Registration fixture

Abstract

A registration fixture for use with a surgical navigation system for registration of medical images with a three-dimensional tracking space includes a base frame adapted to be mounted over a flat panel detector of an x-ray medical imaging device and a side frame having optical tracking markers and mounted to the base frame. The base frame includes a first set of radio-opaque markers embedded therein in a first predetermined pattern and arranged on a plane and a second set of radio-opaque markers embedded therein in a second predetermined pattern and likewise arranged on another plane, the second set of radio-opaque markers being spaced apart from the first set of radio-opaque markers. The side frame has a plurality of optical tracking markers and is configured to be detachably mounted to the base frame without piercing a sterile drape to be interposed between the base frame and the side frame.

Description

Technical Field

[0001] This disclosure relates to a location recognition system, and more particularly to the registration of medical images with a three-dimensional tracking space. Background Technology

[0002] Orthopedic surgical navigation can improve patient outcomes by reducing blood loss, radiation dose, and surgical and anesthesia time. It also enhances the accuracy and accessibility of performing complex surgeries. Two surgical navigation workflows that achieve these improvements are fluorescein-guided and preoperative navigation workflows, which require a C-arm imaging device and a fluorescein registration clamp.

[0003] Traditionally, registration fixtures are mounted to the X-ray emitter side. However, in some cases, registration of the navigation system is inaccurate, and attaching the fixture may be inconvenient due to the specific shape of the emitter housing. Therefore, it is desirable to provide a system and method for improving the registration fixture. Summary of the Invention

[0004] According to one aspect of the invention, a registration fixture is provided for use with a surgical navigation system for registration of medical images with a three-dimensional tracking space. The registration fixture includes a bottom frame adapted for mounting above a flat panel detector of an X-ray medical imaging apparatus; and a side frame having optical tracking marks and mounted to the bottom frame. The bottom frame includes a first set of radiopaque marks embedded in a first predetermined pattern and a second set of radiopaque marks embedded in a second predetermined pattern, the second set of radiopaque marks being vertically spaced from the first set of radiopaque marks. The side frame has a plurality of optical tracking marks and is configured to be detachably mounted to the bottom frame without piercing a sterile drape to be inserted between the bottom frame and the side frame.

[0005] These and other systems, methods, objects, features, and advantages of the present invention will become apparent to those skilled in the art from the following detailed description of preferred embodiments and accompanying drawings. All references herein are incorporated herein by reference in their entirety. Attached Figure Description

[0006] The following detailed description of the present invention and certain embodiments thereof can be understood with reference to the following drawings:

[0007] Figure 1 It is a top view of the potential layout for the positions of robotic systems, patients, surgeons and other medical personnel during surgical procedures;

[0008] Figure 2 A robotic system comprising a surgical robot and a camera for positioning relative to a patient, according to one embodiment, is shown.

[0009] Figure 3 A surgical robot system according to an exemplary embodiment is shown;

[0010] Figure 4 A portion of a surgical robot according to an exemplary embodiment is shown;

[0011] Figure 5 A block diagram of a surgical robot according to an exemplary embodiment is shown;

[0012] Figure 6 A surgical robot according to an exemplary embodiment is shown;

[0013] Figures 7A to 7C An end effector according to an exemplary embodiment is shown;

[0014] Figure 8 The surgical instrument and the end effector are shown before and after insertion of the surgical instrument into the end effector according to one embodiment;

[0015] Figures 9A to 9C Parts of an end effector and a robotic arm according to an exemplary embodiment are shown;

[0016] Figure 10 A dynamic reference array, imaging array, and other components according to an exemplary embodiment are shown;

[0017] Figure 11 A registration method according to an exemplary implementation is illustrated;

[0018] Figures 12A to 12B An embodiment of an imaging apparatus according to an exemplary embodiment is shown;

[0019] Figure 13 An implementation scheme of the navigation fixture is shown.

[0020] Figure 14 An X-ray (fluorescence mirror) collector plate is shown, which illustrates the theoretical projection of small metal spheres (hereinafter referred to as "BB") in two planes at different distances from the source.

[0021] Figure 15 Two X-ray projections obtained from the same transmissive line point from two different perspectives are shown to produce a 3D position.

[0022] Figure 16 An X-ray image obtained through a plane of a collector plate parallel to the grid of BB is shown.

[0023] Figure 17The key dimensions are shown as viewed from a plane perpendicular to the collector plate, with BB positioned in the field of view where its shadow appears on the collector plate.

[0024] Figure 18 The design of the bb pattern on two parallel plates and the fixture that is mounted to the image intensifier of the fluoresce mirror unit is shown.

[0025] Figure 19 The BB pattern of the registration fixture is shown.

[0026] Figure 20 A fluorescence microscope registration fixture consisting of parallel rings with crosshairs is shown.

[0027] Figure 21 The appearance of the ring registration fixture on the X-ray is shown when the X-ray collector is parallel to the plane of the ring and the ring is concentric with the X-ray collector.

[0028] Figure 22 The theoretical appearance of the ring registration fixture on the X-ray is shown when the fixture is at a large angle relative to the collector plate and the ring.

[0029] Figure 23 The transformation steps involving rotation θ around z during coordinate system mapping are shown.

[0030] Figure 24 The transformation steps involving rotation α around y during coordinate system mapping are shown.

[0031] Figure 25 The transformation steps of rotating in a plane to match the perspective of a ray photograph during coordinate system mapping are shown.

[0032] Figure 26 The transformation steps of displacement dx, dy from the center of the coordinate system are shown during the coordinate system mapping process.

[0033] Figure 27 The transformation steps for magnification based on parallax during coordinate system mapping are shown.

[0034] Figure 28 A schematic diagram of key dimensions is shown as viewed from a plane perpendicular to the collector plate, where the ring appears parallel to the collector in the field of view on the collector plate under its shadow.

[0035] Figure 29 The diagram shows a view through the ring, which, viewed from the perspective of the ring plane, forms an arbitrary angle of incidence with the collector plane, with the ring plane both inside and outside the page.

[0036] Figure 30A view through a pair of concentric rings is shown, which, viewed from a perspective through the ring plane, form an arbitrary angle of incidence with the collector plane, where the ring plane is both inside and outside the page.

[0037] Figure 31 The diagram shows a view of a ring at any incident angle as viewed from a rotational perspective.

[0038] Figure 32 A view of a pair of rings at an arbitrary angle of incidence is shown.

[0039] Figure 33 The modeled appearance of two rings with an incident angle of α = 20° around the y-axis on an x-ray (with parallax) is shown.

[0040] Figure 34 The modeling appearance of two parallel rings with an incident angle of α = 24.5° around the y-axis on an x-ray (with parallax) is shown, where the two rings are offset from the center of the x-ray and the major axes of the two ellipses appear to be at a significant angle relative to the y-axis.

[0041] Figure 35 The modeling appearance of two parallel rings with an incident angle of α = 24.5° around the y-axis on an x-ray (with parallax) is shown, where the two rings are offset from the center of the x-ray, and the far-field ellipse has been scaled around the center of the image until the near-field ellipse and the far-field ellipse are equal on their major axes.

[0042] Figure 36 Pincushion distortion is shown.

[0043] Figure 37 The distortion is shown.

[0044] Figure 38 This is a perspective view of a novel registration fixture according to one aspect of the invention, the registration fixture being designed to be attached to a flat panel detector of a medical imaging apparatus.

[0045] Figure 39 This is a plan view of a radiopaque plate according to one aspect of the invention, the radiopaque plate having two vertically spaced sets of embedded non-transmissive markings.

[0046] Figure 40A It is a radiopaque mark with a predetermined pattern. Figure 39 A plan view of the first plate through which rays can pass.

[0047] Figure 40B It is a radiopaque mark with a predetermined pattern. Figure 39 A plan view of the second plate through which rays can pass.

[0048] Figure 41 yes Figure 38 Perspective view of the bottom and side frames of the registration fixture before assembly.

[0049] Figure 42 yes Figure 41 A side view of the motion mount of the side frame, showing the non-piercing clamp.

[0050] Figure 43A yes Figure 38 External perspective view of the alternative non-piercing motion fixture of the registration fixture.

[0051] Figure 43B yes Figure 38 External perspective view of the alternative non-piercing motion fixture of the registration fixture.

[0052] Figure 44 yes Figure 43A A sectional view of the side frame.

[0053] Figure 45 yes Figure 38 A perspective view of the base frame, which has a set of straps and ratchet for attaching to the flat panel detector.

[0054] Figure 46 The use of, as shown Figure 45 The belt and ratchet shown will Figure 38 The bottom frame is attached to the flat panel detector.

[0055] While the invention has been described in conjunction with certain preferred embodiments, other embodiments will also be understood by those skilled in the art and are covered herein. Detailed Implementation

[0056] It should be understood that this disclosure, in its application, is not limited to the construction details and component arrangements shown in the description or accompanying drawings herein. The teachings of this disclosure may be used and practiced in other embodiments and in various ways. Furthermore, it should be understood that the wording and terminology used herein are for descriptive purposes and should not be considered limiting. The use of "comprising," "including," or "having" and variations thereof herein means to include items listed herein and their equivalents, as well as additional items. Unless otherwise specified or limited, the terms "mounted," "connected," "supported," and "coupled," and variations thereof, are used extensively and include direct and indirect mounting, connection, support, and coupling. Furthermore, "connection" and "coupling" are not limited to physical or mechanical connections or linkages.

[0057] The following discussion is provided to enable those skilled in the art to implement and use embodiments of this disclosure. Various modifications to the illustrated embodiments will be apparent to those skilled in the art, and the principles herein can be applied to other embodiments and applications without departing from the embodiments of this disclosure. Therefore, embodiments are not intended to be limited to those shown, but should have the broadest scope consistent with the principles and features disclosed herein. Refer to the accompanying drawings, in which similar elements have similar reference numerals. The drawings are not necessarily drawn to scale, depict selected embodiments, and are not intended to limit the scope of embodiments. Those skilled in the art will recognize that the examples provided herein have many useful alternative forms and fall within the scope of embodiments.

[0058] Now turn to the attached diagram. Figure 1 and Figure 2 A surgical robot system 100 according to an exemplary embodiment is illustrated. The surgical robot system 100 may include, for example, a surgical robot 102, one or more robotic arms 104, a base 106, a display 110, an end effector 112 (e.g., including a catheter 114), and one or more tracking markers 118. The surgical robot system 100 may include a patient tracking device 116, which also includes one or more tracking markers 118 adapted for direct attachment to a patient 210 (e.g., to the bone of the patient 210). The surgical robot system 100 may also utilize a camera 200, for example, positioned on a camera holder 202. The camera holder 202 may have any suitable configuration to move, orient, and support the camera 200 in a desired location. The camera 200 may include any suitable camera or multiple cameras, such as one or more infrared cameras (e.g., bifocal or stereophotogrammetry cameras), capable of identifying active and passive tracking markers 118 in a given measurement volume visible from the viewpoint of the camera 200. Camera 200 can scan a given measurement volume and detect light from marker 118 in order to identify and determine the position of marker 118 in three dimensions. For example, active marker 118 may include an infrared emitting marker activated by an electrical signal (e.g., an infrared light-emitting diode (LED)), and passive marker 118 may include retroreflective markers that reflect infrared light emitted, for example, by an illuminator or other suitable device on camera 200 (e.g., they reflect incident IR radiation into the direction of the incident light).

