Medical imaging system and associated devices and methods - Patents.com

Abstract

Systems, methods, and devices for medical imaging are disclosed herein. In some embodiments, a method for imaging an anatomical region includes receiving a plurality of images of the anatomical region from a detector carried by an imaging arm of an x-ray imager. The images can be acquired during a mutual rotation of the imaging arm. The imaging arm can be stabilized by a shim structure during the mutual rotation. The method can also include receiving pose data of the imaging arm from at least one sensor coupled to the imaging arm during the mutual rotation. The method can further include generating a 3D representation of the anatomical region based on the images and the pose data.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of priority to U.S. Provisional Application No. 63 / 172,886, filed April 9, 2021, U.S. Provisional Application No. 63 / 203,270, filed July 15, 2021, and U.S. Provisional Application No. 63 / 260,241, filed August 13, 2021, each of which is incorporated by reference in its entirety herein.

[0002] The present technology relates generally to medical imaging, and more particularly to systems and associated methods and devices for generating three-dimensional (3D) representations of a patient's anatomy. [Background technology]

[0003] 3D anatomical models, such as computed tomography (CT) volumetric reconstructions, are frequently used in image-guided medical procedures to allow physicians to visualize a patient's anatomy in three dimensions and accurately position surgical tools in the appropriate locations. However, 3D models generated from procedure image data may not accurately reflect the actual anatomy during the procedure. Also, if the model is not properly registered to the anatomy, it may be difficult or impossible for the physician to navigate the tools to the correct location, thus compromising the accuracy and effectiveness of the procedure.

[0004] Cone beam computed tomography (CBCT) has been used to generate high-resolution 3D volumetric reconstructions of a patient's anatomy for image guidance during medical procedures. However, many physicians do not have ready access to conventional CBCT imaging systems because these systems are very expensive and are often reserved for use by specialized departments. Tomosynthesis (also known as limited angle tomography) has also been used for intraprocedural imaging, but this technology is not available to produce 3D reconstructions with sufficiently high resolution for many procedures. Thus, improved medical imaging systems and methods are needed. Summary of the Invention [Means for solving the problem]

[0005] The present technology generally relates to systems, methods, and devices for medical imaging. For example, in some embodiments, the systems and methods described herein use a mobile C-arm X-ray imaging device (also referred to herein as a "mobile C-arm device") to generate a 3D reconstruction of a patient's anatomy using CBCT imaging techniques. Unlike conventional systems and devices specialized for CBCT imaging, the mobile C-arm device may lack a motor and / or other automated mechanism for rotating the imaging arm that carries the X-ray source and detector. Instead, the imaging arm is manually rotated through a series of different angles to obtain a sequence of two-dimensional (2D) projection images of the anatomy. In some circumstances, the manual rotation may result in undesirable movement (e.g., oscillation, vibration, shift, flexion) of the imaging arm that may interfere with the quality of the 3D reconstruction generated from the 2D images. In addition, the mobile C-arm device may lack a sensor for obtaining posture data of the imaging arm during image acquisition, which may be required for accurate 3D reconstruction.

[0006] Thus, in some embodiments, a method for imaging an anatomical region includes receiving a plurality of 2D images of the anatomical region from a detector carried by an imaging arm (e.g., a mobile C-arm device) of an X-ray imager. The 2D images can be acquired during manual rotation of the imaging arm. The imaging arm can be stabilized by a shim structure during manual rotation to reduce or prevent undesired movement. The method can also include receiving sensor data from at least one sensor (e.g., an inertial measurement unit (IMU)) coupled to the imaging arm during manual rotation, the sensor data indicating a plurality of orientations of the imaging arm. The method can further include generating a 3D reconstruction of the anatomical region based on the 2D images and the sensor data. The 3D reconstruction can be displayed to a physician or other operator to provide image-based guidance during a medical procedure (e.g., a biopsy or ablation procedure) performed within the anatomical region.

[0007] The embodiments described herein can provide many advantages over conventional imaging techniques. For example, the systems and methods herein can generate high-quality CBCT images of a patient's anatomy using a manually rotating, moving C-arm device rather than a specialized CBCT imaging system. This approach can reduce the cost and increase the availability of CBCT imaging, thus allowing CBCT imaging techniques to be used in many different types of medical procedures. For example, CBCT imaging can be used to generate intra-procedure 3D models of anatomical regions to guide physicians in precisely positioning tools to target locations within the anatomy, e.g., for biopsy, ablation, or other diagnostic or therapeutic procedures. [Brief description of the drawings]

[0008] Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Emphasis instead is placed upon clearly illustrating the principles of the present disclosure.

[0009] [Figure 1A] 1A-1E illustrate a system for imaging a patient in accordance with an embodiment of the present technology. [Figure 1B] 1A-1E illustrate a system for imaging a patient in accordance with an embodiment of the present technology. [Figure 1C] 1A-1E illustrate a system for imaging a patient in accordance with an embodiment of the present technology. [Figure 1D] 1A-1E illustrate a system for imaging a patient in accordance with an embodiment of the present technology. [Figure 1E] 1A-1E illustrate a system for imaging a patient in accordance with an embodiment of the present technology.

[0010] [Figure 2A] 2A and 2B illustrate examples of undesirable movements that can occur with a manually operated imaging device. [Figure 2B] 2A and 2B illustrate examples of undesirable movements that can occur with a manually operated imaging device.

[0011] [Figure 3A] 3A and 3B illustrate a set of shim structures constructed in accordance with an embodiment of the present technology. [Figure 3B] 3A and 3B illustrate a set of shim structures constructed in accordance with an embodiment of the present technology.

[0012] [Figure 3C] 3C and 3D illustrate shim structures having variable thicknesses in accordance with embodiments of the present technology. [Figure 3D] 3C and 3D illustrate shim structures having variable thicknesses in accordance with embodiments of the present technology.

[0013] [Figure 4A] 4A and 4B illustrate a set of L-shaped shim structures constructed in accordance with an embodiment of the present technology. [Figure 4B]4A and 4B illustrate a set of L-shaped shim structures constructed in accordance with an embodiment of the present technology.

[0014] [Figure 4C] 4C and 4D illustrate an adjustable L-shaped shim structure constructed in accordance with an embodiment of the present technology. [Figure 4D] 4C and 4D illustrate an adjustable L-shaped shim structure constructed in accordance with an embodiment of the present technology.

[0015] [Figure 5A] 5A and 5B illustrate a set of U-shaped shim structures constructed in accordance with an embodiment of the present technology. [Figure 5B] 5A and 5B illustrate a set of U-shaped shim structures constructed in accordance with an embodiment of the present technology.

[0016] [Figure 5C] 5C and 5D illustrate an adjustable U-shaped shim structure constructed in accordance with an embodiment of the present technology. [Figure 5D] 5C and 5D illustrate an adjustable U-shaped shim structure constructed in accordance with an embodiment of the present technology.

[0017] [Figure 6A] 6A and 6B illustrate another set of U-shaped shim structures constructed in accordance with an embodiment of the present technology. [Figure 6B] 6A and 6B illustrate another set of U-shaped shim structures constructed in accordance with an embodiment of the present technology.

[0018] [Figure 7A] 7A and 7B illustrate a shim structure with two arm regions constructed in accordance with an embodiment of the present technology. [Figure 7B] 7A and 7B illustrate a shim structure with two arm regions constructed in accordance with an embodiment of the present technology.

[0019] [Figure 7C] 7C and 7D illustrate a shim structure with tapered arm regions constructed in accordance with an embodiment of the present technology. [Figure 7D] 7C and 7D illustrate a shim structure with tapered arm regions constructed in accordance with an embodiment of the present technology.

[0020] [Figure 7E] FIG. 7E illustrates a shim structure including a set of ridges, configured in accordance with an embodiment of the present technology.

[0021] [Figure 7F] FIG. 7F illustrates a shim structure including multiple protrusions, configured in accordance with an embodiment of the present technology.

[0022] [Figure 7G] FIG. 7G illustrates a shim structure including multiple square or rectangular cutouts, configured in accordance with an embodiment of the present technology.

[0023] [Figure 7H] FIG. 7H illustrates a shim structure including a plurality of triangular notches, configured in accordance with an embodiment of the present technology.

[0024] [Figure 8A] 8A and 8B illustrate a set of shim structures with rollers configured in accordance with an embodiment of the present technology. [Figure 8B] 8A and 8B illustrate a set of shim structures with rollers configured in accordance with an embodiment of the present technology.

[0025] [Figure 9A] 9A-9F illustrate a shim structure with mounting features configured in accordance with an embodiment of the present technology. [Figure 9B] 9A-9F illustrate a shim structure with mounting features configured in accordance with an embodiment of the present technology. [Figure 9C] 9A-9F illustrate a shim structure with mounting features configured in accordance with an embodiment of the present technology. [Figure 9D] 9A-9F illustrate a shim structure with mounting features configured in accordance with an embodiment of the present technology. [Figure 9E] 9A-9F illustrate a shim structure with mounting features configured in accordance with an embodiment of the present technology. [Figure 9F] 9A-9F illustrate a shim structure with mounting features configured in accordance with an embodiment of the present technology.

[0026] [Figure 10A] 10A-10D illustrate another shim structure with a mounting mechanism configured in accordance with an embodiment of the present technology. [Figure 10B] 10A-10D illustrate another shim structure with a mounting mechanism configured in accordance with an embodiment of the present technology. [Figure 10C] 10A-10D illustrate another shim structure with a mounting mechanism configured in accordance with an embodiment of the present technology. [Figure 10D] 10A-10D illustrate another shim structure with a mounting mechanism configured in accordance with an embodiment of the present technology.

[0027] [Figure 11] FIG. 11 is a graph illustrating the motion of the motion sensor on the C-arm detector with and without shim stabilization.

[0028] [Figure 12] FIG. 12 illustrates an example of undesirable movement that can occur with a manually operated imaging device.

[0029] [Figure 13A] 13A and 13B illustrate a lever structure configured in accordance with an embodiment of the present technology. [Figure 13B] 13A and 13B illustrate a lever structure configured in accordance with an embodiment of the present technology.

[0030] [Figure 13C] FIG. 13C illustrates an adjustable lever structure constructed in accordance with an embodiment of the present technology.

[0031] [Figure 13D] FIG. 13D illustrates another adjustable lever structure constructed in accordance with an embodiment of the present technology.

[0032] [Figure 14A] 14A and 14B illustrate a lever structure in accordance with an embodiment of the present technology. [Figure 14B] 14A and 14B illustrate a lever structure in accordance with an embodiment of the present technology.

[0033] [Figure 14C] FIG. 14C illustrates another lever structure constructed in accordance with an embodiment of the present technology.

[0034] [Figure 14D] 14D and 14E illustrate an adjustable lever structure constructed in accordance with an embodiment of the present technology. [Figure 14E] 14D and 14E illustrate an adjustable lever structure constructed in accordance with an embodiment of the present technology.

[0035] [Figure 15] FIG. 15 illustrates a motion sensor coupled to an imaging device in accordance with an embodiment of the present technology.

[0036] [Figure 16] FIG. 16 illustrates a motion sensor and a radiation sensor coupled to an imaging device in accordance with an embodiment of the present technology.

[0037] [Figure 17A] 17A and 17B illustrate an attachment device configured in accordance with an embodiment of the present technology. [Figure 17B]17A and 17B illustrate an attachment device configured in accordance with an embodiment of the present technology.

[0038] [Figure 17C] FIG. 17C illustrates the mounting device of FIGS. 17A and 17B coupled to an imaging device in accordance with an embodiment of the present technology.

[0039] [Figure 17D] FIG. 17D illustrates another attachment device configured in accordance with an embodiment of the present technology.

[0040] [Figure 17E] FIG. 17E illustrates another attachment device configured in accordance with an embodiment of the present technology.

[0041] [Figure 18A] 18A and 18B illustrate a fiducial markerboard for pose estimation, in accordance with an embodiment of the present technology. [Figure 18B] 18A and 18B illustrate a fiducial markerboard for pose estimation, in accordance with an embodiment of the present technology.

[0042] [Figure 18C] FIG. 18C illustrates another fiducial marker board in accordance with an embodiment of the present technology.

[0043] [Figure 18D] FIG. 18D illustrates yet another fiducial marker board in accordance with an embodiment of the present technology.

[0044] [Figure 18E] FIG. 18E illustrates another fiducial marker board in accordance with an embodiment of the present technology.

[0045] [Figure 18F] 18F and 18G illustrate a fiducial marker board and phantom in accordance with an embodiment of the present technology. [Figure 18G]18F and 18G illustrate a fiducial marker board and phantom in accordance with an embodiment of the present technology.

[0046] [Figure 19] FIG. 19 is a flow diagram illustrating a method for operating an imaging device in accordance with an embodiment of the present technology.

[0047] [Figure 20] FIG. 20 is a flow diagram illustrating a method for calibrating an imaging device in accordance with an embodiment of the present technology.

[0048] [Figure 21A] 21A-21D illustrate fiducial marker grids for distortion correction, in accordance with an embodiment of the present technology. [Figure 21B] 21A-21D illustrate fiducial marker grids for distortion correction, in accordance with an embodiment of the present technology. [Figure 21C] 21A-21D illustrate fiducial marker grids for distortion correction, in accordance with an embodiment of the present technology. [Figure 21D] 21A-21D illustrate fiducial marker grids for distortion correction, in accordance with an embodiment of the present technology.

[0049] [Figure 22A] FIG. 22A illustrates a fiducial marker phantom for geometric calibration in accordance with an embodiment of the present technology.

[0050] [Figure 22B] FIG. 22B illustrates another fiducial marker phantom constructed in accordance with an embodiment of the present technology.

[0051] [Figure 22C] FIG. 22C illustrates an assembly that may form part of the fiducial marker phantom of FIG. 22B in accordance with an embodiment of the present technology.

[0052] [Figure 22D]FIG. 22D illustrates another fiducial marker phantom constructed in accordance with an embodiment of the present technology.

[0053] [Figure 23A] FIG. 23A is a flow diagram illustrating a method for imaging an anatomical region in accordance with an embodiment of the present technology.

[0054] [Figure 23B] FIG. 23B is a flow diagram illustrating a method for generating a 3D reconstruction, in accordance with an embodiment of the present technology.

[0055] [Figure 24] FIG. 24 is a flow diagram illustrating a method for preparing an imaging device for image acquisition in accordance with an embodiment of the present technology.

[0056] [Figure 25A] FIG. 25A is a flow diagram illustrating a method for calibration and image acquisition using a fiducial marker board in accordance with an embodiment of the present technology.

[0057] [Figure 25B] FIG. 25B is a flow diagram illustrating a method for operating an imaging device in accordance with an embodiment of the present technology.

[0058] [Figure 26A] FIG. 26A is a CBCT image of the phantom generated by a manually operated imager without calibration or shim stabilization.

[0059] [Figure 26B] FIG. 26B is a CBCT image of the phantom generated by a manually operated imaging device with calibration and shim stabilization in accordance with an embodiment of the present technology.

[0060] [Figure 27A] FIG. 27A is a CBCT image of the lungs generated by a manually operated imaging device without calibration or shim stabilization.

[0061] [Figure 27B] FIG. 27B is a CBCT image of the lungs generated by a manually operated imaging device with calibration and shim stabilization in accordance with an embodiment of the present technology.

[0062] [Figure 27C] FIG. 27C is a CBCT image of the lungs generated using a robotic CBCT imaging system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0063] Embodiments of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings, in which like numerals represent like elements throughout the several views, and in which exemplary embodiments are shown. However, the claimed embodiments may be embodied in many different forms and should not be construed as being limited to the embodiments described herein. The examples described herein are non-limiting examples and are merely examples among other possible examples.

[0064] As used herein, the terms "vertical," "lateral," "upper," and "lower" may refer to the relative orientation or location of a feature of the embodiments disclosed herein in light of the orientation shown in the figures. For example, "upper" or "uppermost" may refer to a feature that is located closer to the top of the page than another feature. However, these terms should be broadly construed to include embodiments having other orientations, such as inverted or tilted orientations, and top / bottom, over / over, above / below, top / bottom, and left / right may be interchanged depending on the orientation.

[0065] Certain embodiments of the present technology are described in the context of medical procedures performed in the lungs, but this is not intended to be limiting. Any of the embodiments disclosed herein can also be used in other types of medical procedures, such as procedures performed on or in the musculoskeletal system, vascular system, abdominal cavity, gastrointestinal tract, genitourinary tract, brain, etc. In addition, any of the embodiments herein can also be used for applications such as surgical tool guidance, biopsy, ablation, chemotherapy administration, surgery, or any other procedure to diagnose or treat a patient.

[0066] The headings provided herein are for convenience only and do not interpret the scope or meaning of the claimed technology.

[0067] I. Technology Overview Lung cancer kills more people each year than breast, prostate, and colon cancers combined. Most lung cancers are diagnosed at late stages, which contributes to high mortality rates. Early diagnosis of lung cancer (e.g., at stages 1-2) can significantly improve survival rates. The first step in diagnosing early stage lung cancer is to perform a lung biopsy on the suspicious nodule or lesion. Bronchoscopic lung biopsy is the traditional biopsy route, but typically suffers from poor success rates (e.g., only 50%-70% of nodules are correctly diagnosed), meaning that many patients' cancer status remains uncertain even after the biopsy procedure. One common reason for non-diagnostic biopsies is the inability of physicians to place the biopsy needle in the correct location within the nodule before collecting the biopsy sample. This situation may arise due to shortcomings in conventional techniques to guide physicians in navigating the needle to the target nodule. For example, conventional techniques typically use a static chest CT scan of the patient acquired prior to the biopsy procedure (e.g., days to weeks prior) that is registered to the patient's anatomy during the procedure (e.g., via electromagnetic (EM) navigation or shape sensing techniques). Registration errors can cause the physician to miss the nodule entirely during needle placement. Also known as CT / body divergence, these errors arise when the pre-procedure scan data does not match the patient's anatomy data acquired during the actual procedure. These differences can arise because the lungs are dynamic, often changing volume from day to day and / or when the patient is under anesthesia. Studies have shown that the average error between a pre-procedure CT scan and the patient's anatomy during the procedure is 1.8 cm, which is larger than many of the lung nodules being biopsied.

[0068] CBCT is an imaging technique capable of producing high-resolution 3D volumetric reconstructions of a patient's anatomy. For bronchoscopic lung biopsy, in-procedure CBCT imaging can be used to ensure that the biopsy needle is properly positioned relative to the target nodule and has been shown to increase diagnostic accuracy by nearly 20%. A typical CBCT procedure involves scanning the patient's body with a cone-shaped x-ray beam that is rotated through a wide arc (e.g., 180°-360°) and acquires a sequence of 2D projection images. A 3D volumetric reconstruction of the anatomy can be generated from the 2D images using image reconstruction techniques such as filtered backprojection or iterative reconstruction. Conventional CBCT imaging systems include a motorized imaging arm for automated, highly controlled rotation of the x-ray source and detector through a smooth arc during image acquisition. These systems are also capable of accurately tracking the pose of the imaging arm across different rotation angles. However, CBCT imaging systems are typically large and very expensive and may not be available to many physicians, such as pulmonologists, who perform lung biopsy procedures.

[0069] Although manually operated mobile C-arm devices are less expensive and more readily available than specialized CBCT imaging systems, they are generally not suitable for CBCT imaging for some or all of the following reasons. First, mobile C-arm devices typically lack a motorized imaging arm and therefore must be rotated manually during image acquisition. However, manual rotation makes it very difficult to produce smooth, isocentered, circular motion of the imaging arm over a sufficiently large angle (e.g., greater than 90°) for CBCT imaging. Due to mechanical instabilities present in many mobile C-arm devices, the imaging arm may exhibit undesirable motions (e.g., oscillations, vibrations, shifts, flexures) during manual rotation, which may move the imaging arm along a non-circular trajectory or otherwise adversely affect the quality of the resulting 3D reconstruction. Second, mobile C-arm devices generally lack the ability to accurately determine the orientation of the imaging arm as it rotates around the patient. In a typical CBCT imaging procedure, hundreds of images are acquired at a rate of 10-50 images / second, and the posture of the imaging arm must be determined for each image. Third, mobile C-arm devices often use image intensifiers as x-ray detectors, which can create significant distortion artifacts that interfere with accurate image reconstruction. Image intensifiers are also relatively heavy (e.g., hundreds of pounds) and therefore can further destabilize the imaging arm during manual rotation.

[0070] Tomosynthesis is a technique that can be used to generate intra-procedural images of a patient's anatomy. However, because tomosynthesis uses a much smaller rotation angle (e.g., 15°-70°) during image acquisition, the resulting images are typically low resolution, lack sufficient depth information, and / or may contain significant distortion. Tomosynthesis is therefore typically not suitable for applications that require highly accurate 3D spatial information.

[0071] Thus, there is a need for imaging techniques that are capable of producing high-resolution 3D representations of a patient's anatomy during a procedure using a low-cost accessible imaging system, such as a mobile C-arm device. The present technology can address these and other challenges by providing systems, methods, and devices for performing CBCT imaging using a manually rotating imaging device, also referred to herein as "manually rotating CBCT" or "mrCBCT". For example, in some embodiments, the systems described herein mechanically stabilize the imaging arm and / or other components of the mobile C-arm device using one or more shim structures (e.g., wedges, blocks, dampers, etc.) that reduce or prevent undesired movement during manual rotation. The systems also include one or more lever structures (e.g., removable or permanently affixed handles) to assist the operator in rotating the imaging arm from a location that is less likely to cause undesired movement. The systems can further include at least one sensor (e.g., a motion sensor such as an IMU) that automatically tracks the orientation of the imaging arm during rotation. The sensor data is synchronized in time to the acquired 2D projection images, allowing for accurate determination of the imaging arm pose for each image. In some embodiments, the system is calibrated before and / or during use to correct for image distortion (e.g., from the image intensifier), determine calibration parameters, compensate for mechanical differences between individual mobile C-arm devices, and / or adjust for variations in the way an operator manually rotates the imaging arm. The approaches described herein can be used to adapt manually operated mobile C-arm devices for CBCT imaging, thus enabling high quality CBCT reconstructions to be produced using relatively inexpensive and accessible imaging equipment.

[0072] II. Medical Imaging Systems and Associated Devices and Methods 1A is a partial schematic diagram of a system 100 for imaging a patient 102, in accordance with an embodiment of the present technology. The system 100 includes an imaging device 104 operably coupled to a console 106. The imaging device 104 can be any suitable device configured to generate an image of a target anatomical region of the patient 102, such as an X-ray imager. In the illustrated embodiment, for example, the imaging device 104 is a mobile C-arm device configured for fluoroscopic imaging. The mobile C-arm device typically includes a manually movable imaging arm 108 (also known as a "C-arm") configured as a curved C-shaped gantry. Examples of mobile C-arm devices include, but are not limited to, the OEC 9900 Elite (GE Healthcare) and the BV Pulsera (Philips). However, in other embodiments, the techniques described herein can be adapted to other types of imaging devices 104 having a manually movable imaging arm 108, such as a G-arm imaging device.

