Method and System for Field of View Preview

Abstract

The present invention provides various methods and systems for a set of devices of an imaging system. In one example, the set of devices includes a first device configured to acquire a first set of image data and a second device configured to acquire a second set of image data along at least one dimension. The first set of data and the second set of data can be compiled to generate a field of view (FOV) preview.

Description

Technical Field

[0001] Embodiments of the subject matter disclosed herein relate to x-ray imaging. Background Art

[0002] Radiographic imaging systems can be used as non-invasive devices for obtaining images of a patient's internal anatomy in medical and industrial applications. An example of a medical radiographic imaging system is a mobile fluoroscopy x-ray imaging system, which can include an x-ray source positioned at one end of a swing arm. A detector can be positioned at the other end of the swing arm. An object (such as a part of a patient's body) can be inserted into the gap between the detector and the source, allowing the object to be irradiated. The x-ray radiation is captured by the detector after passing through the object, enabling an image to be generated.

[0003] The field of view (FOV) of a mobile fluoroscopy x-ray imaging system can be the area of the patient that is irradiated by the x-ray beam when the patient is positioned between the source and the detector. Due to the divergence of the x-ray beam away from the x-ray source, the size of the FOV can vary based on the distance of the irradiated object from the x-ray source. Since the FOV can change frequently, for example, between operations or within an operation, it is desirable to generate an accurate preview of the FOV. Summary of the Invention

[0004] In one embodiment, a method for an imaging system includes generating a first set of multi-dimensional imaging data, generating a second set of data along at least one dimension, and generating a field of view (FOV) preview based on a compilation of the first set of data and the second set of data. In this way, an FOV preview can be generated without irradiating the patient.

[0005] It should be understood that the above summary is provided to introduce in a simplified form selected concepts that are further described in the detailed description. This does not mean identifying key or essential features of the claimed subject matter, the scope of which is uniquely defined by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to embodiments that solve any disadvantages noted above or in any part of this disclosure. Brief Description of the Drawings

[0006] The present invention will be better understood by reading the following description of non-limiting embodiments with reference to the accompanying drawings, in which:

[0007] Figure 1 An example of a mobile x-ray imaging system is shown.

[0008] Figure 2 A first perspective view of a detector housing of a mobile x-ray imaging system is shown, in which a set of cameras for generating a field of view (FOV) preview can be embedded.

[0009] Figure 3 Shows a second perspective view of the detector housing of a mobile x-ray imaging system, in which a set of cameras for generating a FOV preview can be embedded.

[0010] Figure 4 Shows a first view of the moving arm of a mobile x-ray imaging system, with a patient positioned between the x-ray source and the detector of the moving arm.

[0011] Figure 5 Shows a second view of the moving arm of a mobile x-ray imaging system, with a patient positioned between the x-ray source and the detector of the moving arm.

[0012] Figure 6 Shows an example of an x-ray FOV preview that can be displayed on a display monitor.

[0013] Figure 7 Shows a method for processing data provided by a set of cameras to generate an x-ray FOV preview. Detailed Description

[0014] The following description relates to various embodiments of a system for generating a FOV preview for medical imaging. The system can be included in an imaging system (such as a mobile fluoroscopy system as shown) to provide a representation of the size and shape of the x-ray FOV. Generating the FOV preview can include projecting the irradiated contour of the FOV onto the patient and / or displaying an image of the FOV on a display device (such as a monitor). The system can include a set of devices mounted adjacent to the detector of the imaging system, the positioning of which is shown in Figure 1 and Figure 2 and Figure 3 In some examples, the set of devices can be a set of cameras. The set of cameras can be oriented at specific angles to provide images that can be compiled to infer a complete x-ray FOV preview, which can be displayed at the display device. The tilt and FOV of the set of cameras are shown in Figure 4 and Figure 5 and an example of an x-ray FOV preview that can be displayed to an operator and / or surgeon on a display monitor is depicted in Figure 6 A method for combining three-dimensional and two-dimensional data acquired via the set of cameras into a final frame accurately depicting the x-ray FOV is shown in Figure 7

[0015] Figures 1 to 6An exemplary configuration showing the relative positioning of various components is presented. At least in one example, if elements are shown as being in direct contact or directly coupled to each other, such elements may be referred to as being in direct contact or directly coupled, respectively. Similarly, at least in one example, elements that are adjacent or neighboring to each other may be adjacent or neighboring to each other, respectively. For example, components that are arranged to be in coplanar contact may be referred to as being in coplanar contact. Also, for instance, in at least one example, elements that are positioned to be spaced apart from each other and have only space therebetween without other components may be so described. Also, elements that are shown as being above / below each other, on opposite sides of each other, or between the left / right sides of each other may be so described relative to each other. Additionally, as shown in the figure, in at least one example, the topmost element or point of an element may be referred to as the "top" of the component, and the bottommost element or point of an element may be referred to as the "bottom" of the component. As used herein, top / bottom, upper / lower, above / below may be with respect to the vertical axis of the figure and may be used to describe the positioning of elements in the figure relative to each other. Thus, in one example, an element that is shown as being above other elements is vertically positioned above the other elements. Also, the shapes of the elements shown in the figure may be referred to as having those shapes (e.g., such as being circular, straight, planar, curved, round, chamfered, angled, etc.). Additionally, in at least one example, elements that are shown as intersecting each other may be referred to as intersecting elements or intersecting each other. Further, in one example, an element that is shown as being within another element or being shown as being outside another element may be so described.

