WO2009150593A1 - Appareil destiné à déterminer une propriété d’un objet - Google Patents

Appareil destiné à déterminer une propriété d’un objet Download PDF

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Publication number
WO2009150593A1
WO2009150593A1 PCT/IB2009/052388 IB2009052388W WO2009150593A1 WO 2009150593 A1 WO2009150593 A1 WO 2009150593A1 IB 2009052388 W IB2009052388 W IB 2009052388W WO 2009150593 A1 WO2009150593 A1 WO 2009150593A1
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WO
WIPO (PCT)
Prior art keywords
acoustic wave
light
property
casing
unit
Prior art date
Application number
PCT/IB2009/052388
Other languages
English (en)
Inventor
Rachel E. Thilwind
Jan F. Suijver
Szabolcs Deladi
Original Assignee
Koninklijke Philips Electronics N.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Koninklijke Philips Electronics N.V. filed Critical Koninklijke Philips Electronics N.V.
Publication of WO2009150593A1 publication Critical patent/WO2009150593A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
    • A61B8/12—Diagnosis using ultrasonic, sonic or infrasonic waves in body cavities or body tracts, e.g. by using catheters
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/0059—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence
    • A61B5/0082—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence adapted for particular medical purposes
    • A61B5/0084—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence adapted for particular medical purposes for introduction into the body, e.g. by catheters
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/0093—Detecting, measuring or recording by applying one single type of energy and measuring its conversion into another type of energy
    • A61B5/0095—Detecting, measuring or recording by applying one single type of energy and measuring its conversion into another type of energy by applying light and detecting acoustic waves, i.e. photoacoustic measurements
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/12—Arrangements for detecting or locating foreign bodies
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A61B18/14—Probes or electrodes therefor
    • A61B18/1492—Probes or electrodes therefor having a flexible, catheter-like structure, e.g. for heart ablation
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
    • A61B2017/00017—Electrical control of surgical instruments
    • A61B2017/00022—Sensing or detecting at the treatment site
    • A61B2017/00106—Sensing or detecting at the treatment site ultrasonic
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/44—Constructional features of apparatus for radiation diagnosis
    • A61B6/4423—Constructional features of apparatus for radiation diagnosis related to hygiene or sterilisation

Definitions

  • the present invention relates to an apparatus, a casing, a method and a computer program for determining a property of an object.
  • the invention relates further to an apparatus for influencing an object and for determining a property of the object.
  • US 2006/0122583 Al discloses an apparatus for forming a hole in a region of the heart muscle wall comprising a catheter, which contains an optical fibre for transmitting ablation laser light to the heart muscle wall for ablating heart tissue.
  • the optical fibre is arranged centrally within the catheter and an acoustic detector is located close to the optical fibre within the catheter.
  • the ablation laser light is transmitted to the heart muscle wall and ablates the same.
  • a shock wave is generated in the heart muscle wall by the ablation laser light and the acoustic energy of the shock wave is detected by the acoustic detector for determining a thickness of the heart muscle wall.
  • sensing laser light which comprises an intensity being not large enough for ablating heart tissue
  • sensing laser light is transmitted via the optical fibre to the heart muscle wall and coupled into the same, wherein an acoustic wave is generated within the heart muscle wall by the sensing laser light, which is detected by the acoustic detector for determining the depth of the ablated hole in the heart muscle wall.
  • This apparatus has the drawback that the ablation functionality and the sensing functionality are fully integrated in the apparatus and cannot be separated. It is, for example, not possible to use the sensing functionality of the apparatus with another ablation catheter. This reduces the flexibility of the choice of ablation catheters or yields high ablation catheter production costs, if each ablation catheter has to be provided with a sensing functionality.
  • an apparatus for determining a property of an object comprising a casing comprising an inner region for receiving an object influencing unit for influencing the object and an outer region enclosing the inner region, wherein the outer region comprises: a light transmission unit for transmitting light to the object for coupling light into the object for generating an acoustic wave within the object, an acoustic wave sensing element for sensing the acoustic wave.
  • the invention is based on the idea that because of the arrangement of the light transmission unit and the acoustic wave sensing element in the outer region of the casing the inner region is free for receiving one of several object influencing units like ablation catheters or pacing catheters, wherein by inserting an object influencing unit in the casing, a device is formed, which can influence the object and which allows to detect the effect of the influence by using the light transmission unit and the acoustic wave sensing element located in the outer region of the casing. Since one of several object influencing units can be inserted into the inner region of the casing, the flexibility of choice of object influencing units like ablation catheters, which are to be used with a sensing functionality, is increased.
  • the object influencing unit comprises preferentially an energy emitting element, which emits energy to the object.
  • This energy is, for example, optical, ultrasonic, microwave or electrical energy.
  • the energy emitting element can have a low temperature for killing tissue by coldness, in particular, by cryoablation, if the object is tissue of a patient, for example, heart tissue of a patient.
  • the object influencing unit, in particular, the energy applying unit is preferentially used for an ablation procedure performed at a heart of a patient.
  • the casing comprises at least one outer cavity defining the outer region and at least one inner cavity defining the inner region.
  • the casing is preferentially a sheath surrounding the inner region, wherein preferentially in the wall of the sheath at least one cavity defines the outer region.
