Shape alignment of a shape-sensing usable device for an imaging system

Abstract

A method of aligning a portion of an optical shape sensing system 10 to an imaging system 48 is described, the portion including a distal multi-core optical fiber 16 and a proximal multi-core optical fiber 14, an optical connector 34 optically connecting the distal optical fiber 16 and the proximal optical fiber 14 to each other, and a launch base 36 fixed to the imaging system 48 and configured to secure the proximal optical fiber 14. In this method, the shape and orientation of the distal optical fiber 16 and a section of the proximal fiber 14 extending from the optical connector 34 to the launch base 36 are optically measured for at least two different positions and / or orientations of the optical connector 34 relative to the object 28. In particular, based on the optical measurements at the first and second positions or orientations of the optical connector 34, the portion of the optical shape system is aligned as a whole to the imaging system 48. A system for implementing this method is also described.

Description

Technical Field

[0001] The present invention generally relates to the field of optical shape sensing (OSS) using fiber optic sensors, also known as FORS (Fiber Optic RealShape). In particular, the present invention relates to a method of aligning a part of an optical shape sensing system with an imaging system, such as an X-ray or MR (magnetic resonance) imaging system. More particularly, the present invention relates to a method of aligning a part of an optical shape sensing system with an imaging system, the part having a distal multi-core optical fiber optically connected to a proximal multi-core optical fiber via an optical connector having a backloading ability. The present invention further relates to corresponding systems and computer programs.

Background Art

[0002] It should be understood that although this specification refers to the use of FORS in the medical or surgical fields, the present invention is not limited thereto.

[0003] In the medical field, there is a clear and continuous trend to replace conventional surgical procedures with minimally invasive interventions. In these minimally invasive interventions, medical devices such as guidewires and catheters are inserted into the body through small incisions. Several visualization techniques exist to navigate medical devices to the required location within the body.

[0004] FORS is a technique for tracking a device, such as a guidewire having an optical fiber, within a patient's body. The overall three-dimensional shape of the device can be reconstructed from the optical interrogation of the optical fibers included in the device. The exact orientation and position of the device are determined in real time in an appropriate coordinate system. In FORS, geometric changes in the device are encoded in the optical field propagating through the optical fibers incorporated in the device. This optical interrogation of the optical fibers provides, in principle, the information necessary to reconstruct in real time the three-dimensional shape of the entire optical fiber (and thus the three-dimensional shape of the device). The reconstructed shape of the optical fiber (and thus the medical device in which the fiber is integrated) is typically displayed in a relevant coordinate system, such as a coordinate system that matches the operating room in which FORS is used, for example, a coordinate system linked to an imaging system, such as an X-ray imaging system or an MR imaging system. The shape and orientation of the FORS-enabled device can then be visualized by co-aligning it with an image of an object, such as the vascular structure of a patient, provided by the imaging system either prior to or during navigation of the device. For this purpose, the FORS-enabled device is typically aligned in the relevant coordinate system, for example, using one or more X-ray or MR images, for example, during setup.

[0005] The optical fibers used to determine the shape of the device (FORS sensor) typically have a plurality of optical cores, for example, a central core and a plurality of outer cores that can be helical around the central core along the length of the optical fiber. For example, the optical fiber can have four cores, namely, one central core and three outer cores that can be arranged at nominally 120° from each other at a fixed distance from the central core.

[0006] In order to make a functional connection between a distal optical fiber, e.g., an optical fiber incorporated in a medical device such as a guide wire, and a proximal optical fiber, e.g., an optical fiber incorporated in a patch cord connected to an optical interrogator, it is important to align the fiber core of the distal fiber with the core of the proximal fiber. A common way to achieve such alignment is to assemble both fibers into an optical connector and fit them into a mating sleeve. Low tolerance elements within the connector, such as ceramic ferrules, ensure the centering of the two fibers within the mating sleeve. A connector key defines the angular alignment between the two optical fibers.

[0007] In certain designs of medical devices, such as guide wires, particularly loadable guide wires, where the outer diameter cannot typically be made larger than a fraction of a millimeter, robust connector keys are difficult to manufacture. In some surgical procedures, the catheter around the optical guide wire needs to be replaced with another one to perform the patient's medical treatment. In these procedures, the optical guide wire remains inside the patient while the catheter around the guide wire is replaced with another one. To replace the catheter, a loadable optical connector is required that can cut the distal optical fiber (e.g., of the guide wire) from the proximal optical fiber (e.g., of the patch cord). After replacing the catheter, the distal and proximal optical fibers are reconnected within the optical connector.

[0008] In certain anticipated FORS system setups, particularly those that support a loadable guidewire, both the shape of the loadable guidewire and the shape of the portion of the patch cord between the interrogator and the guidewire are reconfigured. These two shapes are combined in terms of the optical connection. Due to the manufacturing tolerances and misalignments of the connectors, the exact relative orientation between the two shapes may not be fully known, thereby having an adverse effect on the accuracy of the predicted position and orientation of the components of the medical device (e.g., guidewire) inside the patient.

[0009] Therefore, in order for the optical loadable connector to function properly, it is important that the central core and the outer core of the portion of the optical fiber still inside the patient are properly aligned with the core of the portion of the fiber connected to the interrogator. This applies to the initial connection of the two fibers, as well as the reconnection of the two fibers after disconnection. A method for compensating for the possible improper alignment of the two portions of the distal and proximal fibers within the connector must be found and implemented. Due to the non-zero tolerances in the manufacturing processes of the guidewire containing the optical fiber and the optical connector, there is a high likelihood of misalignment between the distal optical fiber and the proximal optical fiber. The non-zero tolerances, and thus the misalignment, have an adverse effect on the accuracy of the predicted position and orientation of the portion of the medical device (e.g., guidewire) inside the patient, particularly near its distal tip. Precise knowledge of the position of the distal tip of the medical device is essential for the proper treatment of the patient.

[0010] Therefore, despite the non-zero tolerances in the manufacturing processes of the optical fiber and the optical connector, there is still a need for methods and systems that enable a very accurate determination of the position and orientation of, for example, the distal optical fiber constituted by the optical guidewire, in the associated coordinate system of the imaging system. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0011] An object of the present invention is to provide a method for aligning an optical shape sensing system having a distal multi-core optical fiber, a proximal multi-core optical fiber, and an optical connector therebetween, with an imaging system that compensates for possible misalignment of the distal and proximal optical fibers within the connector.

[0012] A further object of the present invention is to provide a method for aligning an optical shape sensing system with an imaging system, which enables accurate re-alignment after cutting and reconnecting the proximal and distal optical fibers.

[0013] A further object of the present invention is to provide an optical shape sensing system that utilizes the method according to the present invention.

[0014] A further object of the present invention is to provide a computer program for executing the method according to the present invention.

Means for Solving the Problems

[0015] According to a first aspect of the present invention, there is provided a method for aligning a part of an optical shape sensing system with an imaging system, the part including a distal multi-core optical fiber and a proximal multi-core optical fiber, an optical connector that optically connects the distal and proximal optical fibers to each other, and a launch base that is fixed to the imaging system and is arranged to fix the proximal optical fiber, the method comprising: i) providing data of at least a part of the distal optical fiber from an image of the imaging system; ii) from the arrangement of the optical connector in a first position and / or orientation, and at the first position or orientation of the optical connector, - optically measuring the shape and orientation of the distal optical fiber; - optically measuring the shape and orientation of a section of the proximal fiber extending from the optical connector to the launch base; iii) from the arrangement of the optical connector at a second position and / or orientation different from the first position or orientation, and at the second position and / or orientation of the optical connector, - optically measuring the shape and orientation of the distal optical fiber; and - optically measuring the shape and orientation of the section of the proximal fiber; iv) aligning at least the portion of the distal fiber with the imaging system based on a shape - shape basis between at least one of the optical shape measurement values at the first and second positions and / or orientations of the optical connector and the provided data; v) aligning the portion of the optical shape system, including the optical connector and the emission base as a whole, with the imaging system based on the optical measurements at the first and second positions and / or orientations of the optical connector. It has.

