WO2011141829A1

WO2011141829A1 - Method and apparatus for dynamic tracking of medical devices using fiber bragg gratings

Info

Publication number: WO2011141829A1
Application number: PCT/IB2011/051359
Authority: WO
Inventors: Adrien Emmanuel Desjardins; Gert 't Hooft; Raymond Chan; Guy Shechter; Bernardus Hendrikus Wilhelmus Hendriks; Nenad Mihajlovic; Maya Ella Barley
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2010-05-11
Filing date: 2011-03-30
Publication date: 2011-11-17

Abstract

A method and apparatus locate medical devices within the human body. A Fiber Bragg Grating system is embedded within a medical device. The shape information described by the Fiber Bragg Grating system is combined with location information of an Electro Magnetic or another marker system to provide more accurate location information of a portion of the medical device.

Description

Method and Apparatus for Dynamic Tracking of Medical Devices

using Fiber Bragg Gratings

Technical Field

[0001] This invention relates to the positioning of needles, catheters and other medical devices during medical treatment. Devices such as needles are used to target tissues within the human body to deliver medication, remove tissues for biopsies or to make diagnostic measurements. Catheters are used to ablate tissues, deliver medication and to clear obstructions in blood vessels and other passages of the body.

Background

[0002] Needles are one of many devices which are placed in specific locations within the human body based on pre-procedural images. The images are obtained with various modalities (imaging technologies) such as magnetic resonance imaging (MRI), computed tomography (CT) or image reconstruction such as XperCT™. One goal of placement is to minimize damage to surrounding tissues by carefully selecting the path of the needle during placement.

[0003] During any procedure accurate knowledge about the location of the needle tip is critical, but proper guidance relative to the image may not be available. For instance, in the case of a CT guided biopsy, the number of images acquired is limited due to concerns about radiation exposure to the patient. If, due to the lack of precise information, incorrect tissues are targeted, there is a risk of an inaccurate diagnosis or a need for repeated procedures, which involves additional risk to the patient and increased costs.

[0004] One method of tracking the position of the needle tip relative to pre-procedural image is to place a marker(s) on the portion of the needle external to the patient and to track the marker in real time by means of a variety of sensors; given an estimation of the needle geometry the computed needle tip position can then be mapped in real time to the pre- procedural image. For instance, optical tracking of the needle can be performed with visual markers using two or more imaging cameras. Alternatively, Electro-Magnetic (EM) navigation can be performed by means of a small EM coil marker placed on the needle and tracked by a set of sensors external to the needle.

[0005] Marker based tracking has the disadvantage that it is often impractical to place more than a few markers on the needle, due to size or cost limitations. When using small diameter needles it may be possible to place markers only on the proximal end that lies external to the patient's body. Significant bending of the needles may occur during placement within the patient which results in a needle tip position that cannot be inferred accurately. This is particularly true when the portion of the needle where the bending occurs does not have a marker.

[0006] Catheters are another device used within the body. One application of catheters is the ablation of a ring of tissue around the pulmonary veins to cure the condition known as atrial fibrillation. Typically this procedure takes place under X-ray guidance. The catheter is visible as a 2D projection under X-ray fluoroscopy which is often insufficient for precision use. In the alternative the catheter is used within an MR system further modifications of the catheter are required to make it trackable. The real-time 3D position of the catheter tip is typically tracked with a system that provides localization by means of electromagnetic and/or impedance measurements. Alternatively, MR guided ablation systems such as the Philips MR-EP catheter with a micro-receiving coil at its tip can be used.

[0007] While the location and orientation of the tip is important, the real-time shape of longer sections of the catheter is also important to the success of the procedure. In the case of ablation procedures it is desirable to create continuous lesion lines which require knowledge of the location and shape of a section of the catheter. The methodology used by the physician is to pull the curved catheter back along the endocardial wall, gradually straightening the catheter tip. Visualization of the distal section of the catheter is used to determine the speed and movement with which the catheter is pulled backwards and to maintain the contact pressure applied to the endocardial wall so that the physician can create a continuous lesion line of ablation. [0008] Another type of catheter which is desirable to image and control is the positioning of a pulmonary vein lasso catheter which must fit snugly around the pulmonary vein ostium in order to improve the procedural success rates. Likewise, accounting for the motion caused by respiration during the placement of a coronary sinus catheter requires detailed information regarding the location of the distal end of the catheter.