[0059] Figure 1 and Figure 2A potential configuration for placing the surgical robotic system 100 in an operating room environment is shown. For example, the robot 102 may be positioned near or beside the patient 210. Although shown near the head of the patient 210, it should be understood that the robot 102 can be positioned at any suitable location near the patient 210, depending on the area of ​​the patient 210 where surgery is being performed. The camera 200 may be separate from the robotic system 100 and positioned at the feet of the patient 210. This position allows the camera 200 to have a direct line of sight to the surgical field 208. Again, it is contemplated that the camera 200 can be positioned at any suitable location with a line of sight to the surgical field 208. In the configuration shown, the surgeon 120 may be positioned opposite the robot 102 but still able to manipulate the end effector 112 and the display 110. The surgical assistant 126 may be positioned opposite the surgeon 120 but still able to access the end effector 112 and the display 110. The positions of the surgeon 120 and the assistant 126 may be interchanged if desired. The traditional area where the anesthesiologist 122 and the nurse or scrub technician 124 are located remains unobstructed by the positions of the robot 102 and the camera 200.

[0060] Regarding other components of the robot 102, the display 110 may be attached to the surgical robot 102, and in other exemplary embodiments, the display 110 may be detached from the surgical robot 102 either within the operating room where the surgical robot 102 is located or at a remote location. An end effector 112 may be coupled to the robotic arm 104 and controlled by at least one motor. In an exemplary embodiment, the end effector 112 may include a conduit 114 capable of receiving and orienting a surgical instrument 608 (further described herein) for performing surgery on the patient 210. As used herein, the term "end-effector" may be used interchangeably with the terms "end-effecter" and "effecter element." Although generally shown with conduit 114, it should be understood that the end effector 112 may be replaced by any suitable instrument suitable for surgical procedures. In some embodiments, the end effector 112 may include any known structure for achieving movement of the surgical instrument 608 in a desired manner.

[0061] Surgical robot 102 is capable of controlling the translation and orientation of end effector 112. For example, robot 102 is capable of moving end effector 112 along the x-axis, y-axis, and z-axis. End effector 112 can be configured to selectively rotate about one or more of the x-axis, y-axis, and z-axis, as well as the Z-frame axis (such that one or more of the Euler angles (e.g., roll, pitch, and / or yaw) associated with end effector 112 can be selectively controlled). In some exemplary embodiments, selective control of the translation and orientation of end effector 112 can allow medical procedures to be performed with significantly improved accuracy compared to conventional robots utilizing, for example, a six-DOF robotic arm that includes only a rotational axis. For example, surgical robot system 100 can be used to manipulate patient 210, and robotic arm 104 can be positioned above patient 210's body, wherein end effector 112 is selectively angled relative to the z-axis toward patient 210's body.

[0062] In some exemplary embodiments, the position of the surgical instrument 608 can be dynamically updated, allowing the surgical robot 102 to know the position of the surgical instrument 608 at any time during the procedure. Therefore, in some exemplary embodiments, the surgical robot 102 can rapidly move the surgical instrument 608 to a desired position without any further assistance from the physician (unless the physician intends otherwise). In some other embodiments, the surgical robot 102 can be configured to correct the path of the surgical instrument 608 if it deviates from a selected, pre-planned trajectory. In some exemplary embodiments, the surgical robot 102 can be configured to allow stopping, modifying, and / or manually controlling the movement of the end effector 112 and / or the surgical instrument 608. Therefore, in use, in the exemplary embodiments, a physician or other user can operate the system 100 and can choose to stop, modify, or manually control the autonomous movement of the end effector 112 and / or the surgical instrument 608. Further details of the surgical robot system 100, including the control and movement of the surgical robot 102 over the surgical instrument 608, can be found in co-pending U.S. Patent Application Serial No. 13 / 924,505, the full text of which is incorporated herein by reference.

[0063] The robotic surgical system 100 may include one or more tracking markers 118 configured to track the movement of a robotic arm 104, an end effector 112, a patient 210, and / or surgical instruments 608 in three dimensions. In an exemplary embodiment, the plurality of tracking markers 118 may be mounted (or otherwise secured) to an outer surface of the robot 102, such as, but not limited to, a base 106 of the robot 102, the robotic arm 104, or the end effector 112. In an exemplary embodiment, at least one of the plurality of tracking markers 118 may be mounted or otherwise secured to the end effector 112. One or more tracking markers 118 may be further mounted (or otherwise secured) to the patient 210. In an exemplary embodiment, the plurality of tracking markers 118 may be positioned on the patient 210 spaced apart from the surgical field 208 to reduce the likelihood of obstruction by the surgeon, surgical instruments, or other parts of the robot 102. Furthermore, one or more tracking markers 118 may be further mounted (or otherwise secured) to surgical instruments 608 (e.g., screwdrivers, dilators, implant inserters, etc.). Thus, the tracking markers 118 enable each of the marked objects (e.g., end effector 112, patient 210, and surgical instruments 608) to be tracked by the robot 102. In an exemplary embodiment, the system 100 can use tracking information collected from each of the marked objects to calculate, for example, the orientation and position of the end effector 112, the surgical instrument 608 (e.g., positioned within a tube 114 of the end effector 112), and the relative position of the patient 210.

[0064] In an exemplary embodiment, one or more of the markers 118 may be optical markers. In some embodiments, the positioning of one or more tracking markers 118 on the end effector 112 can maximize the accuracy of position measurements by being used to check or verify the position of the end effector 112. Further details of the surgical robot system 100, including the control, movement, and tracking of the surgical robot 102 and surgical instruments 608, can be found in co-pending U.S. Patent Application Serial No. 13 / 924,505, the entire contents of which are incorporated herein by reference.

[0065] Exemplary embodiments include one or more markers 118 coupled to surgical instrument 608. In exemplary embodiments, these markers 118, such as those coupled to patient 210 and surgical instrument 608, and those coupled to end effector 112 of robot 102, may include conventional infrared light-emitting diodes (LEDs) or those capable of using commercially available infrared optical tracking systems (such as...). Tracking diode. This is a registered trademark of Northern Digital Inc., Waterloo, Ontario, Canada. In other embodiments, mark 118 may include a conventional reflective ball capable of tracking using a commercially available optical tracking system, such as Polaris Spectra. Polaris Spectra is also a registered trademark of Northern Digital, Inc. In an exemplary embodiment, mark 118 coupled to end effector 112 is an active mark that includes an infrared light-emitting diode that can be turned on and off, and mark 118 coupled to patient 210 and surgical instrument 608 includes a passive reflective ball.

[0066] In an exemplary embodiment, light emitted and / or reflected from marker 118 can be detected by camera 200 and can be used to monitor the position and movement of the marked object. In an alternative embodiment, marker 118 may include a radio frequency and / or electromagnetic reflector or transceiver, and camera 200 may include, or be replaced by, a radio frequency and / or electromagnetic transceiver.

[0067] Similar to the Surgical Robot System 100, Figure 3 A surgical robot system 300 and a camera mount 302 in a docked configuration, conforming to an exemplary embodiment of this disclosure, are shown. The surgical robot system 300 may include a robot 301 comprising a display 304, an upper arm 306, a lower arm 308, an end effector 310, a column 312, casters 314, a cabinet 316, a tablet drawer 318, a connector panel 320, a control panel 322, and an information ring 324. The camera mount 302 may include a camera 326. These components are in... Figure 5 A more detailed description is provided in the text. Figure 3 A surgical robot system 300 in a docked configuration is shown, wherein a camera holder 302 is nested with the robot 301, for example, when not in use. Those skilled in the art will understand that the camera 326 and the robot 301 can be detached from each other and positioned in any suitable location during surgery, for example, as... Figure 1 and Figure 2 As shown. Figure 4 A base 400 conforming to an exemplary embodiment of this disclosure is shown. The base 400 may be part of a surgical robot system 300 and includes a cabinet 316. The cabinet 316 may house certain components of the surgical robot system 300, including but not limited to a battery 402, a power distribution module 404, a platform interface board module 406, a computer 408, a handle 412, and a tablet drawer 414. The connections and relationships between these components are shown in... Figure 5 A more detailed description is provided in the text.

[0068] Figure 5A block diagram illustrating certain components of an exemplary embodiment of a surgical robot system 300 is shown. The surgical robot system 300 may include a platform subsystem 502, a computer subsystem 504, a motion control subsystem 506, and a tracking subsystem 532. The platform subsystem 502 may further include a battery 402, a power distribution module 404, a platform interface board module 406, and a tablet charging station 534. The computer subsystem 504 may further include a computer 408, a display 304, and a speaker 536. The motion control subsystem 506 may further include a drive circuit 508, motors 510, 512, 514, 516, 518, stabilizers 520, 522, 524, 526, an end effector 310, and a controller 538. The tracking subsystem 532 may further include a position sensor 540 and a camera converter 542. The system 300 may also include a foot switch 544 and a tablet computer 546.

[0069] Input power is provided to system 300 via power supply 548, which can be supplied to power distribution module 404. Power distribution module 404 receives the input power and is configured to generate different power supply voltages for other modules, components, and subsystems of system 300. Power distribution module 404 can be configured to provide different voltage supplies to platform interface module 406, which can supply power to other components, such as computer 408, display 304, speaker 536, driver 508, for example, to power motors 512, 514, 516, 518, end effector 310, ring 324, camera converter 542, and other components of system 300 (e.g., fans for cooling electrical components within cabinet 316).

[0070] The power distribution module 404 can also supply power to other components, such as a tablet charging station 534 that may be located within the tablet drawer 318. The tablet charging station 534 can communicate wirelessly or wiredly with the tablet 546 to charge it. The tablet 546 can be used by a surgeon conforming to this disclosure and described herein. The power distribution module 404 can also be connected to a battery 402, which acts as a temporary power source when the power distribution module 404 is not receiving power from the input power 548. At other times, if necessary, the power distribution module 404 can be used to charge the battery 402.

[0071] Other components of the platform subsystem 502 may include a connector panel 320, a control panel 322, and a ring 324. The connector panel 320 is used to connect different devices and components to the system 300 and / or associated components and modules. The connector panel 320 may include one or more ports for accommodating wires or connectors from different components. For example, the connector panel 320 may have: a ground terminal port for grounding the system 300 to other devices, a port for connecting a foot switch 544 to the system 300, and a port for connecting to a tracking subsystem 532, which may include a position sensor 540, a camera converter 542, and a camera 326 associated with a camera mount 302. The connector panel 320 may also include other ports to allow communication with other components such as a computer 408 via USB, Ethernet, or HDMI.

[0072] Control panel 322 provides various buttons or indicators for operating control system 300 and / or providing information about system 300. For example, control panel 322 may include buttons for turning system 300 on or off, raising or lowering column 312, and raising or lowering stabilizers 520-526, which may be designed to engage casters 314 to lock system 300 and prevent physical movement. Other buttons may stop system 300 in an emergency, potentially by cutting off all motor power and applying mechanical brakes to stop all movement. Control panel 322 may also have indicators to inform the user of certain system conditions, such as line power indicators or the charging status of battery 402.