[0016] The method according to the invention enables the accurate alignment and thus the tracking of an optically shape-sensing usable device, despite possible misalignments between the proximal portion of the distal optical fiber and the distal portion of the proximal optical fiber within the optical connector. There are alignment methods that enable the alignment of a FORS-compatible device to an imaging system, but these alignment methods cannot be simply applied to FORS systems that have not only a fixed emission base but also "imperfect" connectors within the optical shape-sensing path, when no connector is present or when a "perfect" connector is present within the optical path. The present invention is based on the insight that not only must the transformation (rotation and translation) from a fixed emission base (which is the starting point of the optical shape measurement) to the coordinate system of the imaging system (i.e., the real world), up to the tip of the three-dimensional shape reconstruction of the device, be determined in the alignment procedure, but also that the transformation at the (imperfect) optical connector between two optically connected fiber portions must be determined in the coordinate system of the imaging system in order to accurately locate a device, such as a guide wire. The transformation at the determined connector is required to compensate for misalignments at the optical connector. In the initial alignment (e.g., during the setup of the shape-sensing system), not only is the transformation from the emission base to the coordinate system of the imaging system unknown, but also the transformation at the optical connector is unknown. With existing conventional alignment procedures, the transformation belonging to the emission base and the transformation belonging to the optical connector cannot be determined separately. In other words, only the combined transformation cannot be determined, but it is not sufficient for accurately locating the distal device in the relevant coordinate system.

[0017] The present invention now overcomes this drawback by being arranged relative to a subject at at least two different positions and / or orientations, for example, where a distal optical fiber can be at least partially inserted, and at each position and / or orientation of the optical connector, the shape and orientation of the distal optical fiber extending from the optical connector to the emission base, as well as the shape of the section of the proximal fiber, are optically measured. That is, during the positioning / alignment procedure of the distal optical fiber with respect to the imaging system, the position and / or orientation of the optical connector is changed at least once, for example, with respect to a subject into which the distal optical fiber can be inserted. For at least one of the different positions and / or orientations of the optical connector, the distal optical fiber is positioned or aligned in the coordinate system of the imaging system based on matching the optically measured shape / orientation with the shape / orientation of the device provided by the data from the image of the imaging system. This results in a virtual transformation with n≥2 with respect to a fixed emission base. From these n≥2 virtual transformations, the actual transformation at the emission base and at the optical connector can be determined. Thus, despite possible misalignments at the optical connector, the alignment of the system from the distal tip of the device, including the emission base, to the emission base with respect to the imaging system can be performed with high accuracy, whereby the position and orientation of the device, in particular its distal tip, can be accurately tracked during the manipulation of the device within the subject. The method according to the present invention can start when the distal optical fiber is inserted into the subject.

[0018] A further advantage of the method according to the present invention is that no additional images from the imaging system are required.

[0019] The alignment data obtained by the alignment method can then be used in the real-time reconfiguration of the device in a treatment or intervention in which the device is used. It is also possible to update the alignment data, for example, continuously, using a Kalman filter or a similar technique.

[0020] It should be understood that the steps of the method described herein can be performed in an order different from the above.

[0021] Preferred embodiments of the invention are defined in the dependent claims and are described herein.

[0022] At least one of steps ii) and iii) may be performed without moving at least a portion of the distal optical fiber such that fewer images, e.g., X-ray images, are required in the alignment process. This can simplify the alignment of the distal optical fiber, and thus the device having the distal optical fiber, with respect to the imaging system based on the image data provided by the imaging system.

[0023] Furthermore, at least a portion of the alignment data obtained in step v) may be stored to obtain the stored alignment data such that it is available after cutting and reconnecting the distal and proximal optical fibers in the optical connector. The stored alignment data can be advantageously used in the realignment process after the fibers in the optical connector have been cut and reconnected, thus reducing the computational effort required after reconnecting the fibers in the connector.

[0024] It may be even more advantageous if at least a portion of the distal optical fiber does not move while cutting and reconnecting the distal and proximal optical fibers in the optical connector. In this embodiment, the shape of the distal optical fiber measured immediately prior to cutting the fiber in the optical connector may be stored as alignment data and can be advantageously used in the realignment process after reconnecting the fiber. Thus, at least a portion of the distal optical fiber has a stable position and orientation during cutting and reconnecting, and this stable position / orientation replaces the X-ray image after reconnection.

[0025] The method may further comprise, after reconnecting the distal optical fiber to the proximal optical fiber in an optical connector, providing stored alignment data; optically measuring the shape and orientation of the distal optical fiber; optically measuring the shape and orientation of the proximal optical fiber from the optical connector to the launch base; and aligning the optical shape sensing system to the imaging system based on making the newly measured shape and orientation of the distal optical fiber equal to the alignment data.

[0026] In connection with the previous embodiment, the stored alignment data may include the shape and orientation of the distal optical fiber optically measured before cutting the distal optical fiber from the proximal optical fiber, or the stored alignment data may include one or more single points along the distal optical fiber. The one or more points may include the entry point of the distal optical fiber into the subject, or any other single or multiple points along the distal optical fiber or the device having the distal optical fiber, such as an anatomical point (e.g., related to a particular anatomical feature).

[0027] In another embodiment, the method includes, after reconnecting the distal optical fiber and the proximal optical fiber, providing stored alignment data; optically measuring the shape and orientation of the distal optical fiber from the placement of the optical connector at a third position and / or orientation, and optically measuring the shape and orientation of the proximal optical fiber from the optical connector to the launch base while the optical connector is at the third position and / or orientation; optically measuring the shape and orientation of the distal optical fiber from the placement of the optical connector at a fourth position and / or orientation, and optically measuring the shape and orientation of the proximal optical fiber from the optical connector to the launch base while the optical connector is at the fourth position and / or orientation; and aligning the optical shape sensing system with the imaging system based on the optical measurements and the provided alignment data at the third and fourth positions and / or orientations of the optical connector. In this embodiment, the alignment data is preferably the alignment of the launch base with respect to the imaging system before the distal optical fiber is cut from the proximal optical fiber. Aligning the optical shape sensing system with the imaging system may include aligning a portion of the distal optical fiber that can be inserted into an object including the distal tip of the distal optical fiber.

[0028] According to a second aspect of the present invention, a method of aligning a portion of an optical shape sensing system with an imaging system is provided after a first alignment is performed, the portion of the optical shape sensing system including a distal multi-core optical fiber and a proximal multi-core optical fiber, an optical connector optically connecting the distal optical fiber and the proximal optical fiber, and a launch base fixed to the imaging system and arranged to fix the proximal optical fiber. After the first alignment, the proximal optical fiber and the distal optical fiber are cut from each other, and the method includes, after reconnecting the proximal optical fiber and the distal optical fiber, i) providing the stored alignment data of the first alignment; ii) placing the optical connector at a first position; optically measuring the shape and orientation of the distal optical fiber; optically measuring the shape and orientation of a section of a proximal fiber extending from an optical connector to a launch base; iii) aligning the portion of the optical shape sensing system as a whole with an imaging system; a) based on making the newly optically measured shape and orientation of the distal optical fiber equal to stored alignment data, the stored alignment data being shape-related or position-related data of the distal optical fiber before cutting the proximal optical fiber from the distal optical fiber, or optically measuring the shape and orientation of the distal optical fiber at a second position and / or orientation and, based on the optical measurements and the stored alignment data at the first and second positions and / or orientations of the optical connector, optically measuring the shape and orientation of a section of the proximal fiber extending from the optical connector to the launch base, the stored alignment data being the data of a first alignment of the launch base, comprising.

