# Patent

## Title
Optic fiber probe

## Abstract

An optic fiber probe system for treating thrombus of a patient comprising at least one optic fiber with at least one confined liquid-fillable void space and a light source for causing a laser-induced liquid/bubble jet that ejects from an opening of the confined void space to breakup the thrombus.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part application of U.S. patent application Ser. No. 10/988,416, filed Nov. 12, 2004, now U.S. Pat. No. 7,297,154, which is a continuation-in-part application of U.S. patent application Ser. No. 10/877,867, filed Jun. 26, 2004, now U.S. Pat. No. 7,153,299, which is a continuation-in-part application of U.S. patent application Ser. No. 10/373,539, filed Feb. 24, 2003, now U.S. Pat. No. 7,004,911, entire contents of all three co-pending applications are incorporated herein by reference.


FIELD OF THE INVENTION
The present invention is generally related to an optical thermal device for treating tissue. More particularly, the present invention relates to an optic fiber probe comprising at least one optic fiber with laser-induced micro pressure wave capability for treating tissue or thrombus within a blood vessel.
BACKGROUND OF THE INVENTION
A total occlusion is present when there is no flow of blood through the artery due to a blockage. An acute total occlusion is usually considered to be an occlusion that has occurred within the past 7 days, especially as the result of a myocardial infarction. A chronic total occlusion is an occlusion that is no longer acute and can be several months or years old. Successful revascularization improves angina status, increases exercise capacity, and reduces the need for late bypass surgery.
The patients of chronic total occlusion frequently present with a change in angina status rather than acute myocardial infarction. Well-developed collaterals may provide flow equivalent to a 90-95% stenosis, which helps maintain myocardial viability and prevents resting myocardial ischemia. Pathologically, the major constituent of a chronic total occlusion is fibrocalcific plaque. These obstructions are often resistant to guidewire crossing, accounting for lower success rate compared to nontotal occlusion.
Compared to PTCA (percutaneous transluminal coronary angioplasty) of nontotal occlusion, revascularization rates for chronic total occlusion remain disappointingly low. The most common reasons for procedural failure include the inability to cross the occlusion with a guidewire, failure to cross the occlusion with a balloon, and failure to dilate the stenosis. Recently, use of the rotablator catheter has decreased procedural failure due to lesion rigidity.
Jenkins in U.S. Pat. No. 5,109,859, entire contents of which are incorporated herein by reference, discloses an ablative laser element aiming at the plaque to ablatively remove the plaque under computer guidance. In one embodiment, the laser is able to fire in a forward direction after first determining the laser's path to be intralumnal in order to create or recanalize a central channel. In another embodiment, the laser is able to fire circumferentially at the arterial wall guided as to depth and direction by the ultrasound computer interface.
Loeb et al. in U.S. Pat. No. 6,845,193, entire contents of which are incorporated herein by reference, discloses a laser device for forming a channel through an occlusion or plaque in a blood vessel. The device comprises a fiber optic conduit which is adapted to be coupled to a source of laser energy, a hollow sheath which covers distal end of the fiber optic conduit and defines a pocket, and a fiber optic lens in the pocket and adapted to receive and direct the laser energy emitted from the fiber optic conduit through the lens onto the occlusion and to form a channel therethrough.
Vulnerable plaques are atherosclerotic plaques associated with erosion and ulceration that prone to rupture leading to acute embolization and thrombus. Until recently, physicians believed that most heart attacks were caused by a gradual buildup of atherosclerotic plaque in the arteries of the heart that eventually impeded blood flow. In fact, up to half of all sudden, out-of-hospital cardiac deaths occur in people with no prior diagnosis of heart disease and over two-thirds of heart attack suffers have blockages in their arteries considered to be clinically insignificant in terms of plaque burden and percent stenosis.
Most ruptured plaques are characterized by a large lipid pool and a thin fibrous cap with macrophage infiltration. On the other hand, calcified plaque deposits typically comprise hard material that restricts blood flow in a blood vessel. But, atherosclerotic plaque may also comprise combinations of soft and hard materials. The main difference between a soft vulnerable plaque and a hard stable plaque lies in the risk for a vulnerable plaque to rupture suddenly. The risk of plaque rupture is greatest when the fibrous cap is very thin or the plaque lipid pool is very large.
The buildup of plaque in the blood vessels is sometimes referred to as atherosclerosis, or hardening of the arteries. Atherosclerosis often begins as a small injury to an artery wall. This injury triggers a cascade of injury and response, inflammation, and healing, which may ultimately lead to the narrowing of the artery. It is generally believed that inflammation in an arterial plaque is the result of a series of biochemical and mechanical changes in the arterial wall. The inflammatory cells collect the debris of the damaged tissue resulting in a core of lipid, including macrophages or foam cells and necrotic tissue that is covered by a thin fibrous cap of scar tissue. If the fibrous cap becomes weakened, eroded, or is subjected to excessive mechanical stress, it may rupture and expose the thrombogenic damaged endothelium and metabolic byproducts to the blood stream that causes blood clotting. If the resulting blood clot is severe enough, it may occlude the artery. If this obstruction persists in a coronary artery, a myocardial infarction or angina may result.
Many vulnerable plaque deposits do not obstruct the flow of blood through the blood vessels. Vulnerable plaques are often undetectable using conventional techniques such as angiography. However, a plaque may rupture suddenly and form a blood clot in the blood vessel lumen causing a blockage and causes heart attack and death. Recently, inflammation has been recognized being associated with the formation and progression of vulnerable plaques. An increase in tissue temperature at a lesion is thought to be caused by the response of the immune system to inflammation and an increase in metabolic activity involved in the healing process. It has been observed that the inflamed necrotic core of a vulnerable plaque maintains itself at a temperature which may be a fraction of a degree to a few degrees higher than the surrounding tissue. Vulnerable plaques are generally characterized by hemodynamically insignificant, variable in size, not calcified, and undetectable with standard anatomic imaging methods.
The inability of common diagnostic methodologies, such as coronary angiography that is the current gold standard technique for diagnosing coronary vessel obstructions, to detect vulnerable plaque has led to a major rush to develop new methods to detect, characterize and treat patients with these types of deposits. Unlike the typical occlusive atherosclerotic lesion, vulnerable plaque deposits are associated with a compensatory enlargement of the vessel wall known as positive lumen remodeling. Selected intravascular imaging techniques for vulnerable plaque include angioscopy, intravascular ultrasound, thermography, optical coherence tomography, elastography, magnetic resonance imaging, nuclear imaging, electrical impedance imaging, shear stress imaging, photonic spectroscopy, and the like. Among them, catheter-based intravascular thermography is the most promising one, which is based on the premise that vulnerable plaques are hotter than surrounding normal tissue and that by measuring these temperature elevation, physicians can determine the exact location and extent of disease.
Casscells and associates (Current Opinion in Cardiology 2002; 17:656-662) reported mechanism of heat production in atherosclerotic plaques by a high metabolic rate in the areas of macrophage accumulation, of which a sub-population strongly expresses mitochondrial uncoupling proteins. The uncoupling proteins are homologs of thermogenin, which is responsible for thermogenesis in brown fat tissue. Further, they measured temperature of living samples with a thermistor and found that plaques showed several regions in which the surface temperatures varied reproducibly by 0.2° C. to 0.3° C. Infrared thermographic images also revealed heterogeneity in temperature among the plaques.
U.S. Pat. No. 5,924,997 to Campbell, entire contents of which are incorporated herein by reference, discloses an intravascular catheter system capable of mapping thermal variations in the temperature of atherosclerotic plaque by a plurality of thermal sensors fixedly attached along the catheter. The thermal sensors are mounted on the catheter shaft and soldered to a conductor while each sensor needs a conductor. The spacing of the mechanical thermal sensors arrangement allows only limited sensors to be placed within a unit length.
U.S. Pat. No. 6,292,695 to Webster, Jr. et al., entire contents of which are incorporated herein by reference, discloses a basket shaped catheter with a plurality of electrodes on each expandable member of the basket, while each electrode may comprise a thermal sensor for temperature monitoring. The spacing of the electrodes with mechanical thermal sensors arrangement allows only limited sensors to be placed within a unit length on each expandable member of the basket.
U.S. Pat. No. 6,450,971 to Andrus et al., entire contents of which are incorporated herein by reference, discloses a balloon catheter having temperature responsive material designed to exhibit at least one predetermined color when the material is in contact with an object having an elevated temperature, wherein a light detector positioned to indirectly detect the color change indicative of suspected lesion. The Andrus et al. balloon catheter uses a moving light detector to map multiple lesion sites within a blood vessel.
U.S. Pat. No. 6,475,159 to Casscells et al, entire contents of which are incorporated herein by reference, discloses an infrared heat-sensing catheter using an infrared fiberoptic system at the tip of the catheter to locate a single inflamed, heat-producing atherosclerotic plaque. The Casscells et al. catheter uses a dragging method to map multiple lesion sites within a blood vessel.
U.S. Pat. No. 6,514,214 to Kokate et al., entire contents of which are incorporated herein by reference, discloses a catheter with at least one temperature sensor disposed proximate to the distal end of the elongate shaft adapted to contact an inner surface of the blood vessel. The Kokate et al. catheter uses a dragging method to map multiple lesion sites within a blood vessel.
None of the above-identified patents discloses a thermal sensing means for measuring a plurality of contiguous points without dragging the device for area thermal mapping. In a co-pending patent application Ser. No. 10/373,539, filed Feb. 24, 2003, there is disclosed an optical thermal mapping device and methods for monitoring the thermal profiles enabling detecting vulnerable plaques within a blood vessel on a real time basis. The thermal mapping of vulnerable plaques using at least one optic fiber with multiple optical gratings are disclosed therein without dragging the device for area thermal mapping. Further in a co-pending patent application Ser. No. 10/877,867, filed Jun. 26, 2004, there is disclosed an optical thermal mapping device comprising multiple optic fibers with optical gratings for monitoring the thermal distribution of, and detecting and photodynamically treating vulnerable plaques within blood vessels.
Optic fibers are hair thin strands of glass or plastic that guide light. The optic fiber has an inner core surrounded by an outer cladding. In order to guide light, the core refractive index is higher than the cladding index. A fiber grating, which the periodic structure of the refractive index is formed inside the core of a fiber, is widely used in the field of fiber-optic communication for wavelength management. The optical grating reflects or transmits a certain portion, wavelength (bandwidth) or intensity, of the light along optic fibers. A fiber Bragg grating is based on the interference of multiple reflection of a light beam in a fiber segment whose index of refraction varies periodically along the length of the fiber. Variations of the refractive index constitute discontinuities that emulate a Bragg structure. If the spacing of the index periods is equal to one half of the wavelength of the light, then the waves will interfere constructively (the round trip of each reflected wave is one wavelength) and a large reflection will occur from the periodic array. Optical signals whose wavelengths are not equal to one half the spacing will travel through the periodic array unaffected.
A periodic variation of the refractive index is formed by exposing the core, such as germanosilicate, of the fiber to an intense ultraviolet (UV) optical interference pattern or mask that has a periodicity equal to the periodicity of the grating to be formed. When the fiber is exposed to an intensive UV pattern, structural defects are formed and thus a permanent variation of the refractive indexes having the same periodicity with the UV pattern. The condition for strong reflection of Bragg wavelength is λ=2×n×d. Where n is the effective refractive index, and d is Bragg spacing or grating period. Both n and d change with changes in temperature due to thermal-optic and thermal expansion effects.
The merits of optic fiber sensors include immunity to electromagnetic interference, high flexibility, remote sensing capability, smaller size of sensing element, lightweight, little thermal/electric conductivity, and easy to fabricate. Optic fiber sensors have been developed for chemical, strain, temperature and pressure sensing, and smart structure inspection. Various fiber-grating configurations have been developed for sensor application. Depending on its configuration, in general, it can be classified as direct and indirect sensors. Direct sensors measure the environmental effects surrounding the grating. Indirect sensors measure the environmental effects at the tip of the fiber and use fiber grating for wavelength management. The sensing signal is obtained through either a transmission or reflection mode. In some aspect of the present invention, it is provided direct fiber grating as direct sensors in a reflection mode.
Fiber gratings reflect light of particular bandwidth, and can act as high-performance optical thermal sensor. The reflected bandwidths are extremely narrow because of the long path lengths possible in optic fibers. Therefore, a minute temperature change surrounding the fibers changes the effective refractive index and grating's periods, thus modulating their reflective wavelength or intensity. When multiple gratings are created in an optic fiber, a multi-point sensor can be monitored simultaneously.
Fiber-grating technologies have been proven and demonstrated with excellent sensing abilities for temperature, pressure, stress and various chemicals detection. They also exhibit extremely long-term stability, and minimal optical losses. Several prior art devices have been described for the performance of a number of optic fiber grating sensors. U.S. Pat. No. 5,627,927 discloses an interferometer fiber grating for sensing the environmental effect at the termination of the fiber. U.S. Pat. No. 6,072,922 discloses a cryogenic fiber optical sensor by introducing additional thermal strain in the fiber to enhance sensor sensitivity. U.S. Pat. No. 5,444,803 discloses a fiber-optic device including fiber grating and mode stripper to admit only one mode for sensor application. U.S. Pat. No. 6,018,160 discloses an apparatus using two optical gratings for sensing aircraft skin temperature and/or strain. The above-referred patents, U.S. Pat. Nos. 5,627,927, 6,072,922 5,444,803, and 6,018,160, entire contents of all being incorporated herein by reference, disclose fiber-grating technology suitably applicable in the present invention for monitoring the thermal distribution of, and detecting vulnerable plaques within a blood vessel.
U.S. Pat. No. 6,753,160 to Adair, entire contents of which are incorporated herein by reference, discloses a method for diagnosis and treatment of arteriosclerotic lesions wherein the method is characterized by introducing a chemical compound to the patient, the compound being a complex of a photosensitive portion and a radioactive portion. Cells which exhibit an affinity for the porphyrin element indicate sites of plaque buildup. The radioactive portion within the compound allows tomographic scanning as well as simultaneous radiation treatment. The complexed compound can be introduced to the patient a desired number of times to provide the necessary radiation treatment and ongoing monitoring of plaque removal.
