138. The distal ring 140 and the proximal ring 142 are each positioned on opposite sides of the photoacoustic transducer 134. The distal ring 140 is fixedly secured around the catheter 130 adjacent to the distal end of the catheter 130 while the proximal ring 142 is slidably around the catheter 130. Each strut 138 is provided with a strap shape and extends between a proximal end that is fixedly secured to the proximal ring 142 at a respective radial or angular position around the circumference of the ring 142, and a distal end that is fixedly secured to the distal ring 140 at a respective radial or angular position around the circumference of the ring 140.

[0164] By translating the proximal ring 142 along the catheter 130, the anchoring mechanism 500 is movable between a rest position (not shown) and an extended position as illustrated in Fig. 7B. When the anchoring mechanism 500 is in the rest position, the distance between each strut 138 and the catheter 130 (e.g., the distance between the center of each strut and the catheter 130) is minimal and the distance between the proximal ring 142 and the distal end of the catheter 130 is maximal. When the anchoring mechanism 500 is in the extended position, the distance between each strut 138 and the catheter 130 is maximal and the distance between the proximal ring 142 and the distal end of the catheter 130 is minimal. By translating the proximal ring 142 towards the distal end of the catheter 130, the struts 138 bend outwardly away from the catheter 130 and the distance between the struts 138 and the catheter 130 in the direction orthogonal to the longitudinal axis of the catheter 130 increases.

[0165] Each strut 138 is made of a flexible and resilient material so that when the anchoring mechanism 500 is in the extended position, the struts 138 may space apart cardiac valve leaflets.

[0166] In some embodiments, the width and / or the material of the struts 138 is chosen to minimally interact with the mechanical waves generated by the photoacoustic transducer 134.

[0167] While in the illustrated embodiment, for each strut 138, the radial position of the proximal end is different from radial position of the distal end so that the strut 138 is provided with a substantially helicoidal shape, it should be understood that the radial position of the proximal end may be identical to radial position of the distal end. In this case, each strut 138 has the shape of a straight strap or band.

[0168] It should be understood that the catheter device 126 further comprises an activation device (not shown) connected to the proximal ring 142 for controlling the position of the proximal ring 142 along the catheter 130.

[0169] While in the illustrated embodiment, the proximal ring 142 is slidable along the catheter 130 and the distal ring 140 has a fixed position relative to the catheter 130, it should be understood that other configurations are possible as long as the struts may be bent. For example, the distal ring 140 may be slidable along the catheter 130 while the proximal ring 142 may have a fixed position relative to the catheter 130. In another example, both the proximal and the distal rings 142 and 140 may be slidably mounted to the catheter 130.

[0170] During a medical treatment of a lesion and in order to visualize the location of a photoacoustic transducer relative to the lesion, medical imaging techniques such as radiography, magnetic resonance imaging, ultrasound imaging, tomography, etc. are typically used. In some embodiments, the catheter device is provided with at least one marker configured to be seen on the medical images to help visualize the position of the photoacoustic transducer relative to the lesion on the medical images. The marker is made of a material or comprises a material that is opaque to the electromagnetic waves used for generating the medical images. For example, the marker may be radiopaque, i.e., opaque to X-rays, when radiography is to be used during the treatment of the lesion. In another example, the marker may be opaque to ultrasounds when ultrasound imaging is to be used during the treatment of the lesion. In the following, the term “radiopaque” is used to referto a marker that is opaque to any type of electromagnetic waves (i.e., not limited to opaque to X-rays) and is visible in any type of medical images.

[0171] The marker is positioned on the catheter device at any adequate position that allows identifying / determining the position of the light scattering section of the optical fiber and / or the position of the photoacoustic transducer on the medical images. For example, the relative position between the marker and the light scattering section and / or the photoacoustic transducer may be predefined so that a user may determine the position of the light scattering section and / or the photoacoustic transducer by seeing the marker on the medical images.