[0016] A mobile fluoroscopy system may utilize a laser to generate a visible x-ray beam center point on a patient positioned between the detector and the source of the system. The visible center point may be, for example, a set of crosshairs projected from the detector side of the mobile arm, thus providing guidance for positioning the patient relative to the x-ray source prior to acquiring an x-ray image of a target portion of the patient's anatomy. Although the visible center point identifies the center of the x-ray beam emitted from the source, the area of the x-ray beam (e.g., the size of the beam relative to the irradiated surface) is not indicated.

[0017] The area of the x-ray beam may vary according to the distance of the patient from the x-ray source. The x-ray beam has a divergent conical shape, and when the patient is positioned closer to the source, the area of the beam may become smaller, thereby reducing the x-ray field of view (FOV) size and increasing the concentration of x-ray photons irradiating the patient. When the patient is positioned farther from the source, the beam may become more diffuse, thereby increasing the FOV size and reducing patient exposure.

[0018] If, for example, images from different regions of a patient are required, the distance between a point of interest (e.g., the target anatomical region of the patient to be imaged) and the focus of the x-ray beam (e.g., the narrowest point of the beam) can vary. Due to different patient body sizes and different anatomical regions to be diagnosed, this distance can also be different for each patient. Relying on a visible center point to adjust the patient's positioning may not determine whether sufficient area of the patient will be included in the x-ray to observe the region of interest. To compensate, at least one preliminary x-ray image can be acquired prior to diagnostic imaging to adjust the patient's positioning relative to the x-ray source. However, preliminary x-ray imaging increases the exposure of both the patient and the operator to x-ray photons.

[0019] In one example, the above problem can be solved by a method for generating a preview of the x-ray FOV that is generated by generating a video image of an expected beam size and pairing the video image with an image acquired by a stereo camera. The image captured by the stereo camera includes data on the distance between the anatomical imaging region and the x-ray detector, the source-to-image distance (SID), and the beam collimation size. The data can be used to calculate the expected FOV size and shape, and the data can be incorporated into the video image to provide an image representing the expected FOV for display on a display device.

[0020] Plotting the data from the stereo camera onto the data from the video image can compensate for distortions and data point losses in the FOV due to the surface contour of the imaging region and other sources of interference. In the case where the stereo camera does not incorporate image data, the resulting FOV preview can provide an inaccurate or incomplete representation of the x-ray FOV. The merging of three-dimensional image data with two-dimensional image data can provide an FOV preview that accurately represents the region of the patient expected to be included in the x-ray image. This region can be enclosed within a boundary having a defined geometry. In this way, preliminary x-ray imaging is avoided and the exposure of the patient and the operator is reduced. The following refers to Figures 2 to 7 Further details of the method are provided, as well as a system for generating an FOV preview, and an exemplary mobile fluoroscopy x-ray imaging system is subsequently described.

[0021] Turning to Figure 1 , a three-dimensional view of an imaging system 100 is disclosed that has a C-arm 104 with an x-ray source 106 positioned directly below an x-ray detector 108. The imaging system 100 also includes a base unit 102 and a display monitor 134. The base portion 156 of the base unit 102 can include a plurality of wheels 160 that allow the imaging system 100 to be transported from one location to another. Each wheel 160 can include a brake that allows the wheel to be locked into a fixed position to prevent movement of the imaging system 100.

[0022] AsFigure 1 As shown, the C-arm 104 may include a C-shaped portion 105 that is connected to an extension portion 107, which is coupled to a transverse member 120 via a rotatable joint 109. The transverse member 120 may be mounted to a base unit 102, which provides support for the C-arm 104. The adjustable locking handle 150 unlocks the C-arm 104, allowing it to rotate via the rotatable joint 109. For example, the C-arm 104 may be configured to rotate at least 180 degrees in each direction via the rotatable joint 109 that couples the C-shaped portion 105 to the extension portion 107 of the C-arm 104.

[0023] In one example, the C-arm 104 may rotate (via the rotatable joint 109) about the central axis 164 of the C-shaped portion 105 to adjust the x-ray source 106 and the detector 108 (positioned at opposite ends of the C-shaped portion of the C-arm 104 along the vertical axis 166) through multiple positions (e.g., at least switching the top and bottom between the vertical position, the detector, and the x-ray source). The C-shaped portion 105 of the C-arm 104 may include a plurality of handle bars 110 that may be held while rotating the C-arm via the rotatable joint 109 to adjust the positions of the x-ray source 106 and the detector 108 before or during the operation of the imaging system 100. The curved handle 118 provided on the detector 108 may be used to adjust the position of the detector 108 relative to the x-ray source 106.

[0024] During the imaging operation, a portion of the patient's body placed in the gap (e.g., void) formed between the x-ray source 106 and the detector 108 may be irradiated with radiation from the x-ray source. The radiation may penetrate the irradiated portion of the patient's body and proceed to the detector 108 that captures the radiation. By penetrating the portion of the patient's body placed between the x-ray source 106 and the detector 108, an image of the patient's body is acquired and relayed via a connection line (e.g., an electrical connection line) to a first display monitor 128, where the image is displayed or stored and retrieved later. In one example, the display monitor may display images captured and processed by the imaging system at the time of shooting and during the imaging process (e.g., in real time).

[0025] The first display monitor 128 may be a unit separate from the C-arm 104 and other components attached to the C-arm 104. The first display monitor 128 may be mounted on a cart 130 that may include a computing unit 132. The computing unit 132 may be communicatively coupled to the first display monitor 128 and may also communicate with a control and computing unit disposed in the base 102 of the imaging system (not shown) via a communication cable or a wireless communication link. The computing unit 132 may be configured to display an x-ray FOV preview and x-ray images acquired via the imaging system 100 at the first display monitor 128.

