Patent Description:
Minimally invasive medical techniques are intended to reduce the amount of tissue that is damaged during medical procedures, thereby reducing patient recovery time, discomfort, and deleterious side effects. Such minimally invasive techniques may be performed through natural orifices in a patient anatomy or through one or more surgical incisions. Through these natural orifices or incisions clinicians may insert minimally invasive medical instruments (including surgical, diagnostic, therapeutic, or biopsy instruments) to reach a target tissue location. To assist with reaching the target tissue location, the location and movement of the medical instruments may be correlated with pre-operative or intra-operative images of the patient anatomy. With the image-guided instruments correlated to the images, the instruments may navigate natural or surgically created passageways in anatomical systems such as the lungs, the colon, the intestines, the kidneys, the heart, the circulatory system, or the like. Traditional instrument tracking systems, including electromagnetic sensing tracking systems, may disturb the clinical environment or workflow. Systems and methods for performing image guided surgery with minimal clinical disturbances are needed.

According to a first aspect of the present invention there is provided the computer program of claim <NUM>.

According to a second aspect of the present invention there is provided the system of claim <NUM>.

Additional aspects of the invention are set out in the dependent claims.

In the following detailed description of the aspects of the invention, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. However, it will be obvious to one skilled in the art that the embodiments of this disclosure may be practiced without these specific details. In other instances well known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the embodiments of the invention. And, to avoid needless descriptive repetition, one or more components or actions described in accordance with one illustrative embodiment can be used or omitted as applicable from other illustrative embodiments.

The embodiments below will describe various instruments and portions of instruments in terms of their state in three-dimensional space. As used herein, the term "position" refers to the location of an object or a portion of an object in a three-dimensional space (e.g., three degrees of translational freedom along Cartesian X, Y, Z coordinates). As used herein, the term "orientation" refers to the rotational placement of an object or a portion of an object (three degrees of rotational freedom - e.g., roll, pitch, and yaw). As used herein, the term "pose" refers to the position of an object or a portion of an object in at least one degree of translational freedom and to the orientation of that object or portion of the object in at least one degree of rotational freedom (up to six total degrees of freedom). As used herein, the term "shape" refers to a set of poses, positions, or orientations measured along an object.

Referring to <FIG> of the drawings, a teleoperated medical system for use in, for example, surgical, diagnostic, therapeutic, or biopsy procedures, is generally indicated by the reference numeral <NUM>. As shown in <FIG>, the teleoperated system <NUM> generally includes a teleoperational manipulator assembly <NUM> for operating a medical instrument <NUM> in performing various procedures on the patient P. The assembly <NUM> is mounted to or near an operating table O. A master assembly <NUM> allows the clinician or surgeon S to view the interventional site and to control the slave manipulator assembly <NUM>.

The master assembly <NUM> may be located at a surgeon's console which is usually located in the same room as operating table O. However, it should be understood that the surgeon S can be located in a different room or a completely different building from the patient P. Master assembly <NUM> generally includes one or more control devices for controlling the manipulator assemblies <NUM>. The control devices may include any number of a variety of input devices, such as joysticks, trackballs, data gloves, trigger-guns, hand-operated controllers, voice recognition devices, body motion or presence sensors, or the like. In some embodiments, the control devices will be provided with the same degrees of freedom as the associated medical instruments <NUM> to provide the surgeon with telepresence, or the perception that the control devices are integral with the instruments <NUM> so that the surgeon has a strong sense of directly controlling instruments <NUM>. In other embodiments, the control devices may have more or fewer degrees of freedom than the associated medical instruments <NUM> and still provide the surgeon with telepresence. In some embodiments, the control devices are manual input devices which move with six degrees of freedom, and which may also include an actuatable handle for actuating instruments (for example, for closing grasping jaws, applying an electrical potential to an electrode, delivering a medicinal treatment, or the like).

The teleoperational assembly <NUM> supports the medical instrument system <NUM> and may include a kinematic structure of one or more non-servo controlled links (e.g., one or more links that may be manually positioned and locked in place, generally referred to as a set-up structure) and a teleoperational manipulator. The teleoperational assembly <NUM> includes plurality of actuators or motors that drive inputs on the medical instrument system <NUM> in response to commands from the control system (e.g., a control system <NUM>). The motors include drive systems that when coupled to the medical instrument system <NUM> may advance the medical instrument into a naturally or surgically created anatomical orifice. Other motorized drive systems may move the distal end of the medical instrument in multiple degrees of freedom, which may include three degrees of linear motion (e.g., linear motion along the X, Y, Z Cartesian axes) and in three degrees of rotational motion (e.g., rotation about the X, Y, Z Cartesian axes). Additionally, the motors can be used to actuate an articulable end effector of the instrument for grasping tissue in the jaws of a biopsy device or the like. Motor position sensors such as resolvers, encoders, potentiometers, and other mechanisms may provide sensor data to the teleoperational assembly describing the rotation and orientation of the motor shafts. This position sensor data may be used to determine motion of the objects manipulated by the motors.

The teleoperational medical system <NUM> also includes a sensor system <NUM> with one or more sub-systems for receiving information about the instruments of the teleoperational assembly. Such sub-systems may include a position sensor system (e.g., an electromagnetic (EM) sensor system); a shape sensor system for determining the position, orientation, speed, velocity, pose, and/or shape of the catheter tip and/or of one or more segments along a flexible body of instrument system <NUM>; and/or a visualization system for capturing images from the distal end of the catheter system.

The visualization system (e.g., visualization system <NUM> of <FIG>) may include a viewing scope assembly that records a concurrent or real-time image of the surgical site and provides the image to the clinician or surgeon S. The concurrent image may be, for example, a two or three dimensional image captured by an endoscope positioned within the surgical site. In this embodiment, the visualization system includes endoscopic components that may be integrally or removably coupled to the medical instrument <NUM>. However in alternative embodiments, a separate endoscope, attached to a separate manipulator assembly may be used with the medical instrument to image the surgical site. The visualization system may be implemented as hardware, firmware, software or a combination thereof which interact with or are otherwise executed by one or more computer processors, which may include the processors of a control system <NUM> (described below). The processors of the control system <NUM> may execute instructions corresponding to processes disclosed herein.