  • the casing is preferentially adapted for being disposable and/or reusable.
  • the casing is adapted such that it is fittable over an object influencing unit like an ablation catheter and/or a pacing catheter.
  • the casing can be elastical and/or can comprise a fixing unit for fixing the casing on the object influencing unit in order to secure the sheath in place.
  • the fixing unit is preferentially attached to the casing and comprises, for example, spring-like elements like spring-like clamps or clasps exerting spring forces, which are arranged within the inner region of the casing and which hold the object influencing unit in place, if the object influencing unit has been introduced into the inner region of the casing. It is further preferred that the inner region is adapted for receiving an ablation catheter and/or a pacing catheter as object influencing unit.
  • the acoustic wave sensed by the acoustic wave sensing unit can be used to determine the property of the object before, during and/or after ablation and/or a pacing. For example, if the object is a heart wall, the temperature, a progression of lesion development between the inner and outer heart wall, in particular, for detecting when the lesion is transmural, can be determined.
  • the light transmission unit comprises preferentially at least one optical fibre. Preferentially, the light transmission unit is arranged cylindrically around the inner region. In particular, the light transmission unit comprises several optical fibres cylindrically arranged around the inner region.
  • the apparatus is preferentially adapted for transmitting acoustic wave generating light simultaneously through the several optical fibres. This allows determining the modification of a property of the object due to the influence of the object influencing unit very accurately, because the acoustic wave for determining the property is sensed around the position, at which the object is influenced. It is further preferred that the acoustic wave sensing element comprises a moveable element being moveable by the acoustic wave. This allows measuring the acoustic wave by measuring the movement of the moveable element.
  • the moveable element is preferentially moveable with respect to the light transmission unit, which is preferentially an optical fibre.
  • the moveable element is moveable by an acoustic wave, for example, because it is in contact with a surface of the object and the surface of the object moves in accordance with the acoustic wave, or because the acoustic wave is transmitted to the moveable element by another medium like a fluid, in particular, blood.
  • An acoustic wave in particular, an ultrasonic wave
  • an ultrasonic wave can be generated within the object, in particular, within tissue of a human heart of a patient by absorbing light in the object. This acoustic wave travels then outwards from the absorption site and is reflected back to the surface of the object. If the acoustic wave passes through the moveable element, the moveable element preferentially moves, in particular, in accordance with the acoustic wave.
  • the moveable element can move as a hole or only a part of the moveable element can move. The movement can also be an internal movement.
  • the light transmission unit comprises an optical fibre, wherein the moveable element is a reflecting element located at an end of the optical fibre such that light guided through the optical fibre is reflectable by the reflecting element.
  • the optical fibre comprises a proximal end and a distal end and the reflecting element is attached to the distal end of the optical fibre, i.e. the reflecting element terminates the optical fibre.
  • the reflecting element is preferentially a film.
  • the reflecting element can be adapted for reflecting sensing light for sensing the movement of the reflecting element and/or for reflecting a part of the acoustic wave generating light. This allows measuring the acoustic wave interferometrically.
  • the reflecting element can be a reflecting structure, in particular, located at a distal end of an optical fibre.
  • the reflecting structure is, for example, a cantilever or a bride-like structure, which are moveable, in particular, oscillate in response to an acoustic wave.
  • the reflecting structure can be adapted for reflecting sensing light for sensing the movement of the reflecting structure and/or for reflecting a part of the acoustic wave generating light.
  • a reflecting structure being a cantilever is described in more detail in "Monolithic fiber-top sensor for critical environments and standard applications", D. Iannuzzi, S. Deladi, V. J. Gadgil, R. G. P. Sanders, H. Schreuders, and M. C. Elwenspoek, Applied Physics Letters. 88, 053501 (2006), which is herewith incorporated by reference.
  • the apparatus comprises at least one optical fibre located within the outer region of the casing for guiding light to or/and from the reflecting element.
  • the reflecting element moves, in particular, in accordance with the generated acoustic wave, wherein, as already mentioned above, the reflecting element can move as a hole or only a part of the reflecting element can move or the movement can also be an internal movement of the moveable reflecting element, which modifies the position of reflection
  • this movement of the reflecting element can be detected by light reflected by the reflecting element.
  • the at least one optical fibre guides light to the reflecting element, wherein the light is preferentially coherent laser light
  • a signal can be generated by detecting the light reflected from the reflecting element, wherein the signal depends on the movement of the reflecting element, and, thus, on the acoustic wave generated in the object by absorbing light.
  • the reflecting element is preferentially an element, which changes a position of reflection, if an acoustic wave passes through the reflecting element, such that the length of the light path of the reflected light is modified, wherein the modification of the length can be measured by using, for example, known interferometric methods and devices, like a Michelson interferometer.
  • the apparatus for determining a property of an object is adapted such that the moveable element is flush with an outer surface of the object influencing unit such that the moveable element is in contact with the object, if the object influencing unit has been inserted in the inner region of the casing for operating and is in contact with the object.
  • the apparatus is preferentially adapted such that the moveable element is in contact with heart tissue, if the radio frequency catheter is in contact with the heart tissue. If the moveable element is in contact with a surface of the object, in particular, with a surface of a heart wall, the propagation of the acoustic wave from the object through the moveable element is improved.