[0029] A method according to a second aspect of re-aligning an optical shape sensing system with an imaging system may be based on stored alignment data obtained by a different alignment process than that according to the first aspect. The method according to the second aspect may be performed after a first alignment of the optical shape sensing system to the imaging system has been performed, and the first alignment may be performed via stored alignment data stored in the optical shape sensing system. The method according to the second aspect, including option a) or b), is itself, i.e., independent of the method according to the first aspect, an invention or considered an invention. It should be understood that the second aspect may have the same or similar embodiments and / or advantages as the method according to the first aspect.

[0030] In a third aspect of the present invention, a system is provided, the system comprising a distal multi-core optical fiber and a proximal multi-core optical fiber, an optical connector optically connecting the distal optical fiber and the proximal optical fiber to each other, a launch base fixed to the imaging system and configured to fix the proximal fiber, i) providing data of at least a part of the distal optical fiber from an image of the imaging system, ii) after arranging the optical connector in a first position and / or orientation,

[0031] - optically measuring the shape and orientation of the distal optical fiber,

[0032] - optically measuring the shape and orientation of a section of the proximal fiber extending from the optical connector to the launch base, iii) after arranging the optical connector in a second position and / or orientation different from the first position and / or orientation, - optically measuring the shape and orientation of the distal optical fiber, - optically measuring the shape and orientation of the said section of the proximal fiber, iv) aligning at least the said part of the distal fiber to the imaging system based on a shape - shape basis between at least one of the optical measurements at the first and second positions and / or orientations of the optical connector and the provided data, v) aligning the system including the optical connector and the launch base as a whole to the imaging system based on the optical measurements at the first and second positions and / or orientations of the optical connector, and a circuit configured as such.

[0033] In a fourth aspect, a computer program having program code means for causing a computer to execute the steps of the method disclosed herein when the computer program is executed on a computer is provided, and a non - transitory computer - readable recording medium storing a computer program product for executing the method disclosed herein when executed by a processor is provided.

[0034] The claimed method, system, and computer program are defined particularly in the dependent claims and are to be understood to have similar and / or identical preferred embodiments as disclosed herein.

[0035] These and other aspects of the invention will become apparent from and be elucidated with reference to the embodiments described hereinafter.

Brief Description of the Drawings

[0036]

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Embodiments for Carrying Out the Invention

[0037] FIG. 1 schematically shows an optical shape sensing system 10 configured to track the shape and orientation of an optically shape-sensable device 12. FIG. 1 shows the system 10 in a medical procedure. It should be understood that the present technology is not limited thereto. The system 10 may be referred to as a FORS system.

[0038] The optical shape sensing system 10 has a proximal multi-core optical fiber 14 and a distal multi-core optical fiber 16. The proximal multi-core optical fiber 14 may be constituted by a patch code. The distal multi-core optical fiber 16 may be included in the device 12. Insert A in FIG. 1 shows an example of a part of the multi-core optical fiber in an enlarged cross-section. Accordingly, the multi-core optical fibers 14 and 16 have a plurality of cores, for example, cores 18, 20, 22, 24 embedded in a cladding 26. The plurality of cores 18, 20, 22, 24 may have one central core 20 surrounded by three outer cores 18, 22, 24. It should be understood that the number of cores is not limited to four and may be two, three, or four or more. The outer cores 18, 22, 24 may be spirally wound around the central core 20. The outer cores may be angularly spaced from each other about the longitudinal central axis of the optical fiber 14 or 16. The central core 20 may be disposed on the longitudinal central axis with some tolerances resulting from the fiber manufacturing process. According to the number of four cores with three outer cores in the present embodiment, the angular spacing between adjacent outer cores is typically 120°, and also has some tolerances resulting from the fiber manufacturing process. In particular, the angles and radial positions of the cores 18, 20, 22, 24 of the distal optical fiber 16 may not be exactly the same as the angles and radial positions of the corresponding cores of the proximal optical fiber 14 due to manufacturing tolerances.

[0039] The distal multi-core optical fiber 16 may be integrated with the device 12. The device 12 may be, for example, a guide wire. The device 12 is shown as being partially inserted into the subject 28. The subject 28 is, for example, a patient's body. The entry or insertion point of the device 12, and thus the distal multi-core optical fiber 16, into the subject 28 is indicated by reference numeral 30 in FIG. 1. The proximal optical fiber 14 and the distal optical fiber 16 are connected via an optical connector 34. The proximal optical fiber 14 and the distal optical fiber 16 may be disconnected from each other at the optical connector 34 and may be reconnected at the optical connector 34. The optical connector 34 forms part of the optical shape sensing system 10. The optical connector 34 connects the distal end of the proximal optical fiber 14 to the proximal end of the distal optical fiber 16. The optical shape sensing system 10 further includes a launch fixture or launch base 36. The launch base 36 is fixed or stationary within the space. In particular, the launch base 36 may be fixed relative to the subject 28 or may be fixed to the table 38 on which the subject 28 is placed. The optical connector 34 is not fixed in space and is movable relative to the subject 28. The launch fixture 36 is configured to fix a portion of the proximal optical fiber 14 in space. The proximal multi-core optical fiber 14 may pass through the launch base 36 and may be connected to the optical shape sensing console 38. The optical shape sensing console 38 may include a light source 40, for example, an adjustable light source that can be swept over a range of optical frequencies. The optical shape sensing console 38 may further include an optical interrogation module 42. The optical shape sensing system 10 may be configured, in particular, as a multi-channel optical frequency domain reflectometry-based dispersion distortion sensing system. The interrogation module 42 may be configured to interrogate the optical fibers 14 and 16, more precisely the fiber cores 18, 20, 22, 24 of the optical fibers 14 and 16.The shape sensing console 38 may further include a shape reconstruction module 44 configured to evaluate the optical signals reflected or backscattered from the optical fibers 14 and 16 and to reconstruct the shape and orientation of the optical fibers 14 and 16 from the reflected or backscattered optical signals. The reconstruction starts at the launch base 36 and extends to the distal tip of the device 12, more precisely to the distal tip of the distal optical fiber 16. The reconstruction module 44 may be configured to display the reconstructed shape and orientation of the device 12, for example, on a display.

[0040] When the light source 22 is swept over a range of optical frequencies (or wavelengths), each of the fiber cores 18, 20, 22, and 24 of the optical fibers 14 and 16 is optically interrogated simultaneously but independently, and each of the reflected light from the fiber cores 18, 20, 22, 24 and the resulting interference pattern from the reference light are evaluated by the shape reconstruction module 44. The distributed strain measurements are used, in particular, for the three-dimensional shape reconstruction of the distal optical fiber 16 and thus of the device 12, and for the visual display of the reconstructed three-dimensional shape and orientation of the device 12.

[0041] In OSS or FORS, the geometric changes of the optical fibers 14 and 16 are encoded in the optical field propagating through the optical fibers. The optical interrogation of the distal optical fiber 16 provides, in principle, the information required to reconstruct in real time the three-dimensional shape of the device 12 having the fiber 16. A more detailed overview of the principles of optical shape sensing can be obtained from US2012 / 0069347A1 and US 8,773,650B2.