Summary

[0009] The applicant has recognized and appreciated that it would be beneficial to have accurate information about the position and shape of medical devices within the human body. The invention described is a system for enhancing the accuracy of position and shape measurements utilizing Fiber Bragg Gratings (FBGs) or other fiber optic shape sensing or localization capability in conjunction with other markers. It is well known that three or more optical fibers with integrated FBGs can be utilized to track a three dimensional shape in real time.

[0010] A FBG is a segment of a longer optical fiber that reflects light in a particular relatively narrow range of wavelengths and transmits light in other ranges. The reflection of light in a particular narrow wavelength range is achieved by adding periodic variations to the refractive index of the fiber core at specific intervals, which creates a wavelength-specific dielectric mirror. In another embodiment of an FBG the variations may run along the entire length of the fiber.

[0011] The multiple variations in the refractive index produce Fresnel reflection at each interface between the different indices. For a particular wavelength, the reflected light is in phase with other reflections so that constructive interference exists for reflection and consequently destructive interference for transmission. The interference is sensitive to strain on the fibers as well as temperature. This means that the FBG in an optical fiber can be used as a sensing element for a strain imparted to the optical fiber.

[0012] One of the advantages of a Bragg grating is that it can be distributed at different positions along the length of an optical fiber. The shape of the optical fiber can be determined by measuring the strain imparted to the fiber at various locations via the change in wavelength of light reflected by the Bragg gratings. Incorporating multiple fibers where each of the fibers contains several Bragg gratings along their lengths into a structure allows the 3-dimensional form of the structure to be determined. A disadvantage of the FBG is that it becomes less effective over longer distances.

[0013] US patent publication no. 20060013523 of Child lers et al. , which is incorporated by reference herein, discloses a system for fiber shape sensing in non-medical applications based on FBG technology.

[0014] In one embodiment of the invention, a hollow needle comprises at least one FBG embedded into the wall of the needle. Each FBG embedded in the needle will be positioned along the length of the needle. Preferably three or more FBGs are embedded in the wall of the needle equally spaced around the circumference of the needle. The proximal end of the needle, e.g. the end external to the body, should contain one or more markers so that a reference point can be established for needle relative to known landmarks on the body. The marker establishes a known reference point for a portion of the needle. Adding information from the FBG along a short length of the needle establishes a precise location for the tip of the needle.

[0015] In another embodiment of the invention, an unmodified needle is combined with a mandrin containing at least one FBG. The mandrin fits inside the hollow of the needle and may be adjusted to a suitable location within the needle. As with the needle described above, the proximal end of the needle should contain one or more markers so that a reference point can be established for needle relative to known landmarks on the body.

[0016] In another embodiment of the invention, a catheter comprising at least one but preferably three fiber Bragg gratings is used to position the tip of the catheter. The catheter should also comprise at least one marker at the proximal end. As with the needle embodiment the marker establishes a known reference point for a portion of the catheter. Adding information from the FBG along a short length of the catheter establishes a precise location for the tip of the catheter.

[0017] The accuracy of the tip position can be further enhanced by the combination of realtime feedback of the marker position along with the feedback from the FBG as input to a shape determination algorithm. The algorithm first estimates the shape of the distal end of the catheter. Data from the fiber Bragg grating is then used to refine the position and the shape of the distal end of the catheter. This refined position and shape is then overlaid on an existing CT or other image to aid in the treatment of the patient.

[0018] In yet another embodiment, a lasso catheter comprising at least one but preferably three fiber Bragg gratings is used to position the loop of a "lasso catheter" in most useful position within the patient.

[0019] As used herein, the term "needle" refers to a cylindrical needle typically comprising a cylindrical void running the length of needle.

[0020] As used herein the term "mandrin" refers to a solid device arranged to fit within the cylindrical void of a needle. The mandrin may be cylindrically shaped or may have any other shape that fits within the cylindrical void of the needle.

[0021] The term "catheter" is used herein to refer to a tube which may be designed to be inserted into a body cavity of duty, e.g. a blood vessel.

[0022] The term "cylindrical" refers to a shape that is an approximation to the geometric shape of a cylinder having a length and circular cross section where the ends of the cylinder are disposed within a plane at right angles to the central axis of length. However, shapes that have a nearly circular cross section or shape having one or both ends that are not disposed within a plane at right angles to the central axis of length are also included within the term "cylindrical".