[0172] In some embodiments, the marker is separate / independent from the light scattering section and the photoacoustic transducer. In some embodiments, the marker is mounted on the catheter, such as on the external face of the catheter, at a predefined position relative to the light scattering section and / or the photoacoustic transducer. For example, when the photoacoustic transducer is mounted on the external face of the catheter, a first marker may be mounted on the external face of the catheter adjacent to the proximal end of the photoacoustic transducer and a second marker may be mounted on the external face of the catheter adjacent to the distal end of the photoacoustic transducer. In other embodiments, the marker is mounted on the optical waveguide at an adequate position relative to the light scattering section.

[0173] In some embodiments, a catheter is provided with at least one marker, as described below, that is mounted / secured to the catheter at a predefined distance from the photoacoustic such as from the center of a photoacoustic transducer. It should be understood that the marker may be secured to the catheter using any adequate method. The marker has specific properties, as described below, that allow the marker to be detectable according to a chosen method of medical imaging. Since the marker is visible on the medical images and the predefined distance is known, it is possible to determine the location of the photoacoustic transducer within the medical image, and therefore relative to the lesion targeted for treatment.

[0174] In some embodiments, the marker is removably mounted to the catheter.

[0175] In some embodiments, the optical fiber is provided with at least one marker. In such embodiments, a distance between the marker and a chosen point of the light scattering section of the optical fiber is known, and a distance between the chosen point of the light scattering section and a chosen point of a photoacoustic transducer secured to a catheter, when the optical fiber is fully inserted into the catheter, is also known. Knowing the relative distances between the marker, the chosen point of the light scattering section and the chosen point of the photoacoustic transducer, the location of the photoacoustic transducer within the medical image can be determined.

[0176] In some embodiments, both the optical fiber and the catheter are each provided a respective marker.

[0177] In some embodiments, the photoacoustic transducer is made of a material having radiopaque properties so that the photoacoustic transducer itself acts as a marker.

[0178] In some embodiments, the anchoring mechanism or a portion thereof is made of a material having radiopaque properties to act as a marker, allowing the anchoring mechanism to be visible in the medical image.

[0179] For example, referring to FIG. 7B, the ring 140 and / or the ring 142 could be made of a radiopaque material to be visible in the medical images, therefore allowing a user to determine, within the medical image, the location of the photoacoustic transducer from the location of the visible ring 140, 142.

[0180] Figs. 8A-8D illustrate one embodiment of a method for treating lesion using the catheter device 126.

[0181] After inserting a guide wire 148 into a cardiac vessel 144 comprising a lesion to be treated located on a cardiac valve leaflet 146, the proximal end of the guidewire 148 is inserted into the aperture of the catheter 130 and the catheter device 126 having the anchoring mechanism 500 in the rest position is inserted into the vessel 144 by sliding the catheter device 126 along the guidewire 148, as illustrated in Fig. 8A.

[0182] The catheter device 126 is further inserted into the vessel 144 until the photoacoustic transducer 134 is located between the cardiac valve leaflets 146, as illustrated in Fig. 8B. The anchoring mechanism 500 is then activated to be in its extended position and the struts 138 extend away from the catheter 130, thereby applying an outward pressure force on the cardiac valve leaflets 146 which move away from one another, as illustrated in Fig. 8C. As a result of the pressure force exerted by the struts 138 on the cardiac valve leaflets 146, the position of the catheter device 126 relative to the vessel 144 is fixed and optionally centered within the vessel 144.

[0183] The guidewire 148 is then removed and an optical fiber such as the optical fiber 26 is inserted into the catheter 130. Light pulses may then be propagated along the optical fiber and mechanical waves are generated and propagate up to the lesion located on the cardiac valve leaflets 146, thereby treating the lesion.