U.S. Pat. No. 6,736,808 to Motamedi et al., entire contents of which are incorporated herein by reference, discloses a catheter capable of both sensing myocardial electrical activity and delivering ablating energy within myocardial tissue, wherein the catheter may have a stabilizer of disk or basket shaped extensions which are attached to the catheter's distal tip. The catheter further comprises electrodes on the outer sheath and contains a movable fiber optic cable that can be percutaneously advanced beyond the catheter body and into the myocardium for myocardial heating and coagulation.
Robinson et al. in U.S. Pat. No. 6,054,449 and No. 6,794,505, entire contents of which are incorporated herein by reference, discloses a broad class of photosensitive compounds having enhanced in vivo target tissue selectivity and versatility in photodynamic therapy. reactive oxygen or chlorin producing photosensitizers are photoactivatable compounds having an affinity for hyperproliferating cells, which when photoactivated, produce cytotoxic reaction products. Some aspects of the present invention relative to a method for treating vulnerable plaque tissue in a blood vessel comprising providing an elongate tubular catheter into intimately contacting the tissue with a plurality of expandable basket optic fibers, each fiber having at least one optical grating facing the tissue-contacting surface alone for measuring the plaque tissue temperature and treating the tissue photodynamically with reactive oxygen and/or chlorin products.
U.S. Pat. Application publication 2004/0092830 and U.S. Pat. Application publication 2004/0093044, entire contents of both are incorporated herein by reference, disclose light delivery catheters for treatment of diseased vessels. Some optic fiber lumen is provided in the catheter shaft for containing a treatment optic fiber for delivering treatment light from a light source at the proximal end of the catheter shaft to the light transmission zone. The light intensity and efficiency is greatly compromised by the obstructive blood flow, including blood cells, platelets, plasma, and other electrolytes in photodynamically treating the lesion. Some aspects of the present invention provides an elongate tubular catheter at about the target tissue region, wherein the catheter comprises at least one optic fiber having at least one optical grating along an axis of the fiber, wherein the fiber further comprises a light transmission zone intimately contacting the tissue region configured for photodynamic therapy
Although many prior art patents are related to percutaneous transluminal coronary angioplasty, none of them discloses an optical medical device system having laser-induced micro pressure wave capability for crossing and breaking-up chronic total or near-total occlusion.
SUMMARY OF THE INVENTION
In accordance with preferred embodiments of the present invention, an optical thermal basket catheter is provided for intravascular measurement of the temperature of a vessel wall. In one aspect of the present invention, it is provided an optical thermal basket catheter comprising an elongate catheter sheath having a lumen, a distal sheath end, and a proximal sheath end; a plurality of optic fibers deployably disposed within the lumen of the catheter sheath, each fiber having a distal fiber portion, a distal fiber end and a proximal fiber end, wherein the plurality of distal fiber portions is suitably expandable in an outwardly radial manner adapted for forming a basket shape and for contacting at least a portion of the vessel wall. Each fiber has at least one optical grating along an axis of the fiber; and a light source has a light beam, wherein the light beam is coupled into the plurality of optic fibers, wherein the at least one optical grating reflects a certain wavelength or intensity of the light beam, the certain wavelength or intensity of the reflected light beam being correlated to the temperature of the portion of the vessel wall.
Another object of this invention is to provide a ready to use, highly sensitive and accurate catheter-based optic fiber sensor system for detecting vulnerable plaque. Thermographic images reveals heterogeneity in temperature profiles among the vulnerable plaques.
Another object of this invention is to provide a ready to use, highly sensitive and accurate device-based optic fiber sensor probe for detecting inflammation in coronary arteries or tissue regions such as a breast or a heart, wherein the probe is a catheter, a cannula or a hollow needle with side opening. In some aspect, it is provided an optical thermal device for monitoring temperature of a tissue region of a patient comprising an elongate tubular element comprising at least one optic fiber that contacts the tissue region; the at least one optic fiber having at least one optical grating along an axis of the fiber; and a light source having a light beam, wherein the light beam is coupled into the at least one optic fiber. The at least one optical grating along the axis of the fiber reflects a certain wavelength or intensity of the light beam, the certain wavelength or intensity of the reflected light beam being correlated to the temperature of the tissue region.
Another object of this invention is to combine a 4-French or smaller catheter with an expandable and externally controllable basket with multiple build-in flexible optic fibers, each fiber with multiple gratings, for suitably accessing an intravascular vessel and measuring the local temperature distribution of the vessel wall.
Another object of this invention is to provide an optical thermal device or an optical thermal basket catheter by using optic fiber gratings with thermal resolution of 0.001° C. to 5.0° C., preferably between 0.01° C. and 1.0° C.
It is a further object of the present invention to provide an optical thermal device or an optical thermal basket catheter by using optic fiber gratings having a length between 0.2 and 40 mm.
In still another aspect of the present invention, it is provided a method for monitoring temperature of a tissue region of a patient, the method comprising deploying an elongate tubular element into contacting the tissue region, wherein the elongate tubular element comprises at least one optic fiber. The fiber has at least one optical grating along an axis of the fiber, and a light source having a light beam is coupled into the at least one optic fiber; the optical grating reflecting a certain wavelength or intensity of the light beam, and the certain wavelength or intensity of the reflected light beam being correlated to the temperature of the tissue region.
The present optic fiber medical device has the advantages of simple, real-time, and easy operation. The probe also provides accurate and reproducible results. It should be understood, however, that the detail description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Further, as will become apparent to those skilled in the art, the teaching of the present invention can be applied to medical devices for measuring temperature at a variety of body parts.
Some aspects of the invention provide an optical apparatus for treating tissue of a patient comprising: an elongate tubular element having a lumen, a distal end, and a proximal end; a support scaffold structure deployable out of the distal end of the tubular element, wherein the support scaffold structure comprises a plurality of basket arms extendable outwardly for fixing or stabilizing the support scaffold in place when deployed, the support scaffold structure having a longitudinal middle optic fiber that emits light; and a light source having a light beam, wherein the light beam is coupled into the middle optic fiber.
Some aspects of the invention provide a method for treating a tissue region of a patient, the method comprising: a) providing an elongate tubular catheter into contacting the tissue region, wherein the elongate tubular catheter comprises a plurality of peripheral optic fibers in a support scaffold structure that is radially expandable and a middle optic fiber, each fiber having at least one optical grating along the axis of the fiber, wherein the middle fiber further comprises a light transmission zone configured for photodynamic therapy; b) monitoring a temperature of the tissue region, wherein a light source having a light beam is coupled into each optic fiber; the at least one optical grating reflecting a certain wavelength or intensity of the light beam, and the certain wavelength or intensity of the reflected light beam being correlated to the temperature; c) administering a therapeutically effective amount of at least one photosensitizer composition, wherein the photosensitizer composition is localized to the tissue region; d) light activating the photosensitizer composition to produce a phototoxic species, wherein the activating light is transmitted from the middle fiber; and e) treating the tissue region photodynamically.
Further, some aspects of the invention relate to an optical thermal basket catheter for monitoring temperature of a vessel wall of a patient comprising: a) an elongate catheter sheath having a lumen, a distal sheath end, and a proximal sheath end; b) a plurality of outer optic fibers deployably disposed within the lumen of the catheter sheath, each outer fiber having a distal fiber portion, a distal fiber end and a proximal fiber end, wherein the plurality of distal fiber portions is suitably expandable in an outwardly radial manner configured for forming a basket shape and for contacting at least a portion of the vessel wall, each outer fiber having at least one optical grating along an axis of the fiber; c) a longitudinal middle optic fiber spaced about equally from each expanded outer fiber, wherein the middle fiber emits a light energy suitable for photodynamic therapy; and d) a light source having a light beam, wherein the light beam is coupled into the plurality of outer and middle optic fibers, wherein the at least one optical grating reflects a certain wavelength or intensity of the light beam, the certain wavelength or intensity of the reflected light beam being correlated to known temperature.
Some aspects of the invention relate to a method for photodynamically treating a tissue region of a patient, the method comprising: a) providing an elongate tubular catheter at about the tissue region, wherein the catheter comprises at least one optic fiber having at least one optical grating along an axis of the fiber, wherein the fiber further comprises a light transmission zone intimately contacting the tissue region configured for photodynamic therapy; b) administering a therapeutically effective amount of at least one photosensitizer composition, wherein the photosensitizer composition is at least partially localized to the tissue region; c) light activating the localized photosensitizer composition to produce a phototoxic species, wherein the activating light is transmitted from the at least one optic fiber; and d) treating the tissue region photodynamically. In one embodiment, the step of providing the elongate tubular catheter is via a percutaneous procedure.
In a further embodiment, the elongate tubular catheter comprises a plurality of optic fibers in a support scaffold structure that is radially expandable, and wherein at least one optic fiber comprises a light transmission zone intimately contacting the tissue region configured for photodynamic therapy.
In a further embodiment, the tissue region is vulnerable plaque of a blood vessel. In an alternate embodiment, the tissue region is a vessel wall of a blood vessel.
In a further embodiment, the phototoxic species is reactive oxygen and/or chlorin. In one embodiment, the optical grating is a Bragg grating or a long period grating. In another embodiment, the optical grating is coated with a material having a thermal coefficient that is greater than a thermal coefficient of the fiber. In a further embodiment, the at least one optic fiber further comprises an optical diffraction means for simultaneously measuring multiple peaks of the reflected light beam. In a further embodiment, the optical grating has a length between 0.2 and 40 mm.
In a further embodiment, the method of photodynamically treating a tissue region of a patient further comprises a step of monitoring temperature of the tissue region, wherein a light source having a light beam is coupled into the at least one optic fiber; the at least one optical grating reflecting a certain wavelength or intensity of the light beam, and the certain wavelength or intensity of the reflected light beam being correlated to the temperature. In one embodiment, the monitored temperature is between 0.001 and 5.0° C.
Some aspects of the invention relate to a method for photodynamically treating a tissue region of a patient, the method comprising: a) providing a device with at least one optic fiber, wherein the fiber comprises a light transmission zone intimately contacting the tissue region configured for photodynamic therapy; b) administering a therapeutically effective amount of at least one photosensitizer composition, wherein the photosensitizer composition is at least partially localized to the tissue region; c) light activating the localized photosensitizer composition to produce a phototoxic species, wherein the activating light is transmitted from the at least one optic fiber; and d) treating the tissue region photodynamically. In a further embodiment, the device is a catheter or a cannula.
Some aspects of the invention relate to an optic fiber probe for generating a laser-induced liquid/bubble jet comprising a fiber core for transmitting light beam, a cladding layer enclosing a majority of the fiber core, and at least one liquid-filled confined enclosure located at adjacent to an edge of the fiber core, wherein each enclosure comprises a venting opening.
In one embodiment, the edge of the fiber core of the optic fiber probe is located at a distal end of the fiber core. In a further embodiment, the venting opening of the confined enclosure of the optic fiber probe is configured to direct the laser-induced liquid/bubble jet at a direction essentially parallel to a reference axial line or at a direction with an acute angle to a reference axial line.
In one embodiment, the edge of the fiber core of the optic fiber probe is located at a circumferential side of the fiber core. In a further embodiment, the venting opening of the confined enclosure is configured to direct the laser-induced liquid/bubble jet at a direction with an angle to a reference axial line, and wherein the angle is between 45 and 135 degrees.
In one embodiment, the optic fiber probe of the present invention further comprises a light source having a light beam, wherein the light beam is coupled into the fiber core of the optic fiber probe, and wherein the light beam is configured to cause the laser-induced liquid/bubble jet that ejects from the venting opening of the enclosure. In a further embodiment, the light source of the optic fiber probe comprises Ho:YAG laser energy.
In one embodiment, the external surface of the cladding layer of the optic fiber probe is loaded with a thrombolytic agent selected from a group consisting of tissue plasminogen activator (tPA), streptokinase, and urokinase. In another embodiment, the thrombolytic agent is mixed with a drug carrier before being loaded onto the external surface of the cladding layer of the optic fiber probe. In still another embodiment, the liquid in the liquid-filled enclosure comprises a thrombolytic agent.
In one embodiment, the cross-sectional area of the venting opening is smaller than an average cross-sectional area of the enclosure of the optic fiber probe. In another embodiment, a portion of the fiber optic probe is bulged at about the enclosure, the bulged portion being sized and configured to accommodate an enlarged enclosure volume.
Some aspects of the invention relate to an optic fiber probe for treating tissue or treating thrombus of a patient comprising: (a) an elongate probe sheath having a lumen, a distal sheath end, a venting opening, and at least one liquid-fillable void space in liquid communication with the venting opening; (b) at least one optic fiber deployably disposed within the lumen of the probe sheath, the at least one optic fiber comprising a fiber core for transmitting light beam, a cladding layer surrounding and enclosing a majority of the fiber core, wherein a distal end of the fiber core is located at about an proximal edge of the liquid-fillable void space; and (c) a light source having a light beam, wherein the light beam is coupled into the fiber core, wherein the light beam is configured to cause a laser-induced liquid/bubble jet for treating the tissue or treating the thrombus of the patient. In a further embodiment, the probe is selected from a group consisting of a catheter, a cannula, a needle, a basket-type catheter, and an implant.
Some aspects of the invention relate to a method of treating thrombus, comprising: (a) providing a laser-induced liquid/bubble jet system, wherein the system comprises a laser energy source, an optic fiber probe for transmitting laser beam from the laser energy source, wherein the probe comprises a confined enclosure with at least one exit opening located at a distal end of the probe; (b) delivering the optic fiber probe through a blood vessel to about the thrombus; (c) forwarding the distal end of the probe against the thrombus; and (d) applying a pulse of the laser beam to generate a pulsed liquid/bubble jet for treating the thrombus. In a further embodiment, the thrombus comprises chronic total occlusion or chronic near-total occlusion.