[0073] Ring 324 can be a visual indicator used to notify the user of system 300 of different operating modes of system 300 and to issue certain warnings to the user.

[0074] Computer subsystem 504 includes computer 408, display 304, and speaker 536. Computer 504 includes an operating system and software for operating system 300. Computer 504 can receive and process information from other components (e.g., tracking subsystem 532, platform subsystem 502, and / or motion control subsystem 506) to display information to a user. Furthermore, computer subsystem 504 may also include speaker 536 to provide audio to the user.

[0075] The tracking subsystem 532 may include a position sensor 504 and a converter 542. The tracking subsystem 532 may correspond to a camera mount 302 including a camera 326, such as... Figure 3The position sensor 504 may be a camera 326. A tracking subsystem can track the position of certain markings located on different components of the system 300 and / or instruments used by the user during surgery. This tracking can be performed in a manner consistent with this disclosure, including using infrared technology to track the position of active or passive elements such as LEDs or reflective markings. The position, orientation, and location of structures with these types of markings can be provided to a computer 408, which can then display them to the user on a display 304. For example, a surgical instrument 608 with these types of markings and tracked in this manner (which may be referred to as a navigation space) can be displayed to the user in relation to a three-dimensional image of the patient's anatomy. A motion control subsystem 506 can be configured to physically move the column 312, upper arm 306, lower arm 308, or rotary end effector 310. Physical movement can be performed using one or more motors 510-518. For example, motor 510 can be configured to vertically raise or lower the vertical column 312. Figure 3 As shown, motor 512 can be configured to laterally move upper arm 308 about the engagement point with column 312. Figure 3 As shown, motor 514 can be configured to laterally move the lower arm 308 about its engagement point with the upper arm 308. Motors 516 and 518 can be configured such that one motor can control rolling and the other can control tilting to move the end effector 310, thereby providing multiple angles at which the end effector 310 can move. These movements can be implemented by controller 538, which can control these movements via load sensors disposed on the end effector 310, and activate these movements by a user engaging these load sensors, thereby moving the system 300 in a desired manner.

[0076] Furthermore, system 300 can provide automatic movement of the column 312, upper arm 306, and lower arm 308 by having the user indicate the position of surgical instruments or components on a three-dimensional image of the patient's anatomy on display 304 (which may be a touchscreen input device). The user can initiate this automatic movement by pressing a foot switch 544 or some other input device.

[0077] Figure 6A surgical robot system 600 conforming to an exemplary embodiment is illustrated. The surgical robot system 600 may include an end effector 602, a robotic arm 604, a catheter 606, an instrument 608, and a robot base 610. The instrument 608 may be attached to a tracking array 612 including one or more tracking markers (such as marker 118) and having an associated trajectory 614. The trajectory 614 is capable of representing a path of movement configured for the instrument 608 to travel once it is positioned through or secured within the catheter 606, for example, the path of insertion of the instrument 608 into a patient. In exemplary operation, the robot base 610 may be configured to electronically communicate with the robotic arm 604 and the end effector 602, such that the surgical robot system 600 can assist a user (e.g., a surgeon) in manipulating a patient 210. The surgical robot system 600 may be consistent with the previously described surgical robot systems 100 and 300.

[0078] Tracking array 612 can be mounted on instrument 608 to monitor the position and orientation of instrument 608. Tracking array 612 can be attached to instrument 608 and may include tracking markers 804. Figure 8 As best shown, the tracking marker 804 can be, for example, a light-emitting diode and / or other types of reflective markers (e.g., marker 118 as described elsewhere herein). The tracking device can be one or more line-of-sight devices associated with the surgical robotic system. For example, the tracking device can be one or more cameras 200, 326 associated with the surgical robotic systems 100, 300, and can also track the tracking array 612 for the defined or relative orientation of the instrument 608 with respect to the robotic arm 604, the robotic base 610, the end effector 602, and / or the patient 210. The tracking device can conform to those structures described in conjunction with the camera holder 302 and the tracking subsystem 532.

[0079] Figure 7A , Figure 7B and Figure 7CTop, front, and side views of an end effector 602 consistent with an exemplary embodiment are shown respectively. The end effector 602 may include one or more tracking markers 702. Tracking markers 702 may be light-emitting diodes or other types of active and passive markers, such as the previously described tracking marker 118. In the exemplary embodiment, the tracking marker 702 is an active infrared emitting marker activated by an electrical signal (e.g., an infrared light-emitting diode (LED)). Therefore, the tracking marker 702 can be activated such that the infrared marker 702 is visible to cameras 200, 326, or the tracking marker can be deactivated such that the infrared marker 702 is not visible to cameras 200, 326. Thus, when the marker 702 is activated, the end effector 602 can be controlled by systems 100, 300, 600, and when the marker 702 is deactivated, the end effector 602 can be locked in place and cannot be moved by systems 100, 300, 600.

[0080] The marker 702 may be positioned on or within the end effector 602, such that it is visible to one or more cameras 200, 326, or other tracking devices associated with the surgical robot system 100, 300, 600. The cameras 200, 326, or other tracking devices can track the end effector 602 as it moves to different positions and viewing angles by tracking the movement of the marker 702. The position of the marker 702 and / or the end effector 602 may be displayed on the displays 110, 304 associated with the surgical robot system 100, 300, 600, for example, as shown in the image. Figure 2 The display 110 and / or shown Figure 3 The display 304 is shown. The displays 110 and 304 allow the user to ensure that the end effector 602 is in the desired position relative to the robot arm 604, the robot base 610, the patient 210, and / or the user.

[0081] For example, such as Figure 7A As shown, markers 702 can be placed around the surface of end effector 602 such that a tracking device positioned away from surgical field 208 and towards robots 102, 301 and cameras 200, 326 can view at least three of the markers 702 through a series of common orientations of end effector 602 relative to tracking devices 100, 300, 600. For example, distributing markers 702 in this way allows the end effector 602 to be monitored by the tracking device as it is translated and rotated within surgical field 208.

[0082] Furthermore, in an exemplary embodiment, the end effector 602 may be equipped with an infrared (IR) receiver that can detect when the external cameras 200, 326 are ready to read the marker 702. Upon this detection, the end effector 602 may then illuminate the marker 702. The IR receiver's detection that the external cameras 200, 326 are ready to read the marker 702 may indicate a need to synchronize the duty cycle of the marker 702 (which may be a light-emitting diode) with the external cameras 200, 326. This also allows for lower power consumption of the robotic system as a whole, whereby the marker 702 will be illuminated only at appropriate times, rather than continuously. Additionally, in an exemplary embodiment, the marker 702 may be de-energized to prevent interference with other navigational tools, such as different types of surgical instruments 608.

[0083] Figure 8 A type of surgical instrument 608 is illustrated, comprising a tracking array 612 and tracking markers 804. Tracking markers 804 can be of any type described herein, including but not limited to light-emitting diodes or reflective balls. Markers 804 are monitored by tracking devices associated with surgical robot systems 100, 300, 600, and can be one or more of line-of-sight cameras 200, 326. Cameras 200, 326 can track the position of the instrument 608 based on the position and orientation of the tracking array 612 and markers 804. A user (such as surgeon 120) can orient the instrument 608 in such a manner that the tracking array 612 and markers 804 are sufficiently recognized by the tracking devices or cameras 200, 326 to display the instrument 608 and markers 804 on, for example, a display 110 of an exemplary surgical robot system.

[0084] The surgeon 120 can place the instrument 608 into the catheter 606 of the end effector 602 and adjust the manner in which the instrument 608 is placed. Figure 8 As is evident from the description. The hollow tubes or conduits 114, 606 of the end effectors 112, 310, 602 are sized and configured to receive at least a portion of the surgical instrument 608. The conduits 114, 606 are configured to be oriented by the robotic arm 104 such that the insertion and trajectory of the surgical instrument 608 can reach a desired anatomical target within or above the body of the patient 210. The surgical instrument 608 may include at least a portion of a generally cylindrical instrument. Although a screwdriver is illustrated as a surgical tool 608, it should be understood that any suitable surgical tool 608 can be positioned by the end effector 602. For example, the surgical instrument 608 may include one or more of a guidewire, cannula, retractor, drill, reamer, screwdriver, insertion tool, removal tool, etc. Although the hollow tubes 114, 606 are generally shown as having a cylindrical configuration, those skilled in the art will understand that the conduits 114, 606 may have any suitable shape, size, and configuration required to receive the surgical instrument 608 and access the surgical site.

[0085] Figures 9A to 9C An end effector 602 and a portion of a robotic arm 604, conforming to an exemplary embodiment, are shown. The end effector 602 may further include a body 1202 and a gripper 1204. The gripper 1204 may include a handle 1206, a ball bearing 1208, a spring 1210, and a lip 1212. The robotic arm 604 may further include a recess 1214, a mounting plate 1216, a lip 1218, and a magnet 1220.

[0086] The end effector 602 can be mechanically engaged and / or coupled to the surgical robot system and the robotic arm 604 via one or more couplings. For example, the end effector 602 can be coupled to the robotic arm 604 via a positioning coupling and / or a reinforcing coupling. Through these couplings, the end effector 602 can be secured to the robotic arm 604 outside a flexible sterile barrier. In an exemplary embodiment, the positioning coupling may be a magnetic motion mount, and the reinforcing coupling may be a five-bar over-center clamping link.

[0087] Regarding the positioning coupling, the robot arm 604 may include a mounting plate 1216 (which may be made of a non-magnetic material), one or more recesses 1214, a lip 1218, and a magnet 1220. The magnet 1220 is mounted below each of the recesses 1214. A portion of the gripper 1204 may include a magnetic material and is attracted by one or more magnets 1220. Through the magnetic attraction of the gripper 1204 and the robot arm 604, the ball 1208 is placed into the corresponding recess 1214. For example, as... Figure 9B The ball bearing 1208 shown will be placed as follows Figure 9A The recess 1214 is shown. This placement can be considered as a magnetically assisted motion coupling. The magnet 1220 can be configured to be robust enough to support the entire weight of the end effector 602, regardless of the orientation of the end effector 602. The positioning coupling can be any type of motion mount that only restricts six degrees of freedom.

[0088] Regarding the reinforced coupling, a portion of clamp 1204 can be configured as a fixed ground connection, thus clamp 1204 can function as a five-bar linkage. Closing clamp handle 1206 secures end effector 602 to robot arm 604 because lips 1212 and 1218 engage clamp 1204 in a manner that secures end effector 602 and robot arm 604. When clamp handle 1206 is closed, spring 1210 can be stretched or stressed when clamp 1204 is in the locked position. The locked position can be a position that provides access past the center link. Because the closed position is past the center, the link will not open unless a force is applied to clamp handle 1206 to release clamp 1204. Therefore, in the locked position, end effector 602 can be securely fixed to robot arm 604.

[0089] Spring 1210 may be a tensioned bending bundle. Spring 1210 may be made of a material exhibiting high stiffness and high yield strain, such as natural PEEK (polyetheretherketone). The linkage between end effector 602 and robotic arm 604 provides a sterile barrier between end effector 602 and robotic arm 604 without impeding the fastening of the two couplings.