  • At least one optical fibre of the light transmission unit is preferentially adapted for guiding sensing light having a sensing wavelength to the reflecting element and for guiding the acoustic wave generating light to a distal end of the apparatus for determining a property of the object.
  • the sensing wavelength of the sensing light and the acoustic wave generating wavelength of the acoustic wave generating light can be different or can be the same.
  • the sensing wavelength can be optimized for sensing the movement of the reflecting element and the acoustic wave generating wavelength can be optimized for generating an acoustic wave within the object.
  • the sensing wavelength and the acoustic wave generating wavelength can be adapted independently from each other.
  • the reflecting element is optically transparent to at least a part of the acoustic wave generating light.
  • the same optical fibre can be used for transmitting the acoustic wave generating light for coupling into the object and for transmitting light reflected by the reflecting element, which might be a reflected part of the acoustic wave generating light and/or reflected sensing light, back to an interferometrical unit for determining the movement of the reflecting element.
  • the reflecting element and/or at least one optical fibre are adapted such that at least a part of the light guided by the at least one optical fibre can pass the reflecting element beside the reflecting element. This allows using a moveable reflecting element, which is not or not sufficiently transparent for the acoustic wave generating light.
  • the reflecting element can be designed more freely. It is further preferred that the moveable element is adapted for converting a movement of the element into electrical signals being detectable for measuring the acoustic wave.
  • the moveable element preferentially comprises or is attached to a piezoelectric, in particular, a piezoceramic, element for transforming a movement of the moveable element into electrical signals, which can be guided by electrical leads, which can be located in the outer region of the casing, to a measuring device located outside of the casing.
  • This measuring device can be regarded as a property determination unit for determining a property of the object from the sensed acoustic wave.
  • the electrical leads are, for example, electrical wires and/or a conductive coating on an optical fibre.
  • the distal part of the reflecting structure can be coated with a semiconductor material and/or an electrically conductive material. This allows to generate electrical signals by the piezoelectric effect, wherein the electrical signals can be transferred to a measuring device via electrical leads located in the outer region of the casing.
  • the apparatus further comprises a light source for generating the acoustic wave generating light and a property determination unit for determining the property of the object from the sensed acoustic wave.
  • the light source is preferentially adapted for generating laser light pulses.
  • the property determination unit for determining the property of the object can be adapted for determining directly a property of the object like the temperature or, if the object is a heart wall, the lesion development between the inner and outer wall of the heart to detect when the lesion is transmural, and/or the property determination unit can be adapted for providing data, for example, on a display or on a printer, which can be used for determining a property of the object. These data are, for example, data representing the movement of the moveable element in accordance with the acoustic wave.
  • a casing for determining a property of an object comprising an inner region for receiving an object influencing unit for influencing the object and an outer region enclosing the inner region, wherein the outer region comprises: - a light transmission unit for transmitting acoustic wave generating light to the object for coupling the acoustic wave generating light into the object for generating an acoustic wave within the object, an acoustic wave sensing element for sensing the acoustic wave.
  • the casing is or can be separated from an object influencing unit.
  • the casing alone does preferentially does not comprise an ablation catheter or a pacing catheter.
  • an apparatus for influencing an object and for determining a property of the object comprises an object influencing unit and the apparatus for determining a property of the object as defined in claim 1, wherein the object influencing unit is arranged within the inner region of the casing of the apparatus for determining a property of the object.
  • a method for determining a property of an object comprises the steps of: - providing a casing comprising an inner region for receiving an object influencing unit for influencing the object and an outer region enclosing the inner region, wherein the outer region comprises a light transmission unit and an acoustic wave sensing element, transmitting acoustic wave generating light to the object for coupling the acoustic wave generating light into the object for generating an acoustic wave within the object by the light transmission unit, sensing the acoustic wave by the acoustic wave sensing element.
  • a computer program for determining a property of an object comprises program code means for causing an apparatus for determining a property of an object as defined in claim 1 to carry out following steps, when the computer program is run on a computer controlling the apparatus: transmitting acoustic wave generating light to the object for coupling the acoustic wave generating light into the object for generating an acoustic wave within the object by the light transmission unit of the apparatus, sensing the acoustic wave by the acoustic wave sensing element of the apparatus.
  • Fig. 1 shows schematically and exemplarily an embodiment of an apparatus for influencing an object and for determining a property of the object
  • Fig. 2 shows schematically and exemplarily a casing for determining a property of an object, in which an object influencing unit has been introduced, in a sectional view
  • Fig. 3 shows schematically and exemplarily the casing in a sectional view without the object influencing unit
  • Fig. 4 shows schematically and exemplarily an apparatus for determining a property of an object comprising the casing
  • Fig. 5 shows schematically and exemplarily an apparatus for determining a property of an object and an object influencing unit before introducing the object influencing unit into the apparatus for determining a property of an object
  • Fig. 6 shows schematically and exemplarily a fixing unit within a casing of an apparatus for determining a property of an object
  • Fig. 7 shows schematically and exemplarily the apparatus for determining a property of an object and the object influencing unit of Fig. 5 after the object influencing unit has been introduced into the apparatus for determining a property of an object, and
  • Fig. 8 shows schematically and exemplarily a flowchart illustrating an embodiment of a method for determining a property of an object.
