System and method to image data

Abstract

A method and system are disclosed for acquiring image data of a subject. The image data can be collected with an imaging system in a selected manner and / or motion. More than one projection may be combined to generate and create a selected view or visualization of the subject.

Description

SYSTEM AND METHOD TO IMAGE DATAFIELD

[0001] The present disclosure relates to imaging a subject, and particularly to a system and method to acquire image data for generating a selected image visualization.BACKGROUND

[0002] This section provides background information related to the present disclosure which is not necessarily prior art.

[0003] A subject, such as a human patient, may undergo a procedure. The procedure may include a surgical procedure to correct or augment an anatomy of the subject. The augmentation of the anatomy can include various procedures, such as movement or augmentation of bone, insertion of an implant (i.e. an implantable device), or other appropriate procedures.

[0004] A surgeon can perform the procedure on the subject with images of the subject that are based on projections of the subject. The images may be generated with imaging systems such as a magnetic resonance imaging (MRI) system, computed tomography (CT) system, fluoroscopy (e.g. C-Arm imaging systems), or other appropriate imaging systems.SUMMARY

[0005] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

[0006] According to various embodiments, a system to acquire image data of a subject with an imaging system may use x-rays. The subject may be a living patient (e.g.a human patient). The subject may also be a non-living subject, such as an enclosure, a casing, etc. The imaging system may include a moveable source and / or detector that is moveable relative to the subject.

[0007] An imaging system may include the movable source and / or detector to create one or more projections of a subject. The one or more projections may be acquired in a path of movement of the source and / or detector. The plurality of projections may then be combined, such as by stitching together, to generate or form a long view (also referred to as a long film). The various projections may also or alternatively be combined with selected techniques to include a range of image data that is not present in a single projection. Thus, the plurality of projections may include more than one projection acquired at the same pose (e.g., location and orientation) relative to the subject.

[0008] According to various embodiments, the imaging system may acquire one or more projections at selected positions or poses relative to the subject. The subject may include various features that may interfere with a selected quality or acquisition of image data. For example, a member, such as a metallic implant, may be formed of a material that interferes with a selected image data acquisition. For example, x-rays may be attenuated to a degree or amount that limits a quality of an x-ray projection acquired of the subject.

[0009] The imaging system may move relative to the subject. Given the known position of the member, which may be referred to as an interfering object, within the subject, the acquisition of image data projections may be made at poses relative to the subject to minimize interaction with the interfering object. Therefore, the imaging system may be operated and configured to acquire one or more image projections at poses relative to the subject that minimize the amount of the interfering object within the beamof the imaging system. This may allow acquired image data to be at poses that have a selected, including a minimal or selected reduced amount, of interference due to the interfering object.

[0010] Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.DRAWINGS

[0011] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0012] Fig. 1 is an environmental view of an imaging system in an operating theatre;

[0013] Fig. 2 is a detailed schematic view of an imaging system with a dual energy source system;

[0014] Fig. 3 is a schematic illustration of an exemplary sub-plurality of a plurality of imaging system or module positions, according to various embodiments;

[0015] Fig. 4 is a schematic illustration of an exemplary sub-plurality of a plurality of imaging system or module positions and illustrative ray length of a beam portion, according to various embodiments;

[0016] Fig. 5 is a schematic illustration of an exemplary sub-plurality of a plurality of imaging system or module positions and illustrative ray length of a beam portion, according to various embodiments; and

[0017] Fig. 6 is a flowchart for a process of acquiring image data, according to various embodiments.

[0018] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.DETAILED DESCRIPTION

[0019] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0020] The subject disclosure is directed to an exemplary embodiment of a surgical procedure on a subject, such as a human patient. It is understood, however, that the system and methods described herein are merely exemplary and not intended to limit the scope of the claims included herein. In various embodiments, it is understood, that the systems and methods may be incorporated into and / or used on non-animate objects. The systems may be used to, for example, image and register coordinate systems between two systems for use on manufacturing systems, maintenance systems, and the like. For example, automotive assembly may use one or more robotic systems including individual coordinate systems that may be registered together for coordinated or consorted actions. Accordingly, the exemplary illustration of a surgical procedure herein is not intended to limit the scope of the appended claims.