[0026] The first input device 134 may be included in the cart 130 for inputting commands to control or adjust the display of the x-ray image. The first input device 134 may be, for example, a keyboard, a touchpad, a mouse, etc. The cart 130 may be implemented on wheels 136 to allow the cart 130 to be easily repositioned relative to the user and the C-arm 104. In this way, the cart 130 can be positioned beside the surgeon who performs surgery on the patient and / or treats the patient. The viewing angle of the surgeon with respect to the first display monitor 128 can be adjusted by moving the cart 130 as needed.

[0027] In some examples, the imaging system 100 may include more than one display monitor. For example, the second display monitor 138 may be positioned above the base unit 102. The second display monitor 138 may be fixedly attached to the transverse member 120 and may also display an x-ray FOV preview. In some examples, the second display monitor 138 may be configured to display the same display as the first display monitor 138. In other examples, the second display monitor 138 may be positioned such that the operator of the imaging system 100 can view the x-ray FOV preview and the resulting x-ray image and manipulate and adjust the view independently of the first display monitor 138. The manipulation and adjustment of the image displayed on the second display monitor 138 may be provided by the second input device 140. The second input device may be a tablet device, a keyboard, a mouse, etc.

[0028] The base unit 102 may include a control and computing unit that processes instructions or commands sent from the first input device 134 and / or the second input device 140 of the imaging system 100 during the operation of the imaging system 100. The base unit 102 may also include an internal power supply (not shown) that provides power to operate the imaging system 100. Alternatively, the base unit 102 may be connected to an external power supply to power the imaging system 100. The x-ray source 106, the detector 108, the computing unit 132 in the cart 130, and the control and computing unit in the base unit 102 may communicate via a plurality of connection lines (e.g., a plurality of connection lines capable of transmitting instructions and data). In an alternative example, input commands and data may be transmitted between the x-ray source 106, the detector 108, and the base unit 102 via a wireless connection or network, thereby advantageously eliminating the need for connection lines or cables.

[0029] In this way, the imaging system 100 may include: a base unit 102; a C-arm 104 that is coupled to the base unit 102 and includes an x-ray source 106 and a detector 108 positioned at opposite ends of the C-shaped portion 105 of the C-arm 104; and one or more display monitors, for example, a first display monitor 128 and a second display monitor 138.

[0030] The patient can be positioned on a table within the C-arm, between the x-ray source 106 and the detector 108. As described above, the distance between the target anatomical region of the patient and the x-ray source 106 can affect the size of the x-ray FOV. The FOV preview can be generated by adapting the imaging system with a set of cameras. The FOV preview can include displaying an image of the FOV on one or more display devices (such as Figure 1 the display monitors 128 and 138). The set of cameras can include a first camera configured as a stereo camera and a second camera configured as a video camera. The first camera can be used to generate a three-dimensional (3D) image of the surface, and the second camera can be used to acquire a two-dimensional (2D) video image of the surface of the target anatomical region.

[0031] In one example, the first camera can be a binocular infrared camera positioned directly adjacent to the second camera. The first camera can be configured to provide depth data via infrared imaging in combination with a predetermined distance between the target anatomical imaging region and the x-ray source, the SID, the collimator iris geometry, etc. In other examples, the first camera can be any other type of stereo camera. In other examples, the first camera can not be a camera. Instead, based on the known distances and geometries of the detector 108, the x-ray source 106, the patient, and the set of cameras, a distance measuring device (such as an ultrasonic rangefinder) can be paired with the second camera to provide depth data.

[0032] By positioning the set of cameras together on the same side of the detector and similarly tilting both the first camera and the second camera, the FOV of each camera can be similar. In this way, the first camera and the second camera can provide complementary image data, for example, the image data is for the same region of the patient, thus allowing the data from the set of cameras to be matched and compiled. The complementary image data enables image data with different spatial dimensions (such as 3D and 2D data) to be used together to form a complete and accurate x-ray FOV preview.

[0033] The set of cameras can be disposed within the x-ray detector, as shown in the first perspective view 200 and the second perspective view 300 of the detector in Figure 2 and Figure 3 respectively. A set of reference axes 201 is provided for comparison between the views, which indicate the y-axis, the x-axis, and the z-axis. In one example, the y-axis can be parallel to the direction of gravity, the x-axis is parallel to the horizontal direction, and the z-axis is parallel to the lateral direction. The detector 202 of the x-ray imaging system is shown adjacent to the patient 204 but spaced apart from the patient 204 by a distance 206.

[0034] Detector 202 may have a flat rectangular area, such as a panel, which is adapted to receive x-ray photons that have passed through patient 204. A first set of cameras (not shown) may be embedded within the housing 203 of detector 202, in the area indicated by the first dashed circle 208. The first set of cameras may be mounted along the boundary of detector 202 at the front side 220 of detector 202, as shown by the dashed circle 208. A visible light source (such as an infrared laser projector or some other type of light source) may be coupled to the first set of cameras, and the visible light source is similarly positioned along the boundary of detector 202 at the front side 220. The front side 220 of detector 202 may be the side of detector 202 that is closest to the location where a surgeon may be during the operation of the x-ray imaging system. Thus, mounting the first camera adjacent to the surgeon may provide a FOV preview that closely mimics the viewing perspective of the surgeon.