BRIEF DESCRIPTION OF THE DRAWINGS
Additional objects and features of the present invention will become more apparent and the invention itself will be best understood from the following Detailed Description of Exemplary Embodiments, when read with reference to the accompanying drawings.
FIG. 1 shows a fiber with a Bragg grating made by a UV interference pattern.
FIG. 2. shows a cross section view of an optic fiber with multiple gratings, each grating with specific grating period reflecting a specific wavelength or bandwidth of the light.
FIG. 3 shows multiple reflected wavelengths of the light from fiber gratings in a single optic fiber.
FIG. 4 shows an illustrative graph shows a relationship between the wavelength shift and the temperature in the range of body temperature (30-50° C.).
FIG. 5 shows the schematic diagram of a basket catheter with multiple optic fibers with multiple gratings for mapping the temperature distribution in a blood vessel.
FIG. 6 shows the optoelectronic components of the optical thermal device system of the present invention for reflective wavelength measurement.
FIG. 7 shows an overall view of the optical thermal device system having a deployable optic fiber assembly arrangement and the optoelectronic components, constructed in accordance with the principles of the present invention.
FIG. 8A shows one embodiment of a cross-sectional view of the distal end portion of the device system of FIG. 7, the device system having a deployable optic fiber support scaffold structure positioned distal to the distal section of a flexible catheter shaft at a deployed state.
FIG. 8B shows another embodiment of a cross-sectional view of the distal end portion of the device system of FIG. 7, the device system having a deployable optic fiber support scaffold structure positioned distal to the distal section of a flexible catheter shaft at a deployed state.
FIG. 8C shows one embodiment of a cross-sectional view of the distal end portion of the device system of FIG. 7, the device system having a self-expandable support scaffold structure positioned distal to the distal section of a flexible catheter shaft at a deployed state.
FIG. 9A shows one embodiment of a hollow needle probe with side opening.
FIG. 9B shows a side cross-sectional view of the needle probe, section I-I of FIG. 9A.
FIG. 10 shows a detailed description of the middle fiber component of the support scaffold structure positioned at the distal section of a flexible catheter shaft.
FIG. 11 shows one embodiment of a distal section of an optic fiber probe with end-firing laser-induced micro pressure wave capability.
FIG. 12 shows one embodiment of a distal section of an optic fiber probe with side-firing laser-induced micro pressure wave capability.
FIG. 13A shows a first embodiment of a laser angioplasty procedure with direct laser penetrating a thrombus.
FIG. 13B shows a second embodiment of a laser angioplasty procedure with laser-induced micro pressure wave for penetrating a thrombus.



DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
The preferred embodiments of the present invention described below relate particularly to an optical apparatus having diagnostic and/or therapeutic functions. The diagnostic function of the apparatus comprises at least one optic fiber with multiple optical gratings for simultaneously monitoring the thermal profile of and detecting vulnerable plaque within a blood vessel. The therapeutic function of the apparatus comprises at least one optic fiber within a support scaffold for providing adequate light energy to activate photodynamic therapy onto the photosensitized vulnerable plaque. Another therapeutic function of the apparatus comprises at least one optic fiber with micro pressure wave capability for crossing, breaking-up and treating chronic occlusion. In one preferred embodiment, the apparatus is not removed from the blood vessel between diagnostic (for example, thermal mapping) and therapeutic (for example, photodynamic therapy) procedures. While the description sets forth various embodiment specific details, it will be appreciated that the description is illustrative only and should not be construed in any way as limiting the invention. Furthermore, various applications of the invention, and modifications thereto, which may occur to those who are skilled in the art, are also encompassed by the general concepts described below.
Optic Fiber Grating
The advantages of using fiberoptic sensors for medical applications are well known. The non-conductive nature of both quartz and plastic fibers makes them ideal for electrical safety and for non-perturbing use in radiofrequency and microwave environments. Further, when measuring the tissue temperature on an inner wall of a blood vessel, the temperature measured by a non-conductive fiberoptic sensor reflects about the real tissue temperature whereas the temperature measured by a conductive thermocouple or thermister is compromised by the flowing blood stream of the blood vessel. Some aspects of the present invention relate to a basket catheter system having a plurality of expandable basket optic fiber arms, each fiber having a tissue-contacting region and a blood-contacting region, wherein the grating surface is limited to the tissue-contacting region for enhancing the temperature measurement sensitivity. In one embodiment, the blood-contacting region of the optic fiber is not grated. In another embodiment, the blood-contacting region was grated, but insulated or covered thereafter.
The optic fiber grating principles are briefly described herein for reference. The creation of high performance optical components by photolithographically writing periodic variations in the refractive index—“Bragg grating”—directly into the cores of conventional silica-based fibers. Regardless of the method used, the interference pattern must be of high quality, with uniform periodicity, high contrast, and sharp edges. The UV periodicity, as shown in FIG. 1, is formed by means of one of several optical methods (for example, UV mask, diffraction, interferometry, or the like) that generate an interference pattern of alternating minima and maxima of light intensity. The UV source 20 is provided by an excimer laser that operates at a wavelength in the 157-351 nm. The UV or near UV light pattern transmits through the cladding 30 and creates an index perturbation (Δn) 31 with a periodicity 32 in the core 40 of the fiber 10 that depends on the wavelength band in which the grating is designed to operate.
The grating reflectivity, R, for a given mode at enter wavelength (λ) is given by

R=tan h2[πLΔnη(V)/λ]