The teleoperational medical system <NUM> also includes a display system <NUM> for displaying an image or representation of the surgical site and medical instrument system(s) <NUM> generated by sub-systems of the sensor system <NUM>. The display <NUM> and the operator input system <NUM> may be oriented so the operator can control the medical instrument system <NUM> and the operator input system <NUM> with the perception of telepresence.

The display system <NUM> may also display an image of the surgical site and medical instruments captured by the visualization system. The display <NUM> and the control devices may be oriented such that the relative positions of the imaging device in the scope assembly and the medical instruments are similar to the relative positions of the surgeon's eyes and hands so the operator can manipulate the medical instrument <NUM> and the hand control as if viewing the workspace in substantially true presence. By true presence, it is meant that the presentation of an image is a true perspective image simulating the viewpoint of an operator that is physically manipulating the instrument <NUM>.

Alternatively or additionally, the display <NUM> may present images of the surgical site recorded pre-operatively or intra-operatively using image data from imaging technology such as, computed tomography (CT), magnetic resonance imaging (MRI), fluoroscopy, thermography, ultrasound, optical coherence tomography (OCT), thermal imaging, impedance imaging, laser imaging, or nanotube X-ray imaging. The pre-operative or intra-operative image data may be presented as two-dimensional, three-dimensional, or four-dimensional (including e.g., time based or velocity based information) images or as images from models created from the pre-operative or intra-operative image data sets.

In some embodiments often for purposes of imaged guided surgical procedures, the display <NUM> may display a virtual navigational image in which the actual location of the medical instrument <NUM> is registered (i.e., dynamically referenced) with the preoperative or concurrent images/model to present the clinician or surgeon S with a virtual image of the internal surgical site from the viewpoint of the location of the tip of the instrument <NUM>. An image of the tip of the instrument <NUM> or other graphical or alphanumeric indicators may be superimposed on the virtual image to assist the surgeon controlling the medical instrument. Alternatively, the instrument <NUM> may not be visible in the virtual image.

In other embodiments, the display <NUM> may display a virtual navigational image in which the actual location of the medical instrument is registered with preoperative or concurrent images to present the clinician or surgeon S with a virtual image of medical instrument within the surgical site from an external viewpoint. An image of a portion of the medical instrument or other graphical or alphanumeric indicators may be superimposed on the virtual image to assist the surgeon controlling the instrument <NUM>.

The teleoperational medical system <NUM> also includes a control system <NUM>. The control system <NUM> includes at least one memory and at least one computer processor (not shown), and typically a plurality of processors, for effecting control between the medical instrument system <NUM>, the operator input system <NUM>, the sensor system <NUM>, and the display system <NUM>. The control system <NUM> also includes programmed instructions (e.g., a computer-readable medium storing the instructions) to implement some or all of the methods described in accordance with aspects disclosed herein, including instructions for providing pathological information to the display system <NUM>. While control system <NUM> is shown as a single block in the simplified schematic of <FIG>, the system may include two or more data processing circuits with one portion of the processing optionally being performed on or adjacent the teleoperational assembly <NUM>, another portion of the processing being performed at the operator input system <NUM>, and the like. Any of a wide variety of centralized or distributed data processing architectures may be employed. Similarly, the programmed instructions may be implemented as a number of separate programs or subroutines, or they may be integrated into a number of other aspects of the teleoperational systems described herein. In one embodiment, control system <NUM> supports wireless communication protocols such as Bluetooth, IrDA, HomeRF, IEEE <NUM>, DECT, and Wireless Telemetry.

In some embodiments, control system <NUM> may include one or more servo controllers that receive force and/or torque feedback from the medical instrument system <NUM>. Responsive to the feedback, the servo controllers transmit signals to the operator input system <NUM>. The servo controller(s) may also transmit signals instructing teleoperational assembly <NUM> to move the medical instrument system(s) <NUM> which extend into an internal surgical site within the patient body via openings in the body. Any suitable conventional or specialized servo controller may be used. A servo controller may be separate from, or integrated with, teleoperational assembly <NUM>. In some embodiments, the servo controller and teleoperational assembly are provided as part of a teleoperational arm cart positioned adjacent to the patient's body.

The control system <NUM> may further include a virtual visualization system to provide navigation assistance to the medical instrument system(s) <NUM> when used in an image-guided surgical procedure. Virtual navigation using the virtual visualization system is based upon reference to the acquired preoperative or intraoperative dataset of the anatomical passageways. More specifically, the virtual visualization system processes images of the surgical site imaged using imaging technology such as computerized tomography (CT), magnetic resonance imaging (MRI), fluoroscopy, thermography, ultrasound, optical coherence tomography (OCT), thermal imaging, impedance imaging, laser imaging, nanotube X-ray imaging, or the like. Software alone or in combination with manual input is used to convert the recorded images into segmented two dimensional or three dimensional composite representation of a partial or an entire anatomical organ or anatomical region. An image data set is associated with the composite representation. The composite representation and the image data set describe the various locations and shapes of the passageways and their connectivity. The images used to generate the composite representation may be recorded preoperatively or intra-operatively during a clinical procedure. In an alternative embodiment, a virtual visualization system may use standard representations (i.e., not patient specific) or hybrids of a standard representation and patient specific data. The composite representation and any virtual images generated by the composite representation may represent the static posture of a deformable anatomic region during one or more phases of motion (e.g., during an inspiration/ expiration cycle of a lung).

During a virtual navigation procedure, the sensor system <NUM> may be used to compute an approximate location of the instrument with respect to the patient anatomy. The location can be used to produce both macro-level (external) tracking images of the patient anatomy and virtual internal images of the patient anatomy. Various systems for using fiber optic sensors to register and display a medical implement together with preoperatively recorded surgical images, such as those from a virtual visualization system, are known. For example <CIT>)(disclosing "Medical System Providing Dynamic Registration of a Model of an Anatomical Structure for Image-Guided Surgery") discloses one such system.