[0035] In some examples, detector 202 may include an additional second set of cameras. The second set of cameras may be arranged in the area indicated by the second dashed circle 212 on the side of detector 202 that is opposite to the first set of cameras, as Figure 3 shown. The second set of cameras may be similarly mounted along the boundary of detector 202. Both the first set of cameras and the second set of cameras may face outward toward patient 204 to acquire images of the target anatomical area of patient 204 that is irradiated by the x-ray beam. Thus, these sets of cameras may be specifically angled to overlap and generate a continuous cohesive image.

[0036] The detector housing 203 may be configured with only the first set of cameras, only the second set of cameras, or both sets of cameras. When using a single set of cameras, the positioning of that set of cameras may be selected based on the positioning of other components of the imaging system to minimize interference with or blockage of the field of view of that set of cameras. If excessive angling or tilting of a single set of cameras is required, for example, a greater angle that can focus that set of cameras on the target area may be accommodated by positioning that set of cameras within the detector housing 203, or if an incomplete data volume is provided by a single set of cameras, it may be desirable to combine both sets of cameras.

[0037] In some examples, if a high-resolution, accurate representation of the x-ray FOV is not required, the set of cameras may include only stereo cameras (e.g., not including video cameras). In this way, the imaging system may be adapted to two stereo cameras arranged on opposite sides of the detector, and each stereo camera is tilted such that the FOV of each camera is centered on the x-ray FOV passing through the patient.

[0038] In Figure 4 and Figure 5 the inclination of at least one set of cameras in the imaging system is depicted, through Figure 4 the first view 400 in Figure 5the second view 500 therein. The movable arm 402 of the imaging system, such as Figure 1 the C-arm 104, is shown in the first view 400 such that the patient 404 positioned between the detector 406 and the x-ray source 408 of the movable arm 402 is viewed along the y-z plane. In one example, the y-z plane may be the sagittal plane. In the second view 500, the patient 404 is shown longitudinally aligned with the y-x plane, which may be, for example, the axial plane.

[0039] A set of cameras 410 may be mounted in the housing 412 of the detector 406. As described above, the set of cameras 410 may include a stereo camera and a video camera to acquire 3D images and streaming video images of the target anatomical region of the patient 404. The stereo camera and the video camera may be positioned adjacent to each other, aligned along the z-axis or the x-axis, and coupled within a single housing.

[0040] In the axial plane, as Figure 4 shown, the set of cameras 410 (e.g., both the stereo camera and the video camera) may be positioned at the front side 401 of the detector 406 where the surgeon may stand. The set of cameras 410 may be aligned with the central axis 414 (and the centerline of the movable arm 402) and positioned in the central region between the first side 424 and the second side 426 of the detector housing 412. The FOV 418 of the set of cameras 410 is depicted as a shaded equilateral triangle in Figure 4 and is projected downward with respect to the y-axis and centered along the central axis 414. The dimension 420 of the FOV418 projected onto the top surface of the patient 404 may be similar to the dimension of the x-ray beam 422 at the top surface of the patient 404, which is emitted by the x-ray source 408.

[0041] The FOV 418 of the set of cameras 410 may diverge away from the set of cameras 410 at an angle α along the axial plane. In one example, the angle α may be 60 degrees. However, in other examples, the angle α may vary within a range between 40 degrees and 90 degrees depending on the spacing and orientation of the stereo camera and the video camera relative to each other.

[0042] Along the axial plane, as Figure 5 shown, the set of cameras 410 may be tilted with respect to the central axis 414 of the movable arm 402. For example, the set of cameras 410 may have an axis 502 tilted at a first angle θ with respect to the central axis 414. In one example, the first angle θ may be between 30 degrees and 40 degrees. For example, the first angle θ may be 37 degrees. As shown in the shaded triangular region, the field of view (FOV) 418 of the set of cameras 410 may have a second angle β between 40 degrees and 60 degrees, such as, for example, 50 degrees. As Figure 4 and Figure 5As shown, the size 420 of the FOV 418 of the set of cameras 410 projected onto the top surface of the patient 404 can vary depending on the distance of the patient 404 from the detector 406 .

[0043] The set of cameras 410 is positioned along the front side 401 of the detector housing 412. Figure 4 4. In this way, the set of cameras 410 is tilted at a first angle θ so as to center the FOV 418 within a portion of the patient 404 that is illuminated by the x-ray beam 422 emitted from the source 408. In other examples, the set of cameras 410 may alternatively be arranged at a second side 426 of the detector housing 412 that is opposite to the first side 424. When mounted at the second side 426, the set of cameras 410 may also be tilted at the first angle θ but from an opposite direction relative to the central axis 414, for example, at a tilt of -37 degrees relative to the central axis 414. However, other examples may include the set of cameras 410 tilted at a different angle at the second side 426 than when the set of cameras 410 is located at the first side 424. In other examples, the detector housing 412 may include two sets of cameras that are positioned at opposite sides of the detector 406 and are tilted similarly or differently so that the FOV of each set of cameras is centered along the x-ray beam 422.

[0044] The FOV 418 of the set of cameras 410 may be similar to the x-ray FOV of an imaging system. In other words, the area of ​​the patient 404 that is illuminated and detected to generate an image may be the area covered by the FOV 418 of the set of cameras 410. When generated from data from the set of cameras 410 and displayed to a user at a display device, the shape of the FOV (e.g., the shape of both the set of cameras 410 and the x-ray imaging system in which the set of cameras 410 is implemented) may be configured as a rounded square or a square circle. Figure 6 The figure shows that the display device (such as Figure 1 1 and 138). The display 600 includes a FOV preview 601 on the left side of the display 600, which can be a streaming video image of the patient's surface.