[0184] In embodiments in which the photoacoustic transducer is mounted on the external face of the elongated body or in a recess present on the inner face of the elongated body, the aperture of the elongated body may be designed to have a smaller cross-sectional size (e.g., a smaller diameter) and / or the external cross-sectional size of the elongated body (e.g., the external diameter) may be smaller, in comparison to systems in which the photoacoustic transducer would be mounted on the optical waveguide.

[0185] In embodiments in which the elongated body comprises an aperture extending therealong, such as a catheter comprising a lumen, well known guidewire techniques may be used. For example, the lumen may allow flushing or injection of medication or contrast media. The lumen may also be used to aspirate small thrombotic material therethrough.

[0186] In some embodiments, having the photoacoustic transducer mounted on the catheter or integral with the catheter rather than mounted on the optical waveguide allows for reducing the distance between the photoacoustic transducer and the lesion to be treated which in turn slows for more targeted and focused mechanical waves as well as higher amplitude mechanical waves reaching the lesion.

[0187] In some embodiments, having the photoacoustic transducer mounted on the catheter or integral with the catheter rather than mounted on the optical waveguide allows for reducing the interference between the generated mechanical waves and the structure of the catheter assembly, thereby resulting in greater amplitude mechanical waves reaching the lesion to be treated. For example, when the photoacoustic transducer is mounted on the external face of the catheter, the generated mechanical waves directly propagate into the fluid (such as blood) up to the lesion to be treated without interfering with the components of the catheter device such as the catheter wall.

[0188] In some embodiments, having the photoacoustic transducer mounted on the catheter or integral with the catheter rather than mounted on the optical waveguide allows for propagating higher amplitude light (such as higher amplitude optical pulses) into the optical waveguide without heating the optical waveguide. Such heating of the optical waveguide may cause at least some of the following drawbacks: thermal expansion, thermal stress (which may affect the integrity of the waveguide), refractive index change (which may affect light propagation and efficiency) and degradation over time (repeated heating / cooling cycles may lead to fatigue, degradation and / or delamination). Therefore, such drawbacks may be reduced, minimized or avoided when the photoacoustic transducer is located on the catheter rather than on the optical. It should also be noted that the photoacoustic transducer, when located on the catheter, may be cooled down by the flow of fluid (such as blood flow) that propagates around the catheter. Such as a cool down effect could not be achieved if the photoacoustic transducer would be positioned on the optical waveguide since there would substantially be no flow of fluid around the optical waveguide inserted into the catheter.

[0189] In some embodiments in which light pulses are coupled into the optical waveguide to generate mechanical shock waves, the amplitude of the mechanical shock waves is a function of the mechanical expansion characteristics of the photoacoustic transducer material. An increase in the temperature difference between the resting state of the material and its state during pulse application results in a corresponding increase in the amplitude of the mechanical shock wave generated. Conversely, if the photoacoustic transducer material is maintained at an elevated temperature due to reduced coolingefficiency, the temperature differential is reduced, resulting in a decrease in the amplitude of the mechanical shock waves. Consequently, having the photoacoustic transducer mounted on the catheter or integral with the catheter rather than mounted on the optical waveguide allows for a better cooling down of the photoacoustic transducer as explained above and therefore the generation of greater amplitude mechanical waves.

[0190] Modifications and improvements to the above-described implementations of the present technology may become apparent to those skilled in the art. The foregoing description is intended to be exemplary rather than limiting.

Claims

CLAIMSWhat is claimed is:

1. A device for treating a lesion of a subject, the device comprising: an elongated structure extending along a first longitudinal axis between a first proximal end and a first distal end and defining a waveguide -receiving cavity extending from the first proximal end along the first longitudinal axis, the elongated structure comprising a photoacoustic transducer portion, the waveguide -receiving cavity being configured for receiving therein at least a distal section of an optical waveguide extending along a second longitudinal axis between a second proximal end for receiving light and a second distal end, the optical waveguide comprising a light scattering section configured for scattering at least part of the light in at least one direction other than the second longitudinal axis, the photoacoustic transducer portion of the elongated structure being configured for receiving at least some of light scattered by the light scattering section of the optical waveguide when the optical waveguide is inserted into the waveguide-receiving cavity and generating mechanical waves in order to treat the lesion.