[0021] Various members or portions thereof may also be tracked relative to the subject. For example, a tracking system may be incorporated into a navigation system to allow tracking and navigation of one or more instruments (which may be the members) that may be tracked relative to the subject. The subject may also be tracked. The navigation system may include one or more tracking systems that track various portions,such as tracking devices, associated with instruments. The tracking system may include a localizer that is configured to determine the pose of the tracking device in a navigation system coordinate system. The pose may include any number of degrees of freedom, such as a three-dimensional location (e.g., x, y, z) and an orientation (e.g., yaw, pitch, and roll). Techniques, systems, or processes to determine the navigation system coordinate system may include those described at various references including U.S. Pat. No. 8,737,708; U.S. Pat. No. 9,737,235; U.S. Pat. No. 8,503,745; U.S. Pat. No. 8,175,681 ; and U.S. Pat. No. 11 ,135,025; all incorporated herein by reference. In particular, a localizer may be able to track an object within a volume relative to the subject. The navigation volume, in which a device may be tracked, may include or be referred to as the navigation coordinate system or navigation space. A determination or correlation between two coordinate systems may allow for or also be referred to as a registration between two coordinate systems.

[0022] Image data may be acquired for use and / or to generate images, which may also be referred to as image visualizations, of selected portions of a subject. The images may be displayed for viewing by a user, such as a surgeon. In various embodiments, superimposed on at least a portion of the image may be a graphical representation of a tracked portion or member, such as an instrument. The graphical representation may be generated (e.g., by a processor module executing instructions) entirely as a graphic that represents the instrument. According to various embodiments, the graphical representation may be superimposed on the image at an appropriate pose due to registration of an image space (also referred to as an image coordinate system) to a subject space. A method to register a subject space defined by a subject to an image space may include those disclosed in U.S. Pat. Nos. U.S. Pat. No. 8,737,708; U.S. Pat.No. 9,737,235; U.S. Pat. No. 8,503,745; and U.S. Pat. No. 8,175,681 ; all incorporated herein by reference.

[0023] During a selected procedure, the first coordinate system may be registered to the subject space or subject coordinate system due to a selected procedure, such as imaging of the subject. In various embodiments, the first coordinate system may be registered to the subject by imaging the subject with a fiducial portion that is fixed relative to the first member or system, such as a robotic system or other instrument. The known position of the fiducial relative to any portion, such as the robotic system or the subject, may be used to register the subject space relative to any coordinate system in which the fiducial may be determined (e.g., by imaging or detecting (e.g., touching)). A registration of a second coordinate system may allow for tracking of additional elements not fixed to a first portion, such as a robot that has a known coordinate system.

[0024] The tracking of an instrument during a procedure, such as a surgical or operative procedure, allows for navigation of a procedure. The navigation may be used to determine a pose of one or more portions, such as an instrument. The pose may include any number of degrees of freedom, such as a three-dimensional location (e.g., x, y, z) and an orientation (e.g., yaw, pitch, and roll). When image data is used to define an image space it can be correlated or registered to a physical space defined by a subject, such as a patient. According to various embodiments, therefore, the patient defines a patient space in which an instrument can be tracked and navigated. The image space defined by the image data can be registered to the patient space defined by the patient. The registration can occur with the use of fiducials that can be identified in the image data and in the patient space.

[0025] Fig. 1 is a diagrammatic view illustrating an overview of a procedure room or arena. In various embodiments, the procedure room may include a surgical suite in which may be placed a robotic system 20 and a navigation system 26 that can be used for various procedures. The robotic system 20 may include a Mazor X™ robotic guidance system, sold by Mazor Robotics Ltd. having a place of business in Israel and / or Medtronic, Inc. having a place of business in Minnesota, USA and / or as disclosed in U.S. Pat. No. 11 ,135,025, incorporated herein by reference. The robotic system 20 may be used to assist in guiding a selected instrument, such as drills, screws, be an ultrasound (US) probe 33, etc. relative to a subject 30.