[0045] FOV preview 601 may show a boundary 602 outlining a square circle, which may be a set of cameras included in the imaging system (e.g., Figure 4 and Figure 5The boundaries of the FOV of a set of cameras 410). The FOV preview 600 may also include a crosshair 604 centered within the boundary 602 also defined by the light source. The crosshair 604 may indicate the center of the FOV preview 600, which can be used to guide the positioning of the patient relative to the crosshair 604 to ensure that the target anatomical region to be imaged is enclosed by the boundary 602. In some examples, in addition to displaying the FOV preview 601, the boundary 602 and the crosshair 60 may also be illuminated on the patient prior to x-ray imaging.

[0046] Based on the geometry of the set of cameras relative to the source and detector of the imaging system, the boundary 602 may represent the actual size and shape of the expected x-ray FOV. The FOV preview 601 allows the user to view the area of the patient that will be directly irradiated by the x-ray beam and adjust the position of the patient to ensure that the target imaging area is framed within the boundary 602. The streamed video image can be refreshed and updated frequently such that the FOV preview 601 can provide a real-time representation of the expected x-ray FOV.

[0047] The display 600 may also include various icons and buttons below and to the right of the FOV preview 601 to allow the user to adjust the display 600 as needed. For example, a first set of buttons 606 located below the FOV preview 601 may include buttons 608 for rotating the FOV preview 601 and buttons for other adjustments to the orientation of the FOV preview 601. A second set of buttons 610 located to the right of the FOV preview 601 may include, for example, buttons for selecting the display of x-ray parameters, for adjusting the parameters, and for saving the parameters and the FOV preview 601 to a database, as well as buttons for various other modifications to the display 600 and the FOV preview 601. A digital display 612 indicating the current x-ray parameters may also be shown to the right of the FOV preview 601.

[0048] The display 600 may be displayed on a first display monitor (such as Figure 1 display monitor 138) and is positioned adjacent to the location where an operator (e.g., an x-ray technician) may stand when operating the imaging system. The display 600 allows the operator to adjust the view of the FOV preview 601 as needed, e.g., rotate, zoom in / out, etc. Additionally, these sets of buttons enable the operator to change the operating parameters and display settings. Alternatively or in addition, a display similar to the display 600 may also be displayed on a second display monitor (such as Figure 1On the display monitor 128), it is positioned adjacent to the surgeon who performs surgery or diagnosis on the patient. The second display monitor may allow the surgeon to adjust the view of the FOV preview independently of the first display monitor according to the surgeon's preference. The FOV preview can be turned off / on independently of each other at the first display monitor and the second display monitor. In some examples, the display shown on the second display monitor may be different from Figure 6 the display 600. For example, the display on the second display monitor may show the FOV preview and buttons for adjusting the view of the FOV preview, but may not include buttons for adjusting the operating parameters.

[0049] As described above, the FOV preview can be generated from data provided by a set of cameras (including a stereo camera and a video camera). Alternatively, the set of cameras may include only a stereo camera or a distance measurement device combined with a video camera. The data can be combined with geometric data, such as an x-ray detector, an x-ray source, a patient, the distance between the set of cameras, and the tilt of the set of cameras. The stereo images obtained from the stereo camera can be used to determine the size of the x-ray FOV, taking into account both the variable x-ray beam collimation and the distance from the x-ray detector to the target anatomical region of the patient. A stereo depth map of the patient can be created from the stereo images. The video images can be used to display the expected FOV without the need for a preliminary irradiation of the patient.

[0050] By positioning the stereo camera and the video camera on the same side of the detector, the mapping of the output x-ray FOV preview can be performed more effectively, which is caused by the similar positioning of the two cameras with other components of the imaging system (e.g., the patient, the x-ray source, etc.). The cameras may have similar FOVs, so the data from the cameras can be more easily matched. In addition, packaging the stereo camera and the video together may allow the use of an off-the-shelf camera system with corresponding software.

[0051] In one example, the stereo camera can be an off-the-shelf infrared (IR) camera, which is paired with the video camera and is configured to provide a sufficiently high-resolution depth determination even on an uneven surface to generate a complete FOV preview when combined with the data from the video camera. The IR information can be combined with the known collimation and distance between the detector and the target region of the patient to generate a three-dimensional (3D) depth map. The 3D depth map can be used to clip and scale the video images to the target size based on the known collimator iris or blade position and orientation.

[0052] However, curvature in the patient's surface can result in gaps in the 3D depth map created from data of the stereo camera. In some cases, the moving arm of the imaging system may be covered with a transparent sterile drape. Reflections from the sterile drape may further exacerbate the loss of data points in the depth map. Generating a FOV preview using only 3D data may result in holes and distortion of the projected FOV preview.

[0053] For example, it may be challenging to use data from only one type of camera (e.g., a stereo camera) to obtain a FOV preview as an accurate representation of the actual size of the x-ray FOV. Contours in the imaging area of the patient can result in a wide variation in the shape of the projected 2D shape representing the boundary of the x-ray FOV. In other words, projecting a 2D shape (e.g., a square circle) onto a 3D surface (e.g., the patient's anatomy) may result in distortion of the 2D shape. The distortion may not allow the imaging data from the stereo camera to infer an image of the patient's anatomy to generate a FOV preview.

[0054] For example, when projecting a square circle onto the central region of the patient's chest, the FOV preview may be relatively lossless and complete. An image of the central region of the patient's chest defined by the boundary of the FOV preview can be easily created due to the retention of the complete and undistorted contour of the square circle. However, the projection of the same square circle onto the patient's shoulder region may result in a highly distorted projected shape that no longer resembles a square circle. The distortion of the square circle may cause difficulties in determining the actual position and size of the x-ray FOV relative to the patient's anatomy. When displayed on a display device, the image data can be areas of missing data, or may be distorted to such an extent that a FOV preview cannot be generated or displayed. Therefore, preliminary x-ray imaging may be required to position the patient in the desired position relative to the x-ray source, thereby exposing the patient to additional x-ray irradiation.