The teleoperational medical system <NUM> may further include optional operation and support systems (not shown) such as illumination systems, steering control systems, irrigation systems, and/or suction systems. In alternative embodiments, the teleoperational system may include more than one teleoperational assembly and/or more than one operator input system. The exact number of manipulator assemblies will depend on the surgical procedure and the space constraints within the operating room, among other factors. The operator input systems may be collocated, or they may be positioned in separate locations. Multiple operator input systems allow more than one operator to control one or more manipulator assemblies in various combinations.

<FIG> illustrates a medical instrument system <NUM>, which may be used as the medical instrument system <NUM> in an image-guided medical procedure performed with teleoperational medical system <NUM>. Alternatively, the medical instrument system <NUM> may be used for non-teleoperational exploratory procedures or in procedures involving traditional manually operated medical instruments, such as endoscopy. Additionally or alternatively the medical instrument system <NUM> may be used to gather (i.e., measure) a set of data points corresponding to locations with patient anatomic passageways.

The instrument system <NUM> includes a catheter system <NUM> coupled to an instrument body <NUM>. The catheter system <NUM> includes an elongated flexible catheter body <NUM> having a proximal end <NUM> and a distal end or tip portion <NUM>. In one embodiment, the flexible body <NUM> has an approximately <NUM> outer diameter. Other flexible body outer diameters may be larger or smaller. The catheter system <NUM> may optionally include a shape sensor <NUM> for determining the position, orientation, speed, velocity, pose, and/or shape of the catheter tip at distal end <NUM> and/or of one or more segments <NUM> along the body <NUM>. The entire length of the body <NUM>, between the distal end <NUM> and the proximal end <NUM>, may be effectively divided into the segments <NUM>. If the instrument system <NUM> is a medical instrument system <NUM> of a teleoperational medical system <NUM>, the shape sensor <NUM> may be a component of the sensor system <NUM>. If the instrument system <NUM> is manually operated or otherwise used for non-teleoperational procedures, the shape sensor <NUM> may be coupled to a tracking system <NUM> that interrogates the shape sensor and processes the received shape data.

The shape sensor <NUM> may include an optical fiber aligned with the flexible catheter body <NUM> (e.g., provided within an interior channel (not shown) or mounted externally). In one embodiment, the optical fiber has a diameter of approximately <NUM>. In other embodiments, the dimensions may be larger or smaller. The optical fiber of the shape sensor system <NUM> forms a fiber optic bend sensor for determining the shape of the catheter system <NUM>. In one alternative, optical fibers including Fiber Bragg Gratings (FBGs) are used to provide strain measurements in structures in one or more dimensions. Various systems and methods for monitoring the shape and relative position of an optical fiber in three dimensions are described in <CIT>) (disclosing "Fiber optic position and shape sensing device and method relating thereto"); <CIT>) (disclosing "Fiber-optic shape and relative position sensing"); and <CIT>) (disclosing "Optical Fibre Bend Sensor"). Sensors in alternative embodiments may employ other suitable strain sensing techniques, such as Rayleigh scattering, Raman scattering, Brillouin scattering, and Fluorescence scattering. In other alternative embodiments, the shape of the catheter may be determined using other techniques. For example, the history of the catheter's distal tip pose can be used to reconstruct the shape of the device over the interval of time. As another example, historical pose, position, or orientation data may be stored for a known point of an instrument system along a cycle of alternating motion, such as breathing. This stored data may be used to develop shape information about the catheter. Alternatively, a series of positional sensors, such as EM sensors, positioned along the catheter can be used for shape sensing. Alternatively, a history of data from a positional sensor, such as an electromagnetic (EM) sensor, on the instrument system during a procedure may be used to represent the shape of the instrument, particularly if an anatomical passageway is generally static. Alternatively, a wireless device with position or orientation controlled by an external magnetic field may be used for shape sensing. The history of the wireless device's position may be used to determine a shape for the navigated passageways.

The medical instrument system may, optionally, include a position sensor system <NUM>. The position sensor system <NUM> may be a component of an EM sensor system with the sensor <NUM> including one or more conductive coils that may be subjected to an externally generated electromagnetic field. Each coil of the EM sensor system <NUM> then produces an induced electrical signal having characteristics that depend on the position and orientation of the coil relative to the externally generated electromagnetic field. In one embodiment, the EM sensor system may be configured and positioned to measure six degrees of freedom, e.g., three position coordinates X, Y, Z and three orientation angles indicating pitch, yaw, and roll of a base point or five degrees of freedom, e.g., three position coordinates X, Y, Z and two orientation angles indicating pitch and yaw of a base point. Further description of an EM sensor system is provided in <CIT>) (disclosing "Six-Degree of Freedom Tracking System Having a Passive Transponder on the Object Being Tracked"). In some embodiments, the shape sensor may also function as the position sensor because the shape of the sensor together with information about the location of the base of the shape sensor (in the fixed coordinate system of the patient) allows the location of various points along the shape sensor, including the distal tip, to be calculated.

A tracking system <NUM> may include the position sensor system <NUM> and a shape sensor system <NUM> for determining the position, orientation, speed, pose, and/or shape of the distal end <NUM> and of one or more segments <NUM> along the instrument <NUM>. The tracking system <NUM> may be implemented as hardware, firmware, software or a combination thereof which interact with or are otherwise executed by one or more computer processors, which may include the processors of the control system <NUM>.

The flexible catheter body <NUM> includes a channel <NUM> sized and shaped to receive a medical instrument <NUM>. Medical instruments may include, for example, image capture probes, biopsy instruments, laser ablation fibers, or other surgical, diagnostic, or therapeutic tools. Medical tools may include end effectors having a single working member such as a scalpel, a blunt blade, an optical fiber, or an electrode. Other end effectors may include, for example, forceps, graspers, scissors, or clip appliers. Examples of electrically activated end effectors include electrosurgical electrodes, transducers, sensors, and the like. In various embodiments, the medical tool <NUM> may be an image capture probe that includes a distal portion with a stereoscopic or monoscopic camera at or near the distal end <NUM> of the flexible catheter body <NUM> for capturing images (including video images) that are processed by a visualization system <NUM> for display. The image capture probe may include a cable coupled to the camera for transmitting the captured image data. Alternatively, the image capture instrument may be a fiber-optic bundle, such as a fiberscope, that couples to the visualization system. The image capture instrument may be single or multi-spectral, for example capturing image data in one or more of the visible, infrared, or ultraviolet spectrums.