[0026] The robotic system 20 may include a mount 34 that fixes a portion, such as a robotic base 38, relative to the subject 30. The robotic system 20 may include one or more arms 40 that are moveable or pivotable relative to the subject 30, such as including an end effector 44. The end effector 44 may be any appropriate portion, such as a tube, guide, or passage member. Affixed to and / or in place of the end effector may be the imaging system that may be the US probe 33. A robotic processor module 53 may be used to control (e.g., execute instructions) to move and determine a pose of the end effector, such as relative to the base 34. The pose of the base 34 may be known in a coordinate system, such as the patient space of the patient 30 and / or the image coordinate system due to a registration as discussed above and exemplary disclosed in U.S. Pat. No. 11 ,135,025, incorporated herein by reference.

[0027] The navigation system 26 can be used to navigate the various portions due to the tracked the pose of one or more tracking devices, tracking devices may include a robot tracking device 54, a subject tracking device 58, an imaging system tracking device62, a tool tracking device 66, and / or an US probe tracking device 81 . Each of the trackingdevices may be used to track one or more portions, including those illustrated as being attached to the respective tracking devices.

[0028] An imaging device or system 80 may be an additional or alternative imaging system that may be used to acquire pre-, intra-, or post-operative or real-time image data of a subject, such as the subject 30, and may be tracked with the image system tracking device 62. It will be understood, however, that any appropriate subject can be imaged and any appropriate procedure may be performed relative to the subject. In the example shown, the imaging device 80 comprises an O-arm® imaging device sold by Medtronic Navigation, Inc. having a place of business in Louisville, Colorado, USA. The imaging device 80 may have a generally annular gantry housing 82 in which an image capturing portion is moveably placed. The imaging device 80 can include those disclosed in U.S. Pat. Nos. 7,188,998; 7,108,421 ; 7,106,825; 7,001 ,045; and 6,940,941 ; all of which are incorporated herein by reference, or any appropriate portions thereof. It is further appreciated that the imaging device 80 may include in addition or alternatively a fluoroscopic C-arm. Other exemplary imaging devices may include fluoroscopes such as bi-plane fluoroscopic systems, ceiling mounted fluoroscopic systems, cath-lab fluoroscopic systems, fixed C-arm fluoroscopic systems, isocentric C-arm fluoroscopic systems, 3D fluoroscopic systems, etc. Other appropriate imaging devices can also include MRI, CT, ultrasound, etc. The various imaging systems may include or use one or more imaging modalities, such as x-ray, magnetic resonance, ultrasound, Positron emission tomography (PET) scans, combinations thereof, etc.

[0029] The position of the imaging system 33, 80, and / or portions therein such as the image capturing portion, can be precisely known relative to any other portion of the imaging device 33, 80. Also, the respective tracking devices may be used to track one ormore portions of the respective imaging systems. The precise positioning and / or tracking can allow the imaging system 33, 80 and / or the navigation system 26 to know its position relative to the patient 30 or other references. In addition, as discussed herein, the precise knowledge of the position of the image capturing portion can be used in conjunction with a tracking system to determine the position of the image capturing portion and the image data relative to the tracked subject, such as the patient 30. The pose (e.g., distance from a selected portion of the US probe 33 and / or the tracking device 81) may be determined or predetermined and saved for recall with a calibration process and / or jig, such as that disclosed in U.S. Pat. Nos. 7,831 ,082; 8,320,653; and 9,138,204, all incorporated herein by reference.

[0030] The imaging device 80 can be tracked with a tracking device 62. As discussed herein, this may allow the pose of one or more portions of the imaging system 80 to be known at a selected time, such as while acquiring image data of the subject 30. Moreover, the pose of the imaging system or portion thereof may be planned and moved to a planned pose relative to the subject 30. Also, the tracking device 81 can be associated directly with the US probe 33. The US probe 33 may, therefore, be directly tracked with a navigation system as discussed herein. In addition or alternatively, the US probe 33 may be positioned and tracked with the robotic system 20. Regardless, image data defining an image space acquired of the patient 30 can, according to various embodiments, be registered (e.g., manually, inherently, or automatically) relative to an object space. The object space can be the space defined by a patient 30 in the navigation system 26.