[0023] The term "marker" refers to a marker attached to a medical device for the purpose of automatic location by technical means. The marker may be optical and thus can be located in space by one or more cameras. The marker may be resonant with a radio frequency or

Magnetic Resonant field and thus be located by use of a radio frequency based system or any other EM based system. The marker may be opaque to X-rays and thus be located with CT or X- ray equipment. In another embodiment an acoustic marker may be used in conjunction with an ultrasound system. [0024] It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the inventive subject matter disclosed herein. It should also be appreciated that terminology explicitly employed herein that also may appear in any disclosure incorporated by reference should be accorded a meaning most consistent with the particular concepts disclosed herein.

Brief Description of the Drawings

[0025] In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention.

[0026] FIG. 1 illustrates a Fiber Bragg Grating within a fiber optic cable.

[0027] FIG. 2 graphs the reflective index of a Fiber Bragg Grating

[0028] FIG. 3A illustrates the spectral response of the input light for a Fiber Bragg Grating.

[0029] FIG. 3B illustrates the spectral response of the transmitted light for a Fiber Bragg Grating.

[0030] FIG. 3C illustrates the spectral response of the reflected light for a Fiber Bragg Grating.

[0031] FIG. 4 illustrates a Fiber Bragg Grating system.

[0032] FIG. 5 illustrates a Fiber Bragg Grating within a curved portion of a fiber optic cable.

[0033] FIG. 6 illustrates a cross section view along the long axis of a needle which comprises a Fiber Bragg Grating within the walls of the needle.

[0034] FIG. 7 illustrates a cross section view perpendicular to the long axis of a needle which comprises a Fiber Bragg Grating within the walls of the needle. [0035] FIG. 8 illustrates a cross section view along the long axis of a needle which comprises a Fiber Bragg Grating within a mandrin.

[0036] FIG. 9 illustrates a cross section view perpendicular to the long axis of a needle which comprises a Fiber Bragg Grating within a mandrin.

[0037] FIG. 10 illustrates a three dimensional representation of a heart showing the placement of three different catheter applications.

[0038] FIG. 11 illustrates the placement of three FBGs within a catheter.

[0039] FIG. 12 illustrates a flowchart where data from a marker system is combined with data from a FBG system.

[0040] FIG. 13 illustrates a flowchart where data from a marker system is combined with data from a FBG system.

Detailed Description

[0041] Applicant has recognized and appreciated that it would be beneficial to refine the location information supplied by a marker with shape information supplied by an FBG system or other fiber optic shape sensing or localization system when placing a medical device within the human body. Marker technology is often limited by the size of the marker and available locations on the medical device, the FBG has reduced accuracy when used over a long distances. The invention combines multiple technologies coupled to the suitable mechanical placement of markers and FBGs yield improved location information of a critical portion(s) of medical devices in a three dimensional space.

[0042] In the following detailed description, for purposes of explanation and not limitation, representative embodiments disclosing specific details are set forth in order to provide a thorough understanding of the claimed invention. However, it will be apparent to one having ordinary skill in the art having had the benefit of the present disclosure that other

embodiments according to the present teachings that depart from the specific details disclosed herein remain within the scope of the appended claims. For example, although the invention is discussed herein with regard to FBGs, it is understood to include fiber optics for shape sensing or localization generally, including, for example, with or without the presence of FBGs or other optics, sensing or localization from detection of variation in one or more sections in a fiber using back scattering, optical fiber force sensing, fiber location sensors or Rayleigh scattering. Moreover, descriptions of well-known apparatuses and methods may be omitted so as to not obscure the description of the representative embodiments. Such methods and apparatuses are clearly within the scope of the claimed invention However, other configurations and applications of this approach are contemplated without deviating from the scope or spirit of the claimed invention.

[0043] Referring to FIG. 1, an optical fiber 100 having a cladding 101 and a fiber core 102 is shown as is well known in the prior art. The fiber core comprises a Fiber Bragg Grating (FBG) 110. The FBG 110 is comprised a group of one or more changes 111 in the refractive index of the fiber core, where each change forms an interface. The interfaces having a consistent spacing 112 (the period is designated by the Greek symbol lambda) therebetween. The changes in the refractive index are shown in the graph of FIG. 2 as a consistent shift between two values. The graph of FIG. 2 shows the amount of change in refractive index in the vertical direction and the changes with respect to the distance along the long dimension of the fiber core.