[0073] The imaging arm 108 can carry a radiation source 110 (e.g., an X-ray source) and a detector 112 (e.g., an X-ray detector, such as an image intensifier or a flat panel detector). The radiation source 110 can be mounted to a first end portion 114 of the imaging arm 108, and the detector 112 can be mounted to a second end portion 116 of the imaging arm 108 opposite the first end portion 114. During a medical procedure, the imaging arm 108 can be positioned near the patient 102 such that a target anatomical region is located between the radiation source 110 and the detector 112. The imaging arm 108 can be rotated to a desired orientation (e.g., angle) relative to the target anatomical region. The radiation source 110 can output radiation (e.g., X-rays) that travels through the patient's body to the detector 112 and generates a 2D image (also referred to herein as a "projection image") of the anatomical region. The image data can be output as a still or video image. In some embodiments, the imaging arm 108 is rotated through a sequence of different poses to acquire multiple 2D projection images. The images can be used to generate a 3D representation of the anatomical region (also referred to herein as a "3D reconstruction," "volume reconstruction," "image reconstruction," or "CBCT reconstruction"). The 3D representation can be displayed as a 3D model or rendering and / or as one or more 2D image slices (also referred to herein as a "CBCT image" or "reconstructed image").

[0074] In some embodiments, the imaging arm 108 is coupled to a base 118 by a support arm 120. The base 118 can act as a counterweight for the imaging arm 108, the radiation source 110, and the detector 112. As shown in FIG. 1A, the base 118 can be a mobile structure including wheels for positioning the imaging device 104 at various locations relative to the patient 102. However, in other embodiments, the base 118 can be a stationary structure. The base 118 can also carry various functional components for receiving, storing, and / or processing image data from the detector 112, as discussed further below.

[0075] A support arm 120 (also referred to as a "mounting arm" or "pivot arm") can connect the imaging arm 108 to the base 118. The support arm 120 can be an elongated structure having a distal portion 122 that is coupled to the imaging arm 108 and a proximal portion 124 that is coupled to the base 118. Although the support arm 120 is depicted in FIG. 1A as an L-shaped structure (an "L-arm") having a vertical section and a horizontal section, in other embodiments, the support arm 120 can have a different shape (e.g., a curved shape).

[0076] The imaging arm 108 can be configured to rotate in multiple directions relative to the base 118. For example, FIG. 1B is a partial schematic diagram of the imaging device 104 during orbital rotation. As shown in FIG. 1B, during orbital rotation, the imaging arm 108 rotates relative to the support arm 120 and the base 118 along a longitudinal direction, as indicated by arrow 136. Thus, during orbital rotation, the motion trajectory can be located primarily or entirely within the plane of the imaging arm 108. The imaging arm 108 can be slidably coupled to the support arm 120, allowing for orbital rotation of the imaging arm 108. For example, the imaging arm 108 can be connected to the support arm 120 via a first interface 126, which allows the imaging arm 108 to slide along the support arm 120.

[0077] FIG. 1C is a perspective view of the first interface 126, and FIG. 1D is a partial schematic cross-sectional view of the first interface 126 along axis AA in FIG. 1B. Referring together to FIGS. 1C and 1D, the imaging arm 108 can include a pair of rails 138 and a track 140 recessed between the rails 138. The rails 138 can be located on opposite sides of the first interface 126 (e.g., a first side 142 and a second side 144). The distal portion 122 of the support arm 120 can fit between the rails 138 and at least partially within the track 140. The rails 138, the track 140, and the distal portion 122 can collectively form the first interface 126. As best seen in FIG. 1D, the distal portion 122 can include a pair of grooves or notches 146 that engage the rails 138 and secure the distal portion 122 to the track 140. The distal portion 122 may also include one or more wheels or rollers 148 that contact the inner surface of the track 140 so that the imaging arm 108 may slide smoothly relative to the support arm 120 during orbital rotation.

[0078] FIG. 1E is a partial schematic diagram of imaging device 104 during propeller rotation (also known as "angular rotation" or "angulation"). As shown in FIG. 1E, during propeller rotation, imaging arm 108 and support arm 120 rotate in a lateral direction relative to base 118, as indicated by arrow 150. Support arm 120 can be rotatably coupled to base 118 via a second interface 128 (e.g., a pivot joint or other rotatable connection) that allows imaging arm 108 and support arm 120 to pivot relative to base 118. Optionally, imaging device 104 can include a locking mechanism to prevent orbital rotation while imaging arm 108 performs propeller rotation and / or to prevent propeller rotation while imaging arm 108 performs orbital rotation.

[0079] 1A , imaging device 104 can optionally be configured to rotate in other directions as an alternative to or in addition to orbital and / or propeller rotation. For example, in some embodiments, imaging arm 108 and distal portion 122 of support arm 120 are rotatable relative to support arm 120 and the remainder of base 118 (also known as "flip-flop" rotation). Flip-flop rotation can be advantageous in some circumstances to reduce interference with other components (e.g., surgical robotic assemblies) located near surgical table 152.

[0080] The imaging device 104 can be operatively coupled to a console 106 to control the operation of the imaging device 104. As shown in FIG. 1A, the console 106 can be a mobile structure with wheels, thus allowing the console 106 to be moved independently of the imaging device 104. However, in other embodiments, the console 106 can be a stationary structure. The console 106 can be attached to the imaging device 104 by wires, cables, etc., or can be a separate structure that communicates with the imaging device 104 via wireless communication techniques. The console 106 can include a computing device 130 (e.g., a workstation, personal computer, laptop computer, etc.) that includes one or more processors and memory configured to perform various operations related to image acquisition and / or processing. For example, computing device 130 may perform some or all of the following operations: receiving, organizing, storing, and / or processing data related to generating the 3D reconstruction (e.g., image data, sensor data, calibration data), executing image reconstruction algorithms, executing calibration algorithms, and post-processing, rendering, and / or displaying the 3D reconstruction. Additional examples of operations that may be performed by computing device 130 are described in more detail elsewhere herein.

[0081] The computing device 130 can receive data from various components of the system 100. For example, the computing device 130 can be operatively coupled to the imaging device 104 (e.g., to the radiation source 110, the detector 112, and / or the base 118) via wires and / or wireless communication modalities (e.g., Bluetooth, Wifi) such that the computing device 130 can transmit commands to the imaging device 104 and / or receive data from the imaging device 104. In some embodiments, the computing device 130 transmits commands to the imaging device 104 to cause the imaging device 104 to start acquiring images, stop acquiring images, adjust image acquisition parameters, etc. The imaging device 104 can transmit image data (e.g., projection images acquired by the detector 112) to the computing device 130. The imaging device 104 may also transmit status information to the computing device 130, such as whether the components of the imaging device 104 are functioning properly, whether the imaging device 104 is ready for image acquisition, whether the imaging device 104 is currently acquiring an image, etc.

[0082] Optionally, computing device 130 can also receive other types of data from imaging device 104. In the embodiment of FIG. 1A, for example, imaging device 104 includes at least one sensor 154 configured to generate sensor data indicative of a posture of imaging arm 108. The sensor data can be transmitted via wired or wireless communication to computing device 130 for use in the image processing techniques described herein. Additional details of the configuration and operation of sensor 154 are provided below.

[0083] The console 106 may include various user interface components that enable an operator (e.g., a doctor, nurse, technician, or other health care professional) to interact with the computing device 130. For example, the operator may enter commands into the computing device 130 via suitable input devices (e.g., a keyboard, mouse, joystick, touch screen, microphone). The console 106 may also include a display 132 (e.g., a monitor or touch screen) for outputting image data, sensor data, reconstruction data, status information, control information, and / or any other suitable information to the operator. Optionally, the base 118 may also include a secondary display 134 for outputting information to the operator.

[0084] Although FIG. 1A illustrates the console 106 as being separate from the imaging device 104, in other embodiments, the console 106 can be physically connected to the imaging device 104 (e.g., to the base 118) by wires, cables, or the like. Additionally, in other embodiments, the base 118 can include a separate computing device and / or input device such that the imaging device 104 can also be controlled from the base 118. In such embodiments, the computing device located within the base 118 can be configured to perform any of the image acquisition and / or processing operations described herein. Optionally, the console 106 can be integrated with the base 118 (e.g., the computing device 130 is located within the base 118) or omitted entirely such that the imaging device 104 is controlled entirely from the base 118. In some embodiments, the system 100 includes multiple consoles 106 (e.g., at least two consoles 106), each with a separate computing device 130. Any of the processes described herein may be performed on a single console 106 or across any suitable combination of multiple consoles 106 .

[0085] A. Stability Devices and Methods 1A , system 100 can be used to perform imaging procedures in which an operator manually rotates imaging arm 108 during imaging acquisition, such as an mrCBCT procedure. In such an embodiment, imaging apparatus 104 can be a manually operated device lacking any motor or other actuator for automatically rotating imaging arm 108. For example, one or both of first interface 126 and second interface 128 may lack any automated mechanisms for actuating orbital and propeller rotation, respectively, of imaging arm 108. Instead, a user manually applies rotational forces to imaging arm 108 and / or support arm 120 during an mrCBCT procedure.

[0086] In some embodiments, the imaging procedure involves performing a propeller rotation of the imaging arm 108. The propeller rotation may be advantageous for mrCBCT or other imaging techniques that involve rotating the imaging arm 108 through a relatively large rotation angle. For example, the mrCBCT or similar imaging procedure may involve rotating the imaging arm 108 through a range of at least 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, 180°, 190°, 200°, 210°, 220°, 230°, 240°, 250°, 260°, 270°, 280°, 290°, 300°, 310°, 320°, 330°, 340°, 350°, or 360°. The total rotation can be in the range of 90°-360°, 90°-270°, 90°-180°, 120°-360°, 120°-270°, 120°-180°, 180°-360°, or 180°-270°. As described above, a large rotation angle may be required to capture a sufficient number of images from different angles or rotational positions to generate an accurate high-resolution 3D reconstruction of the anatomy. In many situations, it is not possible to achieve such a large rotation angle using orbital rotation. For example, as shown in FIG. 1A, when the imaging device 104 is positioned at one end of the patient's body (e.g., near the head and / or torso of the patient 102), the orbital rotation of the imaging arm 108 may be constrained to a relatively limited rotation angle (e.g., less than 90°) by the location of the patient 102 and / or the operating table 152.

[0087] Larger rotation angles can be achieved using propeller rotation, even in the configuration shown in FIG. 1A. However, propeller rotation may not be as mechanically stable as orbital rotation, especially when rotational forces are applied manually. Thus, in the absence of a stabilization mechanism (e.g., when shim structure 156 is omitted), imaging arm 108 may exhibit undesirable movement during manual propeller rotation that may adversely affect the quality of the resulting CBCT reconstruction. Examples of undesirable movement that may occur include, but are not limited to, oscillations, vibrations, sudden deviations, flexures, and / or other non-uniform motions that cause imaging arm 108 to deviate from a desired trajectory (e.g., a smooth, single-plane, isocenter, and / or circular trajectory). Undesirable movement may occur due to mechanical instabilities of imaging device 104, such as, for example, weight imbalance between radiation source 110 and detector 112 and mechanical slack in first interface 126 and / or second interface 128. In some embodiments, the detector 112 is much heavier than the radiation source 110 (e.g., an image intensifier can weigh hundreds of pounds). As a result, during propeller rotation, the imaging arm 108 may shift relative to the support arm 120, and / or the support arm 120 may shift relative to the base 118. Such movement may cause the center of rotation of the imaging arm 108 to shift during image acquisition, which may cause the projection images acquired by the detector 112 to be misaligned. 3D reconstructions resulting from such misaligned projection images may contain significant image artifacts and / or may lack sufficient spatial resolution for use in many medical procedures.

[0088] 2A and 2B illustrate examples of undesirable movement that may occur at the first interface 126 during manual propeller rotation of the imaging arm 108 in the absence of a stabilization mechanism. With reference to both FIGS. 2A and 2B, the first interface 126 may include spaces, gaps, etc. between various components of the imaging arm 108 and the support arm 120 (e.g., between the rails 138, the tracks 140, the distal portion 122, the grooves 146, and / or the wheels 148). This mechanical slack may allow the imaging arm 108 and the support arm 120 to shift relative to one another even when the imaging arm 108 is locked and prevented from orbital rotation. For example, the first and second sides 142, 144 of the first interface 126 may each include a first gap 202, a second gap 204, and / or a third gap 206. The gaps 202-204 can be located between the rail 138 of the imaging arm 108 and the groove 146 in the distal portion 122 of the support arm 120 (in FIGS. 2A and 2B, the gaps 202-204 are labeled only on the second side 144 for simplicity purposes). In the illustrated embodiment, the first gap 202 is between the lower surface of the rail 138 and the upper surface of the groove 146, the second gap 204 is between the lateral surface of the rail 138 and the lateral surface of the groove 146, and the third gap 206 is between the lower surface of the rail 138 and the upper surface of the groove 146. Due to the presence of the gaps 202-206, the imaging arm 108 can be biased in a vertical direction 208 ( FIG. 2A ) and / or a lateral direction 210 ( FIG. 2B ) relative to the support arm 120.

[0089] Referring again to FIG. 1A, in some embodiments, the system 100 can include features to reduce or prevent undesired movement that may occur during an mrCBCT procedure. For example, the system 100 can include one or more shim structures 156 for mechanically stabilizing certain portions of the imaging device 104 (the shim structures 156 are omitted in FIGS. 1B-1E for simplicity purposes only). The shim structures 156 can be removable or permanent components that are coupled to the imaging device 104 in one or more locations to reduce or prevent undesired movement during manual rotation. In the illustrated embodiment, the system 100 includes two shim structures 156 positioned at opposite ends of the first interface 126 between the imaging arm 108 and the support arm 120. Optionally, the system 100 can include four shim structures 156, one at each end of the first interface 126 and on each side 142, 144 of the first interface 126. Alternatively, or in combination, the system 100 may also include one or more shim structures 156 elsewhere in the imaging device 104 (e.g., at the second interface 128). Any suitable number of shim structures 156 may be used, such as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or more shim structures.

[0090] The shim structure 156 disclosed herein can make it easier for a user to create smooth uniform movement of the imaging arm 108 over a wide rotation angle without the use of a motor or other automated actuation mechanism. Thus, the projection images generated by the detector 112 may exhibit significantly reduced misalignment compared to projection images generated without the shim structure 156, thus improving the accuracy and resolution of the resulting 3D reconstruction. The shim structure 156 can also create a more consistent rotational path of the imaging arm 108, which may significantly improve the accuracy of the calibration process disclosed herein. Additional examples and features of the shim structure 156 that can be used in conjunction with the imaging device 104 are described in more detail below in connection with FIGS. 3A-10D.

[0091] 3A-10D illustrate representative examples of shim structures that may be used to stabilize an imaging device, in accordance with embodiments of the present technology. Although the shim structures of FIG. 3A-10D are described and illustrated with reference to components of the imaging device 104 of FIG. 1A, it should be understood that the shim structures may also be used with other imaging devices and systems. In addition, any of the features of the shim structures of FIG. 3A-10D may be combined with one another.

[0092] 3A is a partial schematic cross-sectional view of the first interface 126 with a set of shim structures 302a, 302b configured in accordance with an embodiment of the present technology. Referring initially to FIG. 3A, the shim structures 302a, 302b can be used to stabilize the first interface 126 between the imaging arm 108 and the support arm 120 of the imaging device 104. In the illustrated embodiment, the shim structures 302a, 302b are positioned on the first and second sides 142, 144 of the first interface 126, respectively. The shim structures 302a, 302b can fit within the first gap 202 between the imaging arm 108 and the support arm 120. The shim structures 302a, 302b can partially or completely fill the first gap 202 and thus prevent or reduce undesired movement of the imaging arm 108 relative to the support arm 120 when the imaging arm 108 is manually rotated. In some embodiments, the shim structures 302a, 302b are removable components that are temporarily inserted into the first interface 126 to stabilize the imaging arm 108 and the support arm 120 during manual operation. The shim structures 302a, 302b can be held in place by friction and / or mechanical interference, or by other mechanisms. However, in other embodiments, the shim structures 302a, 302b can be permanently affixed within the first interface 126.

[0093] 3B is a perspective view of an individual shim structure 302a. The shim structure 302a can be an elongated member (e.g., a block, a wedge, a panel) configured to fill the space between the imaging arm 108 and the support arm 120. The shim structure 302a can be made of any material suitable for damping, impeding, or otherwise preventing movement of the imaging arm 108 relative to the support arm 120, including rigid or compliant materials. The geometry of the shim structure 302a can also be varied as desired. In the illustrated embodiment, for example, the shim structure 302a has a rectangular shape. In other embodiments, the shim structure 302a can have any other suitable shape, such as a square, trapezoid, triangle, circle, oval, etc. The dimensions of the shim structure 302a can be configured to provide a desired fit between the imaging arm 108 and the support arm 120. For example, the shim structure 302a can have a length L1 in the range of 1 cm to 20 cm, a width W1 in the range of 0.3 cm to 5 cm, and a thickness T1 in the range of 1 mm to 15 mm. The thickness T1 can be equal to or approximately equal to the height of the first gap 202 (FIG. 3A), and the length L1 and width W1 can be greater than or equal to the lateral dimensions of the first gap 202.

[0094] Shim structure 302b can be the same or generally similar to shim structure 302a. For example, shim structures 302a, 302b can both have the same geometry (e.g., size, shape). However, in other embodiments, shim structure 302b can have a different geometry than shim structure 302a, e.g., shim structure 302b can be larger or smaller than shim structure 302a, can have a different shape than shim structure 302a, etc. Optionally, either shim structure 302a or shim structure 302b can be omitted such that only one of the sides of first interface 126 includes a shim structure.

[0095] 3C is a side view of a shim structure 302c having a variable thickness T2, in accordance with an embodiment of the present technology. The shim structure 302c can be generally similar to the shim structure 302a and / or shim structure 302b, except that the thickness T2 of the shim structure 302c decreases along the length L2 of the shim structure 302c, such that the shim structure 302c is thicker at the first end region 304 and thinner at the second end region 306. In the illustrated embodiment, for example, the shim structure 302c has a triangular cross-sectional shape, and the angle of the shim structure 302c at the second end region 306 is less than or equal to 80°, 70°, 60°, 50°, 45°, 40°, 35°, 30°, 25°, 20°, 15°, 10°, or 5°.

[0096] 3D is a partial schematic side view of a set of shim structures 302c, 302c positioned at the first interface 126 in accordance with an embodiment of the present technology. In the illustrated embodiment, the shim structure 302d has a tapered wedge shape that is the same as or similar to the shim structure 302c. However, in other embodiments, one or both of the shim structures 302c, 302d can be replaced with a shim structure having a different shape, such as the rectangular shape of the shim structure 302a in FIG. 3B. As shown in FIG. 3D, the shim structures 302c, 302d can be inserted into the space at the first and second ends 308, 310, respectively, of the first interface 126 between the distal portion 122 of the support arm 120 and the imaging arm 108. Although FIG. 3D shows two shim structures 302c, 302d, in some embodiments, the first interface 126 can include two shim structures on either side 142, 144 of the first end 308 and two shim structures on either side 142, 144 of the second end 310, for a total of four shim structures.

[0097] FIG. 4A is a partial schematic cross-sectional view of the first interface 126 with a set of L-shaped shim structures 402a, 402b, and FIG. 4B is a perspective view of an individual shim structure 402a, in accordance with an embodiment of the present technology. Referring together to FIGS. 4A and 4B, the shim structures 402a, 402b can be inserted between the imaging arm 108 and the support arm 120 at the first and second sides 142, 144 of the first interface 126, respectively. Each of the shim structures 402a, 402b can include a first panel 404 connected to a second panel 406 to form an L-shaped structure. The first panel 404 and the second panel 406 can fit within the first gap 202 and the second gap 204, respectively, between the imaging arm 108 and the support arm 120. The first and second panels 404, 406 can be integrally formed with one another as a single unitary component, or can be separate components that are coupled to one another via adhesives, bonding, fasteners, etc. In the illustrated embodiment, the first and second panels 404, 406 are connected with a fixed geometry and are not moveable relative to one another. However, in other embodiments, the first and second panels 404, 406 can be moveably coupled to one another, as described further below.

[0098] The first and second panels 404, 406 can each be a flattened elongate member having a geometry (e.g., size, shape) selected to conform to the shape of the first and second gaps 202, 204. For example, the angle between the first and second panels 404, 406 can be greater than or equal to 10°, 20°, 30°, 40°, 45°, 50°, 60°, 70°, 80°, 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, or 170°. The first and second panels 404, 406 can each have any suitable shape, such as rectangular, square, etc. The dimensions of the first and second panels 404, 406 can also be varied as desired. In the illustrated embodiment, for example, the first and second panels 404, 406 have the same length L3 (e.g., in the range of 1 cm to 20 cm) and thickness T3 (e.g., in the range of 1 mm to 15 mm), but different widths W3 and W4, respectively. The width W3 of the first panel 404 can be greater than the width W4 of the second panel 406. For example, the width W3 can be in the range of 0.3 cm to 5 cm, and the width W4 can be in the range of 0.1 cm to 3 cm. However, in other embodiments, the width W3 of the first panel 404 can be less than or equal to the width W4 of the second panel 406. The first and second panels 404, 406 can also have different lengths and / or thicknesses. Additionally, although both the first and second panels 404, 406 are depicted as having a uniform thickness T3, in other embodiments, the first and / or second panels 404, 406 can instead have a variable thickness (e.g., a tapered thickness similar to shim structure 302c in FIG. 3C).

[0099] 4C and 4D are perspective views of an adjustable L-shaped shim structure 402c configured in accordance with an embodiment of the present technology. The shim structure 402c includes a first panel 408 and a second panel 410 connected to each other via an adjustable connection 412. In the illustrated embodiment, the first and second panels 408, 410 each have a rectangular or square flattened section 414 connected to a tapered section 416. In other embodiments, the first and / or second panels 408, 410 can have different shapes, as discussed elsewhere herein. For example, the first panel 408 and the second panel 410 can be the same as or similar to the first panel 404 and the second panel 406 of FIGS. 4A and 4B, respectively.

[0100] The adjustable connection 412 can be any attachment mechanism (e.g., joint, hinge, pivot, etc.) that allows the first and second panels 408, 410 to move (e.g., translate and / or rotate) independently relative to one another. For example, as shown in FIGS. 4C and 4D, the adjustable connection 412 can be a slidable connection that allows the first and second panels 408, 410 to slide relative to one another along a longitudinal direction 418. In some embodiments, the adjustable connection 412 is configured similar to a sliding dovetail connection and includes a rod or bolt on an edge of one panel (e.g., the first panel 408) that slides within a receptacle or groove on the edge of the other panel (e.g., the second panel 410). The adjustable connection 412 can allow the first and second panels 408, 410 to slide relative to one another over a predetermined distance (e.g., a distance in the range of 3 cm to 5 cm). The adjustable connection 412 may include positive stops to prevent the first and second panels 408, 410 from moving more than a predetermined distance and / or from completely separating from one another.