[0031] The patient 30 can also be tracked as the patient moves with a patient tracking device, DRF, or tracker 58. Alternatively, or in addition thereto, the patient 30 may be fixed within navigation space defined by the navigation system 26 to allow forregistration. As discussed further herein, registration of the image space to the patient space or subject space allows for navigation of the instrument 68 with the image data. When navigating the instrument 68, a position of the instrument 68 can be illustrated relative to image data acquired of the patient 30 on a display device 84. An additional and / or alternative display device 84’ may also be present to display an image. Various tracking systems, such as one including an optical localizer 88 or an electromagnetic (EM) localizer 92 can be used to track the instrument 68.

[0032] More than one tracking system can be used to track the instrument 68 in the navigation system 26. According to various embodiments, these tracking systems can include an electromagnetic tracking (EM) system having the EM localizer 94, an optical tracking system having the optical localizer 88 and / or other appropriate tracking systems not illustrated such as an ultrasound tracking system, or other appropriate tracking systems. One or more of the tracking systems can be used to track selected tracking devices, as discussed herein, sequentially or simultaneously. It will be understood, unless discussed otherwise, that a tracking device can be a portion trackable with a selected tracking system. A tracking device need not refer to the entire member or structure to which the tracking device is affixed or associated.

[0033] Image data acquired from the imaging system 33, 80 or any appropriate imaging system, can be acquired at and / or forwarded from an image device controller 96, that may include a processor module 97, to a navigation computer and / or processor system 102 that can be a part of a controller or work station 98 having the display 84 and a user interface 106. The processor system 102 may be a processor module, as discussed herein, including integral memory or a communication system to access external memory for executing instructions and / or operated as a specific integrated circuit (e.g., ASIC). Itwill also be understood that the image data is not necessarily first retained in the controller 96, but may also be directly transmitted to the work station 98. The work station 98 can provide facilities for displaying the image data as an image 108 on the display 84, saving, digitally manipulating, or printing a hard copy image of the received image data. The user interface 106, which may be a keyboard, mouse, touch pen, touch screen or other suitable device, allows the user 72 to provide inputs to control the imaging device 80, via the image device controller 96, or adjust the display settings of the display 84. The work station 98 may also direct the image device controller 96 to adjust the image capturing portion of the imaging device 80 to obtain various two-dimensional images along different planes in order to generate one or more representative two-dimensional and three-dimensional image data that may be used to generate two-dimensional, three-dimensional, or a more than of either or both images.

[0034] With continuing reference to FIG. 1 , the navigation system 26 can further include any one or more tracking system, such as the tracking system including either or both of the electromagnetic (EM) localizer 94 and / or the optical localizer 88. The tracking systems may include a controller and interface portion 110. The controller 110 can be connected to the processor portion 102, which can include a processor included within a computer. The EM tracking system may include the STEALTHSTATION® AXIEM™ Navigation System, sold by Medtronic Navigation, Inc. having a place of business in Louisville, Colorado; or can be the EM tracking system described in U.S. Pat. No. 7,751 ,865; U.S. Pat. No. 5,983,126; U.S. Pat. No. 5,913,820; or U.S. Pat. No. 5,592,939; all of which are herein incorporated by reference. It will be understood that the navigation system 26 may also be or include any appropriate tracking system, including aSTEALTHSTATION® TREON® or S7™ tracking systems having an optical localizer,which may be used as the optical localizer 88, and sold by Medtronic Navigation, Inc. of Louisville, Colorado. Other tracking systems include an acoustic, radiation, radar, etc. The navigation system 26 and / or tracking system may be a hybrid system that includes components from multiple tracking systems. The tracking systems can be used according to generally known or described techniques in the above incorporated references. Details will not be included herein except when to clarify selected operation of the subject disclosure.

[0035] Various portions of the navigation system 26, such as the instrument 68, and others as will be described in detail below, can be equipped with at least one, and generally multiple, of the tracking devices 66. The instrument can also include more than one type or modality of tracking device 66, such as an EM tracking device and / or an optical tracking device. According to various embodiments, the navigation system 26 can be used to track the instrument 68 relative to the patient 30. The instrument 68 can be tracked with the tracking system, as discussed above. Image data of the patient 30, or an appropriate subject, can be used to assist the user 72 in guiding the instrument 68. The image data, which may include one or more image data or images, may be registered to the patient 30. The image data defines an image space that is registered to the patient space defined by the patient 30. The registration can be performed as discussed herein, automatically, manually, or combinations thereof.