[0090] The reinforcing coupling can be a link with multiple spring members. The reinforcing coupling can be latched using a cam or a friction-based mechanism. The reinforcing coupling can also be a sufficiently strong electromagnet that facilitates the fastening of the end effector 102 to the robot arm 604. The reinforcing coupling can be a multi-piece collar that is completely separable from the end effector 602 and / or the robot arm 604, sliding on the interface between the end effector 602 and the robot arm 604, and tightened by a screw mechanism, an over-center link, or a cam mechanism.

[0091] refer to Figure 10 and Figure 11 Certain registration procedures can be performed before or during surgery to track patient objects and target anatomical structures in navigation and image spaces. To perform this registration, methods such as... Figure 10 The registration system 1400 is shown.

[0092] To track the position of patient 210, patient tracking device 116 may include a patient fixation device 1402 to be secured to a rigid anatomical structure of patient 210, and a dynamic reference base (DRB) 1404 may be securely attached to the patient fixation device 1402. For example, the patient fixation device 1402 may be inserted into an opening 1406 of the dynamic reference base 1404. The dynamic reference base 1404 may include markings 1408 visible to tracking devices such as tracking subsystem 532. As previously described herein, these markings 1408 may be optical markings or reflective spheres, such as tracking markings 118.

[0093] The patient fixation device 1402 is attached to a rigid anatomical structure of the patient 210 and remains attached throughout the surgical procedure. In an exemplary embodiment, the patient fixation device 1402 is attached to a rigid region of the patient 210, such as bone located away from the target anatomical structure undergoing surgery. To track the target anatomical structure, a dynamic reference base 1404 is associated with the target anatomical structure using a registration clamp temporarily placed on or near the target anatomical structure to align the dynamic reference base 1404 with the target anatomical structure.

[0094] The registration clamp 1410 is attached to the patient fixation device 1402 using the pivot arm 1412. The pivot arm 1412 is attached to the patient fixation device 1402 by inserting the patient fixation device 1402 through the opening 1414 of the registration clamp 1410. The pivot arm 1412 is attached to the registration clamp 1410 by, for example, inserting a knob 1416 through the opening 1418 of the pivot arm 1412.

[0095] Using the pivot arm 1412, the registration jig 1410 can be positioned above the target anatomical structure, and its position can be determined in both image and navigation space using tracking markers 1420 and / or reference points 1422 on the registration jig 1410. The registration jig 1410 may include a set of markers 1420 visible in the navigation space (e.g., markers 1420 may be detected by the tracking subsystem 532). As previously described herein, the tracking markers 1420 may be optical markers visible in infrared light. The registration jig 1410 may also include a set of reference points 1422 visible in the imaging space (e.g., a three-dimensional CT image), such as bearing balls. (See also: Regarding...) Figure 11 In more detail, using the registration clamp 1410, the target anatomical structure can be associated with the dynamic reference base 1404, thereby allowing the depiction of the object in navigation space to overlay on the image of the anatomical structure. The dynamic reference base 1404, located away from the target anatomical structure, can serve as a reference point, thereby allowing the registration clamp 1410 and / or pivot arm 1412 to be removed from the surgical area.

[0096] Figure 11 An exemplary method 1500 for registration is provided in accordance with this disclosure. Method 1500 begins at step 1502, wherein a graphical representation (or image) of the target anatomical structure is imported into system 100, 300, 600, such as computer 408. The graphical representation may be a three-dimensional CT or fluorescence microscopy scan of the target anatomical structure of patient 210, which includes a detectable imaging pattern of registration fixture 1410 and reference points 1420.

[0097] At step 1504, the imaging pattern of reference point 1420 is detected and registered in the imaging space and stored in computer 408. Optionally, at this time at step 1506, a graphic representation of registration fixture 1410 can be overlaid on the image of the target anatomical structure.

[0098] At step 1508, the navigation pattern of the registration jig 1410 is detected and registered by identifying marker 1420. Marker 1420 may be an optical marker identified in the navigation space via infrared light by the tracking subsystem 532 through the position sensor 540. Therefore, the position, orientation, and other information of the target anatomical structure are registered in the navigation space. Thus, the registration jig 1410 can be identified in the image space using reference point 1422 and in the navigation space using marker 1420. At step 1510, the registration of the registration jig 1410 in the image space is transferred to the navigation space. For example, this transfer is accomplished relative to the position of the navigation pattern of marker 1420 by using the relative position of the imaging pattern of reference point 1422.

[0099] At step 1512, the registration of the navigation space (already registered with the image space) of the registration jig 1410 is further transferred to the navigation space of the dynamic registration array 1404 attached to the patient fixation device 1402. Therefore, since the navigation space is associated with the image space, the registration jig 1410 can be removed and the target anatomical structure in both the navigation space and the image space can be tracked using the dynamic reference base 1404.

[0100] At steps 1514 and 1516, the navigation space may overlay the image space and the object with markings visible in the navigation space (e.g., a surgical instrument 608 with optical markings 804). The object can be tracked by a graphical representation of the surgical instrument 608 on an image of the target anatomical structure.

[0101] Figures 12A to 12B An imaging device 1304 is shown that can be used in conjunction with robotic systems 100, 300, and 600 to acquire preoperative, intraoperative, postoperative, and / or real-time image data of patient 210. Imaging system 1304 can be used to image any suitable subject for any suitable surgical procedure. Imaging system 1304 can be any imaging device, such as imaging device 1306 and / or C-arm 1308. It may be necessary to acquire X-rays of patient 210 from multiple different locations without frequent manual repositioning of patient 210 (which may be required in X-ray systems). Figure 12AAs shown, the imaging system 1304 can be in the form of a C-arm 1308, which includes an elongated C-shaped member terminating at a relatively distal end 1312 of the "C" shape. The C-shaped member 1130 may further include an X-ray source 1314 and an image receiver 1316. The space within the C-arm 1308 provides space for a physician to care for the patient, substantially unaffected by the X-ray support structure 1318. Figure 12B As shown, the imaging system may include an imaging device 1306 having a gantry housing 1324 attached to a support structure imaging device support structure 1328, such as a wheeled trolley 1330 with wheels 1332, which can enclose an image capture section (not shown). The image capture section may include an X-ray source and / or emitting section and an X-ray receiving and / or image receiving section, which may be positioned approximately 180 degrees apart from each other and mounted on a rotor (not shown) relative to the trajectory of the image capture section. The image capture section may be operable to rotate 360 ​​degrees during image acquisition. The image capture section may rotate about a center point and / or axis, thereby allowing image data of the patient 210 to be acquired from multiple directions or multiple planes. Although certain imaging systems 1304 are illustrated herein, it should be understood that those skilled in the art can choose any suitable imaging system.

[0102] Methods exist for displaying simulated projections of surgical instruments overlaid on fluorescein images to assist surgical procedures through unidirectional registration of medical images with tracking space. For example, a calibration clamp can be attached to the image intensifier of the fluorescein, such as... Figure 13 As shown. The clamp comprises rows of small metal spheres (hereinafter referred to as "BBs") with a known spacing that appear on the X-ray image, and also includes an optical tracking array that provides the clamp's three-dimensional (3D) position in the tracking space. Through image processing and geometric calculations, it is determined how the tool placed in the X-ray path should be represented as a projection on the X-ray image. The 3D position of the tool to which the tracking array is attached is tracked in the coordinate system of a tracker (e.g., a camera). A graphical representation of the tool is then overlaid on the X-ray image to provide a "virtual fluoroscope" that has approximately the same visual information as would be seen when continuous X-rays are obtained while the tool is held in the surgical field. The advantage of this method is that patients and medical personnel are exposed to less radiation because the virtual fluoroscope provides continuous updates of the tool's position overlaid on a single X-ray image.

[0103] Although this method maps the 3D tool position to a two-dimensional (2D) medical image, the application does not necessarily need to map the points detected on the 2D medical image to the 3D tracking space; that is, to co-register the medical image space with the tracking space. However, such a mapping can be obtained by considering the vectors extending from the transmitter to the collector. Figure 14An X-ray collector plate 1702 is shown, illustrating the theoretical projections of BB 1710 into two planes 1704 and 1706 at different distances from the source 1708. The X-ray collector plate 1702, plane 1 1706, and plane 2 1704 are shown as parallel and concentric. In this case, it is assumed that the X-ray emitter 1708 is a point, and the rays from the source to the collector propagate from that point in a conical pattern. Due to this conical pattern, BB 1710 from plane 1 1706 appears magnified on the X-ray collector plate 1702 relative to BB 1710 from plane 2 1704, even though they are actually separated by the same distance in this example. This phenomenon is called parallax.

[0104] Considering situations where one X-ray view is obtained from a significantly different perspective than the other, such as Figure 15 As shown, and where the precise positions of the collector and emitter in 3D are known by tracing or other means, vectors extending in a conical pattern from the emitter to the collector can be traced back to the location where they intersect with the point of interest anatomical point 1802 present in both views. In this case, "vector" can mean the vector determined from the visible X-ray shadow of the BB, or any vector calculated (e.g., interpolated) to match the conical pattern derived from the visible X-ray shadow. The 3D position of the point of interest can then be determined because a unique solution exists at the intersection of the vectors from the two views. That is, the 3D position of the reference point cannot be derived from one view because the point can be located anywhere along the vector from the source to the emitter and will appear at the same location on the collector plate. The second view provides the unique position along the vector where the point must be.

[0105] Figure 14 Only four BBs 1710 on two parallel planes 1704 and 1706 are shown. These BBs can provide a basis for methods to detect the position of an object in 3D from multiple 2D x-ray views. However, for better accuracy, alternative methods such as... Figure 16 The dense grid of BBs (e.g., dozens or hundreds) allows for more accurate vector interpolation. Using more BBs allows for even more accurate interpolation and ultimately better 3D accuracy, but the X-ray shadows from more BBs also prevent surgeons from visualizing the anatomical structures of interest on X-ray images.

[0106] The implicit assumption is that the positions of the collector plate and the emission source are known in 3D during both emissions. For example, the collector plate could have an attached tracking array, and therefore its 3D position would be directly tracked. Trackers could also be placed on the emitter. However, this has drawbacks, primarily that the tracking field needs to be very large to observe both trackers, where the distance between the collector and emitter is typically about one meter. Tracking systems such as optical trackers can have a tracking field of less than one cubic meter. Additionally, for some clinically typical X-ray emissions, the emitter can be positioned outside the field of view. The emitter source position could instead be calibrated relative to the collector array, but the extrapolation accuracy defining the emitter position may be lower where the distance between the collector and emitter is large and there are different amounts of sag when the fluoroscope is oriented differently. Alternatively, the position could be determined based on a known spacing d. ab Calculate the distance and orientation of the emitter source relative to the collector using fluorescence mirror images of two parallel planes of BB from 1712, such as... Figure 14 and Figure 17 As shown. The formula provided in Formula 1 is based on Figure 17 The geometric structure depicted in the text was established in 2000.

[0107] Formula 1:

[0108]

[0109]

[0110] in,

[0111] ·d ec It is the distance from the transmitter to the collector, measured in millimeters.