The medical instrument <NUM> may house cables, linkages, or other actuation controls (not shown) that extend between the proximal and distal ends of the instrument to controllably bend the distal end of the instrument. Steerable instruments are described in detail in <CIT>) (disclosing "Articulated Surgical Instrument for Performing Minimally Invasive Surgery with Enhanced Dexterity and Sensitivity") and <CIT>) (disclosing "Passive Preload and Capstan Drive for Surgical Instruments").

The flexible catheter body <NUM> may also houses cables, linkages, or other steering controls (not shown) that extend between the housing <NUM> and the distal end <NUM> to controllably bend the distal end <NUM> as shown, for example, by the broken dashed line depictions <NUM> of the distal end. Steerable catheters are described in detail in <CIT>) (disclosing "Catheter with Removable Vision Probe"). In embodiments in which the instrument system <NUM> is actuated by a teleoperational assembly, the housing <NUM> may include drive inputs that removably couple to and receive power from motorized drive elements of the teleoperational assembly. In embodiments in which the instrument system <NUM> is manually operated, the housing <NUM> may include gripping features, manual actuators, or other components for manually controlling the motion of the instrument system. The catheter system may be steerable or, alternatively, the system may be non-steerable with no integrated mechanism for operator control of the instrument bending. Also or alternatively, one or more lumens, through which medical instruments can be deployed and used at a target surgical location, are defined in the walls of the flexible body <NUM>.

In various embodiments, the medical instrument system <NUM> may include a flexible bronchial instrument, such as a bronchoscope or bronchial catheter, for use in examination, diagnosis, biopsy, or treatment of a lung. The system <NUM> is also suited for navigation and treatment of other tissues, via natural or surgically created connected passageways, in any of a variety of anatomical systems, including the colon, the intestines, the kidneys, the brain, the heart, the circulatory system, and the like.

The information from the tracking system <NUM> may be sent to a navigation system <NUM> where it is combined with information from the visualization system <NUM> and/or the preoperatively obtained models to provide the surgeon or other operator with real-time position information on the display system <NUM> for use in the control of the instrument <NUM>. The control system <NUM> may utilize the position information as feedback for positioning the instrument <NUM>. Various systems for using fiber optic sensors to register and display a surgical instrument with surgical images are provided in <CIT>, disclosing, "Medical System Providing Dynamic Registration of a Model of an Anatomical Structure for Image-Guided Surgery".

In the embodiment of <FIG>, the instrument <NUM> is teleoperated within the teleoperational medical system <NUM>. In an alternative embodiment, the teleoperational assembly <NUM> may be replaced by direct operator control. In the direct operation alternative, various handles and operator interfaces may be included for hand-held operation of the instrument.

In alternative embodiments, the teleoperated system may include more than one slave manipulator assembly and/or more than one master assembly. The exact number of manipulator assemblies will depend on the medical procedure and the space constraints within the operating room, among other factors. The master assemblies may be collocated, or they may be positioned in separate locations. Multiple master assemblies allow more than one operator to control one or more slave manipulator assemblies in various combinations.

As shown in greater detail in <FIG>, medical tool(s) <NUM> for such procedures as surgery, biopsy, ablation, illumination, irrigation, or suction can be deployed through the channel <NUM> of the flexible body <NUM> and used at a target location within the anatomy. If, for example, the tool <NUM> is a biopsy instrument, it may be used to remove sample tissue or a sampling of cells from a target anatomical location. The medical tool <NUM> may be used with an image capture probe also within the flexible body <NUM>. Alternatively, the tool <NUM> may itself be the image capture probe. The tool <NUM> may be advanced from the opening of the channel <NUM> to perform the procedure and then retracted back into the channel when the procedure is complete. The medical tool <NUM> may be removed from the proximal end <NUM> of the catheter flexible body or from another optional instrument port (not shown) along the flexible body.

<FIG> illustrates the catheter system <NUM> positioned within an anatomic passageway of a patient anatomy. In this embodiment, the anatomic passageway is an airway of a human lung. In alternative embodiments, the catheter system <NUM> may be used in other passageways of an anatomy.

<FIG> is a flowchart illustrating a general method <NUM> for use in an image guided surgical procedure. At a process <NUM>, pre-operative or intra-operative image data is obtained from imaging technology such as, computed tomography (CT), magnetic resonance imaging (MRI), fluoroscopy, thermography, ultrasound, optical coherence tomography (OCT), thermal imaging, impedance imaging, laser imaging, or nanotube X-ray imaging. The pre-operative or intra-operative image data may correspond to two-dimensional, three-dimensional, or four-dimensional (including e.g., time based or velocity based information) images. For example, the image data may represent the human lungs <NUM> of <FIG>. At a process <NUM>, computer software alone or in combination with manual input is used to convert the recorded images into a segmented two dimensional or three dimensional composite representation or model of a partial or an entire anatomical organ or anatomical region. The composite representation and the image data set describe the various locations and shapes of the passageways and their connectivity. More specifically, during the segmentation process the images are partitioned into segments or elements (e.g., pixels or voxels) that share certain characteristics or computed properties such as color, density, intensity, and texture. This segmentation process results in a two- or three-dimensional reconstruction that forms a model of the target anatomy based on the obtained image. To represent the model, the segmentation process may delineate sets of voxels representing the target anatomy and then apply a function, such as marching cube function, to obtain a 3D surface that encloses the voxels This segmentation process results in a two- or three-dimensional reconstruction that forms a model of the target anatomy based on the obtained image. To represent the model, the segmentation process may delineate sets of voxels representing the target anatomy and then apply a function, such as marching cube function, to obtain a 3D surface that encloses the voxels. Additionally or alternatively, the model may include a centerline model that includes a set of interconnected line segments or points extending through the centers of the modeled passageways. Where the model includes a centerline model including a set of interconnected line segments, those line segments may be converted to a cloud or set of points. By converting the line segments, a desired quantity of points corresponding to the interconnected line segments can be selected manually or automatically. At a process <NUM>, the anatomic model data is registered to the patient anatomy prior to and/or during the course of an image-guided surgical procedure on the patient. Generally, registration involves the matching of measured point to points of the model through the use of rigid and/or non-rigid transforms. Measured points may be generated using landmarks in the anatomy, electromagnetic coils scanned and tracked during the procedure, or a shape sensor system. The measured points may be generated for use in an iterative closest point (ICP) technique described in detail at <FIG> and elsewhere in this disclosure. Other point set registration methods may also be used in registration processes within the scope of this disclosure.