Where L is the length of the grating, Δn is the magnitude of index perturbation, and η (V) a function of fiber parameter V that represents the fraction of the integrated mode intensity contained in the core 40. The core diameter of the single mode fiber is typically less than 10 μm, while the total fiber diameter is approximately 0.1-2 mm. A smaller optic fiber of less than 100 μm may also be useful in certain medical applications.
Multiplexing of several grating 51, 52, 53, 54, as shown in FIG. 2, written in the same fiber 10 allows the creation of a distributed sensor capable of measuring the spatial profile of a temperature quantity. Each grating 51, 52, 53, 54, fabricated with different periodicity 32, reflects a specific wavelength. For illustration purposes, when a light beam 91 (with λ1 to λ5) from a broadband light source, an ultra wideband light source, or multiple-wavelength light source 98 (shown in FIG. 6) is input into the fiber, the multiple gratings reflect a first portion 92 (λ1 to λ4) and transmit a second portion 93 (λ5) of the light depending on the effective index of the grating. Therefore, by monitoring the shift of a specific reflected wavelength, for example, as shown in grating 2 of the FIG. 3, the local temperature in the vessel wall at that grating can be correlatively measured externally. The total length of each grating is about 1 to 5 mm, and the reflectivity can be greater than −20 db. FIG. 4 shows an example of the correlated wavelength shift versus temperature at 37° C. in the range of human body temperature. The actual correlative relationship between the wavelength shift and the temperature of a specific fiber device system could be calibrated and established when the fibers are in a simulated operating shape, configuration and conditions.
The temperature resolution of the intrinsic silica core fiber Bragg grating is approximately 0.01 nm/° C. To obtain a resolution of 0.1° C., the spectrum analyzer must resolve the shift of the reflected wavelength to an accuracy of about 0.001 nm. Various methods are commonly used to increase temperature resolution. The first method is to apply temperature sensitive materials or polymers, such as PMMA, onto the cladding 30 at grating area, thus leads to a large temperature change or a larger temperature coefficient (Δn/ΔT). The second method to enhance the temperature resolution is to use long-period grating. For typical Bragg grating, the grating periodicity (d) 32 is 0.5-10 μm, while for long period fiber grating (LPG), the periodicity can be as large as several hundred micrometers. The larger grating periodicity, d, in LPG will lead to a larger wavelength shift, Δλ. The higher order resonant peaks of LPG are very sensitive to its ambient refractive index. The wavelength shift of long period grating can be two to three orders of magnitude larger than that of Bragg grating. An LPG-based temperature sensor can easily achieve a resolution of about 0.001° C.
Multi-Fibers Catheter
FIG. 5 shows a distal portion basket-type arrangement of an optical thermal basket catheter loaded with multiple small and flexible optic fibers 50, 60, 70, 80, and each fiber is incorporated with multiple optical grating elements 51, 52, 53, 54, 61, 62, 63. A 6 French catheter or smaller with an expandable and externally controllable basket arrangement 21 can support 4 to 10 fibers depending on the design dimension and configuration. One method to deploy and radially expand the optic fiber basket is to utilize a highly flexible pulling wire 23 (also shown in FIG. 8A). In one embodiment, the tip 85 of the pulling wire 23 is secured to the tip bundle 83 of the flexible optic fibers 50, 60, 70, 80.
To enhance the outward expansion property, the optic fibers may suitably be slightly preshaped. In some aspect of the present invention, the basket catheter may comprise an inflatable balloon sized and configured to expand the fibers radially outward during the deployment and temperature sensing state. In one further aspect of the present invention, each of the fibers may be supported intimately by an expandable wire during the deployment and temperature sensing state. The basket catheter 19 permits good thermal contact of the optical grating elements on the optic fiber with the arterial wall. Each optic fiber sensors (that is, optical grating elements) are sized, configured and suitably located on the optic fiber enabling optimal contact with the target inner surface of a blood vessel, allowing monitoring of temperature upon expansion and in contact with the vulnerable plaque. The total sensing length in each fiber is approximately 2-5 cm. The length of the optic fiber is comparable to the length of the catheter. By using an optical thermal basket catheter system, it does not need to drag the catheter for mapping a whole region of interest.
The optical thermal basket catheter system, as shown in FIG. 6, is integrated with a light source 98, a fiber splitting coupler 94, wavelength diffraction elements 96, and an optical signal detection system 97. Light from a broadband light-emitting diode (LED) or an ultra wideband light source travels through a single-mode fiber 50 to reach the grating 51, 52, 53, 54. Diode lasers, such as broadband diode lasers (1.3-1.55 μm) that cover the fiber communication wavelengths, are also available. Some lamp sources, such as a tungsten lamp, which are broadband light sources that cover the entire near infrared range, are also suitable as a continuous light source. Though the light source has a broad bandwidth; the reflected light from the grating is relatively narrow. The reflected light propagates back in the same fiber 50 and is coupled into a detection fiber by an optical coupler 94. Optic fiber couplers are used extensively in optic fiber communication systems. The most common couplers are fused fiber and directional coupler, which split the optical signal from one fiber into two fibers with different intensity ratio. The signal demultiplexing is constructed with a focusing/collimating lens 95, a diffraction grating 96, and a two dimensional CCD (charge coupled device) array 97.
The spectral peaks associated with each grating are physically separated by the diffraction grating 96 and illuminated on the CCD 97. The movement of the peak on CCD is related to the peak shift due to temperature change originated from fiber grating. When multiple signal fibers are aligned linearly in front of the entrance of the diffraction grating 96, a 2-D CCD provides the ability to simultaneously monitor multiple reflection spectra from multiple fibers. The detector 97 is interfaced through an analog-to-digital converter to an advanced signal processor in a computer. The real-time data acquisition software supports digital processing with a thermal resolution of 0.001° C. The temperature distributions obtained from the multiple sensors offer a thermographic mapping of the entire vessel walls. The circumferential and longitudinal thermal profiles of the vessel wall can also be displayed. The system is calibrated under simulated operating conditions to remove other non-thermal effects. In general, the data acquisition and analysis of the optical parameters are well known to an ordinary person who is skilled in the art.
FIG. 7 shows an overall view of the optical thermal device system having a deployable optic fiber assembly arrangement and the optoelectronic components, constructed in accordance with the principles of the present invention. As shown in FIG. 7, one preferred embodiment of the thermal device system comprises an elongate tubular element (for example, a catheter shaft, a cannula, or a hollow needle) 11, the catheter shaft having a distal section 12, a shaft distal end 13, a shaft proximal end 14, and at least one lumen 18 extending between the shaft proximal end 14 and the shaft distal end 13, wherein the at least one lumen 18 may have at least one opening 71 at the shaft distal end 13 of the catheter shaft 11. A handle 15 is attached to the shaft proximal end 14 of the catheter shaft 11, wherein the handle 15 has a cavity for allowing at least one fiber 50, 60, 70, 80 and/or the pulling wire 23 to pass through.
In some aspect of the present invention, the optical thermal medical device 19 is for monitoring temperature of a tissue region of a patient without a need for dragging the device along the tissue wall. The device comprises an elongate tubular element comprising at least one optic fiber that contacts the tissue region; the at least one optic fiber having at least one optical grating along an axis of the fiber; and a light source having a light beam, wherein the light beam is coupled into the at least one optic fiber; wherein the at least one optical grating along the axis of the fiber reflects a certain wavelength or intensity of the light beam, the certain wavelength or intensity of the reflected light beam being correlated to the temperature of the tissue region.
In one preferred embodiment, the optical thermal medical device is a basket catheter. As shown in FIG. 8A, the optical thermal device system may comprise a pulling wire 23 inside the lumen 18 of the catheter shaft 11. The pulling wire or connecting wire 23 has a distal end and a proximal end, wherein the distal end of the pulling wire 23 is joined to the distal joint 83 of the basket fibers, and wherein the proximal end of the pulling wire is secured to the pulling mechanism 16 mounted on the handle 15. The pulling mechanism 16 may be a special push-pull controller or the like on the handle 15 adapted for the push-pull operation of the pulling wire 23. The fiber assembly arrangement, including an optic fiber bundles of fibers 50, 60, 70, 80 with gratings, is mounted at about the distal section 12 of the catheter shaft 11, wherein the fiber assembly arrangement comprises a plurality of preshaped expandable basket fiber members 50, 60, 70, 80, each basket fiber having a fiber distal end and a fiber proximal end, wherein the fiber distal ends of the preshaped expandable basket fibers are joined at a basket distal joint 83. The fiber assembly arrangement is associated the fiber assembly deployment mechanism 17, which is actuatable to deploy the arrangement out of the distal end opening 71 of the catheter shaft 11. Prior to activating the wire 23, the wire 23 is aligned in parallel with the fibers 50, 60, 70, 80. During deployment phase, the fibers are first deployed outside of the distal end 13 of the catheter by a deployment mechanism 17. When the wire 23 is pulled by a pulling mechanism 16 located at the handle 15 of the basket catheter 19 externally, the optic fibers will expand outwardly and form a basket.
In another embodiment as shown in FIG. 8B, the optical apparatus or device system is a basket type catheter with a support scaffold structure, comprising a middle temperature sensor or optic fiber 23A. The middle optic fiber 23A is located longitudinally at about equal distances from any axial basket members 50, 60, 70, and 80. In one aspect, the device system has a deployable support scaffold structure 21 positioned distal to the distal section of a flexible catheter shaft 11 at a deployed state. In another aspect, the deployment of the support scaffold structure is self-expandable. In one embodiment, the middle optic fiber 23A is configured for emitting adequate and proper light energy enabling desired photodynamic activation onto the surrounding tissue of a blood vessel or body conduit that is photosensitized.
In still another embodiment as shown in FIG. 8C, it shows a cross-sectional view of the distal end portion of the device system of FIG. 7. The device system has a deployable scaffold structure positioned distal to the distal section of a flexible catheter shaft 11 at a deployed state and located at the distal section of the flexible catheter shaft at a pre-deployed state. In one embodiment, the middle optic fiber 23A is configured for emitting adequate and proper light energy enabling desired photodynamic therapy onto the surrounding tissue of a blood vessel or body conduit. Some aspects of the invention relate to an optical apparatus for treating tissue comprising a light emitting optic fiber for providing adequate light energy to initiate photodynamic therapy onto the photosensitized vulnerable plaque, wherein the optic apparatus comprises a support scaffold to stabilize the apparatus and to maintain the emitting optic fiber at essentially the middle of the longitudinal support scaffold structure.
FIG. 10 shows a detailed description of the middle optic fiber 23A of the support scaffold arrangement 21 positioned distal to the shaft distal end 13 of a flexible catheter shaft 11 at a deployed state. In one embodiment, the middle optic fiber 23A comprises a distal end 24 and a proximal end 25 that is optically connected to the light source 98 that has at least one light beam, wherein the light beam is coupled into the middle optic fiber 23A. In a further embodiment, the optic fiber 23A comprises a grated fiber section 27 for monitoring the surrounding temperature or environment conditions and a roughened emitting zone 29 configured for emitting the desired light energy for photodynamic therapy through either the end surface 28 and/or the circumferential surface 26 of the middle fiber 23A.
The emitting zone 29 is generally located at and covers about the axial length of the monitoring fibers on the basket members 50, 60, 70, 80 so as to enable photodynamic therapy once the abnormal temperatures (and hence vulnerable plaque indications) are identified by using the disclosed catheter having dual diagnostic and therapeutic functions. In one alternate embodiment, the emitting zone covers beyond the axial length of the monitoring fibers on the basket members. In some such embodiments, the optic fiber 23A of the support scaffold structure is configured for thermally treating vulnerable plaque in the absence of photosensitizers. In some aspects of the invention, the wavelength of the fiber optic light for temperature sensing is generally in the range of 1 to 2 μm, preferably in the range of 1.3 to 1.6 μm, whereas the wavelength of the fiber optic light for photodynamic therapy is generally in the range of 500 to 800 nm, preferably in the range of 600 to 800 nm. Some aspects of the invention relate to an optical apparatus system having at least one light source having a first light beam with a first wavelength λN and a second light beam with a second wavelength λE, wherein the first light beam is coupled into the plurality of outer optic fibers and the middle fiber, wherein the at least one optical grating reflects a certain wavelength or intensity of the light beam, the certain wavelength or intensity of the reflected light beam being correlated to known temperature as shown in FIGS. 2 and 4, and wherein the second light beam is coupled into the middle optic fiber for causing photodynamic therapy.
The fiber assembly deployment mechanism 17 is mounted on the handle 15, wherein the fiber assembly deployment mechanism 17 is attached to the proximal end of the fiber bundle. The plurality of preshaped expandable basket fibers is suitably expanded at a deployed state, whereas the plurality of preshaped expandable basket fibers is retracted within the lumen 18 at a non-deployed state. During the insertion into or removal of the medical device from a patient, the fiber assembly arrangement is at a non-deployed state.
In some aspect, the device system further comprises a wire guide shaft at the distal section 12 of the catheter shaft 11, the wire guide shaft defining a wire guide lumen 35, the wire guide shaft having a proximal end and a distal end, wherein the wire guide lumen 35 has at least one opening at the distal end and at least one opening at the proximal end of the wire guide shaft, wherein the wire guide shaft is used for introducing the device system into a vascular vessel over a pre-introduced guidewire. The wire guide lumen 35 may be located close to one side of the wire guide shaft for rapid exchange of the optic fiber device system over the guidewire. For guiding the device system of the present invention into a blood vessel, the distal section 12 may further comprise an externally detectable imaging element, such as an ultrasound transducer, an electromagnetic chip, an MRI coil, a short range radiofrequency antenna, or the like.
Therefore in some aspect, it is provided an optical thermal basket catheter for monitoring temperature of a vessel wall of a patient comprising: (a) an elongate catheter sheath having a lumen, a distal sheath end, and a proximal sheath end; (b) a plurality of optic fibers deployably disposed within the lumen of the catheter sheath, each fiber having a distal fiber portion, a distal fiber end and a proximal fiber end, wherein the plurality of distal fiber portions is suitably expandable in an outwardly radial manner adapted for forming a basket shape and for contacting at least a portion of the vessel wall, each fiber having at least one optical grating along an axis of the fiber; and (c) a light source having a light beam, wherein the light beam is coupled into the plurality of optic fibers, wherein the at least one optical grating reflects a certain wavelength or intensity of the light beam, the certain wavelength or intensity of the reflected light beam being correlated to the temperature of the portion of the vessel wall.
In another preferred embodiment, the optical thermal device for monitoring temperature of a tissue region of a patient is a steerable or flexible probe. The probe comprises an elongate tubular element comprising at least one optic fiber that contacts the tissue region; the at least one optic fiber having at least one optical grating along an axis of the fiber; and a light source having a light beam, wherein the light beam is coupled into the at least one optic fiber; wherein the at least one optical grating along the axis of the fiber reflects a certain wavelength or intensity of the light beam, the certain wavelength or intensity of the reflected light beam being correlated to the temperature of the tissue region.