[0112] ·k is a scaling factor that converts the pixel coordinates on the fluoroscope output to mm;

[0113] ·l a It is the lateral distance in mm between BB1a and BB2a within plane A;

[0114] ·l b It is the lateral distance in mm between BB1b and BB2b in plane B;

[0115] ·y 1a It is the lateral distance in mm from the center beam to BB1a;

[0116] ·y 1b It is the lateral distance in mm from the center beam to BB1b;

[0117] ·y 2a It is the lateral distance in mm from the center beam to BB2a;

[0118] ·y 2b It is the lateral distance in mm from the center beam to BB2b;

[0119] ·z ea It is the distance in mm from the transmitter to plane A (BB1a and BB2a);

[0120] ·z eb It is the distance in mm from the transmitter to plane B (BB1b and BB2b);

[0121] ·d ab It is the longitudinal distance between plane A and plane B, measured in mm;

[0122] ·L 2a It is the distance in pixel coordinates between the shadows of BB in plane A above the collector; and

[0123] ·L 2b It is the distance in pixel coordinates between the shadows of BB in plane B above the collector.

[0124] For d ec Solving for the results

[0125] Formula 2:

[0126]

[0127] Therefore, if the spacing between the planes and the spacing between the blocks (BBs) are known, the distance from the emitter to the collector can be determined through image processing of the X-ray images containing these BBs. Note that... Figure 17 This indicates the measurement of the distance between the shadows of two adjacent bounding boxes (BBs) in two planes. During the procedure, the distances between several pairs of BBs on the X-ray image can be measured, and the average of these distances is taken. Additionally, Figure 17 This shows that the distance between BB on plane A and plane B is the same; however, their physical distances may be different, and this is explained by l in the formula. a and l b To illustrate. During implementation, it may be desirable to offset the BBs rather than space them by the same distance and align them to prevent their projections from partially obscuring each other.

[0128] This method for defining the position of the emitter relative to the collector utilizes two parallel plates in defining the orientation and distance of the emitter. With the registration fixture mounted to the collector, it is assumed that the direction from the emitter to the collector is perpendicular to the plane of the collector and the plane containing the BB. If this assumption is not true, the projections of the BB from the near-field and far-field planes will not symmetrically overlay the X-ray image. For a given angular deviation of the X-ray plane relative to the BB plane, the offset of the BB shadow relative to the symmetrical projection is proportional to the distance between the BB planes, where a larger plane spacing manifests as a larger lateral displacement of the projection on the X-ray image. Through geometry, the lateral offset of the BB shadow can be used to accurately determine the actual orientation of the BB plane relative to the collector plane, and thus determine the position of the emitter in 3D, or to manually or automatically adjust the orientation of the registration fixture on the image intensifier until the BB plane and the collector plate are truly coplanar.

[0129] The scaling factor k is given in the above formula, but this factor is necessary for the subsequent 3D-to-2D mapping of the 3D coordinates of the generalized point. In general, Formula 3 holds in order to map a 3D point with coordinates x, y, z to a 2D x-ray image with the x and y axes aligned with the Cartesian coordinate system.

[0130] Formula 3:

[0131]

[0132]

[0133] Where X is the coordinate axis of the 2D x-ray image aligned with the Cartesian X-axis, Y is the coordinate axis of the 2D x-ray image aligned with the Cartesian y-axis, and z is the Cartesian axis perpendicular to the x-ray image.

[0134] If two fluorescence emission points are obtained at orientations at most 90 degrees apart, such as a typical pre- and post-clinical emission and a typical transverse clinical emission, then (X1, Y1) can be defined as the x-ray coordinates (x, y, z) of the point when it appears on x-ray image 1 (e.g., pre- and post-clinical image). The Cartesian coordinates of the point in the local coordinate system aligned with this x-ray plane can be defined as (x1, y1, z1). Similarly, (X2, Y2) can be defined as the x-ray coordinates of the same point appearing on x-ray image 2 (e.g., transverse image). The Cartesian coordinates of the point in the local coordinate system aligned with this x-ray plane can be defined as (x2, y2, z2). Because the tracking system can be used to detect the 3D position of the x-ray collector when the fluorescence microscope is in each orientation, the transformation T12 from Cartesian coordinate system 1 to Cartesian coordinate system 2 is known, where T12 is a standard 4×4 transformation matrix commonly used in the art. Therefore, there exists a unique solution to Equation 4.

[0135] Formula 4:

[0136]

[0137]

[0138]

[0139]

[0140] as well as

[0141]

[0142] It should be noted that each of the two coordinate systems is oriented such that its z-axis is perpendicular to each x-ray plane, its origin is at each x-ray plane, and its origins for both x and y axes are at the center of the x-ray plane. The directions of x and y relative to the x-ray plane can be arbitrary. By using, for example, 3D optical tracking to track the position of the x-ray plane in 3D, the positions of the first and second 3D coordinate systems (T) can be determined. 12 The conversion of ).

[0143] The method used to define the 3D Cartesian coordinate system associated with two fluorescein views assumes that the BBs are uniformly projected onto the image intensifier. However, distortions are commonly associated with images obtained from fluorescein, such as pincushion distortion, S-distortion, etc. These types of distortions can be corrected using image processing before applying the methods described herein. Distortion correction can take advantage of the fact that the BBs are arranged in a symmetrical pattern on the registration apparatus. Therefore, X-rays projected through a known symmetrical pattern should produce an image with matching symmetry. The spacing between the BBs and the alignment of the rows of BBs can be determined by image processing and compared with the expected projection of the BBs. Algorithms commonly known in image processing (such as affine transformations, etc.) can be used to force the projected X-ray image to match the known and expected symmetry. Since the same correction can also be applied to anatomical images on X-rays, the resulting X-ray image should represent an undistorted projection and should allow for efficient computation of registration as described herein.

[0144] In the implementation scheme, the symmetrical pattern used to correct distortion can be as follows: Figure 16 The square pattern shown has BB distributed in a radially symmetrical pattern in a polar coordinate system around the center of the image, where BB shares a common radius and azimuth, or as shown in the image. Figure 18 and Figure 19 The fixture can be used to determine any suitable pattern. As long as the pattern of the actual BB embedded in the registration fixture is known, the corresponding shadow of the BB on the X-ray image can be predicted, and distortion correction can be applied to force the image to match the expected pattern.

[0145] The process of 2D-to-3D mapping of an image relies on the correct interpretation of orientation on the X-ray image. For example, if the 2D X-ray image is a front-to-back image, it must be known whether the 2D image represents emission with the emitter in front and the collector behind, or emission with the emitter behind and the collector in front. Additionally, since fluorescence microscope images are typically circular, there must be a way to accurately determine which direction points left, right, up, or down based on the BB shadow. The BB plane of the fixture provides information for alignment correction, such as using the BB closest to the X-ray collector to provide information on the rotationally oriented X-ray image, and also provides information about reflection, such as the BB pattern determining whether the positive z-direction extends away from the visible plane from the front or back. In an embodiment, the fixture may include an outer ring of a large BB arranged such that it uniquely identifies aspects of alignment, such as image rotation and flipping. The pattern of the BB used to identify orientation and / or flipping can be selected based on the pattern's ability to provide unique combinations of image rotation and flipping, and based on the pattern's ability to provide redundant BBs to increase detection reliability. Excess BBs may be important because not all BBs may be visible on any given X-ray emission due to obstruction of the BB shadow by tools or implants, or poor X-ray penetration through a portion of the image.

[0146] In the implementation scheme, a ring with varying spacing of BBs can be used around the periphery of a standard circular fluorescein image, such as... Figure 19 As shown, the shadows of surrounding BBs form bit codes (e.g., 32-bit codes). In an implementation, a first plane 2202 with a first dot array and a second plane 2204 with a second dot array can be projected to form a combined image 2206. The code length should be chosen such that the BBs are spaced far enough apart that the chance of an error causing a BB to mistakenly fall into an adjacent bit position when detecting its location is small, while still providing enough information to robustly handle missing bits. If only a subset of existing BBs is detected, some of which BB shadows cannot be detected, comparison of the subset with a known template can provide correct image orientation and flipping, regardless of which BBs are missing. If a subset with a larger number of missing BBs is detected, the algorithm can determine the correct image orientation and flipping. In implementations aware of algorithm limitations, the system may require a specific minimum number of BBs to be detected before allowing the algorithm to continue.

[0147] In the implementation, orientation matching can utilize a point matching algorithm (e.g., the Kabsch point matching algorithm) or other suitable point matching algorithm, which assumes that the two point sets are scaled identically. The algorithm then determines the transformation between the two point sets, one from orientation BB detection and the other from the fixture 3D model. The orientation markers of the fixture can then be projected into the image space. Since the two point sets need to be scaled identically, the algorithm tests the range of projection scaling to find the best match. Once the best match is found, the transformation is scaled appropriately, and the algorithm assigns point correspondences between the detected image markers and the physical fixture markers. The resulting transformation can then be applied to the image to rotate and / or flip the image, thereby producing alignment with the fixture.

[0148] Ring registration fixture :

[0149] As an alternative for establishing a directional BB array, a loop or other shape, such as one formed of a radiopaque material like metallic wire, can be used as a reference point in the registration fixture. (Reference) Figure 20 The diagram illustrates a ring registration fixture 2300, in which two parallel rings 2304 and 2306 have the same or different diameters (e.g., between 50 mm and 300 mm) and are concentrically positioned in parallel planes spaced apart (e.g., 50 mm to 300 mm apart). To facilitate identification of the centers of rings 2304 and 2306, the rings may also have one or more crosshairs 2308A and 2308B, formed from wire or other radiopaque material having the same or different diameters as the rings themselves. Some desirable features of the rings include perfectly circular rings whose crosshairs pass through an accurate center, such that the diameter of the projected ellipse and the intersection of the crosshairs are accurate, and so on. Additionally, it may be desirable for the ring's cross-section to be circular rather than flat, so that if the ring is at an angle relative to the X-ray image, it is projected correctly. Feasible methods for forming the rings include welding or otherwise attaching wire segments, rapid prototyping (3D printing) using radiopaque construction materials, etching in the same manner as used for manufacturing printed circuit boards, etc.

[0150] When acquiring X-ray images of the ring registration fixture 2300 simultaneously centered on the collector plate, it should appear as two concentric circles 2402 and 2404, such as Figure 21 As shown above. If an X-ray image is acquired when the ring registration fixture 2300 is not parallel to or centered on the collector plate, it will appear as two ellipses 2502 and 2504, such as Figure 22 As shown.

[0151] Furthermore, the tracking markers 2302A-D can be used as a reference for ring positioning of the ring registration fixture 2300 in 3D, such as using an optical marker array, magnetic sensors, or other similar 3D tracking methods. For reference, it may be convenient to define a local coordinate system on the registration fixture 2300. For example, the reference local coordinate system could have its origin located at the center of a ring closer to the X-ray emitter, where the second (e.g., parallel) ring is closer to the collector, and the x-axis and y-axis could coincide with the crosshairs identifying the center of the first ring, where the z-axis coincides with the vector connecting the centers of the two rings.

[0152] In one implementation, the 3D to 2D mapping points using a ring registration fixture can utilize vectors passing through known points on two rings, which are created to form a conical pattern, which is then used to interpolate vectors passing through the region of interest.