[0101] During use, the adjustable connection 412 allows the first and second panels 408, 410 to move independently to provide an improved fit with the first interface 126 (FIG. 4A). For example, the first and second panels 408, 410 can be sequentially inserted into the first gap 202 and the second gap 204 of the first interface 126, respectively. In some embodiments, the shim structure 402c is initially installed in a partially separated configuration, as shown in FIG. 4C, and the second panel 410 is displaced vertically relative to the first panel 408. The first panel 408 can be inserted into the first gap 202 between the imaging arm 108 and the support arm 120. The second panel 410 can then be moved downwardly to align with the first panel 408, as shown in FIG. 4D, until the second panel 410 fits into the second gap 204 between the imaging arm 108 and the support arm 120. Alternatively, the order can be reversed, with the second panel 410 inserted before the first panel 408. The adjustable connections 412 can allow each panel to be independently advanced to the appropriate insertion depth for stability, which can be advantageous in situations where different spaces within the first interface 126 have different dimensions.

[0102] FIG 5A is a partial schematic cross-sectional view of the first interface 126 with a set of U-shaped shim structures 502a, 502b configured in accordance with an embodiment of the present technology, and FIG 5B is a perspective view of an individual shim structure 502a. Referring together to FIG 5A and 5B, the shim structures 502a, 502b can be inserted between the imaging arm 108 and the support arm 120 at the first and second sides 142, 144 of the first interface 126, respectively. Each of the shim structures 502a, 502b can include a first panel 504, a second panel 506, and a third panel 508 interconnected to form a U-shaped structure. The shim structures 502a, 502b can be positioned such that the first panel 504 fills the first gap 202, the second panel 506 fills the second gap 204, and the third panel 508 fills the third gap 206, respectively. The first and third panels 504, 508 can engage upper and lower surfaces of the rail 138 to affix the shim structures 502a, 502b to the imaging arm 108. The panels 504-508 can be integrally formed with one another as a single unitary component, or can be separate components that are coupled to one another via adhesives, bonding, fasteners, etc. In the illustrated embodiment, the panels 504-508 are connected with a fixed geometry and are not movable relative to one another. However, in other embodiments, some or all of the panels 504-508 can be movably coupled to one another, as described further below.

[0103] Each of the panels 504-508 can be a flattened elongate member having a geometry (e.g., size, shape) selected to conform to the shape of the gap 202-206, respectively. For example, the angle between a pair of connected panels (e.g., first and second panels 504, 506; second and third panels 506, 508) can each, independently, be greater than or equal to 10°, 20°, 30°, 40°, 45°, 50°, 60°, 70°, 80°, 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, or 170°. Each of the panels 504-508 can have any suitable shape, such as rectangular, square, etc. The dimensions of the panels 504-508 can also be varied as desired. In the illustrated embodiment, for example, the panels 504-508 have the same length L5 (e.g., in the range of 1 cm to 20 cm) and thickness T5 (e.g., in the range of 1 mm to 15 mm), but different widths W5, W6, and W7, respectively. For example, the width W5 of the first panel 504 can be greater than or equal to the width W7 of the third panel 508, which can be greater than the width W6 of the second panel 506. For example, the width W5 can be in the range of 0.3 cm to 5 cm, the width W6 can be in the range of 0.1 cm to 3 cm, and the width W7 can be in the range of 0.3 cm to 5 cm. However, in other embodiments, the panels 504-508 can have different dimensions, for example, the width W6 can be greater than or equal to the width W5 and / or width W7, some or all of the panels 504-508 can have different lengths, etc. Additionally, although the panels 504-508 are each depicted as having a uniform thickness T5, in other embodiments, some or all of the panels 504-508 can instead have a variable thickness (e.g., a tapered thickness, similar to shim structure 302c of FIG. 3C).

[0104] 5C and 5D are perspective views of a U-shaped shim structure 502c with slidable connections configured in accordance with an embodiment of the present technology. The shim structure 502c includes a first panel 510, a second panel 512, and a third panel 514 connected to each other via a first adjustable connection 516 and a second adjustable connection 518. The first and second panels 510, 512 can be joined along their side edges by the first adjustable connection 516, and the second and third panels 512, 514 can be joined along their side edges by the second adjustable connection 518. In the illustrated embodiment, the panels 510-514 each have a rectangular or square flattened section connected to a tapered section. In other embodiments, some or all of the panels 510-514 can have different shapes, as discussed elsewhere herein. Optionally, panels 510-514 can be the same as or similar to panels 504-508 of Figures 5A and 5B, respectively.

[0105] The first and second adjustable connections 516, 518 can each include any suitable attachment mechanism (e.g., joints, hinges, pivots, etc.) that allows the corresponding panels to move (e.g., translate and / or rotate) independently relative to one another. For example, as shown in Figures 5C and 5D, the first and second adjustable connections 516, 518 can both be slidable connections (e.g., slidable dovetail connections) that allow the panels 510-514 to translate relative to one another, for example, along a longitudinal direction 520. The first and second adjustable connections 516, 518 can include any of the features described above with respect to the adjustable connection 412 of Figures 4C and 4D.

[0106] The first and second adjustable connections 516, 518 can allow the panels 510-512 to move independently to provide an improved fit with the first interface 126. For example, the panels 510-514 can be sequentially inserted into the gaps 202-206 of the first interface 126 (FIG. 5A), respectively. In some embodiments, the shim structure 502c is initially installed in a partially separated configuration, such as the configuration shown in FIG. 5C, with the first panel 510 and the third panel 514 vertically displaced relative to the second panel 512. The panels 510-514 can then be sequentially inserted into the corresponding gaps 202-206 in any suitable order. For example, the second panel 512 can be inserted before the first and third panels 510, 514, and then the first panel 510 can be inserted before the third panel 514, or vice versa. As another example, the first panel 510 can be inserted first, followed by the second panel 512, then the third panel 514. When the shim structure 502c is fully inserted, the panels 510-514 can be generally aligned with one another, for example, as shown in the configuration of FIG.

[0107] FIG 6A is a partial schematic cross-sectional view of the first interface 126 with a set of U-shaped shim structures 602a, 602b configured in accordance with an embodiment of the present technology, and FIG 6B is a perspective view of an individual shim structure 602a. Referring together to FIG 6A and 6B, the shim structures 602a, 602b can be inserted between the imaging arm 108 and the support arm 120 at the first and second sides 142, 144, respectively, of the first interface 126. Each of the shim structures 602a, 602b can include a first panel 604, a second panel 606, and a third panel 608 interconnected to form a U-shaped structure. The shim structures 602a, 602b can each be positioned such that the first panel 604 fills the first gap 202, the second panel 606 fills the second gap 204, and the third panel 608 extends along an outer surface of the imaging arm 108 proximate the rail 138. In some embodiments, the first and second panels 604, 606 can prevent movement of the imaging arm 108 relative to the support arm 120, while the third panel 608 can engage the outer surface of the rail 138 and secure the shim structures 602a, 602b in place.

[0108] The panels 604-608 can be integrally formed with one another as a single unitary component, or can be separate components that are coupled to one another via adhesives, bonds, fasteners, etc. In some embodiments, the panels 604-608 are connected with a fixed geometry and are not moveable relative to one another. In other embodiments, some or all of the panels 604-608 can be movably coupled to one another via adjustable connections, as described above with reference to Figures 5C and 5D.

[0109] Each of the panels 604-608 can be a flattened elongate member having a geometry (e.g., size, shape) selected to conform to the shape of the gap 202, 204 and the outer surface of the imaging arm 108. For example, the angle between any pair of connected panels (e.g., first and second panels 604, 606; first and third panels 604, 608) can each, independently, be greater than or equal to 10°, 20°, 30°, 40°, 45°, 50°, 60°, 70°, 80°, 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, or 170°. Each of the panels 604-608 can have any suitable shape, such as rectangular, square, etc. The dimensions of the panels 604-608 can also be varied as desired. In the illustrated embodiment, for example, panels 604-608 have the same length L8 (e.g., in the range of 1 cm to 20 cm) and thickness T8 (e.g., in the range of 1 mm to 15 mm), but different widths W8, W9, and W10, respectively. 10 The width W8 of the first panel 604 is smaller than the width W9 of the second panel 606 and / or the width W of the third panel 608. 10 The width W9 of the second panel 606 can be greater than the width W of the third panel 608. 10 In some embodiments, the width W8 is in the range of 0.3 cm to 5 cm, the width W9 is in the range of 0.1 cm to 3 cm, and the width W 10 However, in other embodiments, the panels 604-608 can have different dimensions, for example, width W8 is smaller than width W9 and / or width W 10 , some or all of the panels 604-608 can have different lengths, etc. Additionally, while the panels 604-608 are each depicted as having a uniform thickness T8, in other embodiments, some or all of the panels 604-608 can instead have a variable thickness (e.g., a tapered thickness, similar to shim structure 302c of FIG. 3C).

[0110] FIG. 7A is a partial schematic cross-sectional view of a first interface 126 with a shim structure 702a, and FIG. 7B is a perspective view of the shim structure 702a, in accordance with an embodiment of the present technology. Referring together to FIGs. 7A and 7B, the shim structure 702a includes a first arm region 704 and a second arm region 706 interconnected by a bridge region 708 to form a flattened horseshoe- or U-shaped structure. The first arm region 704 can be a flattened elongated member (e.g., panel, block, wedge) including a first end portion 712 coupled to one side of the bridge region 708 and a second end portion 714 spaced apart from the bridge region 708. Similarly, the second arm region 706 can be a flattened elongate member (e.g., panel, block, wedge) including a first end portion 716 coupled to the other side of the bridge region 708 and a second end portion 718 spaced apart from the bridge region 708. As best seen in FIG. 7A, the first and second arm regions 704, 706 can fit into the first gap 202 at the first and second sides 142, 144 of the first interface 126, respectively, to stabilize the imaging arm 108 and the support arm 120. The first and second arm regions 704, 706 can be generally similar to the shim structures 302a, 302b of FIG. 3A, except that the first and second arm regions 704, 706 are interconnected by the bridge region 708 rather than being separate discrete structures.

[0111] The bridge region 708 can be a flattened elongated member (e.g., a panel, block, strip, connector, etc.) that extends laterally from the first side 142 of the first interface 126 to the second side 144 of the first interface 126 and joins the first and second arm regions 704, 706 to one another. The regions 704-708 can be integrally formed with one another as a single unitary component, or can be separate components that are coupled to one another via adhesives, bonding, fasteners, etc. The regions 704-708 can be connected to one another with a fixed geometry, or can be movably coupled to one another via an adjustable (e.g., slidable) connection, as discussed elsewhere herein.

[0112] In some embodiments, the first and second arm regions 704, 706 prevent movement of the imaging arm 108 relative to the support arm 120, while the bridge region 708 secures the first and second arm regions 704, 706 in place, for example, by applying an inward force on the first and second arm regions 704, 706 during rotation of the imaging arm 108. The bridge region 708 may also be beneficial to ensure that the first and second arm regions 704, 706 are positioned at approximately the same insertion depth into the first gap 202 on either side 142, 144 of the first interface 126. Optionally, the shim structure 702a may also include a handle (not shown) connected to the bridge region 708 to facilitate insertion and / or removal of the shim structure 702a from the first interface 126.

[0113] The geometry (e.g., size, shape) of the first and second arm regions 704, 706 can be selected to conform to the shape of the first gap 202. In addition, the geometry and configuration of the regions 704-708 can define a recess or cavity 710 within the shim structure 702a that accommodates the distal portion 122 of the support arm 120 and / or the outer surface of the imaging arm 108. In the illustrated embodiment, the first and second arm regions 704, 706 and the bridge region 708 each have a rectangular shape. However, in other embodiments, any of the regions 704-708 can have a different shape (e.g., square, triangular, etc.). The dimensions of the regions 704-708 can also be varied as desired. In the illustrated embodiment, for example, the first and second arm regions 704, 706 have the same length L 11 (For example, within the range of 1cm to 20cm) and width W 11 (For example, in the range of 0.3 cm to 5 cm) and thickness T 11 (eg, in the range of 1 mm to 15 mm). Alternatively, the first and second arm regions 704, 706 can have different lengths, widths, and / or thicknesses.

[0114] The bridge region 708 is spaced apart from the length L of the first and second arm regions 704, 706. 11 Less than the length L 12 For example, the length L 12 The width W of the first and second arm regions 704, 706 can be less than or equal to 10 cm, or can be in the range of 5 cm to 0.3 cm. 11 Greater than or equal to width W 12 For example, the width W 12 However, in other embodiments, the width W 12 is the width W of the first and second arm regions 704, 706 11 The bridge region 708 can be less than the same thickness T as the first and second arm regions 704, 706. 11or may have a different (e.g., greater or smaller) thickness.

[0115] 7C is a perspective view of a shim structure 702b configured in accordance with an embodiment of the present technology. The shim structure 702b can be the same as or generally similar to the shim structure 702a of FIGS. 7A and 7B, except that the first arm region 704 and the second arm region 706 each have a tapered and / or wedge-shaped shape. As shown in FIG. 7C, the first and second arm regions 704, 706 each have a first thickness T 13 and at its second end portions 714, 718, a second thickness T 14 The first thickness T 13 is the second thickness T 14 For example, the first thickness T 13 The second thickness T can be at least 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, or 15 mm, or in the range of 4 mm to 8 mm. 14 can be less than 5 mm, 4 mm, 3 mm, 2 mm, 1 mm, 0.5 mm, or 0.1 mm, or in the range of 4 mm to 0.1 mm. Optionally, the first and second arm regions 704, 706 can each be tapered and have a triangular cross-sectional shape (e.g., similar to shim structure 302c of FIG. 3C) with an angle at the respective second end portion 714, 718 being less than or equal to 80°, 70°, 60°, 50°, 45°, 40°, 35°, 30°, 25°, 20°, 15°, 10°, or 5°.

[0116] 7D is a perspective view of a shim structure 702b positioned at the first interface 126 according to an embodiment of the present technology. As shown in FIG. 7D, the shim structure 702b is positioned at one end of the first interface 126, with the first and second arm regions 704, 706 inserted into the space between the imaging arm 108 and the distal portion 122 of the support arm 120, and the bridge region 708 extending laterally across the imaging arm 108. The presence of the bridge region 708 can help a user visually confirm whether the first and second arm regions 704, 706 are positioned at approximately the same insertion depth within the first interface 126, which can be beneficial for improving mechanical stability during manual rotation. Optionally, another shim structure, the same as or similar to the shim structure 702b, can be positioned at the other end of the first interface 126 (not shown in FIG. 7D).

[0117] Figures 7E-7H illustrate additional shim structures 702c-702f configured in accordance with embodiments of the present technology. Shim structures 702c-702f can be generally similar to shim structures 702a, 702b of Figures 7A-7D. Thus, discussion of shim structures 702c-702f will be limited to those features that differ from the embodiments of Figures 7A-7D. In addition, any of the features of shim structures 702c-702f can be combined with the embodiments of Figures 7A-7D and / or with each other.

[0118] 7E is a perspective view of a shim structure 702c including a set of ridges 720 configured in accordance with an embodiment of the present technology. The ridges 720 can be elongated ridge structures located at or near the inner edges of the first and second arm regions 704, 706. In the illustrated embodiment, each ridge 720 extends only partially along the length of the respective first or second arm region 704, 706, terminating before where the arm region connects to the bridge region 708. However, in other embodiments, each ridge 720 can extend along the entire length of the respective first or second arm region 704, 706. When the shim structure 702c is inserted into the first interface 126, the ridges 720 can extend above the surfaces of the first and second arm regions 704, 706 to further secure the shim structure 702c in place.

[0119] 7F is a perspective view of a shim structure 702d including a plurality of protrusions 722 configured in accordance with an embodiment of the present technology. As shown in FIG. 7F, the protrusions 722 are located along the inner surface of the first and second arm regions 704, 706 and extend inwardly into the recesses 710. When the shim structure 702d is positioned at the first interface 126, the protrusions 722 can engage the distal portion 122 of the support arm 120 and secure the shim structure 702d in place. The shim structure 702d can include any suitable number of protrusions 722, such as one, two, three, four, five, ten, fifteen, twenty, or more protrusions 722. Although the protrusions 722 are depicted as being rounded semicircular bumps, in other embodiments, the protrusions 722 can have different shapes, such as square, rectangular, triangular, etc. Optionally, the protrusions 722 can be angled toward the bridge region 708 to further lock the shim structure 702d in place. The dimensions and spacing of the protrusions 722 can also be varied, as desired. For example, the protrusions 722 can each have a width and / or height in the range of 1 mm to 10 mm and can be spaced apart from one another by a distance in the range of 1 mm to 10 mm.

[0120] FIG. 7G is a perspective view of a shim structure 702e including a plurality of square or rectangular cutouts 724. As shown in FIG. 7G, the cutouts 724 are located along the inner surface of the first and second arm regions 704, 706. The cutouts 724 can form a tooth-like texture along the inner surface of the first and second arm regions 704, 706 to improve engagement between the shim structure 702e and the support arm 120. The shim structure 702e can include any suitable number of cutouts 724, such as one, two, three, four, five, ten, fifteen, twenty, or more notches 724. The dimensions and spacing of the notches 724 can be varied as desired, for example, the notches 724 can each have a width and / or depth in the range of 1 mm to 10 mm and can be spaced apart from one another by a distance in the range of 1 mm to 10 mm.

[0121] 7H is a perspective view of a shim structure 702f that includes multiple triangular cutouts 726. The cutouts 726 can be oriented such that the base of each triangular cutout 726 is connected to the recess 710 and the apex of each triangular cutout 726 points away from the recess 710. The spacing, size, and function of the cutouts 726 can otherwise be generally similar to the square or rectangular cutouts 724 of FIG.

[0122] In some embodiments, when a shim structure described herein is installed in the first interface 126 between the imaging arm 108 and the support arm 120, the shim structure can reduce or prevent the imaging arm 108 from sliding relative to the support arm 120, thus preventing orbital rotation of the imaging arm 108. Alternatively, the shim structure described herein can be configured to allow orbital rotation of the imaging arm 108, which may improve convenience and ease of use.

[0123] 8A is a partial schematic cross-sectional view of a first interface with a set of shim structures 802a, 802b with rollers 804 according to an embodiment of the present technology, and FIG. 8B is a perspective view of an individual shim structure 802a. The shim structures 802a, 802b may each include a panel 806, for example, similar to the shim structures 302a, 302b of FIGS. 3A and 3B. One or more rollers 804 (e.g., wheels, ball bearings, etc.) may be embedded in or otherwise coupled to the panel 806. The rollers 804 may protrude outward from an upper and / or lower surface of the panel 806. Thus, when the shim structures 802a, 802b are inserted into the first interface 126, the rollers 804 may contact a surface of the imaging arm 108 and / or the support arm 120, allowing these components to slide relative to one another. In the illustrated embodiment, for example, roller 804 contacts a lower surface of rail 138 of imaging arm 108 and an upper surface of groove 146 formed in distal portion 122 of support arm 120. Thus, imaging arm 108 can be rotated in an orbital rotational direction while still being stabilized by shim structures 802a, 802b for propeller rotation.

[0124] In some embodiments, the shim structures described herein are configured to be permanently or temporarily attached to the imaging device 104 even when not in use. For example, the shim structures can be coupled to a portion of the imaging device 104 (e.g., to the imaging arm 108) via a mounting mechanism. The mounting mechanism can allow the shim structures to be moved between an engaged configuration, in which the shim structures stabilize the imaging device 104 for manual rotation as described elsewhere herein, and a disengaged configuration, in which the shim structures remain attached to the imaging device 104 by the mounting mechanism but do not stabilize the imaging device 104. In the disengaged configuration, the components of the imaging device 104 (e.g., the imaging arm 108 and the support arm 120) can move freely relative to one another without being impeded by the shim structures. This approach allows an operator to quickly and easily switch between stabilized and unstabilized operation of the imaging device 104 while reducing the likelihood that the shim structures will be lost when not in use.

[0125] 9A-9F illustrate a shim structure 902 with a mounting feature 904 configured in accordance with an embodiment of the present technology. Referring initially to FIG. 9A, which is a partial schematic top view of the shim structure 902, the shim structure 902 is generally a flattened U-shaped structure similar to the shim structures 702a and 702b of FIGS. 7A-7D. For example, the shim structure 902 can include a first arm region 906, a second arm region 908, and a bridge region 910 connecting the first and second arm regions 906, 908. The shim structure 902 can optionally include a handle 912 coupled to the bridge region 910 to enable an operator to engage and disengage the shim structure 902 from the first interface 126 of the imaging device 104, as described further below.

[0126] In some embodiments, the mounting mechanism 904 is also a flattened U-shaped structure including a separate first arm region 914, a second arm region 916, and a bridge region 918. The first arm region 914 of the mounting mechanism 904 can be coupled to the first arm region 906 of the shim structure 902 via a first hinge 920, and the second arm region 916 of the mounting mechanism 904 can be coupled to the second arm region 908 of the shim structure 902 via a second hinge 922. The bridge region 918 can be a bar or similar structure that engages a portion of the imaging device 104 and prevents the shim structure 902 from being removed from the imaging arm 108.

[0127] 9B and 9C are partial schematic side views of the shim structure 902 and the mounting mechanism 904 in a straightened ( FIG. 9B ) and bent ( FIG. 9C ) state. As shown in FIG. 9B , in the straightened state, the longitudinal axis of the shim structure 902 can be generally aligned with (e.g., parallel to) the longitudinal axis of the mounting mechanism 904. As shown in FIG. 9C , in the bent state, the shim structure 902 can pivot relative to the mounting mechanism 904 about the first and second hinges 920, 922 such that the longitudinal axis of the shim structure 902 is offset from (e.g., perpendicular to) the longitudinal axis of the mounting mechanism 904.

[0128] 9D-9F are partial schematic side views of a shim structure 902 and a mounting mechanism 904 during use, in accordance with an embodiment of the present technology. Referring initially to FIG. 9D, the mounting mechanism 904 can be positioned at a first interface 126 between the imaging arm 108 and a distal portion 122 of the support arm 120. In some embodiments, a bridge region 918 of the mounting mechanism 904 is inserted into a groove 146 (FIG. 1C) between the distal portion 122 of the support arm 120 and a rail 138 (FIG. 1C) of the imaging arm 108, in an orientation that extends laterally across a track 140 (FIG. 1C) of the imaging arm 108. Thus, the distal portion 122 of the support arm 120, located within the track 140, can obstruct the mounting mechanism 904, and thus the shim structure 902, from being removed from the first interface 126. In such an embodiment, the shim structure 902 can be coupled to the mounting feature 904 after the mounting feature 904 is inserted into the first interface 126 .

[0129] When stabilization is not required, the shim structure 902 can be placed in a disengaged configuration, as shown in FIG. 9D. In the disengaged configuration, the shim structure 902 is positioned out and away from the first interface 126. To prevent the shim structure 902 from inadvertently sliding into the first interface 126 (e.g., due to gravity or if bumped by an operator), the shim structure 902 can be rotated to a bent state. In some embodiments, the bridge region 918 of the mounting mechanism 904 is sufficiently low profile such that the imaging arm 108 can move relative to the support arm 120 (e.g., along an orbital rotational direction) when the shim structure 902 is in the disengaged configuration.