Other registration methods for use with image-guided surgery often involve the use of technologies based on electromagnetic or impedance sensing. Metallic objects or certain electronic devices used in the surgical environment may create disturbances that impair the quality of the sensed data. Other methods of registration may obstruct the clinical workflow. The systems and methods described below perform registration based upon ICP, or another point set registration algorithm, and the calibrated movement of a point gathering instrument with a fiber optic shape sensor, thus eliminating or minimizing disruptions in the surgical environment. Other registration techniques may be used to register a set of measured points to a pre-operative model or a model obtained using another modality. In the embodiments described below, EM sensors on the patient and the instrument and optical tracking systems for the instrument may be eliminated.

<FIG>, <FIG> illustrate some of the steps of the general method <NUM> illustrated in <FIG> illustrates a segmented model <NUM> of a set of anatomic passageways created from pre-operative or intra-operative imaging data. In this embodiment, the passageways are airways of a human lung. Due to naturally occurring limitations or to limitations set by an operator, the segmented model <NUM> may not include all of the passageways present within the human lungs. For example, relatively narrow and/or distal passageways of the lungs may not be fully included in the segmented model <NUM>. The segment model <NUM> may be a three-dimensional model, such as a mesh model, that including the walls defining the interior lumens or passageways of the lungs.

Based on the segmented model <NUM>, a centerline segmented model <NUM> may be generated as shown in <FIG>. The centerline segmented model <NUM> may include a set of three-dimensional straight lines or a set of curved lines that correspond to the approximate center of the passageways contained in the segmented model <NUM>. The higher the resolution of the model, the more accurately the set of straight or curved lines will correspond to the center of the passageways. Representing the lungs with the centerline segmented model <NUM> may provide a smaller set of data that is more efficiently processed by one or more processors or processing cores than the data set of the segmented model <NUM>, which represents the walls of the passageways. In this way the functioning of the control system <NUM> may be improved. As shown in <FIG>, the centerline segmented model <NUM> includes several branch points, some of which are highlighted for visibility in <FIG>. The branch points A, B, C, D, and E are shown at each of several of the branch points. The branch point A may represent the point in the model at which the trachea divides into the left and right principal bronchi. The right principal bronchus may be identified in the centerline segment model <NUM> as being located between branch points A and B. Similarly, secondary bronchi are identified by the branch points B and C and between the branch points B and E. Another generation may be defined between branch points C and D. Each of these generations may be associated with a representation of the diameter of the lumen of the corresponding passageway. In some embodiments, the centerline model <NUM> may include an average diameter value of each segmented generation. The average diameter value may be a patient-specific value or a more general value derived from multiple patients.

In some embodiments, the centerline segmented model <NUM> is represented in data as a cloud, set, or collection of points in three-dimensional space, rather than as continuous lines. <FIG> illustrates the centerline segmented model <NUM> as a set of points <NUM>. In data, each of the points of the set of model points may include coordinates such as a set of XM, YM, and ZM, coordinates, or other coordinates that identify the location of each point in the three-dimensional space. In some embodiments, each of the points may include a generation identifier that identifies which passageway generation the points are associated with and/or a diameter or radius value associated with that portion of the centerline segmented model <NUM>. In some embodiments, information describing the radius or diameter associated with a given point may be provided as part of a separate data set.

After the centerline segmented model <NUM> is generated and stored in data as the set of points <NUM> shown in <FIG>, the centerline segmented model <NUM> may be retrieved from data storage for use in an image-guided surgical procedure. In order to use the centerline segmented model <NUM> in the image-guided surgical procedure, the model <NUM> may be registered to associate the modeled passageways in the model <NUM> with the patient's actual anatomy as present in a surgical environment. Use of the model <NUM> in point set registration includes using the set of points <NUM> from the model <NUM>.

6A and 6B illustrate an exemplary surgical environment <NUM> according to some embodiments, with a surgical coordinate system XS, YS, ZS, in which a patient P is positioned on a platform <NUM>. The patient P may be stationary within the surgical environment in the sense that gross patient movement is limited by sedation, restraint, or other means. Cyclic anatomic motion including respiration and cardiac motion of the patient P continues. Within the surgical environment <NUM>, a point gathering instrument <NUM> is coupled to an instrument carriage <NUM>. In various embodiments, the point gathering instrument <NUM> may use EM sensors, shape-sensors, and/or other sensor modalities. The instrument carriage <NUM> is mounted to an insertion stage <NUM> fixed within the surgical environment <NUM>. Alternatively, the insertion stage <NUM> may be movable but have a known location (e.g., via a tracking sensor or other tracking device) within the surgical coordinate system. The instrument carriage <NUM> may be a component of a teleoperational manipulator assembly (e.g., assembly <NUM>) that couples to the instrument <NUM> to control insertion motion (i.e. motion in an XS direction) and, optionally, motion of a distal end of the instrument in multiple directions including yaw, pitch, and roll. The instrument carriage <NUM> or the insertion stage <NUM> may include servomotors (not shown) that control motion of the instrument carriage along the insertion stage.