In some aspect, the elongate tubular element of the probe is a catheter, a cannula, or a hollow needle with side opening. The tissue region of interest comprises a vessel wall of a blood vessel, a heart or a breast of the patient. In another aspect, the optical grating is a long period grating or Bragg grating, wherein the optical grating is coated with a material having a thermal coefficient that is greater than a thermal coefficient of the fiber. The optical thermal device may further comprise an optical diffraction means for simultaneously measuring multiple peaks of the reflected light beam. Typically, the optical grating has a length between 0.2 and 40 mm, whereas the probe has a temperature resolution between 0.001 to 1.0° C.
FIG. 9A shows one embodiment of a hollow needle probe 72 with side opening 76, wherein the surface of an enclosed optic fiber 10 is exposed to and contacts with the surrounding tissue through the opening 76. In a preferred embodiment, the needle probe 72 comprises a handle 73 and a needle body that is hollow, wherein the needle body is comprised of a distal needle portion 74B, a proximal needle portion 74A and at least two connecting bars 75A, 75B securely coupling the distal needle portion 74B and the proximal needle portion 74A. Further, the proximal needle portion 74A is securely attached to the handle 73. The distal needle portion 74B further comprises a penetrating end 77 that is suitably sharpened for easily penetrating into and through tissue, such as a heart or a breast.
Within the hollow cavity of the needle body, there provides an optic fiber 10 with gratings 51, 52, 53. FIG. 9B shows a side cross-sectional view of the needle probe 72, section I-I of FIG. 9A. The optic fiber 10 comprises the cladding 30 and the core 40. In one aspect, the optic fiber is securely held within the needle body in a way such that the surface of the fiber is exposed to a target tissue for mapping the tissue temperature or detecting the diseases, for example, the breast tumor or cancer. In another aspect, the optic fiber 10 is integrated with a light source, a fiber splitting coupler, wavelength diffraction elements, and an optical signal detection system as described above in FIG. 6. In one embodiment, the optic fiber of the needle probe further comprises a section configured for emitting adequate and proper light energy enabling desired photodynamic therapy onto the surrounding tissue. Some aspects of the invention relate to an optical apparatus for treating tissue comprising a light emitting optic fiber for providing adequate light energy to initiate photodynamic therapy onto the photosensitized tumor/cancer, breast tumor, breast cancer, and the like.
The optic fiber sensors system has several operational advantages including immunity to electromagnetic interference, high flexibility, remote sensing capability, smaller size of sensing element, lightweight, and easy to fabricate. It is one preferred aspect of the present invention to provide an optic fiber sensor for chemical composition, stress-strain tissue elasticity, temperature and pressure sensing of the blood vessel wall related to vulnerable plaque.
Vulnerable Plaque
Every year, more than one million people in the United States experience a sudden cardiac event (acute coronary syndromes and/or sudden cardiac death). Though a large portion of this population has no prior symptom, a thrombus identifies a culprit plaque that might be ruptured or nonruptured. Plaque rupture is the most common type of plaque complication, accounting for about 70% of fatal acute myocardial infarctions and/or sudden coronary death (Circulation 2003; 108:1664-1672 and Circulation 2003; 108:1772-1778). The vulnerable plaque considered responsible for acute coronary events based on retrospective autopsy studies had a large lipid pool, a thin cap, and macrophage-dense inflammation on or beneath its surface.
The risk of plaque rupture is related to two factors: the intrinsic individual plaque character that influences vulnerability and an extrinsic force triggering plaque disruption (Reviews in Cardiovascular Medicine 2004; 5(suppl 2):S22-S33). Because angiography provides only a contrast-filled luminal silhouette, it tends to underestimate the severity of coronary atherosclerosis. Accordingly, the development of novel imaging techniques has become one of the most important research areas in the field of vulnerable plaque. Some imaging techniques for detection of vulnerable plaque include intravascular ultrasound, angioscopy, optical coherence tomography, thermography, spectroscopy, magnetic resonance imaging, computed tomography, serum markers, and others.
With emerging fiber optic approaches to detect the vulnerable plaque via thermography, the same fiber optic technology can be used to treat vulnerable plaque. Photodynamic therapy is a unique modality that combines systemic and local approaches to inhibit plaque formation, cause plaque regress, and enable the diagnosis and stabilization of vulnerable plaque. This approach involves the combination of a chemical photosensitizer and visible light at a specific wavelength to selectively illuminate and activate the photosensitizer, thus leading to the production of singlet radical oxygen species, which mediates apoptosis. A previous animal study has demonstrated that motexafin lutetium, a photosensitizer derived from the porphyrin molecule, binds LDL receptors and is transported into microphage-rich plaque. In the same study, a significant decrease in macrophages and a mild decrease in atheroma were observed without damage to the normal vessel wall in the area of photoactivation (Cardiovascular Research 2001; 49:449-455).
Photosensitive tumor-seeking drugs with a strong absorption and large fluorescence quantum yield in the far visible or near infrared regions have become available. Ho et al. In U.S. Pat. No. 5,660,181, entire contents of which are incorporated herein by reference, discloses an apparatus for in-depth three dimensional tumor mapping including (A) a light source; (B) a multi-fiber bundle including at least one illumination fiber and at least two receiving fibers, the at least one illumination fiber being connected to the light source; (C) a spectrometer connected to the at least two receiving fibers; and (D) a hybrid neural network connected to the spectrometer, the hybrid neural network including a principle component analysis processor and a neural network classifier. The characteristic spectral signature of these photosensitized drugs can improve early cancer diagnosis. Because near-infrared light can penetrate much deeper into tissue than visible and ultraviolet light, the use of such drugs makes possible tissue diagnosis at a significantly greater depth than was previously accessible.
Photodynamic Therapy
It is one object of the present invention to provide an optical apparatus for treating tissue comprising a light emitting optic fiber for providing desired light energy to initiate photodynamic therapy onto the photosensitized tissue, such as vulnerable plaque. In one embodiment, the optical apparatus has both diagnostic and therapeutic functions. Some aspects of the invention provide an optical apparatus for treating tissue of a patient comprising: an elongate tubular element having a lumen, a distal end, and a proximal end; a support scaffold structure deployable out of the distal end of the tubular element, wherein the support scaffold structure comprises a plurality of basket arms extendable outwardly for fixing/stabilizing the support scaffold in place when deployed, the support scaffold structure comprises at least one optic fiber that emits light; and a light source having a light beam, wherein the light beam is coupled into the at least one optic fiber.
Photodynamic therapy (PDT) is a treatment that uses a drug, called a photosensitizer or photosensitizing agent, and a particular type of light. When photosensitizers are exposed to a specific wavelength of light, they produce a form of oxygen that kills nearby cells. Each photosensitizer is activated by light of a specific wavelength. This wavelength determines how far the light can travel into the body. Thus, doctors use specific photosensitizers and wavelengths of light to treat different areas of the body with PDT. In the first step of PDT for tissue treatment, a photosensitizing agent is injected into the bloodstream. The agent is absorbed by cells all over the body, but may stay in particular cells longer than it does in normal cells. At some specific period after injection, the target tissue is exposed to light. The photosensitizer in the target tissue absorbs the light and produces an active form of oxygen that destroys nearby undesired cells. The light used for PDT can come from a laser or other sources of light. Laser light can be directed through an optic fiber to deliver light to areas inside the body. For example, a fiber optic cable can be inserted through an endoscope (a thin, lighted tube used to look at tissues inside the body) into the lungs or esophagus to treat cancer in these organs. Other light sources include light-emitting diodes (LEDs), which may be used for surface tumors, such as skin cancer.
U.S. Patent Application publication No. 2004/0092830, entire contents of which are incorporated herein by reference, discloses a catheter for detecting and treating diseased tissue in a blood vessel or other hollow body organ. The catheter comprises an elongated tubular catheter shaft having a distal end comprising a light transmission zone with a diagnostic optic fiber having a distal end terminating within the light transmission zone for emitting and receiving light through the light transmission zone for use in connection with a diagnostic method for detecting diseased tissue.
U.S. Patent Application publication No. 2004/0093044, entire contents of which are incorporated herein by reference, discloses light delivery catheters for use in PDT therapeutic methods that require illumination of target tissue within a blood vessel or other hollow body organ. An improved catheter comprises a catheter shaft having a light treatment zone at its distal end. A light guide, such as an optic fiber, in the catheter shaft transmits light from a light source at the proximal end of the catheter shaft to the light treatment zone. An occlusion balloon is positioned on the distal end of the catheter shaft adjacent to the light treatment zone. The balloon means tends to block the blood flow during treatment and causes undesired side effects.
U.S. Pat. No. 6,096,030, entire contents of which are incorporated herein by reference, discloses a light delivery catheter for use in PDT treatment, including a hollow shaft with a balloon at its distal end. A light guide extends along the sheath and has a light-radiating portion of light source at its end within the balloon. The balloon is positioned at the target site and target tissue is irradiated causing destruction of the target tissue. The balloon means tends to block the blood flow during treatment and causes undesired side effects.
U.S. Patent Application publication No. 2004/0057900, entire contents of which are incorporated herein by reference, discloses detectably labeled macrophage scavenger receptor antagonists useful for the diagnosis and monitoring of vulnerable plaque by administering to a patient a detectably labeled scavenger receptor antagonist and detecting or imaging the location of the pathologies. This invention also provides pharmaceutically acceptable compositions comprising the detectably labeled scavenger receptor antagonists of the present invention.
U.S. Patent Application publication No. 2004/0057900, entire contents of which are incorporated herein by reference, discloses a method of stabilizing a vulnerable plaque in a subject comprising the steps of: a) administering a therapeutically effective amount of at least one photosensitizer composition, wherein the photosensitizer composition is localized to the vulnerable plaque; and b) light activating the photosensitizer composition to produce a phototoxic species; and c) stabilizing the vulnerable plaque against rupture.
U.S. Pat. No. 6,054,449, entire contents of which are incorporated herein by reference, discloses a method for employing photoactivatable compounds for diagnosing such diseases as atherosclerosis, restenosis, cancer, cancer precursors, noncancerous hyperproliferative diseases, psoriasis, macular degeneration, glaucoma and viruses. Photodynamic therapy has been applied in cardiovascular medicine for at least two broad indications: treatment of atherosclerosis and inhibition of restenosis due to intimal hyperplasia after vascular interventions. Hematoporphyrin derivative was the first of a number of photosensitizers with demonstrable, selective accumulation within atheromatous plaques. Subsequent studies have underscored the affinity of porphyrin derivatives for atheromatous plaques in rabbits and miniswine. Hematoporphyrin and its derivatives provide a new aid for detection of malignant disease and atheromatous plaques because they tend to accumulate in malignant/atheromatous tissue with subsequent red fluorescence for optical viewing (J Thoracic and Cardiovasc Surg 1961; 42:623-629).
Ho et al. reported (SPIE 1996; 2675: 89-98) a photodynamic drug detection system for measurement of drug uptake. (Most photodynamic drugs emit strong fluorescence at near infrared region. Scanning and measuring the fluorescence intensity over the area of interest can map out the drug distribution in the areas of tumor or plaque. Since tumor and plaque tend to have higher metabolic rate, the drug concentration is higher in these areas. Therefore, photodynamic drug offers an optical method for localize tumors or plaque.) The system uses near infrared laser excitation, a special fiber configuration and long wavelength 680 nm fluorescence analysis to monitor the drug concentration in tissue in real time. Some aspects of the present invention relate to an optic fiber basket catheter with the photodynamic drug detection system for monitoring the drug (for example, photosensitizers) concentration in plaque tissue.
A photosensitizer is used in the disclosed methods at a dosage that facilitates the increase of vascular permeability to deliver a drug of interest. A useful dosage of a photosensitizer for the disclosed methods depends, for example, on a variety of properties of the activating light (e.g., wavelength, energy, energy density, and intensity), the optical properties of the target tissue and properties of the photosensitizer. In certain embodiments, photosensitizers useful for the described methods of this invention include, but are not limited to, members of the following classes of compounds: porphyrins, chlorins, bacteriochlorins, purpurins, phthalocyanines, naphthalocyanines, texaphyrins, and non-tetrapyrrole photosensitizers. For example, the photosensitizer may be, but is not limited to, Photofrin, benzoporphyrin derivatives, tin ethyl etiopurpurin (SnET2), sulfonated chloroaluminum phthalocyanines and methylene blue, and any combination of any or all of the above.
A photosensitizer useful for the described methods of the invention may be supplied to the organism of interest by any means known to the skilled artisan including, but not limited to, oral, local, slow release implant, systemic injection (e.g., venous, arterial, lymphatic), local injection (e.g., slow release formulations), hydrogel polymers, inhalation delivery (e.g., dry powder, particulates), electroporation-mediated, iontophoresis or electrophoresis mediated, microspheres or nanospheres, liposomes, erythrocyte shells, implantable delivery devices, local drug delivery catheter, perivascular delivery, pericardial delivery, and eluting stent delivery. A photosensitizer useful for the described methods may be prepared or formulated for supply to the organism of interest in any medium known to the skilled artisan including, but not limited to, tablet, solution, gel, aerosol, dry powder, biomolecular matrix, and inhalation.
As illustrated in U.S. Patent Application publication No. 2004/0071632, entire contents of which are incorporated herein by reference, it is disclosed that IK17 can be labeled with photodynamic compounds that emit energy upon stimulation with an appropriate wavelength of light that can be administered by the use of a catheterized light source of the invention. Activation of the compound may ablate the atherosclerotic plaque or inhibit the growth of the plaque.
Yock at 2003 TCT meeting in Washington, D.C., reported photodynamic modulation of vulnerable plaque with antrin (that is, motexafin lutetium) in animal and clinical studies. Motexafin lutetium is excitable by light at about a wavelength of 740 nm that penetrates tissue and is water soluble with short plasma half life and no significant phototoxicity. Further, it is preferentially absorbed by atheromatous plaque. Animal study data indicate that motexafin lutetium localizes in atheromatous plaque and in intimal hyperplasia, variably reduces plaque in rabbit models of atherosclerosis, reduces intimal hyperplasia in rat models, and consistently depletes macrophages across animal models. The clinical implications are: reducing plaque cellularity would have a positive effect on restenosis; and a preferential uptake by macrophages could mean stabilization of vulnerable plaque. Some aspects of the invention relate to a method of diagnosing and photodynamically treating vulnerable plaque comprising using a basket type support scaffold catheter with light irradiating capability for desired photodynamic therapy.
The radiation used in the described methods, in certain embodiments, is calibrated so that it enhances vascular permeability at the selected site in the organism of interest when applied to the chosen type and dose of photosensitizer. Radiation used in the described methods of the invention is preferably calibrated, for example, by choosing the appropriate wavelength, power, power density, energy density, and time of application relative to the time of supply of the photosensitizer to the organism. In certain embodiments, the radiation wavelength used in the described methods is absorbed by the photosensitizer used. In certain preferred embodiments, the radiation wavelength used in the described methods is such that the absorption coefficient at the chosen wavelength for the photosensitizer used is at least about 20 percent of the highest absorption coefficient for that photosensitizer on the spectrum of electromagnetic radiation of from about 280 nm to about 1700 nm.