[0044] The principle exercised by the operation of a FBG is a Fresnel reflection at each of the interfaces. For some wavelengths the reflected light of the various interfaces is in phase with the light from similar other interfaces in the group so that constructive interference exists for the reflection of these wavelengths of light by the group of interfaces. As a consequence, destructive interference for transmission of those wavelengths through the group of interfaces is also obtained. The net result is a "notch" filter for some wavelengths of light. The

characteristics of the "notch" filter may be selected based on the nature of the changes made in the refractive index, the number of changes made in the refractive index and the spacing between the changes in the refractive index.

[0045] A graph of the broad spectrum of input light to the FBG is shown in FIG. 3A. The graph shows the amplitude of light in the vertical direction vs. the wavelength of light in the horizontal direction. A graph of the light transmitted by the FBG is shown in FIG. 3B. The notch of light which is not transmitted is apparent in FIG. 3B. A graph of the light reflected by the FBG is shown in FIG. 3C. The spectrum of the reflected light has a center frequency at λ_Β 320.

[0046] The center frequency at λ_Β 320 is sensitive to both a strain on the fiber core as well as a change in temperature. The relative shift of the center frequency Δλ_Β/ λ_Β due to the strain S and the change in temperature T is given by the formula: Δλ_Β/ λ_Β = C_S*S + C_T*T. The coefficients of strain and temperature are designated Cs and Ct respectively. Given a fixed temperature the FBG can be used to sense strain on the optical fiber at a particular location.

[0047] FIG. 4 shows an embodiment of a FBG system 400 in which all connections may be made via an optical fiber. The source light may come from a swept source (SS) laser system 403 which is connected to an optical isolator 405 which is then connected to an optical

interferometer apparatus. The optical isolator 405 may prevent spurious light reflected from the optical interferometer to interfere with the swept source laser 403. The optical

interferometer may be comprised of a splitter 411, two circulators 406A and 406B, and a combiner 412. The isolator 405 is connected to the splitter 411. The splitter has two output connections, one connected to the first circulator 406A which is then connected to the FBG 408 which comprises a distribution of Bragg gratings. The second output is connected to the second circulator 406B which then connected to a reference fiber with a fixed mirror (MR) 407. The reflected light from the gratings in the fiber 408 is directed towards the combiner 412 via the first circulator 406A. Similarly the light from the reference mirror 407 is also directed towards the combiner 412 via the second circulator 406B. The two output arms of the combiner 412 are input to the two input channels of a differential detector 404.

[0048] The first input port of the differential detector 404 measures the reflected light of the fiber with Bragg reflectors superimposed on the reflected light from the reference arm. The second input port of the differential detector 404 makes the same measurement except that the phase relation of the two light signals has a changed sign (or an additional radians as shown below). The difference signal constitutes the interference between the light signal from the Bragg reflectors and the light signal from the reference arm. [0049] The light from the reference arm has intensity ir based on a corresponding electric field Er so that Ir Is proportional to the square of Er. The light from the Bragg fiber has intensity im and a corresponding electric: field Em with a phase difference φ.

[0050] The intensity from the first port, of the combiner 412 is proportional to:

[0051] I Er -t- Em * cos{<j>) j ² - j Er j ¹ + j Em j ^z + 2. j Erj . j Em | χο$(φ)

[0052] The intensity from the second port, of the combiner 412 will be proportional to:

[0053] j Er + Em. α>$(φ+π) j ² - j Erj ² + j Em j - 2, j Er j . j Em | χοείφ)

[0054] With the differential detector 404 one measures the difference signal:

[00551 Δ! = II - 12 ~ 4 * j Er j * j Em j * cos )

[0056] Sweeping the optical source over a substantial wavelength range allows the measurement of both the amplitude and the phase of the Fresnel reflection coefficient of the FBG over a range of values. By way of Fourier analysis such measurements can be transformed to complex reflection coefficients as a function of position along the device under test and thus discern the shape of the FBG.

[0057] A different technique using multiple FBGs within a single fiber optic cable uses the timing differences between reflections from different FBGs which all have the same center frequency for the reflected light. This method can be combined with other methods to detect the strain in a large number of FBGs within a single optical fiber.