The point gathering instrument <NUM> may include a flexible catheter <NUM> coupled to a proximal rigid instrument body <NUM>. The rigid instrument body <NUM> is coupled and fixed relative to the instrument carriage <NUM>. In the illustrated embodiment, an optical fiber shape sensor <NUM> is fixed at a proximal reference point <NUM> on the rigid instrument body <NUM>. In this embodiment, the reference point <NUM> is located outside of the patient anatomic passageways, but in alternative embodiments, the reference point may travel within the patient. In an alternative embodiment, the point <NUM> of the sensor <NUM> may be movable along the body <NUM> but the location of the point may be known (e.g., via a tracking sensor or other tracking device). The shape sensor <NUM> measures a shape from the reference point <NUM> to another point such as the distal end <NUM> of the catheter <NUM>. The point gathering instrument <NUM> may be substantially similar to the medical instrument system <NUM>.

A position measuring device <NUM> provides information about the position of the rigid instrument body <NUM> as it moves on the insertion stage <NUM> along an insertion axis A. The position measuring device <NUM> may include resolvers, encoders, potentiometers, and other mechanisms that determine the rotation and orientation of the motor shafts controlling the motion of the instrument carriage <NUM> and consequently the motion of the rigidly attached instrument body <NUM>. In this embodiment, the insertion stage <NUM> is linear, but in alternative embodiments it may be curved or have a combination of curved and linear sections. Optionally, the linear track may be collapsible as described, for example, in <CIT>)(disclosing "Guide Apparatus For Delivery Of A Flexible Instrument And Methods Of Use"). <FIG> shows the instrument body <NUM> and carriage <NUM> in a retracted position along the insertion stage <NUM>. In this retracted position, the proximal point <NUM> is at a position L<NUM> on the axis A. In this position along the insertion stage <NUM> an Xs component of the location of the point <NUM> may be set to a zero or original value. With this retracted position of the instrument body <NUM> and carriage <NUM>, the distal end <NUM> of the catheter may be positioned just inside an entry orifice of the patient P. Also in this position, the position measuring device may be set to a zero or original value (e.g. I=<NUM>). In <FIG>, the instrument body <NUM> and the carriage <NUM> have advanced along the linear track of the insertion stage <NUM> and the distal end of the catheter <NUM> has advanced into the patient P. In this advanced position, the proximal point <NUM> is at a position L<NUM> on the axis A.

Embodiments of the point gathering instrument <NUM> may collect measured points using any number of modalities, including EM sensing and shape-sensing. As the measurement points are collected from within the passageways of a patient, the points are stored in a data storage device, such as a memory. The set of measured points may be stored in a database that includes at least some, but may include all, of the measured points obtained during the procedure or immediately before the procedure. As stored in memory, each of the points may be represented by data comprising coordinates of the point, a timestamp, and a relative sensor position or individual sensor ID (when multiple sensors distributed along a length of the point gathering instrument <NUM> are used to determine the location of several points simultaneously). In some embodiments, data representing each point may also include a respiratory phase marker that indicates the respiratory phase of the patient in which the point was collected.

<FIG> is a flowchart illustrating a method <NUM> used to provide guidance to a clinician in an image-guided surgical procedure on the patient P in the surgical environment <NUM>, according to an embodiment of the present disclosure. The method <NUM> is illustrated in <FIG> as a set of blocks, steps, operations, or processes. Not all of the illustrated, enumerated operations may be performed in all embodiments of the method <NUM>. Additionally, some additional operations that are not expressly illustrated in <FIG> may be included before, after, in between, or as part of the enumerated processes. Some embodiments of the method <NUM> include instructions corresponded to the processes of the method <NUM> as stored in a memory. These instructions may be executed by a processor like a processor of the control system <NUM>.

Thus, some embodiments of the method <NUM> may begin at a process <NUM>, in which a calibration procedure is performed to calibrate, with a position measuring device like the point gathering instrument <NUM> or another suitable device, a relative position and/or orientation of a sensor reference point along an insertion path. For example, the point gathering instrument <NUM> of <FIG> may be used to determine a position and orientation of the point <NUM> as the carriage <NUM> moves from a retracted position with the point <NUM> at location L<NUM> to an advanced position with the point <NUM> at the location L<NUM>. The calibration procedure determines the direction of the movement of the point <NUM> for each change in the position measuring device <NUM>. In this embodiment, where the insertion stage <NUM> restricts movement of the carriage <NUM> to a linear path, the calibration procedure determines the direction of the straight line. One such calibration method is to measure the difference in position between two points along the straight section of the catheter; the direction of that difference vector is the direction of the insertion axis. An alternative method is to constrain a known point of the catheter (e.g. the tip) in a fixed location and to measure the relative position of point <NUM> with respect to that known fixed point as the backend traverses along the insertion axis, and then to fit a direction vector to this collection of measured points. From the slope of the insertion stage track, the position and orientation of the point <NUM> in the surgical environment <NUM> may be determined for every corresponding measurement of the position measuring device <NUM>. In an alternative embodiment, if the insertion stage has a curved or otherwise non-linear shape, the calibration procedure may determine the non-linear shape so that for every measurement of the position device, the position and orientation of the point <NUM> in the surgical environment may be determined. For example, the distal tip of the catheter may be held in a fixed position while the instrument body is routed along the non-linear insertion stage. The position and orientation data collected by the shape sensor from the fixed point <NUM> is correlated with the position measuring device data as the instrument body is routed along the insertion stage, thus calibrating movement of the point <NUM> along the axis A of the insertion stage <NUM>.