[0042] When an appropriate coordinate system or reference frame is provided, it is possible to know the exact orientation and position of the device 12 in real time. In order to know the exact orientation and position of the device 12 with respect to the image provided by the imaging system, it is necessary to align the optical shape sensing system 10 from the emission base 36 to the tip 46 of the distal optical fiber 16, and thus to the tip 46 of the device 12, with the imaging system. Such an imaging system is indicated by reference numeral 48 in FIG. 1. The imaging system 48 may be an X-ray imaging system or any other imaging system, such as a magnetic resonance (MR) imaging system. FIG. 1 shows a coordinate system 50 having x, y, and z axes. In order to reproduce the shape and orientation of the distal optical fiber 16, and thus of the device 12, and to display it exactly superimposed on the image provided by the imaging system 48, it is necessary to accurately align the optical shape sensing system 10 from the emission base 36 to the tip 46 of the device 12 with the associated coordinate system 50 defined by the imaging system 48. The shape reconstruction of the optical fibers 14 and 16 up to the tip 46 starts from the emission base 36, which also has to be accurately aligned with the imaging system 48.

[0043] When there is no connector such as connector 34 between the launch base 36 and the tip 46 of the optical fiber 16, there is a well-functioning alignment method. When the optical connector 34 exists to make a functional connection between the distal optical fiber 16 and the proximal optical fiber 14, it is important to positionally adjust the fiber cores 18, 20, 22, 24 of the distal optical fiber 16 with the corresponding cores 18, 20, 22, and 24 of the proximal optical fiber 14. A common way to achieve such positional adjustment is to provide an optical connector having low-tolerance elements within the connector, such as a ceramic ferrule, to ensure centering and clocking of the two fibers within the mating sleeve. Appropriate clocking is achieved by a connector key that defines the angular alignment between the outer cores of the two optical fibers. However, in certain designs of the medical device 12, such as a guidewire, particularly a backloadable guidewire, where the outer diameter typically cannot be made larger than a fraction of a millimeter, a robust connector key is difficult to manufacture. This is even more applicable to so-called connectors having a backload function. In some surgical procedures, the catheters around the optical guidewire need to be exchanged with each other to perform the patient's medical treatment. In these procedures, the optical guidewire remains inside the patient, while the catheters around the guidewire are exchanged with each other. Therefore, a backloadable optical connector 34 that can cut the distal optical fiber from the proximal optical fiber to exchange the catheter is required. After exchanging the catheter, the distal and proximal optical fibers 14 and 16 are reconnected within the optical connector 34. Due to the non-zero tolerances in the manufacturing processes of the optical fibers such as the optical fibers 14 and / or 16 and the manufacturing process of the optical connector 34, misalignment is most likely to occur between the fiber cores 18, 20, 22, 24 of the distal optical fiber 16 and the proximal optical fiber 14. Non-zero tolerances, and thus misalignment, have an adverse effect on the accuracy of the predicted position and orientation of the device 12, particularly near its distal tip 46.

[0044] As described above, when there is no optical connector 34, or when there is a complete optical connector in the optical path from the emission base 36 to the distal tip 46 of the optical fiber 16, there exists a method of aligning a device such as device 12 in the associated coordinate system linked to the imaging system. In these alignment methods, the mathematical transformation required to match the optically determined shape of device 12 to the shape of, for example, two images of device 12, such as two X-ray images created at different angles, is determined. FIG. 2 schematically shows an exemplary shape of device 12 near its distal tip. Device 12 can be located using one shape transformation such that the projection of this shape onto the plane of the image matches the shape of device 12 within the image. In FIG. 2, TIFF2025517910000002.tif1416 indicates the normal vector on the image plane.

[0045] Alternatively, such alignment may be performed based on at least one image and thus based on the projection of the shape onto the plane of the image. This is particularly relevant when it is assumed that the imaging system is characterized by the plane of projection and / or when, during the execution of the alignment of the entire optical shape sensing system 10 as disclosed herein, it is assumed that device 12 does not move significantly in a third dimension (defined as being parallel to vector TIFF2025517910000003.tif1416).

[0046] Alternatively or in combination, such alignment may be an update of a previous alignment that uses previous alignment shape-related data as a reference, as disclosed, for example, in WO2017135609.

[0047] Alternatively or in combination, such alignment may be based on shape - shape between 3D shape data and 2D X - ray image data that uses image segmentation techniques for extracting the device from a 2D image and recovery of the pose of the 3D shape relative to the X - ray source of the image, as disclosed in WO2013001388. Alternatively or in combination, the alignment may include 3D image data, e.g., 3D X - ray - based data (e.g., acquired prior to the procedure), or a 3D image model representing anatomical features, a so - called “pre - operative” 3D image, and an imaging process configured to project the 3D image data onto the plane of the provided (real - time) 2D X - ray image data, optionally with additional fine - tuning techniques of the model for better matching of the images acquired as needed, as known in the art, or techniques for extracting a 2D plane from the 3D image data and searching for a best match with the provided (real - time) 2D image data, and an imaging process that enables association of the provided 2D image with the pre - operative 3D image. Then, the alignment may be based on a shape - shape method between the 3D shape data (projected onto the plane of the 2D image) and the 2D X - ray image data, and the third dimension of the alignment is derived from the relationship with the pre - operative 3D image.

[0048] Alternatively or in combination, other methods of shape - shape alignment may be implemented as long as they can be used to align the optical shape sensing system 10 according to the present disclosure.

[0049] If there is an optical connector 34 in the optical path from the emission base 36 to the tip 46 of the device 12, not only the transformation belonging to the emission base 36 but also the transformation at the optical connector 34 is unknown. With existing alignment methods, these two unknown transformations cannot be determined separately. Only the combined transformation can be determined.

[0050] FIG. 3 shows again the drawing of FIG. 1, the transformation T from the emission base 36 where the proximal optical fiber 14 is fixed to the isocenter PCL→ISOand the conversion T from the proximal optical fiber 14 to the distal optical fiber 16 within the connector 34 GWC→PCC is shown together with. The isocenter is fixedly linked to the imaging system 48, i.e., the relevant coordinate system to which the device 12 is to be aligned.

[0051] FIG. 4 shows an overview of the conversion in the path of the device 12 from the isocenter to the tip 46 of the device 12. The conversion T from the isocenter to the device tip 46 (GWT) GWT→ISO =T PCL→ISO T GWT→PCL can be determined using the existing alignment method described above with respect to FIG. 2.

[0052] Optical interrogation of the optical fiber 16 provides a measurement signal by which the shape and orientation of the device 12 relative to the emission base 36 are determined. Thus, the conversion T from the device tip 46 to the emission base 36 GWT→PCL is known from these measured signals.

[0053] Next, the static conversion T from the emission base 36 to the ISO center PCL→ISO is T PCL→ISO =T GWT→ISO T -1 GWT→PCL is obtained from.

[0054] Thus, for all subsequent transient movements of the device 12 (both outside and inside the object 28), the shape and orientation of the device 12 are obtained from optically interrogating the optical fiber 16 and processing the measured signals, particularly near the distal tip 46. T GWT→ISO (t)=T PCL→ISO T GWT→PCL (t)

[0055] Since the proximal fiber 14 is fixed to the emission base 36, the conversion T PCL→ISO remains stationary during movement of the device 12.