[0058] FIG. 5 shows a section of a medical device 500 with three fiber optic cables 505A, 505B and 505C disposed within the length of the medical device 500. Each of the fiber optic cables 505A, 505B and 505C further comprise FBGs disposed along the length of the fiber optical cables 505A, 505B and 505C. The portions of the medical device 500 which comprise the portions of the fiber optic cables 505A, 505B and 505C where the FBGs reside are shown as 510A, 510B and 510C. The FBGs arranged along the lengths of the fiber optic cables 505A, 505B and 505C are interrogated using an interferometer according to an embodiment of the invention. Alternately the FBGs can be frequency multiplexed, time multiplexed or both frequency and time multiplexed. [0059] When the medical device 500 is bent as is shown in FIG. 5, different strains will be imparted on the different FBGs of each of the fiber optic cables 505A, 505B and 505C. The different strains will shift the center frequencies of each FBG according to the amount of strain put upon that section of that fiber optic cable 505A-505C.

[0060] Given the fiber optic cables 505A, 505B and 505C arranged along the length of the medical device 500, the shift of the center frequencies of various FBGs will allow a prediction of the shape of the medical device in a three dimensional space according to known methods. Each of the embodiments of the invention use the strain measurement of the FBGs embedded within the medical devices to compute critical positioning information of the medical device in a three dimensional space. The three dimensional space may be within a human body.

[0061] FIG. 6 shows a cross sectional view of an embodiment of the invention as a needle 600 having a distal end 606 and a proximal end 607. The cross sectional view is parallel to a long central axis X-X'. The needle 600 has a cylindrical shape having an exterior surface 608 centered on the axis X-X' and having an interior surface 609 of a cylindrical void 660. The cylindrical void 669 is also centered on the axis X-X'. The cylindrical void 660 may penetrate either distal end 606, or proximal end 607 or both ends of needle 600.

[0062] The needle 600 further comprises at least one marker 640 attached close to the exterior of the distal end 607 of needle 600. The needle 600 further comprises at least one but preferably three fiber optic cables 605A, 605B and and a third one which is not shown, disposed within the wall of the needle 600 i.e. between the exterior surface 608 and the interior surface 609 of the needle 600. Each of the fiber optic cables 605A, 605B etc. comprise at least one FBG (not shown).

[0063] FIG. 7 shows a cross sectional view of a needle 700 perpendicular to the axis X-X' where the view is take between the proximal end and distal end of needle 700. The needle 700 has a cylindrical shape having an exterior surface 708 centered on the axis X-X' and having an interior surface 709 defined by a cylindrical void 760. The cylindrical void 760 is also centered on the axis X-X'. The needle 700 further comprises at least one but preferably three fiber optic cables 705A, 705B and 705C disposed within the wall of the needle 700 i.e. between the exterior surface 708 and the interior surface 709 of the needle 700. Each of the fiber optic cables 705A, 705B and 705C comprise at least one FBG (not shown).

[0064] The fiber optic cables may be evenly distributed within the wall of any of the embodiments of the needle. However other configurations involving uneven distribution of the fiber optic cables are included within the scope of the invention. Although three fiber optic cables are shown in many figures additional fiber optic cables or fewer fiber optic cables are also included within the scope of the invention.

[0065] FIG. 8 shows a cross sectional view of another embodiment of the invention as a needle 800 having a distal end 806 and a proximal end 807. The cross sectional view is parallel to a long central axis Y-Y'. The needle 800 has a cylindrical shape having an exterior surface 808 centered on the axis Y-Y' and having an interior surface 809 of a cylindrical void 860. The cylindrical void 860 is also centered on the axis Y-Y'. The cylindrical void 860 may penetrate either distal end 806, or proximal end 807 or both ends of needle 800.

[0066] The needle 800 further comprises at least one marker 840 attached close to the exterior of the distal end 807 of needle 800. The needle 800 further comprises a mandrin 870 disposed within the cylindrical void 860. The mandrin 870 may fit snugly within void 860 or it may have a loose fit. The mandrin may be pointed at the portion located near the proximal end of the needle 800 or it may have any other shape. The mandrin may have at least one but preferably three fiber optic cables (although only one cable 805 is shown in FIG. 8) disposed within the mandrin 870. Each of the fiber optic cables 805 comprise at least one FBG (not shown).