  • Fig. 1 shows schematically and exemplarily an apparatus for influencing an object and for determining a property of the object.
  • Fig. 1 shows an apparatus for applying energy to an object 2 and for determining a property of the object 2.
  • the object 2 is, in this embodiment, a heart of a patient 4, which is located on a patient table 26.
  • the apparatus 1 comprises an object influencing unit including a catheter 3, in particular, an ablation catheter, including an energy applying unit for applying energy to the object, and an apparatus for determining a property of the object comprising a casing, which is fitted over the energy applying unit, i.e., in this embodiment, over an ablation catheter, and which will be explained in more detail further below.
  • the object influencing unit and the casing of the apparatus for determining a property of the object are located at a distal end 5 of the catheter 3. This distal end 5 of the catheter 3 will also be described in more detail further below.
  • the apparatus 1 for influencing an object and for determining a property of the object comprises a catheter control unit 6, which comprises an electrical energy source 19, in particular, a radio frequency source, for applying energy, in particular, radio frequency energy to the object 2, via the object influencing unit.
  • the catheter control unit 6 further comprises a light source 7, which provides light, which is guided to the distal end 5 of the catheter 3 by a light transmission unit, which is adapted for transmitting at least acoustic wave generating light to the object for coupling the acoustic wave generating light into the object for generating an acoustic wave within the object.
  • the light source 7 is preferentially a pulsed laser, wherein the pulsed laser light is acoustic wave generating light, which is absorbed by the object resulting in an acoustic wave within the object.
  • the light source can comprise one or several laser devices.
  • the light source can comprise a pulsed laser device, which generates acoustic wave generating light, which is absorbed in the object for generating an acoustic wave, and a continuous laser device which generates light for sensing the acoustic wave.
  • the pulsed laser device has preferentially a pulse duration of about 10 ps to about 1 ⁇ s, in particular, in order to ensure ultrasound originating at well-defined positions.
  • the pulsed repetition frequency is preferentially within a range of 10 Hz to 100 kHz.
  • the delivered energy i.e. the applied energy, is within a range of about 1 nJ/pulse to about mJ/pulse. It is further preferred that the delivered energy is about 1 ⁇ j/pulse.
  • the continuous wave laser device is preferentially a single-mode laser having a wave length within the range of about 500 to about 1500 nm.
  • a pulsed laser device can be used for sensing the acoustic wave, wherein the pulse duration is preferentially larger than 10 ps, further preferred larger than 100 ps, if the pulse duration leads to a coherence length, which is sufficient for measuring a movement of the reflecting element caused by an acoustic wave passing through the reflecting element.
  • the pulsed repetition frequency is preferentially larger than about 100 kHz, and the delivered energy is preferentially smaller than about ⁇ j/pulse, if a pulsed laser is used for sensing the acoustic wave, and preferentially smaller than about 10 mW, if a continues wave laser device is used for sensing the acoustic wave.
  • the apparatus for determining a property of the object further comprises an interferometrical unit 8 for generating a signal, which depends on the acoustic wave generated in the object, from light reflected from a moving reflecting element, which is exposed to the acoustic wave.
  • the interferometrical unit 8 can be regarded as the property determination unit for determining a property of the object from the sensed acoustic wave.
  • the interferometrical unit 8 preferentially comprises a display unit or a presentation unit like a monitor or a printer for showing the determined signal.
  • the interferometrical unit 8 is adapted such that it can measure the phase shift in the light reflected from the reflecting element induced by the movement of the reflecting element, wherein the movement of the reflecting element is caused by an acoustic wave.
  • the interferometrical unit 8 comprises, in this embodiment, a Michelson interferometer.
  • the interferometrical unit can comprise another kind of interferometer, like a Mach-Zehnder interferometer.
  • the interferometrical unit can comprise a spectrometer for analyzing light reflected from the object, in particular, from the tissue, which has been guided via an optical fiber from the object to the spectrometer.
  • the spectrometer can be separated from the interferometrical unit, i.e. the spectrometer and the interferometrical unit can be separate units.
  • the interferometrical unit comprising the spectrometer, or the separate interferometrical unit and spectrometer, are arranged such that light reflected from the moveable reflecting element is guided to the interferometrical part and that light that has been reflected from the object, in particular, from the tissue of a heart, is guided to the spectrometer.
  • the spectrometer is, for example, a cryo-cooled high resolution linear InGaAs photodiode array, with a sensitivity between about 0.8 ⁇ m and about 1.7 ⁇ m for working in the near- infrared range, or a silicon CCD device with operating range covering deep UV to VIS/NIR.
  • the apparatus 1 for influencing an object and for determining a property of the object further comprises a steering unit 9 for steering the distal end 5 of the catheter 5 to a desired location within the object 2.
  • a fluoroscopy device images the location of the distal end 5 of the catheter 3 within the patient 3 and, in particular, within the heart 2, which is in this embodiment the object.