[0056] An optical connector, such as optical connector 34, particularly a backloadable connector, when inserted into optical fibers 14, 16 between the launch base 36 and the insertion point 30 of the optical fiber 16 into the subject 28 (here the patient), has an additional unknown transformation T within the optical connector 34 GWC→PCC needs to be determined in order to accurately determine the shape and orientation of the device 12 within the subject 28

[0057] Thus, the transformation T GWT→ISO can be written as follows when the optical connector 34 is considered T GWT→ISO =T PCL→ISO T PCC→PCL T GWC→PCC T GWT→GWC (1)

[0058] Without loss of generality, the abbreviations GWT, PCC, GWC, GWT refer to the case where the device 12 is a guide wire (GW) and the optical fiber 14 is disposed within a patch cord (PC) and have the following meanings

[0059] PCL = patch cord at the launch base 36

[0060] PCC = patch cord at the optical connector 34

[0061] GWC = guide wire at the optical connector 34

[0062] GWT = guide wire tip 46

[0063] The optical determination of the shape and orientation of optical fibers 14 and 16 by the optical shape sensing system 10 starts at the launch base 36. The shape and orientation of the portion of the proximal optical fiber 14 extending from the connector 34 to the launch base 36 (e.g., within the patch cord) are determined from optically measured signals obtained by optically interrogating the proximal optical fiber 14. The connector 34 connects the distal optical fiber 16 (e.g., within a guide wire or device 12) to the proximal optical fiber 14 (e.g., within the patch cord). The shape and orientation of the distal optical fiber 16 from the connector 34 to the distal tip 46 of the optical fiber 16 (e.g., within a guide wire or device 12) are also determined from optically measured signals obtained by interrogating the distal optical fiber 16. At the connector 34, the distal end of the proximal optical fiber 14 and the proximal end of the distal optical fiber 16 are connected by an unknown transformation T GWC→PCC as shown in FIG. 5. Thus, the two unknown transformations that need to be determined are, in particular, the transformation T PCL→ISO from the launch base 36 to the isocenter and the transformation T GWC→PCC within the connector 34, especially when the connector 34 is a connector where misalignment between the proximal optical fiber and the distal optical fiber 16 is likely to occur, such as a backloadable connector.

[0064] In the following, an embodiment of a method for aligning a portion of the optical shape sensing system 10 including the distal multi-core optical fiber 16, the proximal multi-core optical fiber 14, the optical connector 34 that optically connects the distal optical fiber 16 and the proximal optical fiber 14 to each other, and the launch base 36 fixed to the imaging system 48 and configured to fix the proximal optical fiber 14 is described. This method enables the determination of two unknown transformations T PCL→ISO and T GWC→PCC . An embodiment of the method is described with reference to FIG. 7.

[0065] In step S100, data of at least a part of the distal optical fiber 16 from the image of the imaging system 48 is provided. When the imaging system 48 is an X-ray imaging system, the image is an X-ray image of the distal optical fiber 16, particularly in the region of the distal tip 46 of the optical fiber 16.

[0066] In step S102, the optical connector 34 is arranged in a first position or orientation with respect to the object 28. The first position or orientation can be arbitrary. For example, the optical connector 34 may be arranged in position or orientation 1 as shown in FIG. 6. In the first position or orientation 1 of the optical connector 34, step S104 is executed. In step S104, the shape and orientation of the distal optical fiber 16, and the shape and orientation of the section of the proximal optical fiber 14 extending from the optical connector 34 to the emission base 36 are optically measured. That is, the interrogation module 42 optically interrogates the optical fibers 14 and 16, and the shape reconstruction module 44 reconstructs the three-dimensional shape and orientation of the optical fibers 14 and 16 from the backscattered or retroreflected optical signal received from the fibers 14 and 16 to the tip 46 of the distal optical fiber 16.

[0067] In step S106, the optical connector 34 is arranged or oriented in a second position or orientation different from the first position or orientation 1 with respect to the object 28. The second position or orientation is arbitrary, and all that is required is that the second position or orientation is (sufficiently) different from the first position or orientation 1. In FIG. 6, the second position or orientation of the optical connector 34 is indicated by 2.

[0068] In the second position or orientation 2 of the optical connector 34, step S108 is executed. In step S108, the shape and orientation of the distal optical fiber 16, and the shape and orientation of the section of the proximal optical fiber 14 extending from the optical connector 34 to the emission base 36 are optically measured again. This optical measurement of the shape and orientation of the section of the distal optical fiber 16 and the proximal optical fiber 14 is performed in the same manner as the first position or orientation of the optical connector 34.

[0069] In step S110, the portion of the distal fiber 16 for which at least an image of the imaging system is provided is aligned to the imaging system 48 according to an existing alignment method, i.e., based on a shape - shape basis between at least one of the optical shape measurement values in the first or second position or orientation of the optical connector 34 and the provided image. In particular, this alignment step may be performed for each of the positions or orientations of the optical connector 34 and the corresponding optical shape measurement values at these positions.

[0070] Note that step S110 may be performed based on the (X - ray) image data obtained in step S100. Nevertheless, the images may be taken in any order in step S110 or in step S108 where the optical shape measurement is performed. Further, for example, step S110 may be performed after S104 and before step S106, using the optical shape measurement values of the distal and proximal optical fibers 14, 16 in the first position or orientation of the optical connector 34. Also, step S110 may be performed after the optical shape measurement of the distal and proximal optical fibers 14, 16 in the second position or orientation of the optical connector 34, but after step S108 without requiring a further image of the device 12. Another possible sequence of steps may start with step S102, followed by steps S100 and S104 in a random order, and then step S106 may be executed. In step S108, the (X - ray) image may be taken in any order together with the optical shape measurement, or the image may be taken in step S100 or S110.

[0071] Furthermore, it should be understood that steps S104 and S108 may be performed for more than two different positions or orientations of the connector 34 with respect to the object 28. Thus, for n ≧ 2 different positions or orientations of the optical connector 34, n virtual transformations T i GWT→ISO , i = 1, ···, n are obtained. Next, the actual transformation T belonging to the emission base 36 PCL→ISOand the actual transformation T belonging to the optical connector 34 GWC→PCC can be determined from a set of n equations. T i GWT→ISO = T PCL→ISO T i PCC→PCL T GWC→PCC T i GWT→GWC , i = 1, ..., n (2)

[0072] transformation T i PCC→PCL and T i GWT→GWC are obtained from the optically measured and reconstructed shapes and orientations of the optical fiber 16 and the proximal optical fiber 14 for each position or orientation i = 1, ···, n of the optical connector 34. More precisely, the transformation T i PCC→PCL is obtained from the optically measured shape and orientation of the optical fiber 14 from the connector 34 to the launch base 36, and the transformation T i GWT→GWC is obtained from the optically measured shape and orientation of the distal optical fiber 16 from the distal tip 46 to the connector 34. The transformation T i GWT→ISO is obtained from the localization of at least the distal portion of the distal optical fiber 16 in the image of the imaging system (as shown, for example, in FIG. 2). Thus, in the case of n = 2, the unknown transformations T PCL→ISO and T GWC→PCC can be determined by solving the above two (i = 1 and i = 2) equations (2) for these two unknown transformations. It can be convenient to rewrite these equations as follows, T -1 PCL→ISO T i GWT→ISO = T i PCC→PCL T GWC→PCC T i GWT→GWC , i = 1, ..., n (3) Thus, the unknown transformations: T -1 PCL→ISO and T GWC→PCC must be solved. T -1 PCL→ISO and T GWC→PCC become known, the transformation T PCL→ISO can also be easily determined.