Although photodynamic therapy has been extensively researched and is well known to one skilled in the art, none of the prior art teaches a method for simultaneously diagnosing and treating vulnerable plaque via photodynamic therapy using the same catheter or cannula apparatus on a one-step operation. Some aspects of the invention provide a method for treating a tissue region of a patient, the method comprising: a) providing an elongate tubular catheter into contacting the tissue region, wherein the elongate tubular catheter comprises a plurality of peripheral optic fibers in a support scaffold structure and a middle optic fiber, each fiber having at least one optical grating along an axis of the fiber, wherein the middle fiber further comprises a light transmission zone configured for photodynamic therapy; b) monitoring a temperature of the tissue region, wherein a light source having a light beam is coupled into the optic fiber; the at least one optical grating reflecting a certain wavelength or intensity of the light beam, and the certain wavelength or intensity of the reflected light beam being correlated to the temperature; c) administering a therapeutically effective amount of at least one photosensitizer composition, wherein the photosensitizer composition is localized to the tissue region; d) light activating the photosensitizer composition to produce a phototoxic species, wherein the activating light is transmitted from the middle fiber; and f) treating the tissue region photodynamically.
By way of examples, a photosensitizer is administered to a patient under a physician's supervision. An optical apparatus of the invention is inserted into the blood vessel at about the target tissue. The diagnostic function of the apparatus is activated to measure the thermal profiles of the target tissue leading to identifying the vulnerable plaque indication. Once the region of vulnerable plaque at the target tissue is confirmed, the therapeutic function of the apparatus is activated to provide photodynamic light energy to activate the needed photodynamic therapy. The remaining or surrounding tissue outside the irradiation zone would not go through the photodynamic therapy due to the absence of the activating light wavelength. Therefore, the photodynamic treatment is limited to the target tissue locally when the method of the present invention is used comprising a light transmission zone of an optic fiber apparatus intimately contacting the tissue region configured for photodynamic therapy.
Some aspects of the invention relate to a method for photodynamically treating a tissue region of a patient, the method comprising: a) providing an elongate tubular catheter at about the tissue region, wherein the catheter comprises at least one optic fiber having at least one optical grating along an axis of the fiber, wherein the fiber further comprises a light transmission zone intimately contacting the tissue region configured for photodynamic therapy; b) administering a therapeutically effective amount of at least one photosensitizer composition, wherein the photosensitizer composition is at least partially localized to the tissue region; c) light activating the localized photosensitizer composition to produce a phototoxic species, wherein the activating light is transmitted from the at least one optic fiber; and d) treating the tissue region photodynamically. In a further embodiment, the elongate tubular catheter comprises a plurality of optic fibers in a support scaffold structure that is radially expandable, and wherein at least one optic fiber comprises a light transmission zone intimately contacting the tissue region configured for photodynamic therapy.
Some aspects of the invention relate to a method for photodynamically treating a tissue region of a patient, the method comprising: a) providing a device with at least one optic fiber, wherein the fiber comprises a light transmission zone intimately contacting the tissue region configured for photodynamic therapy; b) administering a therapeutically effective amount of at least one photosensitizer composition, wherein the photosensitizer composition is at least partially localized to the tissue region; c) light activating the localized photosensitizer composition to produce a phototoxic species, wherein the activating light is transmitted from the at least one optic fiber; and d) treating the tissue region photodynamically. In a further embodiment, the at least one optic fiber comprises at least one optical grating along an axis of the fiber.
Micro Pressure Wave
High-pressure, well-directed microjets can selectively dissect or breakup the thrombus mass or clots while keeping the surrounding structure intact. The effect is magnified when the microjets contain a liquid/bubble mixture with more bubbles, whereas the mixture has an expanded volume as compared to the source liquid. It was reported recently that Ho:YAG was used to generate a pulsed water-jet knife that minimizes the amount of water flowing into the incision. Unlike the Nd:YAG laser, the wavelength of the Ho:YAG laser is 2.1 μm, which is very close to the 1.9 μm peak absorption of water, and is absorbed many times better than the light from an Nd:YAG laser. Further, Ho:YAG laser energy is also uniformly absorbed by water-bearing tissue or thrombus resulting from thrombus, chronic total occlusion, near-total occlusion, or other causes. When a portion of water is vaporized, the volume increase from a liquid phase to a vapor phase is enormous and causes micro pressure wave or shock wave for intended medical applications of the present invention.
Some aspects of the invention relate to a laser light via an optic fiber to vaporize water or liquid confined in a small space of an instrument, such as a void space at the distal end 44 of an optic fiber 23A or the void space at the side 46 of an optic fiber 42. The laser energy is absorbed by the water or liquid in the confined space, which creates a localized vapor bubble (or bubbles) that expands and ejects a pulse of liquid from the venting opening or exit opening 45 or 48 of the void space 44, or 46, respectively. Increasing the energy of the laser pulses creates higher-pressure water jets. By way of illustration, a standard 1-mm diameter optic fiber is used as the setup configured with a conical shaped void space that ended in a 5-mm long, 100-μm wide nozzle. In general, the void space (also known as “enclosure”) can be any shape that is configured for channeling the liquid/mixture through a small exit port. A 400-μm diameter fiber core 40 of the optic fiber is covered by a cladding of about 300-μm wall thickness circumferentially. The optic fiber transmits Ho-YAG laser energy to the liquid in the confined void space, where it vaporizes a small volume of water and ejected microliter volumes through the nozzle. This phenomenon of vaporizing a small volume of water in a confined space creates micro pressure wave and propagates through the opening into the target thrombus or tissue. Once the water/bubble mixture is ejected, fresh water or liquid enters the void space and the process of laser-induced liquid/bubble jetting repeats again. The pulsed water jet imparts little heat to surrounding tissues.
Hoang in U.S. Pat. No. 5,860,972 issued on Jan. 19, 1999, entire contents of which are incorporated herein by reference, discloses a method of destruction of urinary calculi comprising the steps of providing a laser source and a fiber optic laser delivery device, initiating laser energy transmission from the laser source and delivering an initial pulse of laser radiation to the urinary calculi for detection, generating and continuing to deliver pulses of laser energy to the urinary calculi until the urinary calculi has been fragmented completely, wherein the laser source is a Ho:YAG laser.
Song et al. in U.S. Patent Application publication 2004/0020905, entire contents of which are incorporated herein by reference, discloses a method for cleaning surfaces, the method comprising: securing a surface to be cleaned in a liquid; focusing a laser beam at a point in the liquid to generate a liquid/bubble jet and a shock wave; positioning the point of focus of the laser beam in close proximity to the surface to be cleaned such that the laser-induced liquid/bubble jet and shock wave clean the surface.
FIG. 11 shows one embodiment of a distal section of an optic fiber probe or apparatus with end-firing laser-induced micro pressure wave capability, whereas FIG. 12 shows a side-firing laser-induced micro pressure wave optic fiber probe or apparatus. In an end-firing optic fiber as a medical probe or as a component of a medical device (such as a catheter, a cannula, a needle, or an implant), the optic fiber comprises an active fiber core 40 for light transmission and a protective cladding layer 30, wherein a confined void space 44 is configured and dimensioned to be located adjacent the edge 47 of the active core 40 and allows liquid or water to flow into the void 44 through its opening 45. In one embodiment, the internal wall of the confined void space 45 is configured as a conical shape at an angle θ to channel the expanded liquid jet (that is, liquid/bubble mixture) through the small opening 45. The angle θ is configured between 1 and 170 degrees, preferably between 5 and 90 degrees. In one embodiment, the optic fiber probe of the present invention is equipped and configured with radiopaque or ultrasound visualization capability.
A laser pulse is directed through the fiber core 40 of the optic fiber 23A to the liquid inside the void space. The laser energy vaporizes a small volume or a small portion of liquid and ejects microliter volume of liquid/bubble mixture as a laser-induced liquid/bubble jet 49 through the opening. In one embodiment, the opening 45 comprises at least one nozzle sized, configured, and pointed to some desired direction essentially in parallel to or at an acute angle (preferably about 1 to 45 degrees) from a reference axial line. In another embodiment as shown in FIG. 12, the side opening 48 of the void space 46 comprises at least one nozzle sized, configured, and pointed to some desired direction essentially in perpendicular to or at an angle (preferably between 45 and 135 degrees) from a reference axial line. The distal section 89 of the optic fiber 23A may be enlarged, such as a ball or bulged shape (not shown), to accommodate a desired larger void space 44.
FIG. 13A shows one embodiment of a laser angioplasty procedure with direct laser penetrating a thrombus 37. An optic fiber probe 86 comprises a sheath cover 33 and a front-firing optic fiber 36, wherein the sheath cover comprises a sheath distal end 38A, an enlarged void space or enclosure 34 at about the distal portion of the sheath cover 33, and a distal opening 39 connecting to a distal end 87 of the enclosure 34. Further, the optic fiber 36 comprises a core 40, a cladding layer 30, and a fiber distal end 38B. In one embodiment, the fiber distal end 38A contacts the thrombus 37 for emitting direct laser to penetrate into the thrombus. In another embodiment (as shown in FIG. 13B), the optic fiber 36 is configured or retractably positioned within the sheath cover 33, wherein the fiber distal end 38B is located at about the proximal end 88 of the enclosure (as opposite to the distal end 87 of the enclosure 34). In one embodiment, the cross-sectional area of the opening 39 is smaller than the average cross-sectional area of the middle-bulged enclosure 34.
Some aspects of the invention provide an optic fiber probe for treating tissue or thrombus, particularly thrombus from chronic total occlusion or chronic near-total occlusion, comprising: (a) an elongate probe sheath having a lumen, a distal sheath end, a distal sheath portion, and a liquid-fillable void space located at about the distal sheath portion; (b) an optic fiber deployably disposed within the lumen of the probe sheath; and (c) a light source having a light beam, wherein the light beam is coupled into the at least one optic fiber, wherein the light beam causes a laser-induced liquid/bubble jet that is ejected from an opening of the void space. In one embodiment, the distal end of the optic fiber is located at about another end opposite to the opening of the void space.
Some aspects of the invention relate to a method of treating thrombus, particularly thrombus from chronic total occlusion or chronic near-total occlusion, comprising: (a) providing a laser-induced liquid/bubble jet system, wherein the system comprises a laser energy source, an optic fiber probe for transmitting laser beam, a small volume of liquid confined in an enclosure with at least one exit opening on the enclosure; (b) delivering the optic fiber probe through a blood vessel to about the thrombus site; (c) forwarding the exit opening against the thrombus; and (d) applying a pulse of laser beam to generate pulsed liquid/bubble jet or bubble jet for breaking-up or crossing the thrombus. In one embodiment, the optic fiber probe further comprises an optic lens at its distal end adapted to receive and direct the laser energy emitted from the optic fiber to generate the pulsed liquid/bubble jet. In another embodiment, liquid flows into the enclosure between the pulses of two consecutive laser beams.
In one embodiment, the laser energy source is a battery and the optic fiber probe is an implant. In another embodiment, the laser energy source comprises a photoelectric conversion device that receives and converts energy (such as electromagnetic, ultrasound, or radiofrequency energy) wirelessly from a remote source to the target laser energy source. In another embodiment, the probe system further comprises a distal protective filter or screen for capturing any undesired debris or loosen thrombi. In some embodiment, the liquid for generating micro pressure wave or laser-induced shock wave is blood or plasma from the blood vessel of the patient. Plasma makes up 55% of the volume of blood. Basically, plasma is the fluid portion of the blood which suspends the cells and comprises a solution of approximately 90% water, 7% protein and 3% of various other organic and inorganic solutes.
In some aspects of the invention, the method may comprise a pulse duration in the range from 1 nanosecond to 100 microseconds. In further embodiments, the laser energy source may be selected from a group consisting of a YAG laser (for example, Ho:YAG laser, Nd:YAG laser, or Er:YAG laser), an excimer laser, a CO2 laser, or the like. In further embodiments, the laser fluence of the laser beam is in the range of 0.5 J/cm2 to 100 J/cm2. In further embodiments, the laser beam has a wavelength in the range from 157 nm to 10.6 μm. In some further embodiments, the laser beam has a frequency range from 1 Hz to 10 kHz.
Some aspects of the invention relate to an optic fiber probe system for crossing total or near-total obstructions in arteries or other anatomical conduits, treating tissue, or treating thrombus of a patient comprising: (a) an elongate probe sheath having a lumen, a distal sheath end, and a proximal sheath end; (b) at least one optic fiber deployably disposed within the lumen of the probe sheath, the at least one fiber having a fiber core for transmitting light beam, a cladding layer surrounding a majority of the fiber core, and at least one liquid-fillable void space located at adjacent to an edge of the fiber core; and (c) a light source having a light beam, wherein the light beam is coupled into the at least one optic fiber, wherein the light beam causes a laser-induced liquid/bubble jet that ejects from an opening of the confined void space. In one embodiment, the opening is sized to have an aperture smaller than an averaged cross-sectional diameter or area of the confined void space or enclosure. In some embodiment, the liquid used in the optical probe system of the present invention is blood or plasma from the blood vessel of the patient. In one embodiment, the probe is a catheter, a cannula, a needle, or a basket-type catheter with multiple optic fibers. In another embodiment, each distal fiber portion of the multiple optic fibers of the basket-type catheter is suitably expandable in an outwardly radial manner. Medical applications of the optical probe system of the present invention include treating heart, blood vessels, breast, bones, joints, and other anatomical voids/channels.
In some embodiment, at least a portion of the optic fiber probe surface is loaded or coated with a thrombolytic agent, such as tissue plasminogen activator (tPA), streptokinase, urokinase, and the like enabling to enhance the breaking-up, dissolving, or cleaning of the thrombus. In one embodiment, the thrombolytic agent is loaded or coated onto the probe surface with an inert drug carrier, such as a biocompatible or hemo-compatible polymer. In some embodiments, the probe of the present invention could be used in combination with a conventional PTCA catheter, a guidewire, a laser angioplasty instrument, or a rotablator device for treating thrombus, including chronic total or near-total occlusion.
U.S. Pat. No. 6,918,762 issued on Jul. 19, 2005 entitled “Light-generating instrument” and U.S. Pat. No. 6,291,763 issued on Sep. 19, 2001 entitled “photoelectric conversion device and photo cell”, entire contents of both incorporated herein by reference, disclose the energy converting means for supplying laser energy to the optic fiber probe system of the present invention. The energy converting means is well known to one ordinary skilled in the art.
From the foregoing, it should now be appreciated that an optical therapeutic device comprising at least one optic fiber having laser-induced liquid/bubble jet with micro pressure wave capability for treating blood vessel thrombus has been disclosed. The optical therapeutic device of the present invention is also generally applicable for treating tissue. While the invention has been described with reference to a specific embodiment, the description is illustrative of the invention and is not to be construed as limiting the invention. Various modifications and applications may occur to those skilled in the art without departing from the true spirit and scope of the invention as described by the appended claims.