  • the fluoroscopy device comprises an X-ray source 11, which generates an X-ray beam 15, which is schematically shown in Fig. 1, for traversing a region of the patient, in which the catheter 3, in particular, the distal end 5 of the catheter 3, is present. After the X-ray beam 15 has traversed the patient 4, the X-ray beam 15 is detected by an X-ray detector 12.
  • the X-ray source 11 and the X-ray detector 12 are controlled by a fluoroscopy control unit 13, which preferentially also comprises a display for showing a fluoroscopy image.
  • the apparatus 1 for influencing an object and for determining a property of the object further comprises an apparatus control unit 10 for controlling the apparatus 1, in particular, for controlling the catheter control unit 6 and preferentially the fluoroscopy device.
  • the apparatus control unit 10 preferentially controls the electrical energy source 19, the light source 7, the interferometrical unit 8 and a possible additional spectrometer.
  • An embodiment of a distal end 5 of a catheter 3 is exemplarily and schematically shown in more detail in Fig. 2.
  • the distal end 5 of the catheter 3 comprises a catheter electrode 17, in particular, in this embodiment a radio frequency catheter electrode 17, which is connected to the electrical energy source 19 via a contact lead, which is not shown in Fig. 2.
  • electrical energy in this embodiment, radio frequency energy
  • the catheter 3 comprises a further catheter electrode 41, i.e., in this embodiment, the catheter 3 is of a multi-polar type.
  • the one or several catheter electrodes are preferentially ablation electrodes, pacing electrodes and/or sensing electrodes.
  • the catheter can comprise one or several of these kinds of electrodes.
  • the casing preferentially comprises openings, which correspond to the one or several electrodes and which are preferentially adapted such that the electrode can be in direct contact with the object, in particular, with the tissue of a heart.
  • the object influencing unit can comprise one or more than two electrodes. But, even if more than one electrode is present, also a casing can be used, which comprises only one opening at the distal end for allowing an electrode at the distal tip of a catheter to come into contact with the object. In the figures, only the opening at the distal end can be seen.
  • the catheter 3 is, in this embodiment, an ablation catheter for ablating tissue of a heart wall. The distal end 5 of the catheter 3 is introduced into an inner region 33 of a casing 31.
  • the casing comprises an outer region 35 comprising a light transmission unit 36, which is, in this embodiment, at least one optical fibre, for transmitting acoustic wave generating light to the object 2 for coupling the acoustic wave generating light into the object 2 for generating an acoustic wave within the object 2.
  • the outer region 35 further comprises an acoustic wave sensing element 37 for sensing the acoustic wave generated within the object 2.
  • the outer region 35 of the casing is defined by at least one outer cavity 39, in which the at least one optical fibre is contained, and the inner region 33 is defined by at least one inner cavity 40.
  • the casing is preferentially a sheath surrounding the inner region 33, wherein preferentially in the wall of the sheath at least one outer cavity 39 defines the outer region 35.
  • the casing 31 is, in this embodiment, adapted for being disposable and/or reusable. Thus, the casing can later be removed and either discarded or sterilised for further treatments.
  • the casing 31 is adapted such that is fittable over the ablation catheter 3.
  • the casing 31 can be elastically and/or can comprise a fixing unit for fixing the casing 31 on the ablation catheter 3, like a handle or a lever-like assembly in order to secure the sheath in place. This fixing unit is preferentially located at the proximal end of the casing 31.
  • the casing 31 is, in this embodiment, adapted such that it can be fitted over the ablation catheter 3 such that a moveable element 37 located at a distal end of the at least one optical fibre 36 is in contact with the object 2, whenever the radio frequency catheter electrode 17 is in contact with the object 2.
  • the casing is adapted such that it can be fitted over one of several ablation catheters, in particular, over existing or future radio frequency catheters, a user retains the full flexibility in his choice of ablation catheters, appropriate to the respective ablation procedure and the patient.
  • the casing can be used for the entire ablation procedure in a patient and not just for an ablation lesion at a single location within the heart. This is possible due to the fact, that the casing, in particular, the sheath, is preferentially designed to be compatible with different types of ablation catheters, which may be used during a single ablation procedure.
  • the light transmission unit contained in the outer cavity 39 comprises preferentially several optical fibres 36 cylindrically arranged within the at least one outer cavity 39.
  • the optical fibres 36 can each be located in a single outer cavity or several optical fibres 36 can be located in the same outer cavity.
  • the optical fibres 36 comprise at their distal end the already above mentioned moveable element 37, which is, in this embodiment, the acoustic wave sensing element.
  • the proximal end of the optical fibres 36 is connected to the light source 7.
  • the moveable element 37 which is, in this embodiment, a reflecting element is, for example, a thin-film reflector coated on the distal end of the optical fibres 36.
  • the moveable element 37 is, for example, substantially moveable along the moving direction 22.
  • the moveable element is preferentially moveable with respect to the optical fibres 36 and the casing 31 such that the length of the optical light path of the light reflected by the moveable element 37 is modified.
  • the moveable reflecting element 37 is optically connected to the light source 7 and to the interferometrical unit 8, which comprises, in this embodiment, a spectrometer for analysing light reflected from the object 2, via the optical fibres 36.