At a process <NUM>, the distal end <NUM> of the catheter traverses the patient P's anatomical passageways (e.g., airways of the patient's lungs) recording, via data from the shape sensor <NUM>, location data for the distal end of the catheter and/or other points along the shape of the shape sensor. This location data may include, or be processed to obtain, a set of measured points as described herein. More specifically, the movement of the distal tip of the catheter <NUM> is controlled via teleoperational, manual, or automated control (e.g., via master assembly <NUM>) to survey a portion of the anatomical passageways. For example, teleoperational control signals may cause the carriage <NUM> to move along the axis A, causing the distal tip <NUM> of the catheter to advance or retract within the anatomical passageways. Also or alternatively, teleoperational control signals may cause actuation of control members extending within the surgical instrument to move the distal tip <NUM> in a range of movements including yaw, pitch, and roll. As the catheter is moved within the plurality of passageways, shape sensor data is gathered for multiple locations of the distal tip. In some embodiments, the catheter may extend up to approximately three inches into the various passageways. In some embodiments, the catheter may be extended through or into approximately three branched generations on each side of the lung. The number of generations accessible with the catheter <NUM> may increase as the diameter of the flexible catheter <NUM> decreases and/or the flexibility of the flexible catheter increases.

With reference to <FIG>, shape sensor data is gathered for a set of measured data points D. The measured data points may be store in memory as data sets or point pools with coordinates, timestamps, sensor IDs, respiration phase information, or the like for each gathered point. This collected set of spatial information provided by data points D from the shape sensor or other point collection device may be gathered as the distal end <NUM> of the catheter <NUM> is moved to a plurality of locations within the surgical space <NUM> (i.e., the teleoperational manipulator space). The location of a given collected data point DX in the surgical environment space <NUM> is determined by combining information from the position measuring device <NUM> when the distal end of the catheter is located at the point DX with the shape data from the shape sensor when the distal end of the catheter is located at the point DX. Points may also be collected along the length of the catheter. In both cases, the data from the position measuring device <NUM> and the calibrated path of the fixed sensor point <NUM> provides the position of the sensor point <NUM> in the patient surgical environment <NUM> when the distal end <NUM> of the catheter is at the point DX. For example, encoder data from one or more motors controlling movement of the carriage <NUM> along the track <NUM> and the calibration data from the movement of the carriage along the track provides the position of the sensor point <NUM> in the surgical environment <NUM> when the distal end of the catheter is at the point DX. The shape sensor provides the shape of the instrument between the fixed sensor point <NUM> and the distal end <NUM>. Thus, the location of the point DX (where the distal end <NUM> is located) in the surgical environment space <NUM> can be determined from the calibrated position measuring data and the shape sensor data recorded when the distal end is at point DX. The location in the surgical environment <NUM> coordinate space for all of the data points D in the set of gathered data points (i.e. calibrated position of the proximal point <NUM> together combined with the shape sensor data for the location of the distal end <NUM> relative to the point <NUM>) is a reference set of spatial information for the instrument that can be registered with anatomic model information.

Referring again to <FIG>, at a process <NUM>, one or more of the gathered data points D may correspond to landmark locations in the patient anatomy. In some embodiments, the gathered data points D that correspond to landmarks may be used to seed a registration process, such as an ICP process. This subset of gathered data points D that correspond to one or more landmarks may be referred to as seed points. The data representing the subset of gathered data points D that correspond to landmarks may include a landmark indicator when stored in memory. With reference to <FIG>, a set of anatomical passageways <NUM> include main carinas C1, C2, C3 where the passageways <NUM> fork. A data point D can be gathered for the location of each carina by moving the distal end of the catheter to the respective carina locations. For example, a data point DL1 can be gathered at the carina C<NUM>. A data point DL2 can be gathered at the carina C<NUM>. A data point DL3 can be gathered at the carina C<NUM>. The carinas or other suitable landmarks can be located in the patient surgical environment <NUM> as described above for point DX. The process <NUM> is optional and may be omitted if alternative seeding techniques are used.

Referring again to <FIG>, at a process <NUM> anatomical model information is received. The anatomic model information may be the segmented centerline model <NUM> as described in <FIG>. Referring again to <FIG>, the anatomical model information may be represented as a centerline model <NUM> of branched anatomic passageways. In some embodiments, the model may include one or more landmark points to match to the seed points DL1, DL2, and DL3. These points included in the model to match to the seed points DL1, DL2, and DL3 may not be centerline points in some embodiments, but may be included in the centerline model <NUM> to facilitate seeding of a subsequent registration process. In some embodiments, the centerline model <NUM> may include more model landmark points than ML1, ML2, and ML3.

Referring again to <FIG>, at a process <NUM> registration of the anatomical model information <NUM> with the set of gathered data points D from the surgical environment <NUM> is performed. Registration may be accomplished using a point set registration algorithm such as an iterative cloud point (ICP) technique as described in processes <NUM>-<NUM>, or by implementation of another registration algorithm. At process <NUM>, the ICP registration is seeded with known information about the displacement and orientation relationship between the patient surgical environment and the anatomical model. In this embodiment (<FIG>), for example, the carina landmarks C<NUM>, C<NUM>, C<NUM> are identified in the anatomical model information as points ML1, ML2, ML3. In alternative embodiments, the anatomical model information may be represented in other ways, e.g. as centerline segments or axes of a 3D mesh model. Or alternatively, the model may be expressed as a volume constructed from 3D shapes such as cylinders or as a 3D image. The recorded landmark data points DL1, DL2, DL3 from the patient surgical environment are each matched to a corresponding model points ML1, ML2, ML3. (i.e., DL1 matches to ML1, etc.) With the points matched, an initial transform (e.g., change in position and/or orientation) between landmark data points DL1, DL2, DL3 and model points ML1, ML2, ML3 is determined. The transform may be a rigid transform in which all landmark data points are transformed by the same change in position and orientation or may be a non-rigid transform in which the landmark datapoints are transformed by different changes in position and orientation. The transform determined with the landmark data points DL1, DL2, DL3 may applied to all of the gathered data points D. This seeding process, based on a few landmark points, provides an initial coarse registration of the gathered data points D to the anatomical model.

An alternative method to obtain an initial coarse registration is to use approximately known information about the teleoperational manipulator assembly and the patient location. The teleoperational manipulator assembly may be instrumented with encoders or other sensors that measure the relative pose of the insertion track with respect to gravity. This information may be combined with patient orientation assumptions, e.g., the patient is lying on his back, and the assumption that the insertion track is placed at the patient's mouth. The combined information may thus also provide an approximate relative orientation and position of the instrument with respect to the patient and be sufficient as seeding registration to proceed with full registration.