[0073] Therefore, in step S112 of FIG. 7, the alignment data is calculated to align a part of the optical shape sensing system from the emission base 36 to the tip of the distal fiber 16 including the connector 34 and the emission base 36 with the imaging system 48 based on the optical shape measurement values at the first and second positions or orientations of the optical connector 34.

[0074] Furthermore, the method may further include step S114 in which at least a part of the alignment data obtained in step S112 is stored, for example, in the memory of the optical shape sensing system 10.

[0075] After the alignment of the optical shape sensing system as described above, the device 12 can be accurately tracked and visualized in the correct position and orientation with respect to the coordinate system of the imaging system 48.

[0076] In some surgical procedures, catheters around the optical guide wire need to be exchanged with each other to perform the medical treatment of the patient. In such a procedure, the patch cord having the proximal optical fiber 14 will be cut from the distal optical fiber 16 at the optical connector 34. While the device 12 having the distal optical fiber 16 remains inside the subject 28 (patient), the catheter around the device 12 is replaced with another one. For this purpose, the optical connector 34 may be a backloadable optical connector.

[0077] When the distal optical fiber 16 is cut and then reconnected to the proximal optical fiber 14 at the optical connector 34, the transformation T belonging to the optical connector 34 between the two connection parts of the proximal optical fiber 14 and the distal optical fiber 16 GWC→PCCis changing or may be changing. This changed transformation needs to be determined again to accurately locate the device 12 in the body for further treatment of the patient.

[0078] In other words, the optical shape sensing system 10 from the emission base 36 to the tip 46 of the device 12 must be realigned after reconnecting the distal and proximal optical fibers 16 and 14.

[0079] In the first embodiment of the realignment method according to FIG. 8, the alignment data before the distal and proximal optical fibers 14 and 16 are cut, which is stored as the stored alignment data, is provided in step S120. The stored alignment data may include the shape and orientation of the distal optical fiber 16 optically measured before cutting the distal optical fiber from the proximal optical fiber, or the stored alignment data may include one or more single points along the distal optical fiber 16, particularly the entry point 30 of the distal optical fiber 16 into the object 28. In this embodiment, it is essential that the portion of the distal optical fiber 16 inserted into the object 28 does not move while the distal optical fiber 16 is cut from the proximal optical fiber 14 and reconnected.

[0080] Therefore, the shape and orientation of the distal optical fiber 16 before cutting the optical connector 34 are known. Therefore, the transformation (T PCL→ISO ) belonging to the emission base 36 and the transformation T GWC→PCC = T before GWC→PCC belonging to the optical connector 34 (before cutting) are known. After reconnecting the distal optical fiber 16 in the optical connector 34 to the proximal optical fiber 14, the shape and orientation of the portion of the proximal optical fiber from the connector 34 to the emission base 36 and from the tip 46 of the distal optical fiber 16 to the connector 34 are optically measured and reconstructed in step S122.

[0081] If the stored alignment data includes the device 12 and thus the shape and orientation of the distal optical fiber 16 before cutting, the alignment of the imaging system 48 of the optical shape sensing system 10 from the emission base 36 to the tip 46 of the distal optical fiber 16 can be performed in step S124 by making the newly measured shape and orientation of the distal optical fiber 16 equal to the stored alignment data. If the stored alignment data includes the entry point 30 of the distal optical fiber 16 into the object 28 (or if the stored alignment data includes other points along the device 12), the entry point 30 is newly determined (or other points along the device 12 are newly determined), and the alignment is performed in step S124 by making this or these newly determined points equal to the stored points.

[0082] For the transformation to be determined, the realignment method described previously can be expressed as follows. That is, if the shape and orientation of the device 12 before cutting the optical connector 34 are known, the transformation T PCL→ISO belonging to the emission base 36 and the transformation T before GWC→PCC belonging to the optical connector 34 (before cutting) are known. After reconnecting the distal optical fiber 16 in the optical connector 34 to the proximal optical fiber 14, the shape and orientation of the portion of the optical fiber 14 from the connector 34 to the emission base 36 and the portion of the optical fiber 16 from the tip 46 to the connector 34 are optically measured and reconstructed. Therefore, the transformations T after PCC→PCL and T after GWT→GWC after cutting and reconnecting the optical connector 34 are determined, and the unknown changed transformation T after GWC→PCC needs to be determined. The position of the distal optical fiber 16 within the object 28 was known before cutting the distal optical fiber 16 and was not moved, so it remains at the same position within the object 28 after reconnection. Therefore, the total transformation T GWT→ISO before the cut-reconnect procedure and the total transformation thereafter are the same. T before GWT→ISO =Tafter GWT→ISO = T. This is T PCL→ISO T before PCC→PCL T before GWC→PCC T before GWT→GWC = T = T PCL→ISO T after PCC→PCL T after GWC→PCC T after GWT→GWC (4) or similarly T before PCC→PCL T before GWC→PCC T before GWT→GWC = T -1 PCL→ISO T = T after PCC→PCL T after GWC→PCC T after GWT→GWC (5) results in.

[0083] Here, the conversion T in the connector 34 after GWC→PCC can be determined from the above equation (5).

[0084] FIG. 9 shows another embodiment of a method for (re)aligning a portion of the optical shape sensing system 10 from the launch base 36 to the tip of the distal fiber 16 in an imaging system 48.

[0085] Some steps of this embodiment are similar to the steps of the method according to FIG. 7. Different from the method according to FIG. 7, here, the position and orientation of the emission base 36 are known, and due to the small movement of the distal optical fiber 16 within the device 12 and thus the object 28, the position and orientation of the distal tip 46 of the distal optical fiber 16 are considered unknown. Therefore, taking into account the unknowns, the distal tip 46 of the distal optical fiber 16 and the emission base 36, whose transformation was unknown in the embodiment of FIG. 7, are exchanged here. In other words, the position and orientation of the fiber 14 at the emission base 36 are known before cutting the distal optical fiber 16 from the connector 34, and the emission base 36 is fixed with respect to the real world during the cut - reconnect procedure of the distal optical fiber 16. Therefore, the method according to FIG. 9 starts in step S130 by providing the stored alignment data of the pre - cut alignment, which is the alignment of the emission base 36 to the imaging system 48 before cutting the distal optical fiber 16 from the proximal optical fiber 14, and step S130 is executed after reconnecting the distal optical fiber 16 and the proximal optical fiber 14.

[0086] Next, in step S132, the optical connector 34 is arranged in a first position or orientation.

[0087] In step S134, the shape and orientation of the distal optical fiber 16, and the shape and orientation of the proximal optical fiber 14 from the optical connector 34 to the emission base 36 are optically measured as described above.

[0088] Then, in step S136, the optical connector 34 is arranged in a second position or orientation, and in step S138, the shape and orientation of the distal optical fiber 16 and the proximal optical fiber from the optical connector 34 to the emission base 36 are optically measured again. Note that the second position or orientation is different from the first position or orientation of the optical connector 34. As in the method according to FIG. 7, the optical connector 34 may be arranged in more than two different positions or orientations, and the optical measurements are performed at each of these different positions.

[0089] In step S140, the optical shape sensing system 10 from the launch base 36 to the tip 46 of the distal fiber 16 is aligned with the imaging system 48 based on optical measurements and alignment data at the first and second positions or orientations of the optical connector 34, i.e., the alignment of the launch base 36 with respect to the imaging system 48 before cutting the distal fiber 16 from the proximal fiber 14.

[0090] Note that the position and orientation of the tip of the distal fiber 16 are fixed between the two positions or orientations of the optical connector 34.

[0091] Regarding the transformation, the previously described embodiments can be described as follows.