[0036] Generally, registration allows a translation map to be generated of the physical location of the instrument 68 relative to the image space of the image data. The translation map allows the tracked position of the instrument 68 to be displayed on the display device 84 relative to the image 108. A graphical representation 68i, also referredto as an icon, can be used to illustrate the location of the instrument 68 relative to the image data 108.

[0037] With continuing reference to Fig. 1 , a subject registration system or method can use the tracking device 58. The tracking device 58 may include portions or members 120 that may be trackable, but may also act as or be operable as a fiducial assembly. The fiducial assembly 120 can include a clamp or other fixation portion 124 and the imageable fiducial body 120. It is understood, however, that the members 120 may be separate from the tracking device 58. The fixation portion 124 can be provided to fix any appropriate portion, such as a portion of the anatomy. As illustrated in Fig. 1 , the fiducial assembly 120 can be interconnected with a vertebra 126 and / or a portion of the vertebra 126 which may form a spine. In various embodiments, the connection may be to a spinous process.

[0038] With additional reference to Fig. 2, The imaging system 80 may move, as a whole or in part, relative to the subject 30. For example, the source 174 and the detector 178 can move in a 360° motion around the patient 30. The movement of the source 174 and the detector 178 as a source / detector unit 198 within the gantry 82 may allow the source 174 to remain generally 180° opposed (such as with a fixed inner gantry or rotor or moving system) to the detector 178. Thus, the detector 178 may be referred to as moving around (e.g. in a circle or spiral) of the subject 30 and it is understood that the source 174 remains opposed thereto, unless disclosed otherwise.

[0039] Also, the gantry 82 can move isometrically (also referred as “wag”) relative to the subject 30 generally in the direction of arrow 200 around an axis 202, such as through a cart 160, as illustrated in Fig. 1. The gantry 82 can also tilt relative to a longaxis 206 of the patient 30 illustrated by arrows 210. In tilting, a plane of the gantry 82 may tilt or form a non-orthogonal angle with the axis 206 of the subject 30.

[0040] The gantry 82 may also move longitudinally in the direction of arrows 214 along the line 206 relative to the subject 30 and / or the cart 160. Also, the cart 160 may move to move the gantry 82. Further, the gantry 82 can move up and down generally in the direction of arrows 218 relative to the cart 160 and / or the subject 30, generally transverse to the axis 206 and parallel with the axis 202.

[0041] The movement of the imaging system 80, in whole or in part is to allow for positioning of the source / detector unit (SDU) 198 relative to the subject 30. The imaging device 80 can be precisely controlled to move the SDU 198 relative to the subject 30 to generate precise image data of the 30.

[0042] The source 174, as discussed herein, may include one or more sources of x-rays for imaging the subject 30. In various embodiments, the source 174 may include a single source that may be powered by more than one power source to generate and / or emit x-rays at different energy characteristics. In various embodiments, the source may emit x-rays in at least two different powers, such with varying voltages. Further, more than one x-ray source may be the source 174 that may be powered to emit x-rays with differing energy characteristics at selected times.

[0043] With continuing reference to Fig. 2, according to various embodiments, the source 174 can include a single x-ray tube assembly 250 that can be connected to a switch 254 that can interconnect a first power source 258 via a connection or power line 262. As discussed above, X-rays can be emitted from the x-ray tube 250. According to various embodiments, the x-rays may be emitted in a cone shape 270 towards the detector 178 and generally in the direction from the x-ray tube 250 as indicated by arrow,beam arrow, beam or vector 274. The vector 274 may extend along an axis and may also be referred to as a central axis of the beam. The switch 254 can switch power on or off to the tube 250 to emit x-rays of selected characteristics, as is understood by one skilled in the art.

[0044] The vector or portion 274 may be a central vector or ray within the cone 270 of x-rays. An x-ray beam may be emitted as the cone 270 or other appropriate geometry. The vector 274 may include a selected line or axis relevant for further interaction with the beam, such as with a filter member, as discussed further herein.

[0045] The subject 30 can be positioned within the x-ray cone 270 to allow for acquiring image data of the subject 30 based upon the emission of x-rays in the direction of vector 274 towards the detector 178. Generally, the subject may attenuate, e.g., scatter or absorb, x-rays. The unattenuated x-rays or c-rays that pass through the subject 30 reach the detector 170.