## Claims

1. An optic fiber probe for generating a laser-induced liquid/bubble jet, said probe comprising a distal end, a fiber core for transmitting light beam toward said distal end, a cladding layer enclosing a majority of the fiber core, wherein said cladding layer having a thermal coefficient that is greater than a thermal coefficient of the fiber core, and at least one liquid-filled confined enclosure located at or adjacent said distal end of the fiber core, wherein said at least one enclosure comprises a venting opening and a light beam provides energy for generating said liquid/bubble jet.

2. The optic fiber probe of claim 1, wherein said venting opening is configured to direct the laser-induced liquid/bubble jet at a direction substantially parallel to a reference axial line.

3. The optic fiber probe of claim 1, wherein said venting opening is configured to direct the laser-induced liquid/bubble jet at a direction with an acute angle to a reference axial line.

4. The optic fiber probe of claim 1, wherein said venting opening is located at a circumferential side of the fiber core.

5. The optic fiber probe of claim 4, wherein said venting opening is configured to direct the laser-induced liquid/bubble jet at a direction with an angle to a reference axial line, and wherein the angle is between 45 and 135 degrees.

6. The optic fiber probe of claim 1, further comprising a light source for transmitting said light beam, wherein the light beam is coupled into the fiber core of the optic fiber probe, and wherein the light beam is configured to energize the liquid in said at least one enclosure and cause the laser-induced liquid/bubble jet that ejects from the venting opening of the enclosure.

7. The optic fiber probe of claim 6, wherein the light source comprises Ho:YAG laser energy.

8. The optic fiber probe of claim 1, wherein an external surface of the cladding layer is loaded with a thrombolytic agent selected from the group consisting of tissue plasminogen activator (tPA), streptokinase, and urokinase.

9. The optic fiber probe of claim 8, wherein the thrombolytic agent is mixed with a drug carrier before being loaded onto the external surface of the cladding layer.

10. The optic fiber probe of claim 1, wherein the liquid in the liquid-filled enclosure comprises a thrombolytic agent.

11. The optic fiber probe of claim 10, wherein the thrombolytic agent is selected from the group consisting of tissue plasminogen activator (tPA), streptokinase, urokinase, and combinations thereof.

12. The optic fiber probe of claim 1, wherein a cross-sectional area of the venting opening is smaller than an average cross-sectional area of the enclosure.

13. The optic fiber probe of claim 1, wherein a portion of the enclosure is enlarged.

14. An optic fiber probe for treating tissue or treating thrombus of a patient comprising: (a) an elongate probe sheath having a lumen, a distal sheath end, a venting opening, and at least one liquid-fillable void space in liquid communication with the venting opening; (b) at least one optic fiber deployably disposed within the lumen of the probe sheath, the at least one optic fiber comprising a fiber core for transmitting light beam, a cladding layer surrounding and enclosing a majority of the fiber core, wherein said cladding layer having a thermal coefficient that is greater than a thermal coefficient of the fiber core, wherein a distal end of the fiber core is located at about an proximal edge of the liquid-fillable void space; and (c) a light source having a light beam, wherein the light beam is coupled into said fiber core, wherein the light beam is configured to cause a laser-induced liquid/bubble jet for treating the tissue or treating the thrombus of the patient.

15. The optic fiber probe of claim 14, wherein the light source comprises Ho:YAG laser energy.

16. The optic fiber probe of claim 14, wherein the probe is selected from the group consisting of a catheter, a cannula, a needle, and a basket-type catheter.

17. The optic fiber probe of claim 14, wherein the liquid in the liquid-tillable void space comprises a thrombolytic agent.

18. The optic fiber probe of claim 17, wherein the thrombolytic agent is selected from the group consisting of tissue plasminogen activator (tPA), steptokinase, urokinase, and combinations thereof.

19. The optic fiber probe of claim 14, wherein the light beam from said light source is provided to generate a pulse of said laser-induced liquid/bubble jets.