[0092] For m≧2 different orientations or positions of the connector 34 with respect to the object 28, the shapes and orientations of the proximal fiber 14 and the distal fiber 16 from the optical connector 34 to the launch base 36 are optically measured and reconstructed. The transformation T i PCC→PCL , i = 1,..., m, is obtained from the optically measured shape and orientation of the portion of the fiber 14 from the connector 34 to the launch base 36, and the transformation T i GWT→GWC , i = 1,..., m, is obtained from the optically measured shape and orientation of the portion of the distal fiber 16 from the distal tip 46 to the connector 34. The unknown transformation T GWT→ISO belonging to the distal tip 46, which describes the position and orientation of the device tip 46 with respect to the fixed world, and the transformation T GWC→PCC belonging to the optical connector 34 are determined from the following set of equations.

[0093] T GWT→ISO =T PCL→ISO T i PCC→PCL T GWC→PCC T i GWT→GWC , i = 1,..., m, (6)

[0094] Here, T PCL→ISOis a known transformation belonging to the emission base 36 obtained from previously stored alignment data of, for example, a first alignment.

[0095] Note that the embodiments according to FIGS. 8 and 9 do not require that the method according to FIG. 7 has been previously executed. Embodiments for (re)aligning the optical shape sensing system 10 to the imaging system 48 can be obtained based on stored alignment data obtained by a different (previous or first) alignment process than that of FIG. 7. That is, the embodiments according to FIGS. 8 and 9 may be executed after a first or previous alignment of the optical shape sensing system 10 with respect to the imaging system 48, and the first or previous alignment may be executed via the stored alignment data stored in the optical shape sensing system 10. List of reference numerals in FIGS. 7 to 9: S100 Provide data from the image from the imaging system S102 Arrange the optical connector in a first position / orientation S104 Optically measure the distal / proximal optical fiber S106 Arrange the optical connector in a second position and / or orientation S108 Optically measure the distal / proximal optical fiber S110 Align the distal optical fiber to the imaging system based on the image S112 Align the optical shape system based on the optical measurements at the first and second positions / directions of the optical connector S114 Store the alignment data S120 Provide the stored alignment data S122 Optically measure the distal / proximal optical fiber S124 Equalize the optical measurement with the alignment data S130 Provide the alignment data before cutting S132 Arrange the optical connector in a first position / direction S134 Optically measure the distal / proximal optical fiber S136 Arrange the optical connector in a second position and / or orientation Optically measure the distal / proximal optical fiber Align the optical shape sensing system based on optical measurements at the first and second positions of the optical connector and alignment data before cutting

[0096] Explanation of the solution of the equation according to FIG. 7, FIG. 8, or FIG. 9 The transformation T consists of a rotation with a rotation matrix R and a translation Consists of TIFF2025517910000004.tif1414, Written as TIFF2025517910000005.tif1829. And the inverse transformation is Indicates TIFF2025517910000006.tif1744, and the rotation matrix is RR T = RT R = I. The transformation T is the coordinates of a point in 3D space A vector consisting of TIFF2025517910000007.tif1314 and an additional number 1 Acts on TIFF2025517910000008.tif1314, so T is the vector Acts on TIFF2025517910000009.tif1427, and the transformation is Results in TIFF2025517910000010.tif1455. The first three elements of TIFF2025517910000011.tif1314 describe the transformation of the point TIFF2025517910000012.tif1111, and note that the fourth element is the same as the vector TIFF2025517910000013.tif1111 and is the number 1.

[0097] The rotation matrix can be written as a sequence of rotations about three orthogonal x, y, and z coordinate axes (see, for example, FIG. 10), so R = R z (γ)R y (β)R x (α), where R i, i = x, y, z represent rotations about the coordinate axis i, each having Euler angles α, β, γ. The rotation matrix R i is as follows. TIFF2025517910000014.tif18154Alternatively, (see, for example, FIG. 11), the rotation matrix R is a unit vector having an angle θ TIFF2025517910000015.tif1113The rotation vector representing the rotation about TIFF2025517910000016.tif1122can be derived from. And using Rodrigues' formula, the rotation matrix is TIFF2025517910000017.tif2280and TIFF2025517910000018.tif1922along with, R = I + sinθK+(1 - cosθ)K 2 , (8) is shown. Equations belonging to the embodiments according to FIGS. 7 to 9 Using the above expression of the transformation, the equation for n≥2 for determining the solution of the embodiment according to FIG. 7 is rewritten as follows. TIFF2025517910000019.tif28158Then, the unknown rotation matrices R L and R C as well as the transformation TIFF2025517910000020.tif1313and TIFF2025517910000021.tif1316belonging to the emission base 36 and the (backloadable) optical connector 34, respectively, need to be solved. Similarly, the simplified equation can be rewritten as follows. TIFF2025517910000022.tif23157Then, the unknown rotation matrices Q L and R C as well as the transformations belonging to the emission base 36 and the connector 34, respectively TIFF2025517910000023.tif1513and TIFF2025517910000024.tif1516 needs to be solved. After that, the rotation matrix R of the launch base 36 L and translation TIFF2025517910000025.tif1113 is R L =Q T L and TIFF2025517910000026.tif1026 can be easily found as such.

[0098] Similarly, in the embodiments of FIG. 8 or FIG. 9, the transformation belonging to the connector 34 after the cut - reconnect procedure can be rewritten as follows. TIFF2025517910000027.tif28157 The unknown changed rotation matrix R after the cut - reconnect procedure in the connector 34 C after and the changed transformation TIFF2025517910000028.tif1720 needs to be solved.

[0099] The above equation can form a well-determined set of equations, and thus, in that case, the number of independent equations is larger than the number of unknowns due to inaccuracies in determining the shapes of the proximal fiber 14 (patch code) and the distal fiber 16 (guide wire). These inaccuracies can be caused by the (small) inaccuracies of the measured signals and the (small) inaccuracies (discretization errors) in determining the shape and orientation of the patch code and the guide wire from the measured signals. The set of equations belonging to the embodiment of FIG. 7 or FIG. 9 can be well-determined, especially when n>2. Similarly, the set of equations belonging to the embodiment of FIG. 8 can be well-determined when a plurality of reference points on the guide wire are selected before cutting and these points of the guide wire are matched to the original reference points after reconnecting the guide wire. For the well-determined set of equations belonging to all embodiments of FIGS. 7, 8, or 9, the set of equations can be solved in the least squares sense. Analytical, semi-analytical, and / or numerical methods can be applied to solve the (well-determined) set of equations derived above belonging to the embodiments of FIGS. 7, 8, or 9. The solution is a set of two unknown transformations T PCL→ISO and T GWC→PCC or the unknown modified transformation T after GWC→PCC (after cutting-reconnecting).

[0100] The rotation matrix R in the above transformation T must be guaranteed to satisfy the orthogonality condition RR T =R T R = I. The total set of equations for the unknowns is non-linear, and thus, with the highest certainty, iterative procedures are required to solve them. Since the rotation and translation in the connector 34 are expected to be small, the initial estimate of the rotation matrix R in the connector 34 can be the identity matrix I, and the initial estimate of the translation TIFF2025517910000029.tif1414 can be zero translation TIFF2025517910000030.tif1216.

[0101] In the solution of the embodiment of FIG. 7, if the variation between different orientations / positions of the connector 34 is very small, the resulting set of equations may be in a bad state and it may be difficult or impossible to determine an appropriate unique solution. In that case, the condition number of the gradient matrix (the derivative of the equations with respect to the unknowns) is large. See https: / / en.wikipedia.org / wiki / Condition_number (a problem with a small condition number is said to be well-conditioned, while a problem with a large condition number is said to be ill-conditioned) or https: / / nl.mathworks.com / help / symbolic / cond.html. When the condition number of the set of equations is large, a notification should be given to the operator to magnify the variation in the orientation and / or position of the connector 34.