[0153] In implementation schemes, a series of common transformations (i.e., rotation, translation, magnification) can be applied, such as transformation parameters estimated from features on the image. For example, consider a 3D coordinate system based on a dual-ring fixture, centered on a first ring closer to the emitter as a near-field ring and a second ring closer to the collector as a far-field ring. In this example, the near-field and far-field rings may have the same diameter, and multiple transformations can be applied to map points from this coordinate system to the coordinate system of the collector plate.

[0154] exist Figures 23 to 27 The text describes a non-restricted set of examples of exemplary transformations. Figure 23 Transformation step 1, involving rotation θ around z (e.g., θ is an angle that allows subsequent rotation α around y), is depicted. Note that in this figure, the rings are observed in 3D without parallax, and therefore the near-field and far-field rings completely overlap in their initial orientation. Figure 24 Transformation step 2, involving rotation α around y, is described. Note that the rotation occurs around the center of the near-field ring (e.g., the ring closer to the transmitter). Figure 25 The transformation step 3 is described as rotating in the plane to match the perspective of the ray photograph (e.g., finding the angle deviating from y in the xy plane to obtain the actual axis of rotation, instead of using the y-axis as the axis of rotation for the incident angle α). Figure 26 Step 4 describes the transformation steps from the center of the coordinate system to the displacements dx and dy. Figure 27 Step 5, the transformation step of magnification based on parallax, is described. In this example, after step 5 is completed, the xy plane represents the points mapped to the 2D plane. In step 5, magnification is performed according to Equation 3.

[0155] In this example, on the final image, the near-field ring appears magnified more than the far-field ring because points on the near-field ring have larger z-values ​​than points on the far-field ring. Additionally, the rotation of the ring in the xy-plane may appear different depending on its distance from x,y = 0, 0.

[0156] Therefore, to transform a point in 3D specified in the coordinate system attached to the ring registration fixture into a point in 2D on the x-ray plane, a series of transformations are applied, involving five unknowns: θ, α, φ, dx, and dy. These five unknowns can be estimated using image processing based on the ring itself. Thus, once these five parameters are defined and registration is established, any new point specified as x, y, z in the reference coordinate system can be directly mapped to x-ray image coordinates.

[0157] For many calculations used to determine five parameters from an image, d is required. ec The ratio / k is as described regarding the BB fixture. This ratio can be similarly determined from the X-ray images of the ring obtained when it is oriented parallel to the collector plate. Figure 28 A schematic diagram of key dimensions is shown as viewed from a plane perpendicular to the collector plate, where the ring appears parallel to the collector in the field of view on the collector plate under its shadow. Based on Figure 28 The following formula can be used to determine d. ec / k:

[0158] Formula 5:

[0159]

[0160] in

[0161] d ec It is the distance from the transmitter to the collector, measured in millimeters.

[0162] k is a scaling factor that converts the pixel coordinates on the fluoroscope output to mm;

[0163] l a It is the diameter of ring A;

[0164] l b It is the diameter of ring B;

[0165] y 1a It is the lateral distance in mm from the center beam to the edge of ring A;

[0166] y 1b It is the lateral distance in mm from the center beam to the edge of ring B;

[0167] y 2a It is the lateral distance in mm from the center beam to the opposite edge of ring A;

[0168] y 2b It is the lateral distance in mm from the center beam to the opposite edge of ring B;

[0169] z ea It is the distance in mm from the transmitter to plane A (to ring A);

[0170] z eb It is the distance in mm from the transmitter to plane B (to ring B);

[0171] d ab It is the longitudinal distance between plane A and plane B, measured in mm;

[0172] L 2a It is the diameter of the shadow of ring A on the collector, in pixel coordinates; and

[0173] L 2b It is the diameter of the shadow of ring B on the collector, in pixel coordinates.

[0174] Now we will describe a non-restrictive example of how to determine five unknowns (θ, α, φ, dx, and dy).

[0175] Calculate the incident angle α :

[0176] Consider a conical beam striking a plane at an arbitrary angle relative to the cone and projecting the image onto a collecting plate, such as from... Figure 29 The depicted viewpoint is the perspective observed from a point of view through the ring plane, where the view through the ring forms an arbitrary angle of incidence with the collector plane. As shown in the illustration, the ring plane is both inside and outside the page, where the view originates from the positive z-axis and is guided by reformatted x and y axes as shown in a 3D coordinate system. In this example, the distance d from the top of the cone (e.g., an x-ray emitter) to the collector on which the image is perceived is... ec It is fixed. The subscript "a" is used because there exist objects with the same angle of incidence α and diameter l. 0b A second ring parallel to this, which has the subscript "b". Note that the coordinate system of the plate and the 3D space above it is positioned such that the center of the 2D image is at X. p =0, and the center of 3D space is also at x. r =0.

[0177] based on Figure 29 The following formula holds true:

[0178] Formula 6:

[0179]

[0180]

[0181] refer to Figure 30 Now consider a clamp with two parallel rings of different diameters. Parameter z ea and z eb This represents the distance in the z-direction from the transmitter to the midpoint of each ring (the intersection of the crosshairs). Figure 30 A view through a pair of concentric rings is shown, viewed from a perspective passing through the ring plane, where the concentric rings form an arbitrary angle of incidence with the collector plane, with the ring plane both inside and outside the page (see illustration). Based on Figure 30 The following formula holds true:

[0182] Formula 7:

[0183]

[0184] To solve z ea (and z) eb Consider another perspective of the ring, such as passing through... Figure 31 The widest portion shown provides an observation from Figure 29 and Figure 30 The view of a ring at an arbitrary angle of incidence is taken from a perspective rotated 90 degrees. From this, we can conclude that:

[0185] For ring a

[0186] Formula 8:

[0187]

[0188] For ring b

[0189] Formula 9:

[0190]

[0191] or

[0192] Formula 10:

[0193]

[0194]

[0195] Substitute into equation 7,

[0196] Formula 11:

[0197] z eb -z ea =d ab cosα

[0198]

[0199]

[0200]

[0201] in

[0202] L 2a = The widest diameter of the elliptical projection of ring a in pixel coordinates;

[0203] L 2b = The widest diameter of the elliptical projection of ring b in pixel coordinates;

[0204] d ec = The distance from the transmitter to the collector, in mm;

[0205] d ab =The shortest distance in mm from ring a to ring b;

[0206] k = Conversion factor from pixels to mm;

[0207] l 0a = The known actual diameter of ring a in mm; and

[0208] l 0b = The known actual diameter of ring b in mm.

[0209] Equation 11 specifies the widest and narrowest projections of the measuring ring, and small variations can cause differences in α. It is useful to instead find an equation less sensitive to error based on the displacement of the ring's center. If the lower ring is "magnified" to match a known ratio of the diameters of the upper and lower rings (e.g., a ratio of 1 if the rings have the same diameter), this would be the same as moving the ring upwards in the vertical direction (z-direction), because the value is scaled for each point on the ring in a coordinate system where the ring points are off-zero. Figure 32 It shows the difference between and Figure 29 View a pair of rings at any incident angle from the same perspective. If the far-field ring is magnified to match the magnification of the near-field ring, this is equivalent to physically moving the rings upwards along the z-axis until z... ea =z eb .

[0210] This z-position becomes the z-position of the major axes of the two ellipses. Image processing allows scaling the image of the far-field ellipse around its center until the far-field ellipse diameter matches the expected ratio to the near-field ellipse diameter. For example, if the far-field and near-field rings have the same physical diameter, the far-field ellipse projected by the x-rays will appear smaller than the near-field ellipse. Points on the far-field ellipse can then be scaled so that the new image of the far-field ellipse will have the same diameter as the near-field ellipse. Specifically, the only point that needs scaling can be the center of the far-field ellipse, as defined by the intersection of the crosshairs of the far-field rings. With the far-field ellipse scaled and the near-field ellipse not scaled, the offset of the ellipse center represents the measurement of the opposite side in an image coordinate system within a triangle whose hypotenuse is equal to the distance between the rings. At this z-position, the hypotenuse can be determined in image coordinates, where the hypotenuse is the distance between the rings multiplied by the ratio of the near-field ellipse's major axis to the near-field ring diameter (or multiplied by the scaled ratio of the far-field ellipse's major axis to the far-field ring diameter, which is the same according to the definition of the scaling factor). With the opposite side and the hypotenuse, α can be obtained using the arcsine function.

[0211] Formula 12:

[0212]

[0213] in:

[0214] D cab = Distance between unscaled near-field centers in image coordinates; ellipse and scaled far-field ellipse;

[0215] L 2a = The diameter of the near-field ellipse measured in image coordinates along the axis of rotation (approximately equal to the major axis of the projected ellipse);

[0216] l 0a = Diameter of the near-field ring in mm; and

[0217] d ab = The distance between rings, measured in mm.

[0218] Calculate the azimuth angle φ :

[0219] The azimuth angle φ (the angle required to align the rotation axis of the ring incidence with the y-axis) might appear to be merely an angle relative to the major axis of one of the ellipses. For example, Figure 33The modeling appearance of two rings with an incident angle of α = 20° around the y-axis on x-rays (with parallax) is depicted. The major axes of the two ellipses appear to be oriented in alignment with the y-axis, and therefore the expected azimuth angle is φ = 0°. Superficially, image processing can be used to evaluate the orientation of the major axes of either or both ellipses and use it to determine θ. However, it can be seen that if the rings are located off-center from the image, the major axes of the ellipses do not accurately reflect the azimuth angle. Figure 34 In the example depicted, generated from digital data, there is a significant difference along the major axis of the two ellipses. Figure 34 In the image, the modeling appearance is depicted on the x-rays (with parallax) of two parallel circular rings with an incident angle of α = 24.5° around the y-axis. Both rings are off-center from the center of the x-rays. The major axes of the two ellipses appear to be at a significant angle relative to the y-axis; furthermore, the major axis of the larger ellipse appears to have a different azimuth angle than that of the smaller ellipse. In this case, the azimuth angle is known to be φ = 0°, but image processing does not correctly assign this angle.

[0220] Another consideration is that for small angles, it may be difficult to accurately assess the exact direction of the largest diameter; therefore, methods using the orientation of the ellipse's major axis to find θ may produce lower accuracy results. In the implementation, a method using the length of the ellipse's major axis should produce better results.

[0221] Reference Figure 32 In the scaling exercise described, it can be seen that magnification is equivalent to moving the entire ring upwards along the z-axis. Therefore, if the far-field ring is scaled appropriately, the two elliptical ring images will represent projections at the same z-coordinates of the near-field and far-field rings. If the centers of the near-field and far-field rings are at the same z-coordinate, then the vector connecting them on the x and y axes represents the path of the rotation axis. The actual rotation axis should be perpendicular to this path and also in the xy-plane. Therefore, the rotation axis can be extracted through image processing by first scaling the center of the far-field ring and then tracing the path connecting the centers of the far-field and near-field ring images. In the illustration, Figure 35 The modeling appearance of two parallel rings with an incident angle of α = 24.5° around the y-axis on an x-ray (with parallax) is depicted. Both rings are offset from the center of the x-ray. The far-field ellipse has been scaled around the center of the image until the near-field and far-field ellipses are equal on their major axes. The azimuth angle is known to be φ = 0° (i.e., rotation around the y-axis, see [reference]). Figure 24 This is the correct result after scaling has been performed.