[0055] By matching 3D data with 2D data provided by a camera, the method for creating a FOV preview can be highly tolerant of loss of depth data from the stereo camera. The 3D data can be aligned with the 2D representation of the FOV, thereby using homography to warp and skew the 3D data to form a complete contour of the FOV preview, which can be illuminated onto the patient using visible light. The FOV preview is further displayed on one or more display devices to allow the user to view and manipulate the FOV image. The following references Figure 7 describe further details of the data processing for generating a FOV preview.

[0056] In one example, the projection of 3D data to 2D data is used to project the 3D data back onto the plane of the detector, which can then be cropped to the size of the FOV. For example, streaming video and depth field data can be collected from the set of cameras. As a first option, a 3D depth map can be used to generate a projection back to the centerline of the detector. The 3D depth map can be missing data, especially if the imaging surface is uneven or curved. The missing data can be resolved by combining structured illumination (e.g., illuminating a grid or a set of lines on the imaging surface) with techniques for flattening and averaging the image data, as further described below.

[0057] Alternatively, as a second option, an average depth can be used, which can produce a flat grid at the average distance from the set of cameras to the anatomical imaging region. The second option can be less complex and more continuous than the first option and can be easily used to re-project video images back to the detector centerline. However, the grid can introduce a certain degree of image distortion.

[0058] Unlike conventional mobile fluoroscopy systems that can be configured to provide only a crosshair to indicate the center of the x-ray beam, the process for generating the FOV preview described above for a mobile fluoroscopy system can generate a complete preview of the expected size, shape, and position of the x-ray beam without a preliminary x-ray scan. The patient x-ray dose is reduced by enabling the patient to be more accurately initially positioned relative to the x-ray beam prior to scanning. Additionally, generating the FOV preview via the set of cameras allows for the recording of video images of surgical and medical procedures. Further, the images acquired by the set of cameras can be saved as registered images, allowing for navigation back to the same position and orientation of the mobile arm of the mobile fluoroscopy system.

[0059] For example, the video images can be saved as a position reference by modifying the images to a transparent overlay, which can then be used as the original position for navigation of the mobile arm. In addition to the illuminated square circle projected onto the patient, the FOV preview can also be displayed on a display device (such as a monitor) as a transparent overlay, an opaque image, a live image, or a static image, depicting a view of the patient's anatomy within the FOV. When a pair of monitors is included in the mobile fluoroscopy system, the image can be presented on the left monitor or the right monitor.

[0060] In some examples, when the pair of monitors is included, the FOV preview may be displayed on both monitors, with the monitors facing different directions. In this way, for example, a surgeon may view the first monitor while a technician may view the second monitor. The FOV preview may be independently displayed or turned off on either the first monitor or the second monitor. Additionally, the FOV preview may be rotated as needed via, for example, controllable buttons or icons displayed adjacent to the FOV preview on each of the first monitor and the second monitor, such that the FOV preview may be aligned with the viewpoints of the surgeon and the technician.

[0061] In Figure 7 is shown an example of a method 700 for generating an x-ray FOV for an x-ray imaging system. The imaging system may include a set of cameras, such as Figure 4 and Figure 5 the set of cameras 410, including a first stereo camera and a second video camera. The first camera may provide a 3D image and, in some examples, may be an infrared camera configured to display infrared data. The imaging system may also have a control unit configured with a processor and a memory, where the method 700 may be implemented as executable instructions stored in the non-transitory memory of the control unit.

[0062] At 702, the method includes receiving depth field data from the set of cameras and generating a display frame. Individual video and depth frames may be processed to create a display frame that includes an estimate of the FOV x-ray based on known (such as pre-calibrated) values of the distance from the detector to the patient positioned between the detector and the x-ray source and the beam collimation. At 704, the depth field data is filtered using spatial and temporal filters to reduce noise and holes while retaining edge information. Outlier data points in the depth field data may be discarded, thereby allowing depth data to be generated via filtering.

[0063] At 706, the method includes generating a three-dimensional (3D) point cloud from the depth data. Based on the edge information, the depth data is reduced to points that exist only on the edge of the x-ray FOV to create a 3D point cloud. At 708, the remaining 3D point cloud data (e.g., data not at the edge) is evaluated to determine the x-ray depth position from the x-ray detector. The depth position determination may provide an x-ray estimated position that is closest to the actual distance between the patient and the detector to provide an FOV preview with an accurate representation of the FOV size.

[0064] The x-ray estimated position may be determined via an algorithm that may vary based on the specific application of the imaging system. For example, a set of data utilizing the maximum size of the coplanar slices of the points may be used, but other data sets, such as weighted average depth, may also be used.

[0065] At 710, the method includes rendering a 2D x-ray estimate. The 2D x-ray estimate can be a top-down estimate that incorporates all relevant and desired data, such as collimator iris opening, shutter opening, and rotation, etc. At 712, a homography is determined, such as an isomorphism that maps lines to a projective space of lines. Points in the point cloud data are matched to known positions in the 2D x-ray FOV estimate positions. An open-source software library (such as OpenCV) can be used to transform the data to orient the image from the 2D x-ray estimate to the perspective of the frame of the video image provided by the camera.