[0067] FIG. 9 shows a cross sectional view of a needle 900 perpendicular to the axis Y-Y' where the view is taken between the proximal end and distal end of needle 900. The needle 900 has a cylindrical shape having an exterior surface 908 centered on the axis Y-Y' and having an interior surface 909 defined by cylindrical void 960. The cylindrical void 960 is also centered on the axis Y-Y'. A mandrin 970 is disposed within the void 960. The mandrin may have a cylindrical cross section. The mandrin 970 further comprises at least one but preferably three fiber optic cables 905A, 905B and 905C disposed within the interior of the mandrin 970. Each of the fiber optic cables 905A, 905B and 905C comprise at least one FBG (not shown).

[0068] The fiber optic cables may be even distributed within the interior of the mandrin. However other configurations involving uneven distribution of the fiber optic cables are included within the scope of the invention. Although three fiber optic cables are shown in many figures additional fiber optic cables or fewer fiber optic cables are also included within the scope of the invention.

[0069] Although a cylindrical shape is suggested for exterior the void of the needles in several embodiments other shapes are possible and may be used e.g. a hexagonal cross section.

[0070] FIG. 10 shows a three dimensional view of a human heart. The heart is shown in a non-typical situation with an overlay of three different types of catheters, an ablation catheter 1050, a lasso catheter 1051 and a coronary sinus catheter 1052. Each catheter is shown in the position of typical use for that variety of catheter.

[0071] FIG. 11 shows yet another embodiment of the invention comprising a cross sectional view of a catheter 1100. The catheter 1100 comprises at least one but preferably three fiber optic cables 1105A, 1105B and 1105C disposed within the catheter 1100. Each of the fiber optic cables 1105A, 1105B and 1105C is disposed at a mutual 120 degrees displacement from the other fiber optic cables where the angles are measured relative the center of the cross sectional view of catheter 1100. Each of the fiber optic cables 1105A, 1105B and 1105C comprise at least one but preferably several FBGs.

[0072] FIG. 12 shows a flow chart 1200 describing yet another embodiment of the invention. The flow chart 1200 describes a method of combining information from a conventional marker location system with FBG shape information to refine a modeled location of a portion of a device e.g. the needle shown in FIG. 7 A step 1201 may use an Electro Magnetic (EM) marker system to determine a position of use at least one EM marker(s) as is known in the art which is attached to the needle. A step 1202 may compute the shape of the needle using a FBG system as is known in the art. A step 1203 may integrate the computer calculations of the three dimensional position of the needle tip into a pre-procedural image using the EM sensor location as the anchor location for the three dimensional shape determined by the FBG system. A step 1203 may display the computed needle tip position on the pre-procedural image. Other devices such as catheters may employ the same method.

[0073] FIG. 13 shows a flow chart 1300 describing yet another embodiment of the invention. The flow chart 1300 describes a method of combining information from a conventional marker location system with FBG shape information to refine a modeled location of a portion of a catheter e.g. the catheter shown in FIG. 11. A step 1361 may compute an estimated shape of the tip section of the catheter using a shape determination algorithm in conjunction with the FBG system. A step 1362 may compute an estimated location of the tip of the catheter using the shape determination algorithm in conjunction with the FBG system. A step 1363 may compute an error in the tip position of the catheter by comparing the tip position computed using the FBG in the step 1362 and the position that may be computed by a traditional marker based system in a step 1367. A step 1364 may improve the estimate of the tip section shape by utilizing the error computed in the step 1363. A step 1366 may compute an improved estimate of the location of the tip of the catheter with the use of the shape determination algorithm.

[0074] The method shown in FIG. 13 may be used in an iterative fashion by successive use of the method or by the feedback of information from the output of the process i.e. step 1366 to the step to the step 1361, or to the step 1367 or to both steps 1361 and 1367.

[0075] Although FIG. 12 and FIG. 13 describe systems using an EM marker system other markers systems such as optical tracking systems and real-time tracking of X-ray marker systems as well as any other type of marker system are contemplated and included with the scope of the invention.

[0076] Although FIG. 12 shows a method for placement of a needle tip within a three dimensional space and FIG. 13 shows a method for the placement of a catheter within a three dimensional space, neither method is restricted to use with a particular medical device. The methods shown by FIG. 12 and FIG. 13 may be used individually or together to locate a portion of any medical device include needle tips and the position an shape of any type of catheter. Likewise, although reference is made to a tip or tip section of a medical device, the shape and/or the location of any portion of the medical device or the entirety of the medical device including portions external to a patient may be located in a three dimensional space are within the scope of the invention. Additionally, the embodiments used to locate a portion of a medical device may also be used to locate the position of any other device.