[0222] Angle θ is the angle between the near-field vertical crosshair and the Y-axis, or between the horizontal crosshair and the X-axis, after considering the viewing angle. Therefore, finding the location of the intersection of the crosshair and the ellipse, and then applying the back-incidence angle, will give the intersection in a flat plane, thus allowing the angle θ to be determined from the arctangent of the x and y coordinates of the crosshair intersection.

[0223] It is important to know which crosshair is aligned with the X or Y axis and which direction the crosshair points to +X or +Y. This information can be determined from additional features on the fixture appearing on the X-ray image, such as the BB line or a line near the positive axis of the reference crosshair, or any other suitable feature.

[0224] The offset positions dx and dy represent the offsets of the x and y coordinates of the center of the near-field ring. This point can be directly tracked based on the tracker on the fixture and the corresponding point seen on the resulting x-ray. This point can be used for registration checks. That is, if the guided probe is pointing towards the center of the near-field ring, the image of the probe should show its tip located at the intersection of the crosshairs of the projected ellipse.

[0225] If the registration fixture is attached very precisely to the image intensifier, several parameters mentioned above become zero. That is, the incident angle α, the rotation axis reference φ, and the displacements dx and dy all become zero, thus simplifying the registration process. Therefore, similar to the BB fixture, the intersection of the crosshairs on the X-ray and the ring can be used as an adjustment tool, rather than for extracting transformation parameters. That is, if the X-ray shows a difference in the intersection of the ring's center and edge, such as... Figure 21 The depicted image can be adjusted manually or automatically on the image intensifier until the X-ray is centered, at which point the conversion will be simplified and the mapping will reach its optimal accuracy.

[0226] When using a ring in a registration fixture, distortion correction can be achieved in a manner similar to that applied to BB fixtures. For distortion correction to be effective, additional features are needed on the crosshairs of the ring fixture, with evenly spaced markings along each crosshair. These markings can be ray marks, circles, gaps, or any such features appearing on the visible projection of the X-ray image. Pincushion distortion and S-distortion can then be described and corrected by considering both the linearity of the crosshairs and the spacing between the indices on the crosshairs. Figure 36 and Figure 37 This illustrates the behavior of pincushion distortion and S-distortion on an image when using a ring fixture. It is assumed that since pincushion distortion is radially symmetrical about the image center, only a crosshair and marking are needed to identify and correct it; the crosshair is assumed to pass through the image center from one edge to the other. If the pincushion distortion is asymmetrical at different angles, additional crosshairs may be needed to assess the magnitude of the pincushion in different directions.

[0227] Figure 36 The image illustrates pincushion distortion that can occur when using a fluorescent microscope, which will cause X-rays emitted through a square grid to appear as a pincushion-distorted image 3602. For clarity, the pincushion pattern is shown as more exaggerated than a typical pattern. In the lower part of the figure, a ring with crosshairs and evenly spaced gaps within the crosshairs is shown as undistorted 3604 (left), and then with pincushion distortion 3606 (right). Note that the distortion does not affect the ring, but is clearly shown in the spacing of the gaps within the crosshairs, where the spacing increases from the center outwards to the visible ring. The magnitude of the pincushion distortion is measured as the increase in spacing between the indices from the center of the image to the edge. Similarly, barrel distortion will manifest as a decrease in the spacing from the center of the image to the crosshairs of the ring.

[0228] Figure 37 The diagram illustrates the S-distortion that can occur when using a fluorescent microscope, which will cause X-rays emitted through a square grid to appear as an S-distorted image 3702. For clarity, the S-pattern is shown as more exaggerated than a typical pattern. In the lower part of the figure, a ring with crosshairs is shown as undistorted 3704 (left), and then with S-distortion 3706 (right). Note that the distortion does not affect the ring, but is clearly shown on the already S-shaped crosshairs. The magnitude of the S-distortion is measured based on the amount by which the two crosshairs exhibit an S-shape.

[0229] 3D Surgical Planning in 2D :

[0230] In medical planning, such as when combined with a surgical robot platform, a plan for placing medical objects like surgical screws can be provided in 3D based on 2D images. For example, in such a plan, it can be assumed that the line segment drawn in one of the 2D views to represent the screw has a certain dimension (e.g., in the z-dimension) that enters and leaves the plane on which it is drawn. It can also be assumed that there are some start and end z-coordinates for entering and leaving the plane on which it is drawn. For example, if a pedicle screw is planned on anterior-posterior and transverse X-ray images, a suitable assumption about the z-coordinate could be: the screw size on the transverse X-ray represents the maximum length of the screw. That is, the screw does not enter or leave the plane at an angle, and therefore the tip and tail of the screw have the same z-coordinate in the local coordinate system of the transverse image. For the tip and tail to be equal z-coordinates, a value suitable for placing the screw at the center of the anterior-posterior image can be assumed. That is, for a user selecting x and y coordinates in a transverse planar view, any z-coordinate in the transverse image results in the screw image appearing at the center of the screen on the anterior-posterior image to be used.

[0231] In the implementation, other methods can be used to improve the initial guess about the unknown planning plane. For example, anterior-posterior and lateral images can be used for planning, where the tops of the two images can be oriented to represent the cephalic anatomical direction. If the user is informed by software prompts that they will place the left screw by placing it on the lateral image, the starting position of the screw on the anterior-posterior image may be oriented towards the left side of the screen, assuming the left side of the screen represents the left anatomical direction.

[0232] Once the initial position is specified by the user in one view and guessed or otherwise specified by the software in another view, any subsequent repositioning of the screw in either view can be mapped to the other view by satisfying a forward mapping from 3D coordinates to 2D. For example, the user may have already defined the x, y, z coordinates of the screw tip in a local Cartesian coordinate system associated with the registration fixture during transverse x-rays. If the user then interactively selects and drags the representation of the screw tip via software, they must move the tip in the xy plane of that Cartesian coordinate system, not in its z-direction, because the xy plane of the Cartesian coordinate system is parallel to the image plane. The x and y movements in this local coordinate system (where z movement = 0) can be updated interactively by the user. The resulting x, y, z coordinates associated with the local coordinate systems of the front-back and transverse x-rays are then also updated because the transformation between the local coordinate systems is known through tracking, allowing the planned tip of the screw to be mapped to a new position in the front-back images. By updating one image and then another in sequence, the user can move the screw to a 3D position known relative to two tracked positions of the registration fixture, and therefore known for both camera space and for the robot. The robot can then move to the position that allows the screw to be placed accurately.

[0233] It should be noted that if the two coordinate systems of the image are perpendicular, one representing the front-back and the other the transverse x-ray, then through software interaction, movement of the planned representation of the screw tip or tail in the head-to-tail direction in the front-back view will have the effect of causing the screw tip or tail representation to move head-to-tail by the same amount in the transverse view. However, movement of the screw tip or tail to the left or right in the front-back view may have no effect on the planned tip or tail position in the transverse image. Conversely, forward or backward movement of the screw tip or tail in the transverse image will have no effect on the screw tip or tail position in the front-back image, but head-to-tail movement of the screw tip or tail position in the transverse image will result in the screw tip or tail representation changing head-to-tail by the same amount in both the front-back and transverse images. If the two x-rays are not obtained perpendicularly, movement to the left, right, up, or down in one view of the planned screw tip or tail will cause the representation in the other view to move by at least some amount.

[0234] Although two views have been described for planning, such as a front-to-back and a transverse X-ray, planning for any number of X-ray images can be displayed and updated simultaneously, as long as the tracking information of the registration fixture is acquired when the images are obtained. For example, four images emitted in 45-degree increments can be displayed in the four quadrants of the screen, and the planning screws can be registered to each view. Updating the planning position in one view using software interaction will cause the image in each of the other views to change.

[0235] Figures 38 to 46 A novel registration fixture 2 is shown, which is configured to attach to the flat panel detector 4 side of a medical imaging device, rather than the transmitter side. Figure 38 The registration fixture 2 is ideally suited for use on a C-arm with a digital flat panel detector 4 to utilize digital imaging technology in medical imaging devices, which include lower radiation dose and enhanced image quality compared to image intensifier-based C-arm systems.

[0236] The registration fixture 2 includes a bottom frame 6, a first side frame 8, a second side frame 10, and a motion mount 12 detachably attached to the bottom frame 6. By definition, the motion mount restricts all six degrees of freedom of the side frames 8 and 10 relative to the bottom frame 6.

[0237] The bottom frame 6 is made of aluminum, which has the smallest volume and weight, but it can also be made of any material that is cost-effective, low-density, and high-strength and stiff.

[0238] The ray-permeable plate 14 is attached to the bottom frame 6. Figure 39 In the illustrated embodiment, plate 16 includes two plates 14, 16 that are perpendicularly spaced apart from each other. Orientation plate 14 is positioned closer to the flat panel detector 4, and registration plate 16 is positioned above the orientation plate.

[0239] Each plate is made of a radiopaque material (e.g., carbon fiber, Rohacell foam, acrylic resin, ABS, or similar materials) and houses embedded radiopaque markers 17, 19, which are uniquely configured and oriented for image processing and navigation purposes. In the illustrated embodiment, the radiopaque markers 17, 19 are 1 / 8-inch stainless steel spheres, but can also be composed of any number of radiopaque materials and various geometries.

[0240] In one embodiment, plates 14 and 16 are mounted to a precision flat surface on the bottom frame 6, with the spacing between the two plates between 10 mm and 75 mm. In another embodiment, this range is between 25 mm and 50 mm, which minimizes obstruction within the surgical work area for the clinical team. However, the plate spacing can be increased or decreased to improve accuracy.

[0241] Orientation and registration plates 14 and 16 are aligned with precision positioning pins 20 via a hole and slot structure to achieve optimal plate-to-plate alignment accuracy. The hole, slot, and pin structure of the two plates is unique to prevent incorrect installation.

[0242] Figure 40A An orientation plate 16 is shown having a first set of translucent markings 17 arranged in a predetermined pattern, while Figure 40B A registration plate 18 with a second set of transmissive markings 19 arranged in a predetermined pattern is shown.

[0243] The second set of marks 19 in the registration plate 18 includes a plurality of radiopaque marks that are equidistant from each other in a circular pattern. In the illustrated embodiment, there are 24 evenly spaced marks in the registration plate 18.

[0244] The first set of marks 17 in the orientation plate 16 includes a set of marks spaced apart from each other in a circular pattern, but the spacing between them is uneven. The diameter of the circle formed by the marks 17 is smaller than the diameter of the circle defined by the second set of marks 19 in the registration plate 18. The two circles defined by the marks (the smaller circle defined by mark 17 and the larger circle defined by mark 19) are coaxial and concentric with each other.

[0245] The first set of marks 17 also includes marks extending radially outward from the corresponding marks within a small circle defined by non-uniform marks (e.g., two marks are shown for each corresponding non-uniform interval), such that an imaginary line from the center of the circle intersects the radially extending marks and the corresponding marks in the circle. In the illustrated embodiment, there are 24 marks 17 in the orientation plate 16 (8 marks are located on the small circle, and 8 subsets of 2 marks extend radially from the corresponding marks in the circle). It is important to note that the registration plate 18 and the orientation plate 16 both have the same number of marks, 24 in total.