[0066] At 714, the 2D x-ray FOV image transformed via the open-source software library is modified. Modifying the image includes warping the image using the homography to match the image to the perspective of the video frame. At 716, the method includes blending the warped image into the video frame to output a final display frame. This blending can be repeated for each frame in the video depth stream. The final display frame can be displayed to the user at a display device (such as a monitor). Additionally, the shape of the FOV and the center of the FOV can be projected onto the patient using visible light.

[0067] Method 700 can be a dynamic process, allowing for real-time updates of the FOV preview. For example, method 700 can be computed at a rate of 30 times per second for a 30fps video / depth stream provided by the set of cameras to accommodate changes in the patient's positioning, the positioning of the detector and the x-ray source, the collimator iris size, and the x-ray source shutter, etc. Thus, the FOV preview continuously provides an accurate representation of the expected x-ray beam shape passing through the patient.

[0068] In this way, an x-ray FOV preview can be generated without exposing the patient to additional preliminary irradiation to obtain the preview. The FOV preview can be created based on data from a set of cameras, including a stereo camera and a camera, which are configured to provide 3D and 2D information respectively. The 3D and 2D information can be combined to produce the FOV preview, which is displayed on at least one display device that represents the actual size and position of the x-ray FOV on the patient. The set of cameras can be mounted adjacent to the detector within the detector's housing, allowing the known distance between the detector and the patient to be utilized during the processing of the imaging data.

[0069] The technical effect of obtaining an x-ray FOV preview via data provided by a set of cameras, including a stereo camera and a video camera, is that 3D information from the stereo camera is used to generate a depth map that is mapped to a 2D FOV estimate created from information from the video camera to modify the FOV estimate to a representation of the x-ray FOV size and shape. A further technical effect is that the FOV preview provides a representation of the actual geometry and position of the x-ray FOV, which can be viewed and adjusted by the user by presenting the FOV preview on at least one display device.

[0070] As used herein, an element or step recited in the singular and preceded by the word "a" or "an" should be understood as not excluding a plurality of the elements or steps, unless expressly stated to the contrary. Further, a reference to "one embodiment" of the present invention is not intended to be construed as excluding the existence of additional embodiments that also incorporate the recited features. Additionally, unless expressly stated to the contrary, an embodiment that "comprises," "includes," or "has" an element or elements with a particular property may include additional such elements that do not have that property. The terms "comprising" and "in" are used as concise linguistic equivalents of the corresponding terms "including" and "wherein," respectively. Further, the terms "first," "second," and "third," etc. are used merely as labels and are not intended to impose numerical requirements or a particular positional order on their objects.

[0071] In one embodiment, a method includes generating a first set of multi-dimensional imaging data, generating a second set of data along at least one dimension, and generating a field of view (FOV) preview based on a compilation of the first set of data and the second set of data. In a first example of the method, generating the FOV preview includes projecting the FOV onto a two-dimensional image of a three-dimensional surface of a patient based on the first set of data and the second set of data. A second example of the method optionally includes the first example and further includes wherein generating the first set of multi-dimensional imaging data includes obtaining data from a first imaging device, and generating the second set of data includes obtaining data from a second imaging device, and wherein the first imaging device and the second imaging device are positioned in the same region of the imaging system and are oriented to have an imaging FOV that is the same as the x-ray FOV. A third example of the method optionally includes one or more of the first example and the second example and further includes displaying the generated FOV preview on at least one display device as an image of the surface of the patient framed within the region of the patient defined by an irradiated contour. A fourth example of the method optionally includes one or more of the first example through the third example and further includes wherein displaying the generated FOV preview on at least one display device includes displaying the generated FOV preview on a first monitor adjacent to a technician and on a second monitor adjacent to a surgeon, and wherein the displays on the first monitor and the second monitor are independently adjustable from each other.

[0072] In another embodiment, an imaging system includes: a first device configured to acquire a first set of multi-dimensional image data; a second device configured to acquire a second set of image data along at least one dimension, the second set of data being complementary to the first set of image data; and a field of view (FOV) preview based on a compilation of the first set of data and the second set of data. In a first example of the system, the first device is an infrared imaging camera and the second device is a video camera. A second example of the system optionally includes the first example and further includes where the first device is a distance measurement device and the second device is a video camera. A third example of the system optionally includes one or more of the first example and the second example and further includes where the set of devices is mounted adjacent to a detector of the imaging system, aimed downward along the same side of the detector in an axial plane, the axial plane being perpendicular to the length of the patient that is disposed easily below the detector, and where the patient is positioned between the detector and an x-ray source. A fourth example of the system optionally includes one or more of the first example to the third example and further includes where the set of devices is tilted at a first angle with respect to a vertical axis of the imaging system, and where the first angle is configured to center the field of view of the set of devices with respect to an expected x-ray beam passing through the patient. A fifth example of the system optionally includes one or more of the first example to the fourth example and further includes where the set of devices is aligned with the vertical axis and disposed in a central region with respect to the detector along a sagittal plane of the imaging system, the sagittal plane being perpendicular to the axial plane. A sixth example of the system optionally includes one or more of the first example to the fifth example and further includes where the size and shape of the FOV preview, as indicated by an irradiated boundary, represent the actual size and shape of the expected x-ray beam passing through the patient. A seventh example of the system optionally includes one or more of the first example to the sixth example and further includes where the irradiated boundary is displayed on a display monitor and projected onto an image of the surface of the patient to be irradiated by the x-ray beam. An eighth example of the system optionally includes one or more of the first example to the seventh example and further includes where the FOV preview is displayed on at least one display device as an image of the anatomical region of the patient expected to be irradiated by the x-ray beam.