[0130] 9E, once stabilization is desired, the operator can use the handle 912 to rotate the shim structure 902 to the straightened state. The operator can then use the handle 912 to advance the shim structure 902 into the first interface 126, thereby placing the shim structure 902 in an engaged configuration, as shown in FIG. 9F. In the engaged configuration, the first and second arm regions 906, 908 of the shim structure 902 are positioned within the gap between the support arm 120 and the imaging arm 108, as described elsewhere herein, and can inhibit undesired movement. Once the imaging procedure is completed, the shim structure 902 can be retracted out of the first interface 126 and folded back into the disengaged configuration of FIG. 9D.

[0131] 10A is a partial schematic cross-sectional view of a first interface 126 of an imaging device 104 with a shim structure 1002 and a mounting mechanism 1004, and FIG. 10B is a front view of the shim structure 1002 and mounting mechanism 1004, in accordance with an embodiment of the present technology. As best seen in FIG. 10B, the shim structure 1002 is generally a flattened U-shaped structure similar to the shim structures 702a and 702b of FIGS. 7A-7D. For example, the shim structure 1002 can include a first arm region 1006, a second arm region 1008, and a bridge region 1010 connecting the first and second arm regions 1006, 1008.

[0132] 10A and 10B together, the mounting mechanism 1004 includes a first knob 1012 attached to a first gear 1014 that is coupled to a first arm region 1006 of the shim structure 1002, and a second knob 1016 attached to a second gear 1018 that is coupled to a second arm region 1008 of the shim structure 1002. The first and second knobs 1012, 1016 can be rotated by an operator to pivot the first and second gears 1014, 1018, respectively, which in turn translates the shim structure 1002 between a disengaged and an engaged configuration, as described further below. Optionally, the first and second gears 1014, 1018 can be coupled to one another via a connector 1020 (e.g., a cross bar) such that the first and second arm regions 1006, 1008 are translated in tandem even when only one of the knobs 1012, 1016 is rotated. This configuration can be advantageous to ensure that the first and second arm regions 1006, 1008 are advanced into the gap the same or similar distances on the first and second sides 142, 144 ( FIG. 10A ) of the first interface 126, respectively.

[0133] 10C and 10D are partial schematic side views of a shim structure 1002 and a mounting mechanism 1004 during use, in accordance with an embodiment of the present technology. Referring initially to FIG. 10C, the mounting mechanism 1004 can be positioned at a first interface 126 between the imaging arm 108 and the distal portion 122 of the support arm 120. In some embodiments, the connector 1020 of the mounting mechanism 1004 is inserted into a groove 146 (FIG. 1C) between the distal portion 122 of the support arm 120 and the rail 138 (FIG. 1C) of the imaging arm 108 in an orientation that extends laterally across the track 140 (FIG. 1C) of the imaging arm 108. Alternatively, the connector 1020 can be positioned outside and laterally across the distal portion 122 of the support arm 120.

[0134] When stability is not required, the shim structure 1002 can be placed in a disengaged configuration, as shown in FIG. 10C. In the disengaged configuration, the shim structure 1002 is positioned out and away from the first interface 126. When stability is desired, the operator can rotate the first and / or second knobs 1012, 1016 of the mounting mechanism 1004 to place the shim structure 1002 in an engaged configuration, as shown in FIG. 10D. Rotating the first and / or second knobs 1012, 1016 pivots the first and / or second gears 1014, 1018, advancing the shim structure 1002 forward relative to the mounting mechanism 1004 and into the first interface 126. In the engaged configuration, the first and second arm regions 1006, 1008 of the shim structure 1002 can be positioned within the gap between the support arm 120 and the imaging arm 108 to prevent undesired movement, as described elsewhere herein. Once the imaging procedure is completed, the first and / or second knobs 1012, 1016 can be rotated in the opposite direction to pivot the first and / or second gears 1014, 1018 rearward and retract the shim structure 1002 relative to the mounting mechanism 1004 and out of the first interface 126.

[0135] FIG. 11 is a graph illustrating the motion of an IMU on a C-arm detector with and without shim stabilization. Motion data was generated by an IMU with an accelerometer while the C-arm was manually rotated through a sustained 180° propeller rotation. The x-axis represents the rotational position of the C-arm as measured by the IMU. The y-axis represents the degree of out-of-plane motion (e.g., undesired motion) of the IMU during rotation. In the illustrated embodiment, ideally there is little or no out-of-plane motion (e.g., line 1102), indicating that the detector moves in a single rotational plane. In the absence of a shim structure (line 1104), the IMU motion data contains significant oscillations and tilt jumps corresponding to sudden weight shifts and reverberations caused by mechanical sag and weight imbalance between the C-arm detector and the source. These movements are variable and may not be consistent from rotation to rotation, which may make it difficult or impossible to compensate for such movements using the calibration process described further below. However, when a shim structure is used (line 1106), the IMU motion data exhibits a smooth trajectory with a nearly constant slope (in FIG. 11, the C-arm was stabilized using two shim structures similar to shim structure 702b of FIGS. 7C and 7D). The shim structure can also enable the C-arm to move in a nearly consistent trajectory over multiple rotations, which can make it feasible to compensate for the out-of-plane motion using a calibration process described further below. As shown in FIG. 11, the shim structure can help reduce the out-of-plane motion, but may not completely eliminate it. Any residual out-of-plane motion can be compensated for via a geometric calibration process, as described in more detail below.

[0136] FIG. 12 illustrates an example of undesirable movement that may occur at the second interface 128 during manual rotation of the imaging arm 108. In some cases, the location at which force is applied may affect the stability of the imaging arm 108 during manual rotation. In particular, certain locations may be more likely to cause undesirable and / or non-uniform movement when pushed and / or pulled during manual rotation. For example, when performing manual propeller rotation, it may be mechanically advantageous to apply force to the first and second end portions 114, 116 of the imaging arm 108 because these locations are located farther from the center of rotation (also known as the "pivot point") and therefore require less force to initiate and / or maintain rotation. However, the second interface 128 is mechanically unstable (e.g., due to space, gaps, or other mechanical slack between the base 118 and the support arm 120). In some circumstances, applying a force to the first and second end portions 114, 116 of the imaging arm 108 may result in a larger torque on the second interface 128, which may cause the support arm 120 and imaging arm 108 to shift relative to the base 118 (e.g., along the translation direction 1202) or otherwise exhibit undesirable and / or non-uniform motion.

[0137] In some embodiments, the amount of torque on the second interface 128 can be reduced by applying the rotational force to the proximal portion 124 of the support arm 120 at or near the second interface 128, rather than to the imaging arm 108. However, because this location is closer to the pivot point, the amount of force to perform manual propeller rotation can be significantly increased. In addition, the proximal portion 124 of the support arm 120 may lack a handle or grip to facilitate manual rotation, or a handle at that location may be too small to provide sufficient lever action. Thus, to reduce the amount of force to perform manual propeller rotation at or near the second interface 128, the present technology can provide a temporary or permanent lever structure that attaches the proximal portion 124 of the support arm 120 near the second interface 128 and provides a greater mechanical advantage for rotation.

[0138] 13A-14E illustrate representative examples of lever structures that may be used to facilitate manual rotation of an imaging device, in accordance with embodiments of the present technology. Although the lever structures of FIGs. 13A-14E are described and illustrated with reference to components of the imaging device 104 of FIG. 1A, it should be understood that the lever structures may also be used with other imaging devices and systems. In addition, any of the features of the lever structures of FIGs. 13A-14E may be combined with one another.

[0139] 13A is a partial schematic diagram of an imaging device 104 with a lever structure 1302a, and FIG. 13B is an enlarged cross-sectional view of a support arm 120 with the lever structure 1302a, according to an embodiment of the present technology. The lever structure 1302a is configured to be temporarily or permanently attached to the support arm 120 and assist a user in applying a rotational force to a proximal portion 124 of the support arm 120 during propeller rotation. As best seen in FIG. 13B, the lever structure 1302a includes a handle 1304 coupled to a clamp 1306. The clamp 1306 can include a pair of clamp members 1308 connected to a cross bar 1310 with a fixed geometric shape. The lever structure 1302a can have a fork-like configuration, in which one end of the handle 1304 is coupled to a central portion of the cross bar 1310, and the clamp members 1308 are coupled to an end portion of the cross bar 1310 and extend longitudinally away from the cross bar 1310.

[0140] The handle 1304 can be an elongated rod or shaft configured to be held by one or both of a user's hands. The handle 1304 can be long enough to provide a lever action to rotate the support arm 120 and the imaging arm 108. In some embodiments, for example, the handle 1304 has a length in the range of 10 cm to 70 cm. Optionally, the handle 1304 can include textures, coatings, ergonomic shapes, and / or other suitable features to improve grip.

[0141] The clamping members 1308 can be elongated prongs, arms, or the like configured to secure the lever structure 1302a to the proximal portion 124 of the support arm 120 at or near the second interface 128. The clamping members 1308 can be configured to fit tightly around the support arm 120 such that the lever structure 1302a does not become dislodged when a user applies force to the handle 1304. For example, the spacing between the clamping members 1308 can be in the range of 5 cm to 20 cm. The spacing can be the same or similar to the cross-sectional dimensions of the proximal portion 124 of the support arm 120 to provide a tight fit around the support arm 120. In the illustrated embodiment, the clamping members 1308 are affixed to the cross bar 1310 at an angle such that the spacing between the clamping members 1308 increases with distance from the cross bar 1310. This configuration can allow the clamp members 1308 to fit snugly around the support arm 120 near the pivot point during rotation. Alternatively, the clamp members 1308 can be generally parallel to one another such that the spacing between the clamp members 1308 is constant. Each clamp member 1308 can have a length in the range of 10 cm to 30 cm and a thickness and / or diameter in the range of 1 cm to 5 cm. The clamp members 1308 can have any suitable cross-sectional shape (e.g., square, rectangular, circular).

[0142] 13C is a cross-sectional view of a support arm 120 with an adjustable lever structure 1302b configured in accordance with an embodiment of the present technology. The lever structure 1302b may generally be similar to the lever structure 1302a of FIGS. 13A and 13B, except that the lever structure 1302b includes an adjustable clamp member 1314 that may be moved along a cross bar 1310 and a fixed clamp member 1316 that remains stationary. The adjustable clamp member 1314 may be moved relative to the fixed clamp member 1316 to alter the clamp spacing, which may allow the clamp 1312 to accommodate different support arm geometries. In the illustrated embodiment, for example, the adjustable clamp member 1314 is coupled to a trigger 1318 for repositioning the adjustable clamp member 1314. When the trigger 1318 is squeezed, the adjustable clamp member 1314 may slide along the cross bar 1310 toward and / or away from the fixed clamp member 1316. When the trigger 1318 is released, the adjustable clamping member 1314 can be locked in place at its current position along the cross bar 1310. Optionally, the clamp 1312 can include teeth, detents, and / or other ratchet-like features such that the adjustable clamping member 1314 is movable to a number of different predetermined locations along the cross bar 1310.

[0143] 13D is a cross-sectional view of a support arm 120 with another adjustable lever structure 1302c configured in accordance with an embodiment of the present technology. The lever structure 1302c includes a handle 1304 coupled to a clamp 1320 (e.g., a C-clamp, G-clamp, U-clamp). The clamp 1320 can include a frame 1322 (e.g., a curved, square, or rectangular bracket) having an adjustable pad 1324 at one end and a fixed pad 1326 at the other end. The handle 1304 can be connected to a central portion of the frame 1322 between the two ends. The adjustable pad 1324 can be coupled to a screw 1328, which is rotatable to alter the position of the adjustable pad 1324. Thus, a user can turn the screw 1328 to change the spacing between the adjustable pad 1324 and the fixed pad 1326 to accommodate different support arm geometries.

[0144] 14A is a partial schematic diagram of an imaging device 104 with a lever structure 1402a, and FIG. 14B is a front view of the lever structure 1402a, in accordance with an embodiment of the present technology. Referring initially to FIG. 14A, in some embodiments, the imaging device 104 already includes a handle 1404 at or near the proximal portion 124 of the support arm 120 near the second interface 128. However, the handle 1404 may be too small and may not provide sufficient mechanical advantage to manually rotate the support arm 120 and imaging arm 108. Thus, the lever structure 1402a may be temporarily or permanently coupled to the handle 1404 to provide a longer lever arm and / or otherwise increase the mechanical advantage.

[0145] 14B, the lever structure 1402a can include a first extension member 1406 (e.g., a rod, shaft, or tube) having a pair of hooks 1408. The hooks 1408 can engage the handle 1404 (FIG. 14A) to secure the lever structure 1402a to the support arm 120. The lever structure 1402a can also include a second extension member 1410 (e.g., a rod, shaft, or tube) connected to the first extension member 1406 between the hooks 1408. The second extension member 1410 can be attached to the first extension member 1406 at a 90° angle or any other suitable angle. During use, a user can grip the first extension member 1406 and / or the second extension member 1410 and apply a rotational force to the support arm 120 for propeller rotation. In other embodiments, the second elongate member 1410 can be omitted such that the user applies force using only the first elongate member 1406 .

[0146] 14C is a front view of a lever structure 1402b configured in accordance with an embodiment of the present technology. The lever structure 1402b is the same as the lever structure 1402a of FIGS. 12A and 12B, except that the lever structure 1402b includes a third hook 1412 on the second elongated member 1410. The third hook 1412 can further secure the lever structure 1402b to a handle 1404 on the support arm 120 (FIG. 14A). It should be understood that the lever structures 1402a, 1402b of FIGS. 14A-14C can include any suitable number of hooks (e.g., 1, 2, 3, 4, 5, or more hooks) and the hooks can be in any suitable location on the first elongated member 1406 and / or the second elongated member 1410.

[0147] 14D and 14E are partial schematic cross-sectional views of an adjustable lever structure 1402c coupled to a handle 1404 of an imaging device 104, according to an embodiment of the present technology. Although the lever structure 1402c is depicted as having two hooks 1408 (e.g., similar to the lever structure 1402a of FIGS. 14A and 14B), in other embodiments, the lever structure 1402c can instead have three hooks (e.g., similar to the lever structure 1402b of FIG. 14C). Referring initially to FIG. 14D, the first elongated member 1406 of the lever structure 1402c can include a first section 1414 and a second section 1416 interconnected by an adjustable connection 1418. The adjustable connection 1418 can allow the first and second sections 1414, 1416 to be moved (e.g., translated) relative to one another along a longitudinal axis of the first elongated member 1406. The adjustable connection 1418 can be any suitable joint or mechanism that allows movement of the first section 1414 relative to the second section 1416, such as a slidable mechanism (e.g., a slidable bolt), a screw mechanism (e.g., a threaded bolt), a spring-loaded mechanism, or a combination thereof.

[0148] The first and second sections 1414, 1416 can each include at least one hook 1408 such that the distance between the hooks 1408 can be increased or decreased by varying the separation between the first and second sections 1414, 1416. For example, the hooks 1408 can be initially positioned closer together in a retracted configuration (FIG. 14D) when positioning the lever structure 1402c on the handle 1404, and then pushed outward to an extended configuration (FIG. 14E) to contact and grip the handle 1404. This approach can make it easier to connect the lever structure 1402c to the handle 1404, while also providing a tighter fit and preventing the lever structure 1402c from becoming inadvertently dislodged when force is applied.

[0149] In some embodiments, the systems, methods, and devices disclosed herein reduce or eliminate undesirable movement during manual rotation as measured by some or all of the following measurements: (1) imaging arm motion (e.g., as measured by an IMU or other motion sensor), (2) the amount and type of undesirable motion in the projection images generated by the detector, (3) image quality of the 3D reconstruction generated from the projection images, and / or (4) the physical distance between the imaging arm and the support arm. Each of these measurements is described in more detail below.

[0150] First, as described above with respect to Figure 11, in the absence of any stabilization, the detector will exhibit sudden deviations, oscillations, and / or other undesirable movements. When stabilized using shim structures and / or by rotation from the support arm, these undesirable movements can be significantly reduced resulting in a relatively smooth and unidirectional rotation of the detector.

[0151] Second, in the absence of stabilization, undesired motion (e.g., caused by weight shifts and / or imaging arm flexing) may be seen in the projection image as a sudden jump in all structures in the field of view at the same time in the same direction. This may indicate that the detector's center of rotation was rapidly shifting back and forth rather than maintaining a single center of rotation since all structures moved together in the same direction (while there are structures that move in opposing directions, often based on depth, during rotation). Furthermore, during and / or after the initial shift, the structures may temporarily reverse direction as the imaging arm moves backwards with the oscillation. When the imaging arm is stabilized using shim structures and / or other techniques described herein, the sudden jumps and / or reversed movements in the projection image can be reduced or eliminated entirely.

[0152] Third, it may be difficult or impossible to generate a coherent 3D reconstruction without using the stabilization techniques described herein. For example, undesired motion of the detector may change the center of rotation and thus misalign some or all of the structures in the 3D reconstruction. In some cases, when imaging marker beads in a phantom, the misalignment may cause the beads to appear in the 3D reconstruction as a star-like shape rather than a coherent spherical shape. Similarly, when imaging a cylindrical phantom with a circular marker, the misalignment may cause the circle to appear in the 3D reconstruction as an intermittent semicircle rather than a single continuous circle. This misalignment can be reduced or eliminated by improving the stability of the imaging arm and / or detector during image acquisition, for example, using shim structures and / or rotation from the support arm in combination with the calibration process described below.

[0153] Fourth, in the absence of shim stabilization, the components of the imaging arm (e.g., rail) and support arm (e.g., distal portion of the support arm) may be displaced by distances in the range of 1 mm to 5 mm as measured at various angular rotation points. When a shim structure is used, it may be nearly impossible for the imaging arm rail to move relative to the support arm because the shim structure reduces or prevents sagging between these components, thus resulting in smoother more uniform motion during image acquisition.

[0154] B. SENSORS AND METHODS FOR POSE ESTIMATION 1A , as described above, during an mrCBCT procedure, the imaging arm 108 can be rotated to a number of different angles while the detector 112 acquires 2D images of the patient's anatomy. In some embodiments, to generate a 3D reconstruction from the 2D images, the pose of the imaging arm 108 needs to be determined for each image with a high degree of accuracy. However, as explained above, manually operated imaging devices, such as mobile C-arm devices, may lack the ability to track the pose of the imaging arm 108 with sufficient accuracy for CBCT purposes.

[0155] Thus, the system 100 can include at least one sensor 154 for tracking the orientation of the imaging arm 108 during manual rotation. The sensor 154 can be positioned at any suitable location on the imaging device 104. In the illustrated embodiment, for example, the sensor 154 is positioned on the detector 112. Alternatively, or in combination, the sensor 154 can be positioned at different locations, such as on the radiation source 110, on the imaging arm 108 (e.g., at or near the first end portion 114, at or near the second end portion 116), on the support arm 120 (e.g., at or near the distal portion 122, at or near the proximal portion 124), etc. In addition, while FIG. 1A illustrates a single sensor 154, in other embodiments, the system 100 can include multiple sensors 154 (e.g., two, three, four, five, or more sensors 154) distributed at various locations on the imaging device 104. For example, the system 100 may include a first sensor 154 on the detector 112, a second sensor 154 on the radiation source 110, etc. The sensor 154 may be removably coupled or permanently affixed to the imaging device 104.

[0156] In some embodiments, the spatial configuration of various components of the imaging device 104 is known, so that the pose of the imaging arm 108 can be correlated to the pose of other components of the imaging device 104. For example, in embodiments in which the detector 112 is at a fixed position and orientation relative to the imaging arm 108, the pose of the detector 112 can be calculated from the pose of the imaging arm 108, and vice versa. Thus, any embodiment described herein as using the pose of the imaging arm 108 can be adapted to alternatively or additionally use the pose of the detector 112 (or any other suitable component of the imaging device 104).

[0157] The sensor 154 can be any sensor type suitable for tracking the attitude (e.g., position and / or orientation) of a moving component. For example, the sensor 154 can be configured to track the rotation angle of the imaging arm 108 during manual propeller rotation. Examples of sensors 154 suitable for use with the imaging device 104 include, but are not limited to, motion sensors (e.g., IMUs, accelerometers, gyroscopes, magnetometers), light and / or radiation sensors (e.g., photodiodes), image sensors (e.g., video cameras), EM sensors (e.g., EM trackers or navigation systems), shape sensors (e.g., shape-sensing fibers or cables), or suitable combinations thereof. In embodiments in which the system 100 includes multiple sensors 154, the sensors 154 can be the same or different sensor types. For example, the system 100 can include two motion sensors, i.e., a motion sensor and a photodiode, a motion sensor and a shape sensor, etc.

[0158] In some embodiments, the sensor 154 includes at least one motion sensor, such as a 9-axis IMU with an accelerometer, gyroscope, and / or magnetometer. The motion sensor can be configured to generate motion data (e.g., position and / or orientation data over time) as the imaging arm 108 is manually rotated. The motion sensor can be attached to any portion of the imaging device 104 that undergoes rotation, such as the detector 112, the radiation source 110, the imaging arm 108, the support arm 120, or a combination thereof. In some embodiments, two or more motion sensors are used, with each motion sensor attached to a different portion of the imaging device 104 (e.g., a first motion sensor can be attached to the detector 112 and a second motion sensor can be attached to the radiation source 110).

[0159] 15 is a partial schematic diagram of a motion sensor 1502 coupled to an imaging device 104 via a mounting device 1504 configured in accordance with an embodiment of the present technology. The motion sensor 1502 is coupled to the mounting device 1504, which is in turn coupled to the detector 112 of the imaging device 104. In the embodiment of FIG. 15, the mounting device 1504 is configured to be attached to a side surface of the detector 112. However, in other embodiments, the mounting device 1504 can be configured to be attached to a different portion of the detector 112, such as an upper surface, a lower surface, etc. Optionally, the detector 112 and / or the mounting device 1504 can include alignment markings (e.g., lines, arrows, or other indicators) to guide a user in placing the mounting device 1504 (and thus the motion sensor 1502) in a predetermined position and / or orientation on the detector 112.

[0160] In the illustrated embodiment, the attachment device 1504 is configured as a clip or bracket that attaches to an edge of the detector 112 at or near its lower surface. The clip can include a small, vertically oriented peg with a short edge or overhang that grips the lower edge of the detector 112. Optionally, the clip can include a rotatable screw, which can be spring loaded, and / or otherwise configured to lock into place at a desired location on the detector 112 once positioned. However, in other embodiments, the attachment device 1504 can be configured differently. For example, the attachment device 1504 can instead be configured as a container for holding the motion sensor 1502, such as a small rectangular box that can be placed flat against a flat portion of the detector 112. The container can include loops, handles, openings, etc., allowing the container to be secured to the detector 112 using straps (e.g., straps made from Velcro® or other adhesive material) and / or other fasteners. Optionally, the attachment device 1504 can be omitted entirely and the motion sensor 1502 can instead be coupled directly to the detector 112 via adhesives, fasteners, magnets, straps, or the like.

[0161] The motion sensor 1502 can generate motion data indicative of the pose of the imaging arm 108. For example, as the imaging arm 108 moves (e.g., during manual propeller rotation), the motion sensor 1502 can output motion data over time that represents the position and / or orientation (e.g., rotation angle) of the imaging arm 108. In some embodiments, the motion sensor 1502 generates the motion data independent of the image acquisition performed by the detector 112. Thus, the motion data from the motion sensor 1502 can be synchronized in time or otherwise correlated with the images from the detector 112 to determine the pose of the imaging arm 108 for each image acquired by the detector 112.