[0046] The imaging system 80, according to various embodiments, may operate the x-ray tube 250 to generate two-dimension (2D) x-ray projections of the subject 30, including selected portions of the subject 30, or any area, region or volume of interest, in light of the x-rays impinging upon or being detected on a 2D or flat panel detector, as the detector 178. The 2D x-ray projections can be reconstructed, as discussed herein, to generate and / or display selected images or image visualizations including 2D images, three-dimensional (3D) volumetric models of the subject 28, selected portion of the subject 28, or any area, region or volume of interest, or a plurality of either to generate four dimension (4D) images that may be time varying. As discussed herein, the 2D x-ray projections can be image data acquired with the imaging system 80, while the 3D volumetric models can be generated or model image data.

[0047] For reconstructing or forming the 3D volumetric image, appropriate algebraic techniques include Expectation maximization (EM), Ordered Subsets EM (OS- EM), Simultaneous Algebraic Reconstruction Technique (SART) and Total Variation Minimization (TVM), as generally understood by those skilled in the art. The application to perform a 3D volumetric reconstruction based on the 2D projections allows for efficient and complete volumetric reconstruction. Generally, an algebraic technique can include an iterative process to perform a reconstruction of the subject 30 for display as the image 108.

[0048] The imaging system 80, or portions thereof such as the SDU 198 may be moved relative to the subject 30, such as around along axis of the subject 30. Accordingly, as illustrated in Fig. 2 the imaging system 80 may be positioned such that an anterior-to- posterior projection may be acquired with cone 270 or a lateral projection may be acquired with a cone 270’. Accordingly a plurality of image projections of the subject 30 may be acquired at different perspectives.

[0049] However, as discussed above, the imaging system 80 may also acquire a plurality of projections at a single perspective. For example, with an anterior to posterior projection the switch 254 may operated to switch from the first power source to a second power source 280. Therefore, the beam 270 may be operated at two different powers. The image data acquired of the subject 30 may then also be acquired at two different powers and include at least two different projections. As discussed above other parameters may also be altered at the source. Also, the source may emit x-rays within a spectrum, such as based on a selected power (e.g., 40 keV or 120 keV) or being unfiltered.

[0050] Further, the detector 178 may be operated to collect varying image data of the subject 30. For example, the detector 178 may be a dual power detector, such as a detector that may specifically operate to detect X-rays at two different powers within a single broad spectrum or a single detector able to detect two different powers. For example, a detector such as the detector included with the X-35 series X-ray inspection systems sold by Mettler Toledo having a place of business at Columbus, OH may be provided. The detector 178 may also alternatively include a detector able to detect X-rays at discrete and / or varying spectrum. For example, detectors including those included in the dynamic CMOS X-ray flat detector sold by Teledyne Dalsa having a place of business in Santa Clara, CA may be provided. The detectors may be discretely operated or controlled to detect X-rays at differing spectra.

[0051] As discussed above, the imaging system may be operated with the selected controller. Therefore, the controller may operate the detector of 178 to detect X-rays at discrete spectra and / or selected differing powers. Thus, a plurality of projections may be acquired at a single perspective of the detector 178 relative to the subject 30. The plurality of projections may be evaluated and / or combined to achieve a selected image visualization, as discussed further herein.

[0052] With reference to Fig. 3, the imaging system 80 may move relative to the subject 30, as discussed above. According to various embodiments, therefore, the detector 178 may move to a plurality of poses relative to the subject 30, such as by rotating within the gantry 82. For example, as illustrated in Fig. 3, imaging module 198 may include the detector 178 and the source 174. A pose of the detector may be understood to relate to a pose of any one or all of the imaging module 198, the detector 178, or the source174. The detector may exemplary be positioned in a plurality of poses and the illustratedsix position relative to the subject 13 around a circular path 300 that may be defined within the gantry 82 is merely exemplary. Each of the positions of the detector 178 may be opposed by the source position 174. The source and detector 178 need not be exactly 180° apart from one another, but may generally be positioned substantially opposed to one another. Nevertheless, the detector 178 may detect x-rays that are emitted from the source assembly 174 so that it is generally along the midpoint or vector or ray 274 generally through the center of the gantry 82 to be detected at the detector 178. In various embodiments, the path of the source and detector may be substantially circular, as illustrated by the circular path 300. However, the path 300 need not be circular, as discussed further herein, as the gantry 82 may move relative to the subject 30, as discussed above such as longitudinally in the direction of arrows 210 or in a wag motion 200.