2. The device of claim 1 , wherein the elongated structure comprises an elongated body extending along a third longitudinal axis between a first end and a second end and defining the waveguide-receiving cavity extending from the first end along the third longitudinal axis, the elongated body comprising a section made of a photoacoustic transducer material for receiving the at least some of the light scattered by the light scattering section of the optical waveguide and generating the mechanical waves, the section made of a photoacoustic transducer material corresponding to the photoacoustic transducer portion.

3. The device of claim 1, wherein the elongated structure comprises: an elongated body extending along a third longitudinal axis between a first end and a second end and defining the waveguide -receiving cavity extending from the first end along the third longitudinal axis; anda photoacoustic transducer mounted on the elongated body, the photoacoustic transducer being positioned so as to receive the at least some of the light scattered by the light scattering section of the optical waveguide and generate the mechanical waves, the photoacoustic transducer corresponding to the photoacoustic transducer portion.

4. The device of claim 3, wherein the photoacoustic transducer is mounted on an external face of the elongated body.

5. The device of claim 4, wherein the external face of the elongated body is provided with a recess, the photoacoustic transducer being inserted into the recess.

6. The device of claim 5, wherein a thickness of the recess is equal to a thickness of the photoacoustic transducer.

7. The device of claim 3, wherein the photoacoustic transducer is mounted on an internal face of the elongated body.

8. The device of claim 7, wherein the internal face of the elongated body is provided with a recess, the photoacoustic transducer being inserted into the recess.

9. The device of claim 8, wherein a thickness of the recess is equal to a thickness of the photoacoustic transducer.

10. The device of any one of claims 3 to 9, wherein the photoacoustic transducer comprises a coating of photoacoustic transducer material.

11. The device of any one of claims 1 to 10, wherein a length of the photoacoustic transducer portion is at least equal to a length of the light scattering section of the optical waveguide.

12. The device of any one of claims 1 to 11, wherein a portion of the light scattering section is configured for reflecting at least part of the scattered light.

13. The device of claim 12, wherein the portion of the light scattering section is coated with a light reflecting material.

14. The device of any one of claims 1 to 13, wherein the waveguide -receiving cavity extends between the first proximal end and the first distal end of the elongated structure as to form an opening extending along the elongated structure.

15. The device of claim 14, wherein a cross-sectional size of the opening varies along the first longitudinal axis.

16. The device of any one of claims 1 to 15, wherein the light scattering section is located adjacent to the second distal end of the optical waveguide.

17. The device of any one of claims 1 to 16, wherein the second distal end of the optical waveguide is configured for at least partially reflecting the light.

18. The device of any one of claims 1 to 17, wherein the photoacoustic transducer portion is radiopaque.

19. The device of any one of claims 1 to 17, further comprising a radiopaque marker mounted to one of the optical waveguide and the elongated body.

20. The device of any one of claims 1 to 19, further comprising an anchoring device mounted to the elongated structure for anchoring the device to the subject at a desired position relative to the lesion.

21. The device of claim 20, wherein the anchoring device is movable between a rest position and an extended position, the anchoring device being adjacent to the elongated structure when in the rest position and away from the elongated structure when in the extended position.

22. The device of any one of claims 1 to 21, further comprising the optical waveguide.

23. The device of claim 22, wherein the optical waveguide comprises an optical fiber and the elongated structure comprises a catheter.