[0162] The synchronization can be implemented in many different ways. In the illustrated embodiment, for example, the motion sensor 1502 is coupled to a controller 1506 (e.g., an Arduino microcontroller), which is in turn coupled to an image output device 1508. The image output device 1508 can receive images generated by the detector 112 (e.g., in a video format or any other suitable format). As shown in FIG. 15, the images produced by the detector 112 can be transmitted to the base 118, which can be coupled to the image output device 1508. In other embodiments, the detector 112 can be directly coupled to the image output device 1508. The connections between the motion sensor 1502, the controller 1506, the image output device 1508, the detector 112, and the base 118 can be wired or wireless connections.

[0163] The controller 1506 can collect motion data from the motion sensor 1502 in real time and time-synchronize each image acquired by the image output device 1508 with the motion data from the motion sensor 1502. For example, the controller 1506 can time-stamp the motion data received from the motion sensor 1502. The controller 1508 can then compare the timestamps for the motion data with the timestamps on the image data and associate each image with motion data acquired at the same point in time or over a similar time period. Thus, each image recorded from the image output device 1508 can be associated with a corresponding angle (or a very small range of angles) from the motion sensor 1502.

[0164] 16 is a partial schematic diagram of a motion sensor 1602 and a radiation sensor 1604 attached to an imaging device 104, according to an embodiment of the present technology. The motion sensor 1602 (e.g., an IMU) and the radiation sensor 1604 can be coupled to a mounting device 1606. The mounting device 1606 can be generally similar to the mounting device 1504 of FIG. 15, except that the mounting device 1606 is configured to support both the motion sensor 1602 and the radiation sensor 1604. For example, the mounting device 1606 can be a clip with a vertically oriented peg that can be temporarily coupled to the detector 112. The mounting device 1606 can be mounted on the detector 112 such that the motion sensor 1602 lies along a lateral surface of the detector 112, while the radiation sensor 1604 protrudes, at least partially, into the path of a radiation beam output by the detector 112.

[0165] The radiation sensor 1604 can be any device capable of detecting exposure to radiation (e.g., x-rays), such as a photodiode. For example, the photodiode can include a scintillator made from silicon-based materials and / or other suitable materials, with or without a signal amplifier. Thus, the radiation sensor 1604 can accurately measure the time of image acquisition based on the exposure radiation passing through the radiation sensor 1604 toward the detector 112.

[0166] The motion sensor 1602 and radiation sensor 1604 can each be coupled to a controller 1608 (e.g., an Arduino microcontroller) via a wired or wireless connection. Upon detecting radiation, the radiation sensor 1604 can send a signal to the controller 1608 and generate a timestamp indicating that an image has been acquired. Similarly, the controller 1608 can also determine a timestamp for the motion data produced by the motion sensor 1602. Thus, image acquisition timing can be linked to the timing of rotational measurements from the motion sensor 1602, thus allowing each image generated by the detector 112 to be synchronized in time to a corresponding rotational angle of the imaging arm 108.

[0167] 17A is a top view, FIG. 17B is a side view, and FIG. 17C is a partial schematic diagram of a mounting device 1702a coupled to an imaging device 104 in accordance with an embodiment of the present technology. Initially, referring to both FIGS. 17A and 17B, the mounting device 1702a is configured to support a motion sensor 1704 (e.g., an IMU) and a radiation sensor 1706 (e.g., a photodiode). The mounting device 1702a can include a frame 1708 and one or more clips 1710 located along a perimeter of the frame 1708. Although the frame 1708 is depicted as having a circular shape, in other embodiments, the frame 1708 can have a different shape, such as an oval, square, rectangular, or other suitable shape. The frame 1708 can include a central opening 1712 to allow radiation to pass therethrough. The frame 1708 can also be used to support a fiducial marker grid for calibration procedures, as described in more detail below.

[0168] The clip 1710 can be configured to couple the attachment device 1702a to the detector 112 in a temporary or permanent manner. In some embodiments, the clip 1710 is a small, vertically oriented peg located on the edge of the frame 1708, each having a short edge or overhanging protrusion for gripping the edge of the detector 112. As best seen in FIG. 17C , the clip 1710 can affix the attachment device 1702a to the lower surface of the detector 112, with the frame 1708 located partially or completely out of the radiation path of the detector 112 to avoid attenuating or otherwise interfering with the radiation beam. Optionally, the detector 112, the frame 1708, and / or the clip 1710 can include alignment markers to guide a user in placing the attachment device 1702a in the proper position and / or orientation on the detector 112.

[0169] In some embodiments, the mounting device 1702a includes one or more sites for mounting the motion sensor 1704 and / or radiation sensor 1706 along the frame 1708 and / or clip 1710. For example, the motion sensor 1704 and the radiation sensor 1706 can both be coupled to one of the clips 1710, similar to the configuration of the mounting device 1606 of FIG. 16. The motion sensor 1704 can be located along an edge of the mounting device 1702a and away from the path of the radiation beam, while the radiation sensor 1706 can protrude at least partially below the frame 1708 and into the path of the radiation beam. However, in other embodiments, the motion sensor 1704 and / or radiation sensor 1706 can be in different locations on the mounting device 1702a. The motion sensor 1704 and / or radiation sensor 1706 can each be removably coupled to the mounting device 1702a or permanently affixed to the mounting device 1702a. The motion sensor 1704 and radiation sensor 1706 can be coupled to other components (e.g., a controller, an image output device) to time synchronize the output of the motion sensor 1704 with the images produced by the detector 112, as discussed above with respect to Figures 15 and 16. Optionally, the radiation sensor 1706 can be omitted, such that the mounting device 1702a is used to support only the motion sensor 1704.

[0170] 17D is a side view of an attachment device 1702b configured in accordance with an embodiment of the present technology. The attachment device 1702b may be generally similar to the attachment device 1702a of FIGS. 15A-15C, except that the attachment device 1702b includes a spring-loaded clip 1714 instead of one or more of the clips 1710. The clip 1714 may include a spring-loaded protrusion 1716 that may be retracted when positioning the attachment device 1702b on the detector 112. After the attachment device 1702b is positioned in a desired location, the spring-loaded protrusion 1716 may lock into place around an edge of the detector 112, securing the frame 1708 to the detector 112. The clip 1714 may include a release mechanism (not shown) to retract the spring-loaded protrusion 1716 when removing and / or loading the frame 1708. The mounting device 1702b can optionally be configured to support a motion sensor and / or a radiation sensor (not shown in FIG. 17D), as discussed above with reference to FIGs. 17A and 17B. The mounting device 1702b can also be used to support a fiducial marker grid for calibration procedures, as described in more detail below.

[0171] 17E is a side view of an attachment device 1702c configured in accordance with an embodiment of the present technology. The attachment device 1702c may be generally similar to the attachment device 1702a of FIGS. 15A-15C, except that the attachment device 1702c includes a screw 1718 instead of one or more of the clips 1710. The screw 1718 may be in a retracted position when installing the attachment device 1702c onto the detector 112. After the attachment device 1702c is positioned in a desired location, the screw 1718 may be rotated to advance the screw 1718 toward the detector 112. The screw 1718 may be advanced until it engages an edge of the detector 112, thus securing the frame 1708 to the detector 112. To release the attachment device 1702c, the screw 1718 may be rotated in the opposite direction to retract the screw 1718 away from the detector 112. The mounting device 1702c can optionally be configured to support a motion sensor and / or a radiation sensor (not shown in FIG. 17E), as discussed above with reference to FIGs. 17A and 17B. The mounting device 1702c can also be used to support a fiducial marker grid for calibration procedures, as described in more detail below.

[0172] 1A, the present technology also provides other techniques that may be used to estimate the pose of the imaging arm 108 as an alternative to or in addition to the motion sensor-based techniques described herein. For example, in some embodiments, the pose of the imaging arm 108 can be determined using one or more imaging devices (e.g., video cameras) positioned around the imaging apparatus 104. In such embodiments, the system 100 can include one or more fiducial markers placed at known locations, such as on the patient 102, the operating table 152, and / or components of the imaging apparatus 104 (e.g., the detector 112, the radiation source 110, the imaging arm 108, and / or the support arm 120). The imaging devices can track the markers as the imaging arm 108 is rotated and determine the pose of the imaging arm 108.

[0173] In another example, the system 100 can include a 3D scanner coupled to the imaging arm 108. The 3D scanner can be configured to scan a reference object (e.g., a block) that is mounted at a fixed location relative to the imaging arm 108, such as the operating table 152 and / or the patient's body. The reference object can have a known geometry such that the pose of the imaging arm 108 can be determined from the pose of the reference object within the scan.

[0174] As another example, the orientation of the imaging arm 108 can be determined using a shape sensor (e.g., a shape-sensing fiber or cable). For example, one portion of the shape-sensing cable can be attached to the operating table 152 and another portion to the detector 112. Alternatively, or in combination, one or more shape-sensing cables can be attached elsewhere, such as to the patient 102, the radiation source 110, the imaging arm 108, the support arm 120, or a suitable combination thereof. As the imaging arm 108 is rotated, the change in shape of the shape-sensing cable can be measured and used to calculate the rotation angle of the imaging arm 108.

[0175] In a further example, the shape sensor can be carried by a tool inside the patient's body, such as a shape-sensing endoscope. For example, the tool can output shape data that allows the 3D pose of the tool to be accurately determined prior to image acquisition. The pose of the internal shape sensor in each projection image can be used to estimate the pose of the imaging arm 108 when the image was acquired. For example, the actual pose of the tool can be output as a virtual rendering or representation of the 3D shape of the tool inside the patient's body. The pose of the internal shape sensor in the image can be identified (e.g., using known computer vision and / or image processing techniques) and registered to the virtual representation of the actual pose. The registration can be used to determine the pose of the imaging arm relative to the tool and / or the patient's body for each acquired image.

[0176] In yet another embodiment, an EM sensing system can be used to determine the pose of the imaging arm 108 during rotation. For example, one or more EM sensors or trackers can be positioned at various locations, such as on the patient 102, the operating table 152, the detector 112, the radiation source 110, the imaging arm 108, the support arm 120, or a suitable combination thereof. The position and / or orientation of each EM sensor can be tracked and used to estimate the angle of the imaging arm 108. Optionally, EM sensors can also be carried by tools within the patient's body, such as an endoscope, a biopsy needle, an ablation probe, etc. An internal EM sensor can be used in combination with one or more externally located EM sensors to perform pose estimation.

[0177] In some embodiments, the pose of the imaging arm is estimated using a fiducial marker board placed near the patient's body as an alternative or in combination with other pose estimation techniques described herein. Conventional fiducial marker boards for intra-procedure image-based pose estimation (e.g., for tomosynthesis) are typically flat structures with one or more marker layers. Conventional fiducial marker boards are generally not suitable for imaging techniques with large angle rotation ranges, such as CBCT, because the markers in the board may not be visible at certain angles due to the board's limited vertical height. For example, the markers in a conventional fiducial marker board may be obscured or disappear completely from view when imaged from an outer angle (e.g., at or near 180°). In contrast, the fiducial marker board of the present technology can have a 3D shape in which at least some of the markers are in different planes or are otherwise sufficiently vertically separated so that most or all of the markers remain visible over a wide range of imaging angles. This allows for the estimation of the imaging arm pose over a wide range of imaging angles. In addition, conventional fiducial marker boards are generally not suitable for determining geometric calibration parameters (e.g., pierce point, pitch, roll, etc.) of an imaging device. The fiducial marker boards disclosed herein can be combined with a fiducial marker phantom to perform geometric calibration, which can improve the accuracy of CBCT reconstructions, as described in more detail below.

[0178] 18A is a side view and FIG. 18B is a top view of a fiducial marker board 1800 for determining the pose of an imaging arm according to an embodiment of the present technology. The fiducial marker board 1800 can be positioned adjacent or near the patient's body to provide a reference for estimating the pose of the imaging arm. The fiducial marker board 1800 includes a substrate 1802 (e.g., a radiolucent material) containing a plurality of fiducial markers 1804 (e.g., beads, bearings, flattened disks, etc. made of radiodense or radiopaque material). The markers 1804 can be arranged in a known geometry (e.g., a grid, pattern, or other spatial configuration) such that when the fiducial marker board 1800 is imaged by an imaging device, the pose of the imaging device (e.g., the angle of the imaging arm) relative to the fiducial marker board 1800 can be determined based on the location of the markers 1804 in the acquired image according to techniques known to those skilled in the art.

[0179] As best seen in FIG. 18A, the substrate 1802 can have a non-planar shape (e.g., curved, semicircular, semi-oval, and / or U-shaped) such that at least some of the markers 1804 lie in different planes. In the illustrated embodiment, for example, the substrate 1802 includes a base region 1806 and a pair of curved side walls 1808 that extend upward from the base region 1806 by a height H1. For example, the height H1 can be at least 1 cm, 2 cm, 5 cm, 10 cm, 15 cm, 20 cm, or 30 cm. In some embodiments, the height H1 is greater than or equal to the anterior-posterior height of the patient's torso. The height H1 can be large enough so that most or all of the markers 1804 remain visible even when the fiducial marker board 1800 is imaged from an outside corner (e.g., at or near 180° relative to the surface of the table). Thus, the fiducial marker board 1800 can be used to estimate the pose of the imaging arm over a wider angular range compared to a flat fiducial marker board in which most or all of the markers lie in a single plane. Optionally, the sidewall 1808 can be movably coupled (e.g., via a sliding or pivot connection) to the base region 1806 such that the height H1 can be adjusted, for example, to accommodate different body sizes and / or imaging settings.

[0180] During a medical procedure, the fiducial marker board 1800 can be placed on a surgical table with the base region 1806 resting on the surface of the table and the sidewall 1808 extending upwardly away from the surface. A portion of a patient's body (e.g., the patient's torso) can be positioned on the fiducial marker board 1800 within the cavity formed by the base region 1806 and the sidewall 1808. Multiple 2D projection images can be obtained while an imaging arm of an imaging device is rotated to multiple different angles relative to the patient's body and the fiducial marker board 1800. The 2D projection images can then be analyzed, for example, using a computer vision algorithm or other suitable algorithm to identify the location of the markers 1804 in each image. Optionally, in embodiments where the markers 1804 are made from a metallic material, the images can be processed to remove any imaging artifacts caused by the presence of the metallic material. The identified marker locations can be used to estimate the rotation angle of the imaging arm for each image, using techniques known to those skilled in the art.

[0181] 18C-18G illustrate additional examples of fiducial marker boards 1810-1840 suitable for use with the present technology. Features of the fiducial marker boards 1810-1840 can be generally similar to features of the fiducial marker board 1800 of FIGS. 18A and 18B. Thus, discussion of the fiducial marker boards 1810-1840 of FIGS. 18C-18G will be limited to those features that differ from the embodiment of FIGS. 18A and 18B. Any of the features of the fiducial marker boards 1810-1840 can be combined with each other and / or with features of the fiducial marker board 1800 of FIGS. 18A and 18B.

[0182] 18C is a side view of another fiducial marker board 1810 configured in accordance with an embodiment of the present technology. As shown in FIG. 18C, the markers 1804 in the fiducial marker board 1810 are located only within a portion of the substrate 1802, rather than being distributed throughout the substrate 1802. For example, the markers 1804 can be localized on one lateral side or half of the substrate 1802, such that only one of the side walls 1808 includes the markers 1804. This configuration can be used, for example, in situations where only a single side or section of a patient's body is to be imaged (e.g., during a bronchoscopy procedure performed in a single lung). In such situations, the fiducial marker board 1810 can be positioned such that the markers 1804 are proximate to the side or section of the patient's body to be imaged.

[0183] 18D is a side view of yet another fiducial marker board 1820 configured in accordance with an embodiment of the present technology. The fiducial marker board 1820 includes a single sidewall 1808 rather than two sidewalls 1808. In such an embodiment, the base region 1806 can be extended to provide support for the sidewall 1808 such that the fiducial marker board 1820 is J-shaped. Although the base region 1806 is depicted without any markers 1804, in other embodiments, the base region 1806 can also include markers 1804. The fiducial marker board 1820 can be used when imaging a single side or section of a patient's body. In such a situation, the fiducial marker board 1820 can be positioned such that the single sidewall 1808 is proximate to the side or section of the patient's body to be imaged.

[0184] 18E is a side view of a fiducial marker board 1830 configured in accordance with an embodiment of the present technology. The fiducial marker board 1830 includes a flattened base region 1832 and a pair of straight sidewalls 1834. The sidewalls 1834 can be connected to the base region 1832 at any suitable angle, such as an angle greater than or equal to 90°, 110°, 120°, 130°, 140°, or 150°. The height H2 of the sidewalls 1834 can be large enough so that most or all of the markers 1804 remain visible even when the fiducial marker board 1830 is imaged from an outside angle, which may be the same or similar to the height H1 of the fiducial marker board 1800 of FIGS. 18A and 18B. Optionally, the sidewalls 1834 can be movably coupled to the base region 1832, such that the height H2 can be adjusted as desired.

[0185] Although the fiducial marker board 1830 is illustrated as including markers 1804 throughout the substrate 1802, in other embodiments, the fiducial marker board 1830 can include markers 1804 within only a portion of the substrate 1802 (e.g., similar to the fiducial marker board 1820 of FIG. 18C). Additionally, while the fiducial marker board 1830 is illustrated as having two sidewalls 1834, in other embodiments, the fiducial marker board 1830 can include a single sidewall 1834 (e.g., similar to the fiducial marker board 1830 of FIG. 18D).

[0186] 18F and 18G are side and top views, respectively, of a fiducial marker board 1840 along with a fiducial marker phantom 1842, in accordance with an embodiment of the present technology. The fiducial marker board 1840 can be similar to the fiducial marker board 1830 of FIG. 18E, except that the fiducial marker board 1840 includes a single sidewall 1834 that is connected to a base region 1832. The phantom 1842 can be temporarily coupled to the fiducial marker board 1840 via one or more fasteners 1844 (e.g., pegs, screws, magnets, etc.). The phantom 1842 can include a separate substrate 1846 (e.g., a radiolucent material) containing a plurality of fiducial markers 1848 (e.g., beads, bearings, flattened disks, etc., made from a radiodense or radiopaque material). The markers 1848 can be arranged in a suitable configuration to perform geometric calibration, as further described below with respect to Figures 22A-22D.

[0187] As best seen in FIG. 18G, a phantom 1842 can be positioned over a portion of the base region 1832 that does not include any markers 1804. In such an embodiment, when the fiducial marker board 1840 and the phantom 1842 are imaged together (e.g., during a geometric calibration procedure), the markers 1804 of the fiducial marker board 1840 do not overlap the markers 1848 of the phantom 1842 in the acquired images and can therefore be identified and distinguished from one another. The use of the phantom 1842 in conjunction with the fiducial marker board 1840 to perform geometric calibration and image acquisition is described in further detail below with respect to FIG. 25A.

[0188] C. Methods for Imaging 19-25 illustrate various methods for imaging an anatomical region of a patient using an imaging device such as a mobile C-arm device. Specifically, FIG. 19 provides a general overview of the imaging process, FIGS. 20-22D illustrate methods and devices for calibrating an imaging device, FIGS. 23A and 23B illustrate methods for image acquisition and reconstruction, FIG. 24 illustrates a method for preparing an imaging device for imaging, and FIG. 25A illustrates a method for calibration and imaging using a fiducial marker board. The methods disclosed herein can be performed using any of the embodiments of the systems and devices described herein, such as the system 100 of FIG. 1A. Any of the methods disclosed herein can be performed by an operator (e.g., a doctor, nurse, technician, or other health care professional), a computing device (e.g., computing device 130 of FIG. 1A), or a suitable combination thereof. For example, some processes in the methods can be performed manually by an operator, while other processes in the methods can be performed automatically or semi-automatically by one or more processors of a computing device.

[0189] FIG. 19 is a flow diagram illustrating a method 1900 for operating an imaging device for mrCBCT imaging, according to an embodiment of the present technology. The method 1900 can be implemented using a manually operated imaging device (e.g., a mobile C-arm device) or any other suitable imaging system or device. The method 1900 begins at block 1902, stabilizing the imaging device. As discussed above, mrCBCT imaging can involve stabilizing the imaging device to reduce or prevent undesirable and / or inconsistent movement (e.g., oscillation, bouncing, shifting, flexing, etc.) during manual rotation. For example, the imaging arm can be stabilized using one or more shim structures, such as any of the embodiments described herein with respect to FIGS. 1A and 3A-10D. Alternatively, or in combination, the imaging arm can be rotated by applying a force to the support arm (e.g., to a proximal portion of the support arm or near the center of rotation) rather than by applying a force to the imaging arm. As described above, the force can be applied via one or more lever structures coupled to the support arm, such as any of the embodiments described herein with respect to Figures 13A-14E. However, in other embodiments, the imaging arm can be rotated manually without any shim structures and / or without applying a force to the support arm.

[0190] Alternatively, or in combination, the stabilization process of block 1902 may include other processes. For example, block 1902 may also include adjusting the orbital tilt of the imaging arm, improving weight balance, and / or ensuring that the detector surface remains close to a tangent to the detector path during rotation. Optionally, a motion sensor (e.g., an IMU) may be used to provide feedback on the stability of the imaging arm and / or the effectiveness of a particular stabilization step. For example, the feedback may include information characterizing the quality of stabilization (e.g., whether there is residual oscillation, whether shims should be repositioned), whether the imaging arm's motion trajectory was satisfactory (e.g., whether there was significant tilt during rotation that may be improved by adjusting the orbital tilt of the C-arm and / or adjusting the shim configuration), etc. The motion sensor may be mounted in any suitable location on the imaging device, such as the detector, the radiation source, the imaging arm, and / or the support arm.

[0191] At block 1904, the method 1900 continues with calibrating the imaging device. Calibration can be used to compensate for variations in the imaging environment and / or mechanical properties of the imaging device that may affect image reconstruction. In some embodiments, calibration includes determining one or more calibration parameters (e.g., distortion correction parameters, geometric calibration parameters) that are used in subsequent image acquisition and / or image reconstruction processes to adjust for certain characteristics of the imaging device. Additional details of methods and devices suitable for use in the calibration process of block 1904 are described below with reference to Figures 20-22D.

[0192] Fig. 20 is a flow diagram illustrating a method 2000 for calibrating an imaging device according to an embodiment of the present technology. The method 2000 can be implemented as part of the calibration process of block 1904 of the method 1900 of Fig. 19. As shown in Fig. 20, the calibration process can be subdivided into two parts: distortion correction (blocks 2002 and 2004) and geometric calibration (blocks 2006 and 2008).

[0193] Distortion correction can be performed in embodiments where one or more components (e.g., detectors) of the imaging device are subject to image distortion that can reduce the accuracy of subsequent 3D reconstruction. For example, mobile C-arm devices typically use an image intensifier as a detector, and images generated by the image intensifier can exhibit pincushion and / or barrel distortion, among others. The distortion can also vary depending on the orientation (e.g., angle) of the image intensifier. Thus, method 2000 can include performing a distortion correction process to identify the amount of image distortion in various imaging arm orientations and determining correction parameters that can be applied to the image to reduce or eliminate the distortion. In other embodiments, the distortion correction process can be omitted, for example, when using a flat panel detector rather than an image intensifier.