[0246] All radiopaque markings can be in the form of stainless steel balls or BBs, but they can be made of any suitable radiopaque material.

[0247] The placement, size, and number of radiopaque markers in the registration and orientation plates described above provide optimal parameters for: navigation accuracy, alignment requirements (i.e., the ability to detect sufficient markers and accurately place surgical implants even in the presence of alignment that would truncate the pattern), minimization of anatomical obstruction to the surgeon during navigation surgery, and orientation detection that allows navigation tracking software to deterministically detect whether an image has not been flipped 180 or 90 degrees.

[0248] Although reference plate registration fixture 2 describes a ray-permeable plate 14, they can be implemented as registration fixtures (such as...). Figure 18 As shown, the registration fixture is configured to be attached to the transmitter side of the imaging device.

[0249] The side frame has multiple optical tracking marks and is adapted to be detachably mounted to the bottom frame 6 without piercing the sterilization cover to be inserted between the bottom frame 6 and the side frame.

[0250] like Figure 38 As shown, each side frame includes six flat markings and six spherical markings fixed in relation to the non-transmissive markings. Side frames 8, 10 may be constructed of aluminum or any number of materials that provide sufficient strength, stiffness, weight, and optical properties relative to the system accuracy requirements.

[0251] Among many surface treatment options, the side frames 8, 10 may be sandblasted and black anodized to reduce potential reflections. In the illustrated embodiment, the two side frames 8, 10 are oriented 180 degrees to each other and extend vertically from the bottom frame 6. Each side frame 8, 10 may include mounting features to enable the use of a flat tracking disc 22 and a spherical marker 24. Figure 38 (Only the pillars are shown in the image) to allow both NIR and visible light to be tracked.

[0252] The flat markings 22 and the spherical markings 24 are arranged alternately. In one embodiment, when viewed from their respective sides (i.e. at 180 degrees to each other), the pattern and spacing of the markings 22, 24 on one side frame 8 are the same as the pattern and spacing of the markings 10 on the other side frame 10.

[0253] By using the motion mounting structure 12, the side frames 8, 10 and the bottom frame 6 are self-aligned and precisely oriented.

[0254] Each side frame 8, 10 is designed to be non-interchangeable by combining physical bonding features, which prevents accidental incorrect installation by the user.

[0255] like Figure 38 , Figure 41 and Figure 42As shown, the bottom frame 6 includes three spaced-apart motion mounting points 28 (recesses are shown as three V-shaped blocks), which are configured to be self-aligned to corresponding motion mounting points 26 (shown as three truncated spherical balls) on the bottom frame 6.

[0256] like Figure 42 As shown, the non-piercing clamp 30 includes a rotating pin 34 and a cam handle 36, which is coupled to the rotating pin and configured to move or translate the U-shaped clamp 32 to press the U-shaped clamp against the bottom frame 6. The U-shaped clamp 32 has a slot 42 (see...). Figure 43A The groove accommodates a portion of the side frame 8 to allow translational or sliding movement relative to the side frame, in order to compress or release the bottom frame 6. Figure 38 In the alternative embodiment shown, the U-shaped clamp 32 can be mounted above the side wall of the bottom frame 6, and the handle 38 has a threaded shaft 40 that is threadedly connected to the U-shaped clamp, such that rotation of the handle presses the U-shaped clamp against the bottom frame 6 to secure the side frame 8 to the bottom frame 6.

[0257] The first side frame 8 extends laterally on one side of the bottom frame 6, and its tracking marks 22, 24 are opposite to the bottom frame 6 in a first direction away from the bottom frame, while the second side frame 10 extends laterally on the other side of the bottom frame 6, and its tracking marks 22, 24 are opposite to the bottom frame 6 in a second direction opposite to the first direction.

[0258] like Figure 38 As shown, the first side frame 8 and the second side frame 10 are parallel to each other when mounted to the bottom frame 6. In the illustrated embodiment, the two side frames 8 and 10 are mounted vertically to the bottom frame 6.

[0259] In one embodiment, the spherical tracking mark 24 of the side frames 8, 10 is adapted to reflect infrared light (NIR), while the flat disc mark 22 is adapted to reflect visible light and in some embodiments is also adapted to reflect infrared light (NIR).

[0260] To improve the ability to be mounted on various flat C-arm detector housings, a variety of flexible ratchet belt structures have been designed and implemented.

[0261] Figure 45 A ratchet belt assembly 46 is shown, which includes a set of belts 48, 50; a pad assembly 52; and a ratchet 54 for attachment to a flat panel detector 4. Figure 46 The use of, as shown Figure 45 The ratchet belt assembly 46 shown will Figure 38The bottom frame 6 is attached to the flat panel detector 4. One end of a first belt 50 is rotatably attached to the bottom frame 6, and the other end is attached to a ratchet 54 via a pad assembly 52. ​​One end of a second belt 48 (trapezoidal belt) is rotatably coupled to the bottom frame 6, and the other side is coupled to the ratchet 54 for sliding adjustment relative to the first belt 50. The ratchet 54 allows adjustment of the belts 48, 50 to fit on various flat panel detectors 4. The ratchet belt assembly 46 is available, for example, from M2 Inc. of Colchester, VT. The belts 48, 50 extend from the bottom frame 6 and are configured to wrap around the underside of the flat panel detector 4 to temporarily secure the bottom frame 6 to the detector panel of the X-ray medical imaging apparatus during use.

[0262] In one configuration, the first belt 50 of the ratchet belt assembly is formed by an extension member that includes multiple through holes to improve adjustability. Figure 45 In another configuration, one end of the first band 50 is attached to a hook component, such as a spring-loaded hook, which is attached to a ring or handle located behind the flat panel detector 4.

[0263] The flat panel detector registration fixture 2 described above offers the following advantages.

[0264] Image collimation can be performed while still allowing for appropriate orientation and registration reference marker detection to meet navigation and image processing requirements. Collimation offers significant advantages in terms of image quality, as visualizing patient anatomy in certain scenarios can be extremely challenging without it.

[0265] The optical tracking array is mounted to a precision motion-mount structure using a clamp that prevents puncture of the sterilizing drape. This clamp is designed with a U-shaped geometry that moves via a cam handle integrated as an actuator or a threaded handle (acting as a lead screw) for rigid mounting to the base 6. This mounting strategy protects the integrity of the sterilizing drape.

[0266] The non-puncture side frames 8 and 10 with optical tracking markers facilitate the clamping of separable, sterilizable, and autoclave-compatible side frames, unlike traditional designs that use diaphragm-based puncture installation methods. The side frames 8 and 10, incorporating optical tracking markers, are separable from the bottom frame 6, can utilize disposable markers, and are machine washable and autoclave-compatible. The separable nature of the side frames 8 and 10 allows for optimization to improve accuracy in areas such as dimensional, segment length optimization, and positioning relative to potential operating room obstructions.

[0267] Optical tracking arrays combine passively tracked disks and spheres into a single frame component to facilitate tracking using NIR (spherical markers) and visible light techniques (flat disk markers).

[0268] Incorporate novel radiopaque reference patterns into orientation and registration plates to facilitate image processing and navigation workflows.

[0269] The ratchet belt mounting structure employs a non-deterministic compliant belt to facilitate the mounting of the fluoroscope clamp to various C-arm detector panel geometries. The ratchet belt includes an adjustable extension, tandemly fastened to a compliant pad with a spring-loaded mechanical ratchet, which engages with a flexible trapezoidal belt assembly. The trapezoidal belt may optionally include hook or loop components for mounting to a fixed C-arm handle. Optional safety elements incorporated into the belt assembly include rigid stops.

[0270] The modular ratchet belt assembly can be adjusted along the periphery of the fluorescence mirror clamp using a self-locking U-shaped clamp, combined with a spring-loaded wedge or equivalent positioning and self-locking feature. Considering various C-arm detector housings, the U-shaped clamp facilitates easy adjustment of the ratchet belt assembly by the user.

[0271] In one implementation, the orientation and registration plate spacing has been minimized to between 25 mm and 50 mm, compared to conventional fluorescein clamps with a plate spacing of 100 mm or greater, to minimize obstruction within the surgical workspace of the clinical team. This plate spacing can be reduced or increased to improve accuracy, but it has been minimized to maximize the available workspace for the clinical surgical team.

[0272] While the invention has been disclosed in conjunction with preferred embodiments shown and described in detail, various modifications and improvements thereto will be apparent to those skilled in the art. Therefore, the spirit and scope of the invention are not limited to the foregoing examples, but should be understood to have the broadest meaning permitted by law.

[0273] All references mentioned in this article are hereby incorporated by way of citation.

Claims

1. A registration fixture for registering medical images with a three-dimensional tracking space in conjunction with a surgical navigation system, comprising: A bottom frame adapted to be mounted above a flat panel detector of an x-ray medical imaging apparatus; A plate, the plate being attached to the bottom frame, the plate having a first set of opaque markings embedded therein in a first predetermined pattern and a second set of opaque markings embedded therein in a second predetermined pattern; A side frame having multiple optical tracking marks and adapted to be detachably mounted to the bottom frame without piercing the sterilization cover to be inserted between the bottom frame and the side frame.

2. The registration fixture according to claim 1, wherein the side frame is detachably mounted to the bottom frame via a motion mounting point without piercing the sterilization cover.

3. The registration fixture according to claim 1, wherein: The bottom frame includes at least three spaced-apart motion mounting points; The side frame includes complementary motion mounting points and is adapted to be mounted to corresponding motion mounting points on the bottom frame; as well as A non-piercing clamp, wherein the non-piercing clamp is used to secure the side frame without piercing the sterilization drape.

4. The registration fixture of claim 3, wherein the motion mounting point of the bottom frame includes a plurality of recesses, and the complementary motion mounting point includes a plurality of spherical balls adapted to self-align with the recesses.

5. The registration clamp according to claim 3, wherein the non-piercing tarpaulin clamp comprises: A U-shaped clamp, which can be mounted on the upper side wall of the bottom frame; A handle having a threaded shaft threadedly connected to the U-shaped clamp, such that rotation of the handle presses the U-shaped clamp against the bottom frame to secure the side frame to the bottom frame.

6. The registration clamp according to claim 3, wherein the non-piercing tarpaulin clamp comprises: A U-shaped clamp, which can be mounted on the upper side wall of the bottom frame; Rotary pin; A cam handle is connected to the rotary pin and configured to move the U-shaped clamp so as to press the U-shaped clamp against the bottom frame.

7. The registration fixture according to claim 1, wherein the side frame comprises: A first side frame extends laterally on one side of the bottom frame and has spaced-apart tracking marks that are opposite to the bottom frame in a first direction. The second side frame extends laterally on the other side of the bottom frame and has spaced tracking marks that are opposite to the bottom frame in a second direction opposite to the first direction.

8. The registration fixture of claim 7, wherein the first side frame and the second side frame are parallel to each other when mounted to the bottom frame.

9. The registration fixture of claim 1, wherein the optical tracking mark comprises a plurality of spaced-apart spherical marks adapted to reflect light.

10. The registration fixture of claim 1, wherein the optical tracking marks comprise a plurality of spaced-apart disc marks adapted to reflect light.

Images