At a process <NUM>, with the initial coarse registration performed, the set of gathered data points D is matched to the anatomical model information <NUM> (<FIG>). In this embodiment, the anatomical model information is a set of points along the centerlines of the anatomic model. The ICP algorithm identifies matches between closest points in the gathered data points D and in the set of anatomic model points. In various alternatives, matching may be accomplished by using brute force techniques, KD tree techniques, maximum distance threshold calculations, maximum angle threshold calculations, model centerline points, model mesh points, and/or model volume points. In another embodiment, matching is not required at all, but rather each gathered point is mapped to a nearest point on or within the model using some explicit mapping function or by using a look-up-table. The matching or mapping between gathered points and model points may further be informed by additional criteria such as the insertion depth, respiratory phase, motor torque, velocity, etc..

At a process <NUM>, the motion needed to move the set of gathered data points D to the position and orientation of the matched anatomic model points is determined. More specifically, an overall offset in position and orientation is determined for the set of gathered data points D. <FIG>, for example, illustrates an initial offset of approximately <NUM>° in orientation and <NUM> in displacement between the gathered data points D and the anatomical model information <NUM>.

At a process <NUM>, the set of gathered data points D are transformed using a rigid or non-rigid transformation that applies the computed offset in displacement and orientation to move each point in the set of gathered data points D. As shown in <FIG>, the set of gathered data points D is transformed to converge with the model points <NUM>.

At a process <NUM>, the convergence of the gathered data points D and the matched anatomic model points <NUM> are evaluated. In other words, error factors for orientation and displacement may be determined for each matched point set. If the error factors in aggregate are greater than a threshold value, additional iterations of processes <NUM>-<NUM> may be repeated until the overall position and orientation error factors falls below the threshold value.

The registration process <NUM> may recomputed multiple times during a surgical procedure (e.g. approximately twice per hour, but may be more or less frequently) in response to deformation of the passageways caused by cyclic anatomical motion, instrument forces, or other changes in the patient environment.

After the anatomic model and the patient environment are registered, an image guided surgical procedure may, optionally, be performed. Referring again to <FIG>, at process <NUM>, during a surgical procedure, a current location of a surgical instrument in the surgical environment is determined. More specifically, the data from the position measuring device <NUM> and the calibrated path of the fixed sensor point <NUM> provides the position of the sensor point <NUM> in the patient surgical environment <NUM> when the catheter is in a current location. The shape sensor provides the shape of the instrument between the fixed sensor point <NUM> and the distal end <NUM>. Thus, the current location of the catheter <NUM> and particularly the distal end <NUM> of the catheter in the surgical environment space <NUM> can be determined from the calibrated position measuring data and the shape sensor data.

At process <NUM>, the previously determined registration transforms are applied to the current instrument position and shape data to localize the current instrument to the anatomic model. For example, the current position and orientation for the distal end of the instrument, data point Dcurrent is transformed using the one or more transform iterations determined at process <NUM>. Thus, the data point Dcurrent in the surgical environment <NUM> is transformed to the anatomic model space. In an alternative embodiment, the anatomical model may instead be registered to the surgical environment in which the catheter position data is gathered.

At process <NUM>, optionally, the localized instrument may be displayed with the anatomic model to assist the clinician in an image guided surgery. <FIG> illustrates a display system <NUM> displaying a rendering of anatomical passageways <NUM> of a human lung <NUM> based upon anatomical model information. With the surgical environment space registered to the model space as described above in <FIG>, the current shape of the catheter <NUM> and the location of the distal end <NUM> may be located and displayed concurrently with the rendering of the passageways <NUM>.

Although the systems and methods of this disclosure have been described for use in the connected bronchial passageways of the lung, they are also suited for navigation and treatment of other tissues, via natural or surgically created connected passageways, in any of a variety of anatomical systems including the colon, the intestines, the kidneys, the brain, the heart, the circulatory system, or the like.

One or more elements in embodiments of the invention may be implemented in software to execute on a processor of a computer system such as control system <NUM>. When implemented in software, the elements of the embodiments of the invention are essentially the code segments to perform the necessary tasks. The program or code segments can be stored in a processor readable storage medium or device that may have been downloaded by way of a computer data signal embodied in a carrier wave over a transmission medium or a communication link. The processor readable storage device may include any medium that can store information including an optical medium, semiconductor medium, and magnetic medium. Processor readable storage device examples include an electronic circuit; a semiconductor device, a semiconductor memory device, a read only memory (ROM), a flash memory, an erasable programmable read only memory (EPROM); a floppy diskette, a CD-ROM, an optical disk, a hard disk, or other storage device, The code segments may be downloaded via computer networks such as the Internet, Intranet, etc..

Claim 1:
A computer program comprising instructions which, when the program is executed by a computing system (<NUM>), cause the computing system to perform a registration method, the method comprising the steps of:
receiving, from a shape sensor (<NUM>) of an instrument (<NUM>, <NUM>, <NUM>), a collected set of spatial information for a distal portion (<NUM>, <NUM>) of the instrument at a plurality of locations within a set of anatomical passageways (<NUM>, <NUM>), wherein the collected set of spatial information is measured relative to a reference point (<NUM>) of the instrument;
receiving, from a position measuring device (<NUM>), a set of position information for the reference point (<NUM>) of the instrument when the distal portion (<NUM>, <NUM>) of the instrument is located at each of the plurality of locations, wherein the set of position information is in a surgical environment space (<NUM>);
determining a reference set of spatial information for the distal portion (<NUM>, <NUM>) of the instrument relative to the surgical environment space (<NUM>) by combining the collected set of spatial information measured relative to the reference point (<NUM>) and the set of position information for the reference point (<NUM>) of the instrument;
registering the reference set of spatial information with a set of anatomical model information; and
displaying, using a display system (<NUM>), a rendering of said anatomical passageways (<NUM>, <NUM>) based upon said anatomical model information and the registering.