[0077] While the several embodiments presented show only three optical fibers containing FBG elements other embodiments comprised of four or more optical fibers each of which may contain a FBG are also envisioned and are contained within the scope of the invention.

[0078] While several inventive embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the function and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the inventive embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the inventive teachings is/are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto; inventive embodiments may be practiced otherwise than as specifically described and claimed. Inventive embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and/or methods, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure.

[0079] All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and/or ordinary meanings of the defined terms. [0080] The indefinite articles "a" and "an," as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean "at least one." The phrase "and/or," as used herein in the specification and in the claims, should be understood to mean "either or both" of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with "and/or" should be construed in the same fashion, i.e., "one or more" of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the "and/or" clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to "A and/or B", when used in conjunction with open-ended language such as "comprising" can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[0081] As used herein in the specification and in the claims, "or" should be understood to have the same meaning as "and/or" as defined above. For example, when separating items in a list, "or" or "and/or" shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as "only one of" or "exactly one of," or, when used in the claims, "consisting of," will refer to the inclusion of exactly one element of a number or list of elements. In general, the term "or" as used herein shall only be interpreted as indicating exclusive alternatives (i.e. "one or the other but not both") when preceded by terms of exclusivity, such as "either," "one of," "only one of," or "exactly one of." "Consisting essentially of," when used in the claims, shall have its ordinary meaning as used in the field of patent law.

[0082] Reference numerals, if any, are provided in the claims merely for convenience and are not to be read in any way as limiting.

[0083] As used herein in the specification and in the claims, the phrase "at least one," in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase "at least one" refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, "at least one of A and B" (or, equivalently, "at least one of A or B," or, equivalently "at least one of A and/or B") can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

Claims

1. A medical device location system comprising: at least one marker system, at least one optical fiber wherein a portion of the optical fiber comprises a fiber Bragg grating; an optical integration device connected to the optical fiber; and a computer wherein the location of at least on portion of the medical device is computed using the marker system, wherein the location of at least on portion of the medical device is enhanced using information from the optical interrogation device.

2. The medical device location system of claim 1, wherein the marker system is optical.

3. The medical device location system of claim 1, wherein the marker system is

electromagnetic.

4. The medical device location system of claim 1, wherein the marker system is visible to X- rays.

5. The medical device location system of claim 1, wherein the marker system is acoustic.

6. The medical location system of claim 1, wherein the medical device is a hollow needle.

7. The medical location system of claim 6, wherein the optical fibers are partially contained within the walls of the hollow needle.

8. The medical location system of claim 6, wherein the optical fibers are partially contained within a mandrin.

9. The medical location system of claim 1, wherein the medical device is a catheter.

10. A method of locating a portion of a medical device comprising: locating a portion of the medical device using a marker; computing the shape of a portion of the medical device using information from a fiber optic shape sensing or localization system; and improving the location a portion of the medical device using the computed shape.

11. The method of claim 10, wherein the marker system is optical.

12. The method of claim 10, wherein the marker system is electromagnetic.

13. The method of claim 10, wherein the marker system is visible to X-rays.

14. The method of claim 10, wherein the marker system is acoustic

15. The method of claim 10, wherein the medical device is a hollow needle.

16. The method of claim 15, wherein the optical fibers are partially contained within the walls of the hollow needle.

17. The method of claim 15, wherein the optical fibers are partially contained within a

mandrin.

18. A method of locating a portion of a medical device comprising: estimating the shape of a portion of the medical device using a fiber optic shape sensing or localization system; creating a first estimate of the location of a part of the portion of the medical device using the estimated shape information; creating a second estimate of the location of the part of the portion of the medical device using a marker; computing difference using the first estimated location and the second estimated location; and computing a corrected location of the part of the portion of the medical device.

19. The method of claim 18 further comprising the step of displaying the location of the part of the portion of the medical device on a medical image.

20. The method of claim 18 further comprising the step of refining the estimation the shape of the portion of the medical device by use of the corrected location of the part of the portion of the medical device.