  • the moving reflecting element 27, which is, in this embodiment, the moveable element, reflects sensing light and is at least partly transparent to acoustic wave generating light, which transmits through the moveable reflecting element 37 and is coupled into the tissue of the object 2. Sensing light is guided to the moveable reflecting element 37 via the optical fibres 36 and reflected by the moveable reflecting element 37. Also the acoustic wave generating light is guided by the optical fibres 36.
  • the acoustic wave generating light is at least partly absorbed within the object 2, wherein an acoustic wave is generated, in particular, light pulses are absorbed in the tissue of the heart resulting in a generation of a local thermoelastic wave in the tissue. This wave then travels outwards from the absorption side and is reflected back to the surface of the tissue.
  • the moveable reflecting element 37 is moved, in particular, the thin- film reflector thickness is altered, by the acoustic wave incident upon its surface.
  • This movement of this moveable reflecting element 37 modifies the optical length of the light reflected from the moveable reflecting element 37 via the optical fibres 36 to the interfero metrical unit 8 such that the movement of the moveable reflecting element 37 can be interfero metrically detected by the interferometrical unit 8.
  • the reflected acoustic wave can be detected as an optical signal corresponding to the light absorption in the object, in particular, in the tissue of the human heart.
  • the moveable reflecting element 37 is partly transparent to the acoustic wave generating light such that a part of the acoustic wave generating light, which is guided to the moveable reflecting element 37 via the optical fibres 36, is reflected by the moveable reflecting element 37, and that another part of the acoustic wave generating light transmits through the moveable reflecting element 37 and is coupled into the tissue of the object 2, wherein this part of the acoustic wave generating light is at least partly absorbed in the tissue of the heart for generating an acoustic wave, which moves the moveable reflecting element 37, in particular, which alters the thin- film reflector thickness, wherein an interference signal in the acoustic wave generating light pulse train is created, which is transported via the optical fibre 36 to the interferometrical unit 8.
  • the reflecting element is preferentially a thin moveable element, most preferrably directly placed in flush with the optical fiber behind it.
  • a thin moveable element most preferrably directly placed in flush with the optical fiber behind it.
  • a reflecting metal e.g.: silver, gold, palladium, platinum, tantalum, aluminum, ...) deposited directly on the end facet of the optical fiber.
  • the moveable element 37 is preferentially in flush with the outer surface of the distal end 5 of the catheter electrode 17.
  • the optical fibres 36 can be regarded as sensing optical fibres and pumping optical fibres, wherein sensing light is transmitted with the sensing optical fibres for sensing a movement of the moveable element and wherein acoustic wave generating light is transmitted by the pumping optical fibres to the distal end of the casing 31 for coupling the acoustic wave generating light into the object 2.
  • the moveable element is preferentially located at the distal ends of the sensing optical fibres only.
  • the light source is, in this embodiment, adapted such that sensing light having a sensing wavelength is guided to a moveable element via the sensing optical fibres.
  • the pumping optical fibres are connected to the light source such that pulsed acoustic wave generating laser light is guided to the distal end of the casing for coupling the pulsed laser acoustic wave generating light into the object 2, wherein in the object, in particular, within the tissue of the human heart, a thermoelastic wave is generated, which can be detected by a movement of the moveable element, which is exposed to this acoustic wave.
  • the pumping optical fibres and the sensing optical fibres are preferentially alternately arranged around the inner region 33 within the outer cavity 39.
  • Fig. 2 in a sectional view is schematically and exemplarily shown without the ablation catheter in Fig. 3 in a sectional view.
  • Fig. 4 shows schematically and exemplarily an embodiment of an apparatus for determining a property of an object.
  • the apparatus comprises the casing 31 comprising the inner region 33 and the outer region 35, in which the optical fibres 36 are located, the light source 7 and the interferometrical unit 8, which are connected to the casing, in particular, to the optical fibres 36 within the outer region 35 of the casing 31.
  • the light source 7 is adapted for transmitting acoustic wave generating light simultaneously through the several optical fibres 36.
  • the apparatus for influencing an object and for determining a property of the object which is schematically and exemplarily shown in Fig. 1, is preferentially used during cardiac ablation procedures, wherein the catheter tip, i.e. the tip of the radio frequency catheter electrode 17, must be brought into contact with the tissue being treated.
  • the apparatus for determining a property of an object comprising the casing 31 with the optical fibres 36 and the moving element 37 located at the distal ends of the optical fibres 36, the light source 7 and the interfero metrical unit 8, the tissue status can be monitored to guide the ablation procedure.
  • the tissue status can be monitored in real-time, in particular, in order to detect whether a lesion is transmural or not.
  • the acoustic wave generating light can be directed onto the object 2, in particular, onto the tissue of the heart, via at least one optical fibre, in particular, via all optical fibres, prior to-, during- and even after an ablation procedure.
  • An acoustic wave is generated within the object and the moveable element moves while the acoustic wave passes the moveable element.
  • Light reflected from the moveable element for example, sensing light or a part of the acoustic wave generating light, is reflected by the moveable element and transmitted to the interferometrical unit for generating a signal, which corresponds to the acoustic wave.
  • This signal can be directly provided to a user, for example, via a display or a printer, or can be further processed by a processing unit, which can be a part of the property determination unit, wherein the processing unit correlates the signal amplitude, for example, to tissue temperature at a specific location.