[0073] In yet another embodiment, a method includes: generating a depth map from data provided by a first device of a set of devices; matching the depth map with a field of view (FOV) estimate provided by a second device of the set of devices to generate a complete FOV preview; and displaying the complete FOV preview on at least one display device. In a first example of the method, generating the depth map includes obtaining three-dimensional (3D) image data from the first device, and wherein providing the FOV estimate includes obtaining two-dimensional (2D) image data and video frames from the second device. A second example of the method optionally includes the first example and further includes wherein generating the depth map includes creating 3D point cloud data using one or more of a known distance from a detector of the imaging system to a patient positioned below the detector, a known distance from the set of devices to the patient, and collimator iris geometry. A third example of the method optionally includes one or more of the first example and the second example and further includes wherein matching the depth data with the FOV estimate includes matching points from the 3D point cloud data with known positions in the FOV estimate via a homography to transform the matched data into the perspective of the FOV estimate. A fourth example of the method optionally includes one or more of the first example through the third example and further includes blending the transformed matched data into the video frames to create a complete FOV preview, and wherein the patient region shown in the FOV image bounded by the irradiated bounding box corresponds to the expected size and shape of the x-ray beam. A fifth example of the method optionally includes one or more of the first example through the fourth example and further includes wherein the process for generating the complete FOV preview is repeated for each frame in the video and depth streams provided by the set of devices to continuously update the complete FOV preview.

[0074] This written description uses examples to disclose the invention, including the best mode, and also enables one of ordinary skill in the relevant art to practice the invention, including making and using any device or system and performing any included method. The scope of the invention that can be patented is defined by the claims and may include other examples that occur to one of ordinary skill in the art. If such other examples have structural elements that are not different from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims, then such other examples are intended to fall within the scope of the claims.

Claims

1. A method for an imaging system, comprising: Generate a first set of multi-dimensional imaging data; Generate a second set of data along at least one dimension; And Generate a field-of-view preview based on a compilation of the first set of data and the second set of data, where generating the first set of multi-dimensional imaging data includes obtaining data from a first imaging device, and generating the second set of data includes obtaining data from a second imaging device, and where the first imaging device and the second imaging device are mounted adjacent to a detector of the imaging system; where the first imaging device and the second imaging device are tilted at a first angle relative to a vertical axis of the imaging system, and where the first angle is configured to center the fields of view of the first imaging device and the second imaging device relative to an expected x-ray beam passing through a patient, where the patient is positioned between the detector and the x-ray source.

2. The method according to claim 1, wherein generating the field of view preview comprises projecting the field of view onto a two - dimensional image of the patient's three - dimensional surface based on the first set of data and the second set of data.

3. The method according to claim 1, wherein the first imaging device and the second imaging device are positioned in the same region of the imaging system and are oriented to have an imaging field of view that is the same as the x - ray field of view.

4. The method according to claim 1, further comprising displaying the generated field of view preview on at least one display device as an image of the patient's surface framed within the region of the patient defined by the irradiated profile.

5. An imaging system, comprising: A first imaging device configured to obtain a first set of multi-dimensional image data; A second imaging device configured to obtain a second set of image data along at least one dimension, the second set of data being complementary to the first set of image data; And A field-of-view preview based on a compilation of the first set of data and the second set of data, where the first imaging device and the second imaging device are mounted adjacent to a detector of the imaging system; where the first imaging device and the second imaging device are tilted at a first angle relative to a vertical axis of the imaging system, and where the first angle is configured to center the fields of view of the first imaging device and the second imaging device relative to an expected x-ray beam passing through a patient, where the patient is positioned between the detector and the x-ray source.

6. The imaging system according to claim 5, wherein the first imaging device and the second imaging device are aimed downwardly towards the patient along the same side of the detector along an axial plane that is perpendicular to the length of the patient that is easily disposed below the detector.

7. The imaging system according to claim 6, wherein the first imaging device and the second imaging device are aligned with the vertical axis and are arranged in a central region relative to the detector along the sagittal plane of the imaging system, the sagittal plane being perpendicular to the axial plane.

8. The imaging system according to claim 6, wherein the size and shape of the field of view preview, as indicated by the irradiated boundary, represent the actual size and shape of the expected x - ray beam passing through the patient.

9. The imaging system according to claim 8, wherein the irradiated boundary is displayed on a display monitor and is projected onto an image of the surface of the patient to be irradiated by the x - ray beam.

10. The imaging system according to claim 5, wherein the field of view preview is displayed on at least one display device as an image of the anatomical region of the patient expected to be irradiated by the x-ray beam.

11. A method for an imaging system, comprising: Generate a depth map from data provided by a first device in a set of devices, where generating the depth map includes: Obtain three-dimensional image data from the first device Create three-dimensional point cloud data using one or more of a known distance from the detector of the imaging system to a patient positioned below the detector, a known distance from the set of devices to the patient, and collimator iris geometry; Match the depth map with a field-of-view estimate provided by a second device in the set of devices to generate a complete field-of-view preview; and Display the complete field-of-view preview on at least one display device; where the first device and the second device are tilted at a first angle relative to a vertical axis of the imaging system, and where the first angle is configured to center the fields of view of the first device and the second device relative to an expected x-ray beam passing through a patient, where the patient is positioned between the detector and the x-ray source.

12. The method according to claim 11, wherein providing the field of view estimate includes obtaining two-dimensional image data and video frames from the second device.

13. The method according to claim 11, wherein matching the depth map with the field of view estimate includes matching points from the three-dimensional point cloud data with known positions in the field of view estimate via a homography to convert the matched data into the perspective of the field of view estimate.

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