[0194] In block 2002, the method 2000 can include acquiring a first image of one or more of a set of first fiducial markers ("first fiducial markers"). The first fiducial markers can be radiodense or radiopaque beads, bearings, etc. arranged in a known 2D or 3D geometry, such as a grid, array, pattern, shape, etc. The first fiducial markers can be coupled to the detector in a fixed spatial configuration relative to the detector. The first images can be 2D projection images of the first fiducial markers obtained by the detector as the imaging arm is manually rotated through a number of different poses (e.g., rotation angles). Each first image can be associated with a corresponding pose of the imaging arm using any of the devices and techniques described elsewhere herein, such as the embodiments of Figures 15-18E.

[0195] At block 2004, the method 2000 continues with determining a set of distortion correction parameters based on the first image. The first image can be transmitted to a computing device (e.g., computing device 130 of FIG. 1A), which can analyze the first image and detect the location of the first fiducial marker in the first image (e.g., using image processing and / or computer vision techniques known to those skilled in the art). The computing device can then determine the distortion correction parameters by comparing the location of the first fiducial marker in the first image with the known true location of the first fiducial marker on a grid, array, etc. The distortion correction parameters can represent a set of transformations (e.g., rigid and / or non-rigid transformations, such as rotations, translations, deformations, etc.) that will realign the first fiducial marker in the distorted image to its true location. The distortion correction parameters can be determined through an optimization process according to techniques known to those skilled in the art. This process can be performed for each image to determine appropriate distortion correction parameters for different orientations (e.g., angles) of the imaging arm. The determined distortion correction parameters may then be applied to each image individually, as discussed in further detail below, to remove distortion artifacts due to detector properties and / or detector pose.

[0196] FIG. 21A is a front view of a fiducial marker grid 2102a configured in accordance with an embodiment of the present technology. The grid 2102a can be used to determine distortion correction parameters for an imaging device, for example, as described above with respect to blocks 2002-2004 of FIG. 20. The grid 2102a includes a substrate 2104 containing a plurality of fiducial markers 2106. The substrate 2104 can be made of a radiolucent material, such as acrylonitrile butadiene styrene (ABS), among others. In the illustrated embodiment, the substrate 2104 has a circular shape. In other embodiments, the substrate 2104 can have a different shape, such as a square, a rectangle, an oval, etc. The substrate 2104 can be sized to fit partially or completely across the surface of a typical detector. For example, the substrate 2104 can have a diameter and / or width in the range of 9 inches to 12 inches.

[0197] The markers 2106 can be beads, bearings, flattened disks, etc. made from a radiodense or radiopaque material, such as steel or other metallic material. As shown in FIG. 21A, the markers can be arranged in a regular (e.g., square) grid. In some embodiments, the markers 2106 have a size (e.g., diameter and / or width) in the range of 0.5 mm to 3 mm and are spaced from each other by a distance of 1 cm. In other embodiments, the size and / or arrangement of the markers 2106 can be varied as desired. The grid 2102a can include any suitable number of discrete markers, such as at least 10, 25, 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1,000, or more markers.

[0198] During use, the grid 2102a can be placed adjacent to or near the surface of the detector such that some or all of the markers 2106 are within the field of view of the detector. The grid 2102a can be temporarily coupled to the detector via clips, brackets, clamps, suction cups, Velcro® straps, rubber bands, magnets, or any other suitable attachment mechanism. Optionally, the grid 2102a and / or the detector can include one or more alignment markers so that the grid 2102a can be coupled to the detector in a consistent position and / or orientation.

[0199] In some embodiments, the grid 2102a is coupled to a mounting device that is connected to the detector. For example, the mounting device 1702a of FIGS. 17A-17E can be used to mount the grid 2102a to the detector. In such embodiments, the mounting device 1702a can be coupled to the detector and the grid 2102a can be inserted into or otherwise coupled to the frame 1708 of the mounting device 1702a. After the distortion correction process is completed, the grid 2102a can be removed from the frame 1708 leaving the mounting device 1702a in place, or the mounting device 1702a and the grid 2102a can be removed together.

[0200] Optionally, the grid 2102a may include functional components such as motion sensors (e.g., IMUs) and / or radiation sensors (e.g., photodiodes). The motion sensors and radiation detectors may be used to track the pose of the imaging arm and to time-synchronize the pose data to the acquired images, as discussed above. These components may be embedded within or otherwise coupled to the periphery of the grid 2102a to avoid obscuring the field of view of the detectors. However, in other embodiments, the grid 2102a may not include motion sensors and / or radiation sensors.

[0201] 21B-21D are front views of additional fiducial marker grids 2102b-2102d, configured in accordance with an embodiment of the present technology. The grids 2102b-2102d can be generally similar to the grid 2102a of FIG. 21A. Thus, discussion of the grids 2102b-2102d will be limited to those features that differ from the grid 2102a of FIG. 21A.

[0202] First, referring to FIG. 21B, the markers 2106 in grid 2102b are arranged such that the central portion 2108 has a different pattern than the peripheral portion 2110. This approach can facilitate automated identification of the central portion 2108 of grid 2102b, which can simplify the optimization process for calculating distortion correction parameters. In FIG. 21B, for example, five markers 2106 in the central portion 2108 are connected with radio-dense or radio-opaque lines to form a cross shape. In FIG. 21C, the central marker 2106 in the central portion 2108 of grid 2102c is spaced from the other markers 2106 by a known radial distance such that the central portion 2108 has a lower marker density than the peripheral portion 2110. In FIG. 21D, the central portion 2108 of grid 2102d includes additional markers 2106 such that the central portion 2108 has a higher marker density than the peripheral portion 2110. Alternatively, or in combination, other types of patterns, shapes, geometries, etc. can be used to distinguish the central portion 2108 from the peripheral portion 2110.

[0203] Referring again to FIG. 20, the geometric calibration process of method 2000 can include characterizing the geometry of the imaging device during manual rotation. In some embodiments, geometric calibration is required due to mechanical instability of the imaging device, which can lead to shifts and / or other non-uniform motions during rotation, as described above. For example, manual rotation can cause the imaging arm to deviate from an ideal rotation path for CBCT imaging purposes (e.g., a single-plane, circular rotation path). In addition, components of the imaging device can shift during manual rotation, for example, internal components of the detector can shift relative to the outer housing. Such internal movements can be difficult or impossible to detect using an externally installed sensor (e.g., an IMU coupled to the detector housing), and thus may require an image-based calibration process. In some embodiments, changes in geometry during rotation can cause the projection images acquired by the imaging device to misalign (e.g., the center of rotation shifts between images), which can adversely affect the quality and accuracy of the 3D reconstruction.

[0204] Thus, method 2000 can include determining the geometry of the imaging device at various rotational positions to determine deviations and / or other movements that may occur during subsequent rotations. Based on the determined geometry, method 2000 can calculate a set of geometric calibration parameters that can be used to adjust the projected images to compensate for changes in geometry during rotation. For example, the geometric calibration parameters can represent a set of transformations that, when applied to the projected images, correct any inconsistencies present in the images due to undesired movements of the imaging device.

[0205] In block 2006, the method 2000 includes acquiring a second image of a second set of fiducial markers ("second fiducial markers"). The second fiducial markers can be radiodense or radiopaque beads, bearings, etc., positioned within the phantom in a known 3D configuration. The second images can be 2D projection images acquired by the detector as the imaging arm is manually rotated to multiple different poses relative to the phantom. In some embodiments, the phantom is positioned at or near the isocenter of the imaging arm, and the imaging arm is manually rotated around the phantom (e.g., in the propeller rotation direction) to acquire a second image of the phantom from multiple different rotation angles. Each second image can be associated with a corresponding pose of the imaging arm using any of the devices and techniques described elsewhere herein, such as the embodiments of Figures 15-18E. In embodiments where the pose is determined using a fiducial marker board (e.g., fiducial marker boards 1800-1830 in FIGS. 18A-18E), the phantom can be mounted on or otherwise coupled to the fiducial marker board in a known spatial configuration (e.g., using a stand, in a fixed location on the operating table, etc.).

[0206] At block 2008, the method 2000 continues with determining a set of geometric calibration parameters based on the second image. The second image can be transmitted to a computing device (e.g., computing device 130 of FIG. 1A) for analysis. In some embodiments, the computing device first corrects any image distortion present in the second image using the distortion correction parameters determined in block 2004. The computing device can then analyze the second image and detect the location of the second fiducial marker in the second image (e.g., using image processing and / or computer vision techniques known to those skilled in the art). The computing device can then use the imaged location of the second fiducial marker and the known 3D configuration of the second fiducial marker in the phantom to determine the geometry of the imaging device during the rotation, such as the pierce point, the degree of distortion, pitch, roll, tilt, and / or source / detector distance, among others. For example, the pierce point can represent the center of rotation of the imaging arm and / or the center of a reference coordinate system in the image data. The geometry of the imaging device can be determined using image-based geometric calibration algorithms known to those skilled in the art.

[0207] Geometric calibration parameters can then be calculated based on the determined geometry of the imaging device. As discussed above, the geometric calibration parameters can represent a set of transformations (e.g., rigid and / or non-rigid transformations such as rotations, translations, deformations, etc.) to adjust the projected images at each rotation angle of the imaging device to correct any misalignments that exist. For example, if the pierce point of the imaging device shifts for a particular angle of the imaging arm, the projected images obtained at that angle can be shifted in the opposite direction to realign the pierce point. The determined geometric calibration parameters can be applied to each image individually to realign the images in preparation for image reconstruction, as discussed in more detail below.

[0208] 22A is a perspective view of a fiducial marker phantom 2202a configured in accordance with an embodiment of the present technology. The phantom 2202a can be used to perform a geometric calibration for an imaging device, for example, as described above with respect to blocks 2006-2008 of FIG. 20. The phantom 2202a includes a substrate 2204 containing a plurality of fiducial markers 2206. The substrate 2204 can be made of a radiolucent material (e.g., ABS) and can be manufactured using 3D printing or other suitable techniques. In the illustrated embodiment, the substrate 2204 has an elongated cylindrical shape. The substrate 2204 can have a length in the range of 7 cm to 25 cm and a diameter in the range of 7 cm to 25 cm. Optionally, the substrate 2204 can be hollow, with a sidewall thickness in the range of 0.5 cm to 5 cm. However, in other embodiments, the geometry (e.g., size, shape) of substrate 2204 can be varied as desired, for example, substrate 2204 can be rectangular rather than cylindrical, substrate 2204 can be solid rather than hollow, etc.

[0209] The markers 2206 can be beads, bearings, flattened disks, etc. made of radio-dense or radio-opaque materials such as steel or other metallic materials. The markers 2206 can be embedded in the phantom 2202a at known spatial locations. In the illustrated embodiment, for example, the markers 2206 are arranged in two parallel circles at the first end 2208 and the second end 2210 of the substrate 2204. This arrangement can allow piercing points to be automatically identified in the image of the phantom 2202a by connecting diametrically opposed markers 2206 and determining the intersections of the connections according to techniques known to those skilled in the art. However, in other embodiments, the markers 2206 can be arranged in different geometries and / or positioned at different locations within the substrate 2204 (e.g., between the first and second ends 2208, 2210).

[0210] 22B is a perspective view of another fiducial marker phantom 2202b configured in accordance with an embodiment of the present technology. The phantom 2202b may be generally similar to the phantom 2202a of FIG. 22A, except that the phantom 2202b includes a central marker 2212 that represents the penetration point of the imaging device. The central marker 2212 may be a bead, bearing, or the like made from a radio-dense or radio-opaque material, such as copper or another metal. The use of the central marker 2212 may be advantageous because it allows the location of the penetration point to be identified directly in the image data, rather than indirectly calculated from the locations of other markers (e.g., marker 2206). Although FIG. 22A depicts the phantom 2202b as including a central marker 2212 along with markers 2206 at the first and second ends 2208, 2210 of the substrate 2204, in other embodiments, the marker 2206 can be omitted such that the central marker 2212 is the only marker in the phantom 2202b.

[0211] 22C is a perspective view of an assembly 2214 that may be used to form the phantom 2202b, in accordance with an embodiment of the present technology. The assembly 2214 includes an elongated shaft 2216 (e.g., a rod, peg, tube, etc.) that carries a central marker 2212. The elongated shaft 2216 can be formed via additive manufacturing (e.g., 3D printing) with a recess for receiving the central marker 2212, or the central marker 2212 can be deposited or otherwise formed at a suitable location within the elongated shaft 2216 during an additive manufacturing process.

[0212] The elongated shaft 2216 can be connected to a first disk 2218 and a second disk 2220. The first and second disks 2218, 2220 can be located at or near opposite ends of the elongated shaft 2216. The first and second disks 2218, 2220 can be integrally formed with the elongated shaft 2216 as a single unitary component (e.g., via additive manufacturing). Alternatively, the first and second disks 2218, 2220 can be discrete components that are coupled to the elongated shaft 2216 via fasteners, adhesives, bonding, etc. For example, the first and second disks 2218, 2220 can each include a central hole and the end of the elongated shaft 2216 can fit into the hole to form the assembly 2214.

[0213] 22B and 22C together, to assemble the phantom 2202b, the elongated shaft 2216 can be positioned within the hollow interior cavity of the substrate 2204. The elongated shaft 2216 can have a length the same as or similar to that of the substrate 2204 such that the elongated shaft 2216 extends from a first end 2208 of the substrate 2204 to a second end 2210 of the substrate 2204. In embodiments in which the first and second disks 2218, 2220 are separable from the elongated shaft 2216, the first and second disks 2218, 2220 can then be positioned across the first and second ends 2208, 2210 of the substrate 2204, respectively, and connected to the elongated shaft 2216. The first and second disks 2218, 2220 can be sized to partially or completely cover the first and second ends 2208, 2210 of the substrate 2204. For example, the first and second disks 2218, 2220 can each have a diameter that is the same or similar to the diameter of the first and second ends 2208, 2210, respectively. Optionally, the first and second disks 2218, 2220 can be attached to the substrate 2204 using fasteners (e.g., snaps), adhesive (e.g., tape), or any other suitable technique to ensure that the center marker 2212 is positioned in the center of the phantom 2202b.

[0214] FIG. 22D is a perspective view of a fiducial marker phantom 2202c configured in accordance with an embodiment of the present technology. The phantom 2202c can be generally similar to the phantom 2202b of FIG. 22A, except that the phantom 2202b includes a ring 2222 rather than individual markers at the first and second ends 2208, 2210 of the substrate 2204. In some circumstances, a continuous structure such as the ring 2222 may be easier to identify in a projection image than a discrete marker, which can improve the accuracy of the calibration process. The ring 2222 can be made of a radiodense or radiopaque (e.g., metal) material. The ring 2222 can have a diameter the same as or similar to the diameter of the substrate 2204 and can have a thickness in the range of 1 mm to 5 mm. The ring 2222 can be formed in many different ways. For example, the ring 2222 can be a discrete component that is bonded to the substrate 2204 to form the phantom 2202c. In such an embodiment, the first and second ends 2208, 2210 of the substrate 2204 may include a groove for receiving the ring 2222. Alternatively, the ring 2222 may be formed integrally with the substrate 2204, such as by using an additive manufacturing process in which material is deposited into the substrate 2204 at appropriate locations.

[0215] Referring again to FIG. 20, the various steps of method 2000 can be performed at different times before and / or during an imaging procedure. For example, the distortion correction process of blocks 2002 and 2004 can be performed first before the imaging device is used for mrCBCT imaging. The distortion correction parameters determined in block 2004 can be reused for subsequent mrCBCT procedures performed using the same imaging device such that the distortion correction process does not need to be performed again. For example, the distortion correction parameters can be interpolated or extrapolated to subsequent images, e.g., using an IMU or other sensor, to correlate stored distortion correction parameters at a rotation angle with a similar angle in the subsequent images. However, in other embodiments, the distortion correction process can be performed periodically for the same imaging device (e.g., once per week, month, six months, year, etc.), when there is a significant change in imaging settings (e.g., when the detector is replaced, when the imaging device is moved to a different environment), or even every time the imaging device is used. Alternatively, in embodiments where little or no image distortion is observed (eg, when a flat panel detector is used), the distortion correction processes of blocks 2002 and 2004 can be omitted entirely.

[0216] Similarly, the geometric calibration process of blocks 2006 and 2008 can be performed initially before the imaging device is used for mrCBCT imaging, e.g., after performing distortion correction for the imaging device. The geometric calibration parameters determined in block 2008 can be reused for subsequent mrCBCT procedures performed using the same imaging device, such that the geometric calibration process does not need to be performed again. However, in other embodiments, the geometric calibration process can be performed for the same imaging device periodically (e.g., once per week, month, six months, year, etc.), when there is a significant change in imaging settings, or even each time the imaging device is used (e.g., once before a medical procedure is performed). Optionally, the geometric calibration process of blocks 2006 and 2008 may be omitted entirely.

[0217] 19, at block 1906, method 1900 continues with acquiring images and generating a 3D reconstruction from the images. As described elsewhere herein, the process of block 1906 can be used to perform intra-procedural mrCBCT imaging of targets within a patient's anatomy using a manually operated imaging device that lacks any motors, actuators, etc. for automatically rotating the imaging arm. Representative examples of image acquisition and reconstruction methods that may be performed as part of the imaging process of block 1906 are described below with reference to FIGS. 21A and 21B.

[0218] FIG. 23A is a block diagram illustrating a method 2300 for imaging an anatomical region according to an embodiment of the present technology. Some or all of the steps of the method 2300 can be implemented as part of the image acquisition and reconstruction process of block 1906 of the method 1900 of FIG. 19. The method 2300 begins at block 2302 with manually rotating an imaging arm to a number of different poses. As described above, the imaging arm can be part of an imaging device, such as the imaging device 104 of FIG. 1A. For example, the imaging device can be a mobile C-arm device, and the imaging arm can be a C-arm of the mobile C-arm device. The imaging arm can be rotated around the target anatomical region of the patient along any suitable direction, such as the propeller rotation direction. In some embodiments, the imaging arm is manually rotated to a number of different poses (e.g., angles) relative to the target anatomical region. The imaging arm can be rotated through an arc that is large enough to perform CBCT imaging. For example, the arc can be at least 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, 180°, 190°, 200°, 210°, 220°, 230°, 240°, 250°, 260°, 270°, 280°, 290°, 300°, 310°, 320°, 330°, 340°, 350°, or 360°.

[0219] At block 2304, the method 2300 continues with receiving a plurality of images acquired during the manual rotation. The images can be 2D projection images generated by a detector (e.g., an image intensifier or a flat panel detector) carried by the imaging arm. The method 2300 can include generating any suitable number of images, such as at least 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1,000 images. The images can be generated at a rate of at least 5 images / second, 10 images / second, 20 images / second, 30 images / second, 40 images / second, 50 images / second, or 60 images / second. In some embodiments, the images are generated while the imaging arm is manually rotated through a plurality of different positions such that some or all of the images are acquired at different positions of the imaging arm.

[0220] At block 2306, the method 2300 may include receiving posture data of the imaging arm during manual rotation. The posture data may be generated using any of the techniques and devices described herein. For example, the posture data may be generated based on sensor data from at least one sensor, such as an IMU or another motion sensor, coupled to the imaging arm (e.g., to the detector), to the support arm, or a combination thereof. The sensor data may be processed at various times during the manual rotation to determine the posture of the imaging arm. As described above, the posture of the imaging arm may be estimated without the use of a fiducial marker board or other reference object positioned near the patient. However, in other embodiments, the posture data may be determined using a fiducial marker board, such as the embodiment described above with reference to FIGS. 18A-18E. In such embodiments, the fiducial marker board may be positioned on the operating table in a known spatial configuration relative to the imaging device (e.g., the same spatial configuration used during calibration).

[0221] Optionally, the pose data of block 2306 can also be used to provide feedback to the user regarding the speed, smoothness, and / or other characteristics of the manual rotation. For example, if the imaging arm is being rotated too slowly (e.g., if the estimated total rotation time will take longer than 30 seconds and / or will exceed the automatic shutoff time for the imaging device), the computing device may output an alert (e.g., image, text, sound, etc.) and instruct the user to increase the rotation speed. Conversely, if the imaging arm is being rotated too quickly, the alert may instruct the user to slow down. As another example, the computing device may display a target speed value or range for image acquisition and the actual speed of the imaging arm. The target speed value or range may be based on a predetermined total rotation time for improved image quality, such as a rotation time in the range of 1 second to 20 seconds. In some embodiments, a graphical representation of the rotation speed is displayed to give the operator real-time feedback during the rotation, e.g., to increase, decrease, or maintain the current rotation speed. For example, the representation may show a first indicator when the rotation is at the right speed, a second indicator (e.g., a red indicator) when the speed is too fast, a third indicator (e.g., a green indicator) when the speed is too slow, etc.

[0222] At block 2308, the method 2300 includes generating a 3D reconstruction based on the image received at block 2304 and the pose data received at block 2306. The 3D reconstruction process may include inputting the image into an image reconstruction algorithm, such as a filtered backprojection algorithm, an iterative reconstruction algorithm, or other suitable algorithm known to those skilled in the art. Optionally, the image can be processed before being input into the algorithm, for example, by applying calibration parameters, removing distortion artifacts, correcting misalignments, and / or making other adjustments to prepare the image for reconstruction. An exemplary embodiment of a method for generating a 3D reconstruction is discussed below in connection with FIG. 23B.

[0223] 23B is a flow diagram illustrating a method 2320 for generating a 3D reconstruction from multiple images, according to an embodiment of the present technology. Some or all of the processes of method 2320 can be implemented as part of block 2308 of method 2300 of FIG. 23A. Method 2320 begins at block 2312 with associating pose data with each image. As discussed above, the pose data can be time-synchronized with the projection images generated by the imaging device such that each image is associated with a corresponding pose (e.g., rotation angle) of the imaging arm at or near the time the image was acquired.

[0224] At block 2314, method 2320 may include applying one or more distortion correction parameters to some or all of the images. As discussed above, the distortion correction parameters may be applied to the images to reduce or eliminate distortion present in the images due to, for example, the use of an image intensifier. The distortion correction parameters may be parameters determined in a previous calibration process (e.g., the process of block 2004 of FIG. 20). In some embodiments, the distortion correction parameters are stored as a lookup table (or similar data structure) that records a set of parameters for each angle of the imaging arm. Thus, to correct for distortion in a particular image, the angle of the imaging arm at the time of image acquisition (the "target angle") may be determined using any of the techniques described herein. The stored distortion correction parameters corresponding to the target angle may then be retrieved from the lookup table. If the target angle does not match any of the entries in the lookup table, the distortion correction parameters can be interpolated or extrapolated from other parameters, for example distortion correction parameters stored for the angle closest to the target angle.