  • a processing unit which can be a part of the property determination unit, wherein the processing unit correlates the signal amplitude, for example, to tissue temperature at a specific location.
  • Further information regarding the property of the object in particular, regarding the tissue status, can be achieved by, for example, a computer-based simulation of the tissue status at the treatment side.
  • the determined property of the object, in particular, the tissue status can be used to monitor the progression of the lesion development between the inner and outer walls of the hearts to detect when the lesion is transmural.
  • the photoacoustic signal generated by the interferometrical unit can be used for determining properties of the object, in particular, for characterising the object. This is described in more detail in "Characterisation of post mortem arterial tissue using time-resolved photoacoustic spectroscopy at 436, 461 and 532 nm", Beard, P. C, Mills, T. N., Phys. Med. Biol. 42 (1997) 177-198, which is therewith incorporated by reference.
  • the signal generated by the interferometrical unit depends on the change in the optical properties of the tissue upon ablation, in particular, if the object is a human heart during an ablation procedure.
  • cardiac tissue is ablated, the absorption and scattering coefficients change dramatically, yielding a significant spectral signature which distinguishes healthy tissue from ablated tissue.
  • the acoustic wave generated by the absorption of acoustic wave generating light suffers less from attenuation in tissue and the photoacoustic sensing can therefore be applied to highly scattering, optically thick tissue samples.
  • photoacoustic signals relating to the real-time status of the tissue are obtained.
  • the photoacoustic signal When the tissue is coagulated and an arrhythmia-blocking lesion is created, the photoacoustic signal will indicate this change of the tissue, and the ablation catheter can be removed from the site and/or the application of energy, in particular, with the radio frequency catheter electrode, can be stopped. In this way, the photoacoustic signals can help to control the influencing of the object, in particular the application of energy, in particular, the ablation procedure, and prevent, for example, accidental under- and overheating.
  • the apparatus for determining a property of an object, the casing and the apparatus for determining a property of an object and for influencing an object are preferentially adapted for an application in electrophysiologic applications, in particular, for monitoring of coagulation and lesion development in the arterial wall during catheter-based cardiac ablation procedures.
  • the apparatus for determining a property of an object, the casing and the apparatus for influencing an object and for determining a property of an object can also be adapted for other applications, like the monitoring of a property of an object, to which energy is applied and which is not a heart.
  • This object is, for example, another organ of a human being or of an animal or a technical object, wherein preferentially energy is applied inside of the object.
  • Fig. 5 shows schematically and exemplarily a casing 42 comprising a steering 43 for steering the casing 42 and a handle 44.
  • the casing 42 comprises a light transmitting unit, in particular, optical fibres.
  • the optical fibres and moveable elements located at the distal end of the optical fibres are similar to the optical fibres and the moveable elements described further above with reference to Figs. 2 to 4.
  • Fig. 6 shows schematically and exemplarily a view on a part of the handle 44, which is indicated by a perspective dashed circle in Fig. 5, from the right side in Fig. 5.
  • the casing 42 in particular, the handle 44, comprises a fixing unit 48 comprising at least one spring-like element for holding an object influencing unit in place.
  • the spring-like elements are preferentially spring-like clasps.
  • the spring-like elements can be locked by a locking mechanism, which is not shown in Figs. 5 and 6 for clarity reasons.
  • An object influencing unit can be introduced into the casing 42 and after the object influencing unit has reached its final position preferentially the locking mechanism locks the spring-like elements for keeping the object influencing unit in place.
  • the spring-like elements are preferentially attached to an inner wall of the inner region of the casing 42 or of the handle 44.
  • the steering 46 and the handle 44 can comprise notch elements, wherein these notch elements can be engaged, after the catheter has been introduced into the casing in order to hold the catheter within the casing in place.
  • a lever comprising a recess can be used together with a lug, wherein the lever can be moved such that the recess engages the lug for locking the catheter within the casing.
  • the object influencing unit can be an ablation catheter 45, which is schematically and exemplarily shown in Fig. 5.
  • the ablation catheter 45 comprises one or several catheter electrodes 49, which can be used for ablation, sensing and/or pacing.
  • the ablation catheter 44 further comprises a steering 46 and a handle 47.
  • the steerings 43, 46 are connected to, for example, steering wires, which are located in the outer region of the casing 42 (not shown) and in the ablation catheter 45 for steering the casing and the ablation catheter, respectively.
  • the steerings are standard components and will therefore not be described in more detail.
  • the ablation catheter 45 further comprises a lead 50 at least for transmitting electrical energy to the distal end of the ablation catheter.
  • the casing 42 further comprises a lead 51 for guiding optical and/or electrical signals, in particular, the acoustic wave generating light, to and from the distal end of the casing 42.
  • Fig. 7 shows schematically and exemplarily the ablation catheter 45 introduced into the casing 42 for operation.
  • the casing 31 is provided comprising the inner region 33 for receiving an object influencing unit, like an ablation catheter 3, for influencing the object and an outer region 35 enclosing the inner region 33, wherein the outer region 35 comprises a light transmission unit, in this embodiment, optical fibres, and an acoustic wave sensing element.
  • the acoustic wave sensing element is the moveable element 37 located at the distal ends of the optical fibres 37.