[0102] In the case of a well-determined set of equations, alternatively, the condition number of the least-squares set of equations can be used instead of the condition number of the original set of equations. If the unknowns are represented by the vector TIFF2025517910000031.tif1114 and the set of equations is represented by TIFF2025517910000032.tif1221, then the least-squares solution satisfies TIFF2025517910000033.tif13158, and the matrix TIFF2025517910000034.tif1425 from the condition number is TIFF2025517910000035.tif1316. Instead, it can be used to notify the operator whether the set of equations is well-conditioned or ill-conditioned and whether the variation in the orientation and / or position of the connector block should be magnified. This matrix is used in the application of the Newton iteration procedure to solve a set of well-determined non-linear equations in the least-squares sense when the Newton iteration shows TIFF2025517910000036.tif11155.

[0103] When the distal fiber 16 (guide wire) is severed from the connector 34, the portion of the guide wire within the patient should be kept stable. A notification should be given to the operator to ensure that the portion of the guide wire within the patient is kept in a stable state.

[0104] Reduction of unknowns in the conversion belonging to the optical connector Unknown roll rotation within the connector due to non-zero tolerances in the manufacturing process is expected to have the greatest impact on the inaccuracy of the predicted position of the distal tip region of the device 12. The effects of translation with respect to the position of the distal tip 46 of the device 12 and yaw and pitch rotations about the other two axes within the connector are expected to be negligibly small (see FIG. 12). Thus, the unknown conversion in the connector 34 can probably be simplified to only an unknown roll motion with a roll angle γ as the only unknown variable. In that case, the transformation T GWC→PCC is can be approximated by TIFF2025517910000037.tif22156, where the local z-axis is in the longitudinal direction of the guide wire.

[0105] Although the present invention has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description should be considered to be illustrative or exemplary and not restrictive, and the present invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments will be understood and can be implemented by those skilled in the art when practicing the invention recited in the claims, from a consideration of the drawings, the disclosure, and the appended claims.

[0106] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single element or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain means are recited in mutually different dependent claims does not indicate that a combination of these means cannot be used advantageously.

[0107] The computer program may be stored / distributed on a suitable non-transitory medium such as an optical storage medium or a solid state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems.

[0108] Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. A method for aligning a part of an optical shape sensing system with an imaging system, wherein the part comprises a distal multicore optical fiber and a proximal multicore optical fiber, an optical connector that optically connects the distal optical fiber and the proximal optical fiber to each other, and a firing base fixed to the imaging system and configured to fix the proximal optical fiber, and the method is i) Providing image data of at least a portion of the distal optical fiber from the image from the imaging system, ii) From the arrangement of the optical connector in the first position and / or orientation, and in the first position and / or orientation of the optical connector, -The shape and orientation of the distal optical fiber are measured optically, - A step of optically measuring the shape and orientation of the section of the proximal fiber extending from the optical connector to the emission base, iii) From the arrangement of the optical connector in a second position and / or orientation different from the first position and / or orientation, and in the second position and / or orientation of the optical connector, -The shape and orientation of the distal optical fiber are measured optically, - A step of optically measuring the shape and orientation of the section of the proximal fiber, iv) Aligning at least the portion of the distal fiber with the imaging system based on a shape-shape basis between at least one of the optical shape measurements at the first and second positions and / or orientations of the optical connector and the provided image data; v) Aligning the portion of the optical shape system, including the optical connector and the emission base, as a whole with the imaging system based on the optical measurements of the first and second positions and / or orientations of the optical connector; A method having

2. The method according to claim 1, wherein at least one of steps ii) and iii) is performed without moving at least a portion of the distal optical fiber.

3. The method according to claim 1, further comprising the step of storing at least a portion of the alignment data of the alignment acquired in step v) in order to acquire stored alignment data so that it can be used after the distal optical fiber and the proximal optical fiber in the optical connector are cut and reconnected.

4. The method according to claim 3, wherein during the cutting and reconnection of the distal optical fiber and the proximal optical fiber in the optical connector, at least a portion of the distal optical fiber is not moved while the distal optical fiber is cut from the proximal optical fiber.

5. The method according to claim 3, further comprising the steps of: providing the stored alignment data after reconnecting the distal optical fiber with the proximal optical fiber in the optical connector; optically measuring the shape and orientation of the distal optical fiber; optically measuring the shape and orientation of the proximal optical fiber from the optical connector to the emission base; and aligning the optical shape sensing system with the imaging system based on the newly measured shape and orientation of the distal optical fiber being equal to the alignment data.

6. The method according to claim 5, wherein the stored alignment data includes the shape and orientation of the distal optical fiber as optically measured before the distal optical fiber is cut from the proximal optical fiber.

7. The method according to claim 5, wherein the stored alignment data includes one or more single points along the distal optical fiber.

8. The method according to claim 7, wherein the one or more of the aforementioned points include the point of entry of the distal optical fiber into the object.

9. The method according to claim 3, further comprising the steps of: providing the stored alignment data after reconnecting the distal optical fiber and the proximal optical fiber; optically measuring the shape and orientation of the distal optical fiber from the arrangement of the optical connector in a third position and / or orientation, and optically measuring the shape and orientation of the proximal optical fiber from the optical connector to the emission base while the optical connector is in the third position and / or orientation; optically measuring the shape and orientation of the distal optical fiber from the arrangement of the optical connector in a fourth position and / or orientation, and optically measuring the shape and orientation of the proximal optical fiber from the optical connector to the emission base while the optical connector is in the fourth position and / or orientation; and aligning the optical shape sensing system with the imaging system based on the optical measurements of the optical connector in the third and fourth positions and / or orientations and the provided alignment data.

10. The method according to claim 9, wherein the alignment data is the alignment of the emission base with respect to the imaging system before the distal optical fiber is cut from the proximal optical fiber.

11. The method according to claim 9, wherein aligning the optical shape sensing system with the imaging system includes aligning at least a portion of the distal optical fiber, including the distal tip of the distal optical fiber.

12. A distal multicore optical fiber and a proximal multicore optical fiber configured to be interrogated by an optical interrogation module, an optical connector that optically connects the distal optical fiber and the proximal optical fiber to each other, and a launch base configured to be fixed to an imaging system and configured to fix the proximal fiber, i) Provide image data of at least a portion of the distal optical fiber from the image from the imaging system, ii) After positioning the optical connector in the first position and / or orientation, - The shape and orientation of the interrogated distal optical fiber are optically measured, - Optically measure the shape and orientation of the interrogated proximal fiber section extending from the optical connector to the emission base. iii) After positioning the optical connector in a second position and / or orientation different from the first position or orientation, - The shape and orientation of the interrogated distal optical fiber are optically measured, - The shape and orientation of the section of the interrogated proximal fiber are optically measured, iv) Aligning at least the portion of the distal fiber with the imaging system based on a shape-shape basis between at least one of the optical measurements at the first and second positions or orientations of the optical connector and the provided image data, v) Based on the optical measurements of the first and second positions or orientations of the optical connector, the system including the optical connector and the emission base is aligned as a whole with the imaging system. A circuit configured as follows, A system that has

13. A computer program having program code means for causing a computer to perform steps iv) and v) of the method of claim 1, wherein the computer program is further configured to receive the provided data and to receive the shape and orientation optically measured at the first and second positions and / or orientations of the optical connector.

Images