[0225] At block 2316, method 2320 may include applying one or more geometric calibration parameters to some or all of the images. As discussed above, the geometric correction parameters may be applied to the images to correct any misalignments present in the images due to, for example, imaging arm motion that deviates from a single-plane isocenter trajectory. The distortion correction parameters may be parameters determined in a previous calibration process (e.g., the process of block 2008 of FIG. 20). In some embodiments, the geometric calibration parameters are stored as a lookup table (or similar data structure) that records a set of parameters for each angle of the imaging arm. Thus, when adjusting a particular image, the angle of the imaging arm at the time of image acquisition (the "target angle") may be determined using any of the techniques described herein. The stored geometric calibration parameters corresponding to the target angle are then retrieved from the lookup table. If the target angle does not match any of the entries in the lookup table, the geometric calibration parameters can be interpolated or extrapolated from other parameters, such as the geometric calibration stored for the angle closest to the target angle. The geometric calibration parameters can thus be used to correct images in situations where it is not feasible to use a fiducial marker phantom or other physical calibration reference.

[0226] In some embodiments, the distortion correction parameters of block 2314 and / or the geometric calibration parameters of block 2316 are adjusted based on the posture data of the imaging arm. These adjustments can be made to account for any deviations from the calibration settings. For example, the actual rotational trajectory of the imaging arm during patient imaging ("imaging trajectory") may differ from the rotational trajectory of the imaging device when determining the calibration parameters for the imaging device ("calibration trajectory"), as discussed with respect to FIG. 20. If the imaging trajectory deviates significantly from the calibration trajectory, the original parameters may no longer be sufficient to correct the image distortion and / or image misalignment.

[0227] Thus, method 2320 may further include detecting whether the imaging trajectory deviates significantly from the calibration trajectory, for example, for tilt, pitch, roll, or any other suitable measurement. The deviation may be considered significant, for example, if the magnitude of the difference between the values ​​in the calibration trajectory and the values ​​in the imaging trajectory is at least 5%, 10%, 15%, 20%, 25%, or 50% of the values ​​in the calibration trajectory. The deviation may be detected by comparing the attitude data of the imaging device during the imaging trajectory (e.g., the attitude data of block 2306 of FIG. 23A) with the attitude data of the imaging device during the calibration trajectory (e.g., the attitude data determined during method 2000 of FIG. 20).

[0228] If significant deviations are detected, method 2320 may include updating or otherwise modifying the distortion correction parameters and / or the geometric calibration parameters to account for these deviations. The updates may be made to only the distortion correction parameters, only the geometric calibration parameters, or to both sets of parameters. The updates may be determined based on the pose data of the imaging arm and the known geometry of the imaging device according to techniques known to those skilled in the art. For example, if the imaging arm exhibited a forward tilt of 1.5° at a 90° angular position in the calibration trajectory, but a forward tilt of 2.0° at a 90° angular position in the imaging trajectory, the geometric calibration parameters for images acquired at or near the 90° angular position may be updated to compensate for the difference in forward tilt. Updated geometric calibration parameters can be calculated by determining the extent to which the detected deviations affect the geometry of the imaging device (e.g., with respect to penetration point, skewness, pitch, roll, tilt, and / or source / detector distance), determining the amount and / or direction of additional image misalignment caused by the change in geometry, and then determining parameters that will correct the additional misalignment.

[0229] At block 2318, the method 2320 may continue with generating a 3D reconstruction from the images according to techniques known to those skilled in the art. For example, the 3D reconstruction may be generated using filtered backprojection, iterative reconstruction, and / or other suitable algorithms. Optionally, image interpolation may also be applied to the reconstruction process, if appropriate, to reduce image noise resulting from a reduced number of image acquisition angles.

[0230] The method 2320 of FIG. 23B can be modified in many different ways, as desired. For example, in other embodiments, block 2314 can be omitted, for example, if the imager uses a flat panel detector or is otherwise not expected to produce significant image distortion. As another example, block 2316 can be omitted if the images are not expected to be significantly misaligned. In addition, method 2320 can include other image pre-processing steps not shown in FIG. 23B.

[0231] Referring again to FIG. 23A, at block 2310, method 2300 can optionally include outputting a graphical representation of the 3D reconstruction. The graphical representation can be displayed on an output device (e.g., display 132 and / or secondary display 134 of FIG. 1A) to provide guidance to a user in performing a medical procedure. In some embodiments, the graphical representation includes the 3D reconstruction generated in block 2308, presented, for example, as a 3D model or other virtual rendering. Alternatively, or in combination, the graphical representation can include 2D images (e.g., 2D axial, coronal, and / or sagittal slices) derived from the 3D reconstruction.

[0232] In some embodiments, the user views the graphical representation to verify whether the medical tool is positioned at the target location. For example, the graphical representation can be used to verify whether a biopsy instrument is positioned within a nodule or lesion of interest. As another example, the graphical representation can be used to determine whether an ablation device is positioned at or near the tissue to be ablated. If the tool is properly positioned, the user can proceed to perform the medical procedure. If the graphical representation indicates that the tool is not at the target location, the user can reposition the tool and then repeat some or all of the steps of method 2300 to generate a new 3D reconstruction of the tool and / or target within the anatomy.

[0233] Referring again to FIG. 19, method 1900 may optionally include additional processes not shown in FIG. 19. For example, once the calibration process of block 1904 is completed, method 1900 may optionally include performing a pre-acquisition rotation of the imaging arm. The pre-acquisition rotation may serve as a "practice" rotation to provide feedback to the user regarding the trajectory and quality of the manual rotation. The feedback may be used to adjust the stability, trajectory, speed, quality, and / or other aspects of the manual rotation and / or imager settings. In some embodiments, some or all of the processes associated with the pre-acquisition rotation are performed without any radiation, reducing radiation exposure to the patient. Representative examples of methods that may be performed as part of the pre-acquisition process are described below with reference to FIG. 24.

[0234] FIG. 24 is a flow diagram illustrating a method 2400 of preparing an imaging device for image acquisition, according to an embodiment of the present technology. The method 2400 can be performed before the image acquisition and reconstruction process of block 1906 of FIG. 19. The method 2400 can begin at block 2402, where the field of view of the imaging device can be aligned with a target in an anatomical region. In some embodiments, the field of view in the 3D reconstruction is significantly smaller than the field of view in the projection image. Thus, the alignment process of block 2402 can be performed to ensure that the target region will be visible in the final CBCT image. In some embodiments, the alignment process is performed after the imaging device is stabilized and / or calibrated. However, in other embodiments, the alignment process of block 2402 is optional and may be omitted.

[0235] In some embodiments, the alignment process of block 2402 includes acquiring one or more test images of the patient's anatomy, such as lateral and / or frontal projection images. The computing device can then process the test images to identify image locations that will be present in the image reconstruction. For example, the computing device can overlay an indicator (e.g., a circle or other shape, a shadow, an arrow) on the test image that represents a smaller field of view of the image reconstruction. As another example, the computing device can crop or otherwise remove portions of the test image to remove locations that will not be visible in the image reconstruction. Thus, a user can view the processed test images and determine whether the target will be visible in the image reconstruction. If the target will not be visible, the operator can adjust the positioning of the imaging device and / or the patient and obtain new test images.

[0236] At block 2404, the method may continue with manually rotating the imaging arm of the imaging device to a number of different positions. The manual rotation may be performed under conditions that are the same or similar to those during which actual image acquisition will occur. For example, the imaging device may already be stabilized, calibrated, and / or aligned as discussed above. The user may rotate the imaging arm through a range of at least 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, 180°, 190°, 200°, 210°, 220°, 230°, 240°, 250°, 260°, 270°, 280°, 290°, 300°, 310°, 320°, 330°, 340°, 350°, or 360° along a rotational trajectory that will be used to generate the actual image, such as a propeller rotation.

[0237] At block 2406, method 2400 continues with receiving orientation data of the imaging arm during the manual rotation of block 2404. The orientation data can be generated using any of the devices and techniques described herein. For example, the orientation of the imaging arm can be determined using a motion sensor coupled to the imaging arm. The orientation data can be transmitted to a suitable computing device (e.g., computing device 130 of FIG. 1A) for storage and processing.

[0238] At block 2408, the method 2400 may include comparing the pose data of block 2406 with the calibration pose data. The calibration pose data may include pose data of the imaging arm during a manual rotation performed as part of a previous calibration process (e.g., the geometric calibration process of FIG. 20). The calibration pose data may indicate the trajectory and / or velocity of the imaging arm during the previous calibration rotation. In some embodiments, the characteristics of the manual rotation performed by the user during the actual image acquisition should be as close as possible to the characteristics of the calibration rotation to improve the quality of the image reconstruction. Thus, at block 2408, the computing device may analyze the pose data to determine whether the pre-acquisition rotation significantly deviates from the calibration rotation with respect to trajectory, velocity, stability (e.g., absence of oscillation, deviation, or other undesirable motion), etc.

[0239] At block 2410, the method 2400 may include generating feedback and / or making adjustments to the imaging device based on the comparison performed at block 2408. For example, the computing device may provide feedback to the user as to the extent to which the pre-acquisition rotation deviates from the calibration rotation. The computing device may also provide recommendations as to how to adjust the rotation and / or imaging device to conform more closely to the calibration rotation or otherwise improve the operation of the imaging device. For example, if the imaging device was not stabilized as well in the pre-acquisition rotation as compared to the calibration rotation, the user may adjust the stabilization technique used to improve stability, for example, by adding additional shim structures, changing the type and / or location of shim structures, modifying where forces are applied during the rotation, or any of the other approaches described herein. As another example, if the imaging arm is tilted or otherwise positioned differently than its positioning in the calibration rotation, the computing device may recommend that the user adjust the imaging arm accordingly. In yet another embodiment, the feedback may also indicate whether the pre-acquisition rotation is sufficiently smooth, uniform (eg, circular), and / or at an appropriate speed for image acquisition purposes.

[0240] In some embodiments, the computing device can output a graphical user interface to guide the operator in making the appropriate adjustments. For example, the interface can show a virtual representation of the imaging device along with an indicator (e.g., an arrow) that displays the recommended adjustments. Alternatively, or in combination, the interface can output text instructions that explain the adjustments to be made to the imaging device and / or rotation trajectory. In some embodiments, the interface displays real-time feedback, such as the actual position and / or orientation of the imaging arm (e.g., from IMU and / or other sensor data) as the user makes adjustments, so the user can see if the targeted position and / or orientation has been reached. Optionally, the interface can also output alerts, warnings, or other feedback (e.g., "rotating too fast," "imaging arm too far left") during manual rotation, so the user can adjust the rotation trajectory and / or speed in real time.

[0241] Method 2400 of FIG. 24 can be modified in many different ways, as desired. For example, some or all of the processes of method 2400 can be performed multiple times, e.g., to ensure that a user properly performs manual rotations and / or that an imaging device is properly set up to acquire an image of the target. In some embodiments, some or all of the processes of blocks 2404, 2406, 2408, and / or 2410 are repeated until the pre-acquisition rotation is sufficiently close to the calibration rotation. As another example, the process of acquiring and reviewing test images in block 2402 can be repeated until a user confirms that the target is properly aligned for image reconstruction purposes. Additionally, some or all of the processes of method 2400, such as the processes of blocks 2402 and / or 2410, can be omitted.

[0242] 19, method 1900 can be modified in many different ways. For example, the processes of method 1900 can be performed in a different order. In some embodiments, stabilization may not be necessary to accurately determine calibration parameters and / or perform a pre-acquisition rotation. Thus, the stabilization process of block 1902 can be performed after the calibration process of block 1904. Additionally, some of the processes of method 1900 can be optional. For example, any of the processes of blocks 1902 and / or 1904 can be omitted from method 1900.

[0243] 25A is a flow diagram illustrating a method 2500 for calibration and image acquisition using a fiducial marker board, in accordance with an embodiment of the present technology. Method 2500 can be generally similar to method 1900 of FIG. 19, except that a fiducial marker board is used to estimate the pose (e.g., rotation angle) of the imaging arm during geometric calibration and image acquisition.

[0244] Method 2500 begins at block 2502 with attaching a fiducial marker phantom to a fiducial marker board. The fiducial marker phantom can be any of the embodiments described with respect to Figures 22A-22D, and the fiducial marker board can be any of the embodiments described with respect to Figures 18A-18G.

[0245] At block 2504, method 2500 may include acquiring a set of first images of the fiducial marker phantom and the fiducial marker board. The first images may be 2D projection images acquired by the detector as the imaging arm is manually rotated through a number of different poses (e.g., rotation angles) as described elsewhere herein. Each first image may be associated with a corresponding pose of the imaging arm. The pose of the imaging arm may be determined from markers of the fiducial marker board in the first images as described above with respect to FIGS. 18A-18G.

[0246] At block 2506, method 2500 continues with determining a set of geometric calibration parameters based on the first image. The geometric calibration parameters can be determined by identifying locations of phantom fiducial markers in the first image, as discussed above for block 2006 of method 2000 of FIG. 20. In some embodiments, the combination of the phantom and fiducial marker board allows the geometry of the imaging device (e.g., pierce point, skewness, pitch, roll, tilt, source-detector distance) to be fully determined.

[0247] In block 2508, the method 2500 may include removing the fiducial marker phantom from the fiducial marker board and positioning the patient on the fiducial marker board. For example, the patient may be placed in a supine position with their back resting on the board.

[0248] At block 2510, the method 2500 continues with acquiring a set of second images of the fiducial marker board and the patient. The second images can be 2D projection images acquired by the detector as the imaging arm is manually rotated through a number of different poses (e.g., rotation angles) as described elsewhere herein. Each second image can be associated with a corresponding pose of the imaging arm. The pose of the imaging arm can be determined from the markers of the fiducial marker board in the second images, as described above with respect to Figures 18A-18G.

[0249] At block 2512, method 2500 may include applying geometric calibration parameters to some or all of the second images. The process of block 2512 may be the same as or similar to the process of block 2316 of method 2320 of FIG. 23B. For example, in some embodiments, the geometric calibration parameters of block 2306 are retrieved from a lookup table (or similar data structure) based on the pose (e.g., rotation angle) of the imaging arm as determined using the fiducial marker board. Because the same fiducial marker board is used for both geometric calibration and image acquisition, the pose estimate generated from the fiducial marker board is consistent across these processes and therefore can be used to determine the appropriate geometric calibration parameters to be applied to each second image.

[0250] At block 2514, the method 2500 may include generating a 3D reconstruction based on the second image. The 3D reconstruction may be generated from the second image using any of the techniques described elsewhere herein. Optionally, before the 3D reconstruction is generated, the markers of the fiducial marker board and / or any imaging artifacts caused by the markers may be subtracted from the second image. The subtraction may be performed using computer vision techniques and / or other image processing algorithms known to those skilled in the art.

[0251] FIG. 25B is a flow diagram illustrating a method for operating an imaging device according to an embodiment of the present technology. At block 2502′, the method 2500′ can include positioning a phantom (e.g., a calibration phantom and / or a cylinder) near the imaging device. For example, the phantom can be positioned near the axis of rotation of an imaging arm of the imaging device. At block 2504′, the method can include acquiring a first 2D image using a shim-stabilized imaging arm at a plurality of angles. At block 2506′, the method 2500′ can include acquiring imaging arm pose data based on the first image, including the phantom. In some embodiments, a generic model of the imaging arm pose can be formed for any arbitrary projection angle. At block 2508′, the method 2500′ can include removing the phantom from the center of rotation and placing a fiducial marker board around the patient area of ​​interest. In some embodiments, the fiducial marker board is an L- or J-shaped fiducial marker board. In other embodiments, the fiducial marker board is not an L or J shaped fiducial marker board. At block 2510', the method 2500' may include acquiring second 2D images of both the fiducial marker board and the patient during rotation of the imaging arm at a plurality of angles. At block 2512', the method 2500' may include acquiring second pose data of the imaging arm based on the second images. For example, the method 2500' may include estimating the imaging arm angle for each second image using the known geometry of the fiducial marker board. The method 2500' may include using the angle estimate from the fiducial marker board to reference the generic calibration model generated from the first image to determine the imaging arm pose and other related geometric information for each second image. The method 2500' may include removing the signal of the fiducial marker in the fiducial marker board. At block 2514', the method 2500' may include generating a 3D reconstruction of the image volume using the second image along with estimated pose information determined using angle estimation from the fiducial markerboard.

[0252] In some embodiments of the present technology, a special fiducial board, such as an L- or J-shaped fiducial marker board or other fiducial marker board, can be used in conjunction with a phantom (e.g., a calibration phantom and / or a cylindrical shape) to perform a manually rotated 3D reconstruction. In such an embodiment, the phantom can be configured to determine the pose of the imaging arm using methods known to those skilled in the art. In some embodiments of the methods herein, the phantom can be placed near the center of the imaging arm rotation axis, and a first series of 2D images is obtained using a shim-stabilized imaging arm at multiple angles. The pose of the imaging arm at each image angle can be determined from the corresponding 2D images by tracking and / or segmenting the fiducial markers in the phantom, as known to those skilled in the art. Once the pose of the imaging arm at each image is determined, a general model of the pose of the imaging arm can be formed for any arbitrary projection angle using interpolation / extrapolation techniques known to those skilled in the art.

[0253] The phantom is then removed and the patient area of ​​interest (e.g., chest) can be placed near the imaging arm (such as the isocenter of the C-arm). A fiducial marker board, such as an L- or J-shaped fiducial marker board, can be placed around the patient near the area of ​​interest. The fiducial marker board has an array of radio-dense ball bearings or other markers from which the angular position of the imaging arm can be determined using methods known to those skilled in the art. A second series of 2D images of both the fiducial marker board and the patient can then be acquired during the rotation of the imaging arm at multiple angles. The fiducial markers in the board can then be automatically tracked and segmented using their known pattern. Encoding the fiducial pattern index allows for estimation of the imaging arm angle for each 2D projection image during the second series of images. Once the angle is estimated for each image of the second series of images, the estimated angle can be used to reference a generic calibration model (e.g., a look-up table, etc.) generated from the first series of images. The angles determined from each image in the second series of images are then used to determine the correct posture of the C-arm as modeled from the first series of images and other relevant geometric information. Once the posture of the C-arm is determined, the signals of the fiducial markers in the board can then be virtually (digitally) removed or suppressed from each projection image using techniques known to those skilled in the art (e.g., interpolation of nearby pixels) to limit or prevent metal artifacts in the reconstructed 3D image of the patient. Once the signals from the fiducial markers have been removed, the 3D reconstruction can be performed.

[0254] 26A and 26B are representative CBCT images of a phantom generated using a manual rotating translation C-arm device. The images were obtained using a GE Healthcare OEC 9900 C-arm device with an image intensifier and a rotation angle of about 180 degrees. The phantom was a cylindrical phantom including a set of rings and a central marker, similar to phantom 2202c in FIG. 22D. The image is a cross-sectional view of the phantom showing the cylindrical outer edge and the shaft carrying the central marker (the central marker is not shown in the image). The image in FIG. 26A was generated without the use of calibration or shim stabilization, while the image in FIG. 26B was generated with calibration and shim stabilization according to an embodiment of the present technology. As shown in FIG. 26A, in the absence of calibration and shim stabilization, the image is blurry, misaligned, and contains significant distortion artifacts. In contrast, after calibration and shim stabilization, the image in FIG. 26B accurately and clearly depicts the geometry of the phantom.

[0255] 27A and 27B are representative CBCT images of lungs generated using a manual rotating and moving C-arm device. The images were obtained using a GE Healthcare OEC 9900 C-arm device with an image intensifier and a rotation angle of about 180°, and show a live pig chest with an embedded lung nodule 2702. The image in FIG. 27A was generated without the use of calibration or shim stabilization, while the image in FIG. 27B was generated with calibration and shim stabilization according to an embodiment of the present technology. As shown in FIG. 27A, without calibration and shim stabilization, the anatomical structures are not visible in the resulting image. As shown in FIG. 27B, with calibration and shim stabilization, the resulting image has a sufficiently high spatial resolution and contrast-to-noise ratio to clearly depict anatomical structures in and near the lungs, such as nodule 2702, blood vessels 2704, bronchi 2706, and ribs 2708.

[0256] FIG. 27C is a CBCT image generated using a robotic rotational CBCT imaging system. Specifically, the image was obtained using a Siemens Artis Zeego CBCT system, which is a stationary system using a motorized imaging arm with a rotation angle of about 220°. The image shows the same porcine breast as the images of FIGS. 27A and 27B. As can be seen by comparing FIGS. 27B and 27C, the imaging techniques described herein can produce image reconstructions using a manually operated C-arm device that are comparable in quality to those produced by high-performance specialized CBCT systems.