  • step 102 the casing 31 is fitted over a distal end of an ablation catheter 3.
  • acoustic wave generated light is transmitted to the object and coupled into the object such that an acoustic wave is generated within the object.
  • a generated acoustic wave is sensed by the acoustic wave sensing element, which is, in this embodiment, the moveable element 37, i.e. light, which can be sensing light or a part of the acoustic wave generating light, is reflected by the moving moveable element 37 and is guided back to the interferometrical unit 8 via the optical fibres 36.
  • the interferometrical unit 8 generates a signal, which can be used for determining a property of the object, in particular, for determining the tissue status.
  • Steps 102 and 103 can be performed before, during and/or after the object is influenced by the object influencing unit, in particular, before, during and/or after application of energy, in particular, before, during and/or after ablation of a heart wall.
  • the object influencing unit in particular, before, during and/or after application of energy, in particular, before, during and/or after ablation of a heart wall.
  • the invention can be used in other applications as already mentioned above, for example, for applying energy to another object like another organ of a human being or of an animal or a technical object, wherein the property of the object is determined by using the casing before, during and/or after the object is influenced, in particular, before, during and/or after the energy is applied.
  • the acoustic wave sensing element is a reflecting moveable element
  • another acoustic wave sensing element can be used, for example, the acoustic wave sensing element can be an element which transforms a movement of the moveable element into an electrical signal, which corresponds to the movement of the moveable element and, thus, to the acoustic wave and which can be provided to a user, for example, on a display or on a printer, and/or which can be further processed for determining a property of the object.
  • the acoustic wave sensing element can also be another ultrasound device for sensing an acoustic wave generated by absorbing the acoustic wave generating light in the object.
  • radio frequency is applied to the object
  • other kinds of energy for example, cryogenic, microwave, laser or focused ultra sound energy can be applied to the object.
  • cryogenic, microwave, laser or focused ultra sound energy can be applied to the object.
  • the moveable element is preferably in contact with a surface of the object, in particular, with a surface of a heart, in other embodiments, a distance can be present between the moveable element and the surface, wherein an acoustic wave can still move the moveable element.
  • the acoustic wave can propagate through the blood and pass through the moveable element such that the acoustic wave can be sensed, even if the moveable element is not in contact with a surface of the heart tissue.
  • blood attenuates the acoustic wave, preferentially the distance between the moveable element and the surface of the heart tissue is minimized.
  • the apparatus for determining a property of the object preferentially comprises the moveable element being a reflecting element and an interferometer for measuring phase shifts on the reflected light for determining a movement of the reflecting element caused by an acoustic wave and, thus, for sensing the acoustic wave
  • the acoustic wave can be detected by other means for measuring ultrasound, like an ultrasound array, which is preferentially also integrated in the distal end of the casing.
  • the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality.
  • a single device or other unit may fulfill the functions of several items recited in the claims.
  • the mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.
  • Several functions which are realised by different units in the above described embodiments can be realised by any other number of units, also by only one unit.
  • the light source 7 and the interferometrical unit 8 can also be integrated into a single unit.
  • a computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.
  • a suitable medium such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.

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Abstract

La présente invention concerne un appareil permettant de déterminer une propriété d’un objet (2). Ledit appareil comporte un boîtier (31) comprenant une région interne (33) destinée à accueillir une unité d’influence d’objet (3) pour influencer l’objet (2) et une région externe (35) enfermant la région interne (33). La région externe (35) comprend une unité de transmission lumineuse (36) destinée à transmettre une lumière de génération d’onde acoustique jusqu’à l’objet (2), afin de coupler la lumière de génération d’onde acoustique à l’objet (2) pour générer une onde acoustique dans l’objet (2). En outre, la région externe (35) comprend un élément de détection d’onde acoustique (37) destiné à détecter l’onde acoustique. Le boîtier est de préférence une gaine entourant la région interne (33), avec au moins une cavité (39) de préférence dans la paroi de la gaine définissant la région externe (35).
PCT/IB2009/052388 2008-06-12 2009-06-05 Appareil destiné à déterminer une propriété d’un objet WO2009150593A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012131577A3 (fr) * 2011-03-29 2013-01-17 Koninklijke Philips Electronics N.V. Contrôle d'ablation basé sur l'imagerie fonctionnelle

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001020318A1 (fr) * 1999-09-16 2001-03-22 University College London Ensemble optique de detection interferometrique
US20060241572A1 (en) * 2005-04-26 2006-10-26 Gan Zhou Image-guided laser catheter

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001020318A1 (fr) * 1999-09-16 2001-03-22 University College London Ensemble optique de detection interferometrique
US20060241572A1 (en) * 2005-04-26 2006-10-26 Gan Zhou Image-guided laser catheter

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012131577A3 (fr) * 2011-03-29 2013-01-17 Koninklijke Philips Electronics N.V. Contrôle d'ablation basé sur l'imagerie fonctionnelle
CN103458816A (zh) * 2011-03-29 2013-12-18 皇家飞利浦有限公司 基于功能成像的消融监测
US9743881B2 (en) 2011-03-29 2017-08-29 Koninklijke Philips N.V. Photoacoustic catheter for functional-imaging-based ablation monitoring

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