24. An assembly for treating a lesion of a subject, the device comprising:an optical waveguide extending along a first longitudinal axis between a first proximal end connectable to a light source for receiving light therefrom and a first distal end, the optical waveguide comprising a light scattering section configured for scattering at least part of the light in at least one direction other than the first longitudinal axis; and an elongated structure extending along a second longitudinal axis between a second proximal end and a second distal end and defining a waveguide-receiving cavity extending from the second proximal end along the second longitudinal axis, the waveguide -receiving cavity being configured for receiving at least a section of the optical waveguide comprising the first distal end thereof, the elongated structure comprising a photoacoustic transducer portion configured for converting the light into mechanical waves, the photoacoustic transducer portion of the elongated structure being configured for receiving at least some of light scattered by the light scattering section of the optical waveguide when the optical waveguide is inserted into the waveguide-receiving cavity and generating the mechanical waves in order to treat the lesion.

25. The device of claim 24, wherein the elongated structure comprises an elongated body extending along a third longitudinal axis between a first end and a second end and defining the waveguide -receiving cavity, the elongated body comprising a section made of a photoacoustic transducer material for receiving the at least some of the light scattered by the light scattering section of the optical waveguide and generating the mechanical waves, the section made of a photoacoustic transducer material corresponding to the photoacoustic transducer portion.

26. The assembly of claim 24, wherein the elongated structure comprises: an elongated body extending along a third longitudinal axis between a first end and a second end and defining the waveguide -receiving cavity extending from the first end along the third longitudinal axis; and a photoacoustic transducer mounted on the elongated body, the photoacoustic transducer being positioned so as to receive the at least some of the light scattered by thelight scattering section of the optical waveguide and generate the mechanical waves, the photoacoustic transducer corresponding to the photoacoustic transducer portion.

27. The assembly of claim 26, wherein the photoacoustic transducer is mounted on an external face of the elongated body.

28. The assembly of claim 27, wherein the external face of the elongated body is provided with a recess, the photoacoustic transducer being inserted into the recess.

29. The assembly of claim 28, wherein a thickness of the recess is equal to a thickness of the photoacoustic transducer.

30. The assembly of claim 26, wherein the photoacoustic transducer is mounted on an internal face of the elongated body.

31. The assembly of claim 30, wherein the internal face of the elongated body is provided with a recess, the photoacoustic transducer being inserted into the recess.

32. The assembly of claim 31, wherein a thickness of the recess is equal to a thickness of the photoacoustic transducer.

33. The assembly of any one of claims 26 to 32, wherein the photoacoustic transducer comprises a coating of photoacoustic transducer material.

34. The assembly of any one of claims 24 to 33, wherein a length of the photoacoustic transducer portion is at least equal to a length of the light scattering section of the optical waveguide.

35. The assembly of any one of claims 24 to 34, wherein a portion of the light scattering section is configured for reflecting at least part of the scattered light.

36. The assembly of claim 35, wherein the portion of the light scattering section is coated with a light reflecting material.

37. The assembly of any one of claims 24 to 36, wherein the waveguide-receiving cavity extends between the second proximal end and the second distal end of the elongated structure as to form an opening extending along the elongated structure.

38. The assembly of claim 37, wherein a cross-sectional size of the opening varies along the first longitudinal axis.

39. The assembly of any one of claims 24 to 38, wherein the light scattering section is located adjacent to the first distal end of the optical waveguide.

40. The assembly of any one of claims 24 to 39, wherein the first distal end of the optical waveguide is configured for at least partially reflecting the light.

41. The assembly of any one of claims 24 to 40, wherein the photoacoustic transducer portion is radiopaque.

42. The assembly of any one of claims 24 to 40, further comprising a radiopaque marker mounted to one of the optical waveguide and the elongated body.

43. The assembly of any one of claims 24 to 42, further comprising an anchoring device mounted to the elongated structure for anchoring the elongated structure to the subject at a desired position relative to the lesion.

44. The assembly of claim 43, wherein the anchoring device is movable between a rest position and an extended position, the anchoring device being adjacent to the elongated structure when in the rest position and away from the elongated structure when in the extended position.

45. The assembly of any one of claims 24 to 44, wherein the optical waveguide comprises an optical fiber and the elongated structure comprises a catheter.

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