[0257] Working Example The following examples are included to further illustrate some aspects of the present technology and should not be used to limit the scope of the technology. Example 1 1. A method for imaging an anatomical region, comprising: receiving a plurality of two-dimensional (2D) images of an anatomical region from a detector carried by an imaging arm of an x-ray imaging device, the 2D images being acquired during manual rotation of the imaging arm, the imaging arm being stabilized by a shim structure during the manual rotation; receiving sensor data from at least one sensor coupled to the imaging arm during manual rotation, the sensor data indicative of a plurality of orientations of the imaging arm; generating a 3D representation of the anatomical region based on the 2D image and the sensor data; A method comprising: Example 2 2. The method of example 1, wherein the X-ray imaging device comprises a mobile C-arm device. Example 3 3. The method of any one of the preceding claims, wherein the detector comprises an image intensifier. Example 4 The method of any one of Examples 1-3, wherein the X-ray imaging device comprises a support arm slidably coupled to the imaging arm, and the shim structure is positioned at an interface between the imaging arm and the support arm. Example 5 5. The method of example 4, wherein the shim structure is configured to reduce movement of the imaging arm relative to the support arm. Example 6 6. The method of example 4 or 5, wherein the support arm is rotatably coupled to the movable base, and the support arm and imaging arm are manually rotated relative to the movable base to acquire the 2D image. Example 7 The method of example 6, wherein the manual rotation is actuated by a force applied at or near the interface between the support arm and the movable base. Example 8 The method of example 7, wherein the force is applied to a lever structure coupled at or near the interface between the support arm and the movable base. Example 9 The method of any one of Examples 4-8, wherein the shim structure comprises at least one elongated member configured to fit at least partially within an interface between the imaging arm and the support arm. Example 10 The shim structure is a set of extension members positioned on two sides of an interface between the imaging arm and the support arm; a bridge region connecting the sets of elongate members; The method of Example 9, comprising: Example 11 The method of any one of Examples 1-10, wherein the manual rotation comprises propeller rotation. Example 12 The method of any one of Examples 1-11, wherein the manual rotation comprises a rotation of at least 90 degrees. (Example 13) The method of example 12, wherein the manual rotation comprises a rotation of at least 180 degrees. Example 14 The method of any one of Examples 1-13, wherein the at least one sensor comprises a motion sensor, and the sensor data comprises motion data of an imaging arm. Example 15 15. The method of example 14, wherein the motion sensor comprises an inertial measurement unit (IMU). Example 16 16. The method of example 14 or 15, further comprising determining a plurality of postures of the imaging arm based on the motion data. (Example 17) The method of any one of Examples 1-16, wherein at least one sensor comprises a sensor coupled to the detector. (Example 18) The method of any one of Examples 1-17, wherein generating the 3D representation includes associating each 2D image with a corresponding pose of the imaging arm. (Example 19) 19. The method of example 18, wherein associating each 2D image with a corresponding pose includes identifying a pose of the imaging arm when the 2D image was acquired. (Example 20) The method of any one of Examples 1-19, further comprising applying one or more distortion correction parameters to at least some of the 2D images prior to generating the 3D representation. Example 21 The method of any one of Examples 1-20, further comprising applying one or more geometric calibration parameters to at least some of the 2D images prior to generating the 3D representation. Example 22 The method of any one of Examples 1-21, further comprising outputting real-time feedback to an operator during manual rotation to adjust the rotational speed of the imaging arm. Example 23 The method of any one of Examples 1-22, further comprising outputting a 3D representation on a graphical user interface during a medical procedure performed in the anatomical region. (Example 24) 1. A system for imaging an anatomical region, comprising: a shim structure configured to stabilize manual rotation of an imaging arm of an x-ray imaging device; at least one sensor configured to generate sensor data indicative of a posture of the imaging arm; one or more processors operably coupled to the x-ray imager and the at least one sensor; When operatively coupled to one or more processors and executed by the one or more processors, the system is receiving a sequence of two-dimensional (2D) images of an anatomical region from an x-ray imaging device, the images being acquired during manual rotation of an imaging arm; determining attitude information of the imaging arm during manual rotation of the imaging arm based on the sensor data; generating a 3D reconstruction of the anatomical region based on the 2D image and the pose information; A memory for storing instructions for performing operations, the instructions including: A system comprising: (Example 25) 25. The system of example 24, wherein the X-ray imaging device comprises a mobile C-arm device. (Example 26) The system of any one of Examples 24 to 25, wherein the X-ray imaging device comprises a support arm slidably coupled to the imaging arm, and the shim structure is configured to be positioned at an interface between the imaging arm and the support arm. Example 27 27. The system of example 26, wherein the shim structure is configured to reduce movement of the imaging arm relative to the support arm. (Example 28) 28. The system of example 27, wherein the shim structure prevents orbital rotation of the imaging arm. (Example 29) A system described in any one of Examples 26-28, wherein the support arm is rotatably coupled to a movable base, and the support arm and imaging arm are manually rotated relative to the movable base to acquire 2D images. (Example 30) The system of Example 29, further comprising a lever structure coupled to or near the interface between the support arm and the movable base, the lever structure configured to facilitate manual rotation of the imaging arm. (Example 31) A system described in any one of Examples 26-30, wherein the shim structure comprises at least one elongated member configured to fit, at least in part, within an interface between the imaging arm and the support arm. Example 32 The system of Example 31, wherein the shim structure includes a pair of arm regions positioned on two sides of the interface between the imaging arm and the support arm. (Example 33) 33. The system of example 32, wherein the shim structure includes a bridge region connecting the pair of arm regions. (Example 34) The system of any one of Examples 24-33, wherein the manual rotation comprises angular rotation. Example 35 The system of any one of Examples 24-34, wherein the manual rotation comprises a rotation of at least 90 degrees. (Example 36) A system described in any one of Examples 24-35, wherein at least one sensor comprises a motion sensor and the sensor data comprises motion data of an imaging arm. (Example 37) 37. The system of example 36, wherein the motion sensor comprises an inertial measurement unit (IMU). (Example 38) 38. The system of example 36 or 37, wherein the motion sensor is coupled to the detector. (Example 39) 39. The system of example 38, wherein the motion sensor is coupled to the detector via an attachment device. (Example 40) The system of Example 39, wherein the attachment device comprises a clip, bracket, frame, or container. (Example 41) The system of any one of Examples 24-40, further comprising a controller operably coupled to the at least one sensor, the controller configured to temporally synchronize the 2D image to sensor data generated by the at least one sensor. (Example 42) A system described in any one of Examples 24-41, further comprising a radiation sensor configured to generate a signal in response to detected radiation, the signal being transmitted to a controller to temporally synchronize the 2D image to the sensor data. (Example 43) The system of any one of Examples 24-42, further comprising a display configured to output a graphical representation of the 3D reconstruction. (Example 44) A non-transitory computer readable medium that, when executed by one or more processors of a computing system, causes the computing system to: receiving a plurality of projection images of an anatomical target from a detector carried by an imaging arm of a mobile C-arm device, the projection images being acquired during manual rotation of the imaging arm, the imaging arm being stabilized by a shim structure during the manual rotation; receiving posture data of the imaging arm from at least one sensor coupled to the imaging arm during manual rotation; generating a 3D reconstruction of the anatomical target based on the projection images and the pose data; 23. A non-transitory computer readable medium comprising instructions that cause operations to be performed, including: (Example 45) 1. A method for imaging an anatomical region, comprising: receiving a plurality of two-dimensional (2D) images of an anatomical region from a detector carried by an imaging arm of an x-ray imaging device, the 2D images being acquired during manual rotation of the imaging arm, the imaging arm being stabilized by a shim structure during the manual rotation; receiving attitude data of the imaging arm during manual rotation; generating a 3D representation of the anatomical region based on the 2D image and pose data; A method comprising: (Example 46) The method of example 45, wherein the posture data is generated from an image of a fiducial marker board positioned near an anatomical target. (Example 47) 47. The method of example 46, wherein the fiducial marker board includes a plurality of fiducial markers, at least some of which are located in different planes. (Example 48) 48. The method of example 46 or 47, wherein the fiducial marker board includes a base region and at least one sidewall extending upwardly from the base region. (Example 49) The method of any one of Examples 45-48, wherein the posture data is generated by at least one sensor coupled to the imaging arm. (Example 50) 1. A method for operating an imaging device, comprising: receiving a plurality of first images of the set of first fiducial markers from a detector carried by an imaging arm of an imaging device, the first images being acquired during manual rotation of the imaging arm; determining a set of distortion correction parameters for the imaging device based on the first image; receiving a plurality of second images of the second set of fiducial markers from the detector, the second images being acquired during manual rotation of the imaging arm; determining a set of geometric calibration parameters for the imaging device based on the second image; A method comprising: (Example 51) The method of Example 50, wherein the imaging device is a mobile C-arm device. (Example 52) The method of any one of Examples 50 and 51, wherein the first and second images are each acquired during a propeller rotation of the imaging arm. (Example 53) The method of any one of Examples 50-52, wherein the detector comprises an image intensifier. (Example 54) 54. The method of any one of examples 50-53, wherein the first fiducial markers are arranged in a grid. (Example 55) A method according to any one of Examples 50-54, further comprising determining posture data of the imaging arm associated with the first image using at least one sensor carried by the imaging arm, and the distortion correction parameters are determined based on the posture data. (Example 56) The method of any one of Examples 50-55, wherein the second fiducial marker is placed within the phantom. (Example 57) 57. The method of any one of Examples 50-56, further comprising adjusting at least some of the second images using a set of distortion correction parameters. (Example 58) The method of any one of Examples 50-57, further comprising determining posture data of the imaging arm associated with the second image using at least one sensor carried by the imaging arm, wherein the geometric calibration parameters are determined based on the posture data. (Example 59) 59. The method of example 58, further comprising processing the second image to determine one or more of the following: penetration point, skewness, pitch, roll, tilt, or source / detector distance of the imaging device. (Example 60) receiving second attitude data of the imaging arm from at least one sensor coupled to the imaging arm during the pre-acquisition manual rotation; comparing the second pose data with pose data associated with the second image; outputting feedback to the user based on the comparison; and 60. The method of Example 58 or 59, further comprising: (Example 61) The method of Example 60, wherein the feedback comprises feedback regarding one or more of the following: rotation trajectory, rotation speed, orientation of the imaging arm, position of the imaging arm, or stability of the imaging arm. (Example 62) receiving a plurality of third images of the anatomical region of the patient from the detector, the third images being acquired during manual rotation of the imaging arm, the imaging arm being stabilized by a shim structure during the manual rotation; receiving imaging arm posture data associated with the third image from at least one sensor coupled to the imaging arm; generating a volumetric reconstruction of the anatomical region based on the third image and the pose data; The method of any one of Examples 50-61, further comprising: (Example 63) applying the distortion correction parameters to the third image; applying the geometric calibration parameters to the third image; The method of Example 62, further comprising: (Example 64) 64. The method of embodiment 63, further comprising updating one or more of the distortion correction parameters or geometric calibration parameters based on data from at least one sensor prior to generating the volumetric reconstruction. (Example 65) 1. A system for imaging an anatomical region, comprising: one or more processors; When operatively coupled to one or more processors and executed by the one or more processors, the system is receiving a plurality of first images of the fiducial marker grid from a detector carried by an imaging arm of an x-ray imaging device, the first images being acquired during manual rotation of the imaging arm; determining a set of distortion correction parameters for the imaging device based on the first image; receiving a plurality of second images of the fiducial marker phantom from the detector, the second images being acquired during manual rotation of the imaging arm; determining a set of geometric calibration parameters for the imaging device based on the second image; A memory for storing instructions for performing operations, the instructions including: A system comprising: (Example 66) The system of Example 65, wherein the X-ray imaging device is a mobile C-arm device. (Example 67) The system of embodiment 65 or 66, wherein the first and second images are each acquired during a propeller rotation of the imaging arm. (Example 68) The system of any one of Examples 65-67, wherein the detector comprises an image intensifier. (Example 69) The system described in any one of Examples 65-68, further comprising a base point marker grid. (Example 70) 70. The system of embodiment 69, wherein the fiducial marker grid includes a central portion and a peripheral portion, the central portion having a different pattern than the peripheral portion. (Example 71) The system described in any one of Examples 65-70, further comprising a mounting device for mounting the fiducial marker grid to the detector. (Example 72) The system of Example 71, further comprising a motion sensor, wherein the mounting device is configured to couple the motion sensor to the detector. (Example 73) The system described in any one of Examples 65-72, wherein the operation further includes determining posture data of the imaging arm associated with the first image using a motion sensor, and the distortion correction parameters are determined based on the posture data. (Example 74) The system described in any one of Examples 65-73, further comprising a fiducial marker phantom. (Example 75) The system of Example 74, wherein the fiducial marker phantom includes at least one second fiducial marker in a central portion of the phantom. (Example 76) The Phantom is a first ring at a first end of the phantom; a second ring at a second end of the phantom opposite the first end; The system of embodiment 74 or 75, comprising: (Example 77) The system of any one of Examples 65-76, wherein the operation further includes adjusting at least some of the second images using a set of distortion correction parameters. (Example 78) The system of any one of Examples 65-77, further comprising a motion sensor coupled to the detector. (Example 79) The system of Example 78, wherein the operations further include determining posture data of the imaging arm using a motion sensor, the posture data being associated with the second image, and the geometric calibration parameters being determined based on the posture data. (Example 80) The operation is further receiving second attitude data of the imaging arm from the motion sensor during the pre-acquisition manual rotation; comparing the second pose data with pose data associated with the second image; The system of Example 79, comprising: (Example 81) The system of Example 80, further comprising a display configured to output feedback to a user based on a comparison of the second posture data with the posture data, the feedback comprising feedback regarding one or more of the following: rotation trajectory, rotation speed, orientation of the imaging arm, position of the imaging arm, or stability of the imaging arm. (Example 82) The operation is further receiving a plurality of third images of the anatomical region of the patient from the detector, the third images being acquired during manual rotation of the imaging arm, the imaging arm being stabilized by a shim structure during the manual rotation; receiving imaging arm attitude data associated with the third image from a motion sensor coupled to the detector; adjusting the third image using the distortion correction parameter; adjusting the third image using the geometric calibration parameters; generating a volumetric reconstruction of the anatomical region based on the third image and the pose data; The system of any one of Examples 65-81, comprising: (Example 83) A non-transitory computer readable medium that, when executed by one or more processors of a computing system, causes the computing system to: receiving a plurality of first images of the set of first fiducial markers from a detector carried by an imaging arm of an imaging device, the first images being acquired during manual rotation of the imaging arm; determining a set of distortion correction parameters for the imaging device based on the first image; receiving a plurality of second images of the second set of fiducial markers from the detector, the second images being acquired during manual rotation of the imaging arm; determining a set of geometric calibration parameters for the imaging device based on the second image; 23. A non-transitory computer readable medium comprising instructions that cause operations to be performed, including: (Example 84) 1. A method for imaging an anatomical region, comprising: receiving a plurality of 2D images of the anatomical region from a detector carried by an imaging arm of a mobile C-arm device, the 2D images being acquired during manual rotation of the imaging arm, the imaging arm being stabilized by a shim structure during the manual rotation; receiving data indicative of a plurality of orientations of the imaging arm during manual rotation; generating a 3D reconstruction of the anatomical region based on the 2D images and the data; A method comprising: (Example 85) 85. The method of example 84, wherein the mobile C-arm device comprises a support arm slidably coupled to the imaging arm, and the shim structure is positioned at an interface between the imaging arm and the support arm. (Example 86) 86. The method of example 85, wherein the shim structure is configured to reduce movement of the imaging arm relative to the support arm. (Example 87) The method of example 84 or example 85, wherein the shim structure is configured to fit at least partially within an interface between the imaging arm and the support arm. (Example 88) The shim structure is a pair of arm regions configured to be positioned on two sides of an interface between the imaging arm and the support arm; a bridge region connecting the sets of elongate members; The method of Example 87, comprising: (Example 89) The method of Example 85, wherein the support arm is rotatably coupled to the movable base, and the support arm and imaging arm are manually rotated relative to the movable base to acquire a 2D image. (Example 90) The method of example 89, wherein the manual rotation is actuated by force applied to a lever structure coupled to or near the interface between the support arm and the movable base. (Example 91) The method of any one of Examples 84-90, wherein the manual rotation comprises propeller rotation. (Example 92) The method of any one of Examples 84-91, wherein the manual rotation comprises a rotation of at least 90 degrees. (Example 93) The method of any one of Examples 84-91, wherein data indicating multiple postures of the imaging arm is received from a motion sensor coupled to the imaging arm. (Example 94) 94. The method of example 93, wherein the motion sensor comprises an inertial measurement unit. (Example 95) The method of any one of Examples 84-94, wherein the multiple 2D images include a base board and show multiple postures of the imaging arm, and the data is generated from the 2D images. (Example 96) The method of any one of Examples 84-95, further comprising associating each 2D image with a corresponding posture of the imaging arm at the time the 2D image was acquired. (Example 97) The method of any one of examples 84-96, wherein the 3D reconstruction comprises a cone beam computed tomography reconstruction. (Example 98) The method of any one of Examples 84-97, further comprising applying one or more distortion correction parameters to at least some of the 2D images prior to generating the 3D reconstruction. (Example 99) The method of any one of Examples 84-98, further comprising applying one or more geometric calibration parameters to at least some of the 2D images prior to generating the 3D reconstruction. (Example 100) The method of any one of Examples 84-99, wherein generating the 3D reconstruction is based on pose data previously obtained using an imaging arm. (Example 101) 1. A method for imaging an anatomical region, comprising: receiving a plurality of 2D images of an anatomical region from a detector carried by an imaging arm of an x-ray imaging device, the 2D images being acquired during manual rotation of the imaging arm, the imaging arm being coupled to a shim structure during the manual rotation; receiving attitude data of the imaging arm during manual rotation; generating a 3D representation of the anatomical region based on the 2D image and pose data; A method comprising: (Example 102) The method of example 101, wherein the X-ray imaging device is a mobile C-arm device. (Example 103) The method of example 101 or example 102, wherein the manual rotation comprises a propeller rotation of at least 180 degrees. (Example 104) The method of any one of Examples 101-103, wherein the shim structure prevents orbital rotation of the imaging arm. (Example 105) The method of any one of Examples 101-104, wherein the X-ray imaging device comprises a support arm coupled to the imaging arm, and the shim structure is configured to prevent movement of the imaging arm relative to the support arm. (Example 106) The method of example 105, wherein the shim structure is configured to fill at least one gap in the interface between the support arm and the imaging arm. (Example 107) 107. The method of example 106, wherein the shim structure comprises at least one elongate member configured to be positioned within the at least one gap. (Example 108) A method according to any one of Examples 101-107, wherein the posture data is received from at least one sensor associated with the X-ray imaging device, the at least one sensor comprising a motion sensor coupled to the imaging arm. (Example 109) The method of any one of examples 101-108, further comprising temporally synchronizing the 2D image to the pose data. (Example 110) The method of any one of Examples 101-109, wherein temporally synchronizing the 2D images to the posture data includes identifying the posture of the imaging arm at the time each 2D image was acquired. (Example 111) The method of example 110, wherein the posture comprises a rotation angle of the imaging arm. (Example 112) A method according to any one of Examples 101-111, wherein the posture data is second posture data and generating the 3D reconstruction is based on first posture data previously obtained using the imaging arm. (Example 113) 1. A method for imaging an anatomical region, comprising: receiving a plurality of 2D projection images of an anatomical region from a detector carried by an imaging arm of a mobile C-arm device, the 2D projection images being acquired during manual rotation of the imaging arm, the imaging arm being mechanically stabilized by a shim structure during the manual rotation; determining a plurality of rotation angles of the imaging arm during manual rotation, each rotation angle being associated with a corresponding 2D projection image; generating a 3D reconstruction of the anatomical region based on the 2D projection images and associated rotation angles; outputting the 3D reconstruction on a graphical user interface configured to provide guidance during a medical procedure performed in the anatomical region; A method comprising:

[0258] conclusion Although many of the embodiments are described above with respect to systems, devices, and methods for performing medical procedures in a patient's lungs, the technology is also applicable to other applications and / or other approaches, such as medical procedures performed in other anatomical regions (e.g., the musculoskeletal system). Furthermore, other embodiments are within the scope of the technology in addition to those described herein. In addition, some other embodiments of the technology can have different configurations, components, or procedures than those described herein. Those skilled in the art will therefore understand that the technology can also have other embodiments with additional elements, or that the technology can have other embodiments without some of the features shown with reference to FIGS. 1A-27C and described above.

[0259] The various processes described herein can be implemented, in part or in full, using program code, which includes instructions executable by one or more processors of a computing system to implement specific logical functions or steps in the process. The program code can be stored on any type of computer-readable medium, such as a storage device, including a disk or hard drive. The computer-readable medium containing the code or a portion of the code can include any suitable medium known in the art, such as a non-transitory computer-readable storage medium. Computer readable media can include volatile and nonvolatile, removable and non-removable media implemented in any manner or technology for storage and / or transmission of information, including, but not limited to, random access memory (RAM), read only memory (ROM), electrically erasable programmable read only memory (EEPROM), flash memory, or other memory technology, compact disc read only memory (CD-ROM), digital video disk (DVD), or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage, or other magnetic storage devices, solid state drives (SSD) or other solid state storage devices, or any other medium that can be used to store the desired information and that can be accessed by a system device.

[0260] The description of the embodiments of the present technology is not intended to be exhaustive or to limit the present technology to the precise form disclosed above. Where the context permits, singular or plural terms may also include the plural or singular terms, respectively. Specific embodiments of the present technology and examples thereof are described above for illustrative purposes, but various equivalent modifications are possible within the scope of the present technology, as one of ordinary skill in the art would recognize. For example, while steps are presented in a given order, alternative embodiments may perform the steps in a different order. Various embodiments described herein may also be combined to provide further embodiments.

[0261] As used herein, the terms "generally," "substantially," "about," and similar terms are used as terms of approximation, not degree, and are intended to take into account inherent variations in measured or calculated values ​​that will be recognized by one of ordinary skill in the art.

[0262] Further, unless the word "or" is expressly limited to mean only a single item exclusive of the other items with reference to a list of two or more items, the use of "or" in such a list should be interpreted as including (a) any single item in the list, (b) all of the items in the list, or (c) any combination of items in the list. In addition, the term "comprising" is used throughout to mean including at least the recited features, such that any more of the same features and / or other features of additional types are not excluded. As used herein, the phrase "and / or" refers to A only, B only, and both A and B, as in "A and / or B."

[0263] To the extent that any material incorporated by reference herein conflicts with the present disclosure, the present disclosure will control.

[0264] Also, while specific embodiments are described herein for illustrative purposes, it should be understood that various modifications may be made without departing from the technology. Moreover, although advantages associated with certain embodiments of the technology are described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments necessarily need to exhibit such advantages to fall within the scope of the technology. Thus, the present disclosure and associated technology can encompass other embodiments not explicitly shown or described herein.

Claims

1. 1. A method for imaging an anatomical region, the method comprising: receiving a plurality of 2D images of the anatomical region from a detector carried by an imaging arm of a mobile C-arm device, the 2D images being acquired during manual rotation of the imaging arm, the imaging arm being stabilized by a shim structure during the manual rotation; receiving data indicative of a plurality of orientations of the imaging arm during the manual rotation; generating a 3D reconstruction of the anatomical region based on the 2D images and the data; A method comprising:

2. The method of claim 1 , wherein the mobile C-arm apparatus comprises a support arm slidably coupled to the imaging arm, and the shim structure is positioned at an interface between the imaging arm and the support arm.

3. The method of claim 2 , wherein the shim structure is configured to reduce movement of the imaging arm relative to the support arm.

4. The method of claim 2 , wherein the shim structure is configured to fit at least partially within the interface between the imaging arm and the support arm.

5. The shim structure includes: a pair of arm regions configured to be positioned on two sides of the interface between the imaging arm and the support arm; a bridge region connecting a set of extension members; The method of claim 4 , comprising:

6. The method of claim 2 , wherein the support arm is rotatably coupled to a movable base, and the support arm and the imaging arm are manually rotated relative to the movable base to acquire the 2D image.

7. The method of claim 1, wherein the manual rotation comprises orbital rotation.

8. The method of claim 1 , wherein the manual rotation comprises propeller rotation.

9. The method of claim 1 , wherein the manual rotation comprises a rotation of at least 90 degrees.

10. The method of claim 1 , wherein the data indicative of the multiple poses of the imaging arm is received from a motion sensor coupled to the imaging arm.

11. The method of claim 10 , wherein the motion sensor comprises an inertial measurement unit.

12. The method of claim 1 , wherein the plurality of 2D images includes a fiducial board, and the data indicative of the plurality of poses of the imaging arm is generated from the 2D images.

13. The method of claim 1 , further comprising associating each 2D image with a corresponding pose of the imaging arm at the time the 2D image was acquired.

14. The method of claim 1 , wherein the 3D reconstruction comprises a cone-beam computed tomography reconstruction.

15. The method of claim 1 , further comprising applying one or more distortion correction parameters to at least some of the 2D images prior to generating the 3D reconstruction.

16. The method of claim 1 , further comprising applying one or more geometric calibration parameters to at least some of the 2D images prior to generating the 3D reconstruction.

17. The method of claim 1 , wherein generating the 3D reconstruction is based on pose data previously obtained using the imaging arm.

18. The method of claim 1, further comprising outputting feedback to an operator during the manual rotation to adjust the rotational speed of the imaging arm.

19. The method of claim 1, further comprising outputting the 3D reconstruction on a graphical user interface during a medical procedure performed within the anatomical region.

20. A system for imaging an anatomical region, comprising: one or more processors; a memory operatively coupled to the one or more processors, the memory storing instructions that, when executed by the one or more processors, cause the system to perform a method according to any one of claims 1 to 19; A system comprising:

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