[0053] The detector 178 may be moved relative to the subject 30 to allow for acquisition of image data at a plurality of positions relative to the subject 30. Generally, an image data may be acquired at each of the positions. Each image data acquisition may be a discrete acquisition and may also be referred to as a projection. The projection may be a projection of the x-rays through the subject 30 or through an imaging region relative to the imaging system 80. For example, the subject 30 maybe within the imaging region. Further, various elements or members, such as one or more implants which may exemplary be screws 310, 314 may be in the imaging region.

[0054] Therefore, the portions of the subject and implant portions may attenuate the x-rays in the projections acquired at positions of the detector 178. The detector may be moved a selected amount such as 1 mm, 1cm, 10cm, or the like in any appropriate direction or type of movement achievable by the imaging system 80 between each of theprojections. Each one projection or position of the detector may be distance away for differential distance from another or adjacent position. Accordingly, as exemplary illustrated in Fig. 3, the six projections may be a selective fixed or variable distance from one another and may only be around in the path 300 that may be circular or in a noncircular path. At each of the positions of the detector 178 may allow for the acquisition of a discrete projection at the position of the detector 178 relative to the subject 30 or any imaging region, such as an isocenter, of the imaging system 80.

[0055] As discussed above and further herein, the number of projections may be selected to achieve a selected image data acquisition of the subject 30 or any portion in the imaging system imaging region. The detector 178 may, therefore, acquire image data at any appropriate number of positions such as one, two, three or any number including ten positions, or many tens of positions, or hundreds of positions. The amount of image data acquired may be selected based upon time, patient dosing, efficiency of image reconstruction, or the like.

[0056] Accordingly, if the imaging system 80 generates image data with ionizing radiation, such as x-rays, it may be selected to minimize the projections acquired of the subject 30 while still ensuring an appropriate image data reconstruction or image data acquisition. Generally, image data may be acquired of the subject 30 and, in various embodiments, image data may be used to generate or reconstruct an image. The image 108 may be a direct image of the projection acquired as the detector 178 and / or may be a reconstruction based upon a plurality of image data, such as a plurality of projections. In various embodiments, a plurality of projections may be used to generate two- dimensional, three-dimensional, or time varying images which may also be referred to as a four-dimensional images. Further, the projection to acquire the discrete image data maybe discrete poses of the detector 178 relative to the subject or image region such that the image data projections are acquired as projections or snapshots at a discrete pose of the detector 178.

[0057] With continuing reference to Figs. 1 -3 and with additional to reference to Fig. 4, the imaging system 80 is illustrated schematically. The imaging system 80 may acquire an image data at or with movement of portions of the imaging system, such as the source assembly 174 and the detector 178 as it moves along the path 300’. The path 300’, as illustrated in Fig. 4, need not be a circular path and may be a path selected to acquire image data to a selected or appropriate degree of the subject 30. The trajectory or path may include a selected plurality of positions of the imaging module 198 and projections to image a selected portion of the subject to generate or reconstruct a selected image. The path or trajectory 300 may be based on the portion to be imaged, the shape thereof, or other parameters to acquire image data for the image reconstruction.

[0058] As discussed above and herein, the subject 30 may refer to any imageable or imaging region about which image data is to be acquired. The subject 30 may be a volume, a human patient, a structure, or the like. The subject 30 may have various portions therein, such as soft tissue, bony portions, metallic portions, or the like. In various embodiments, metallic portions may include implants such as one or more pedicle screws. As exemplary illustrated above and herein, the pedicle screw 310 and the pedicle screw 314 may be positioned within the subject 30. Image data may then be selected to be acquired of the subject 30 or region, including the pedicle screws 310, 314. The pedicle screws 310, 314 may be formed of a material, such as a metal or metal alloy, which may interact with the x-rays of the imaging system 80.

[0059] The members, including the screws 310, 314 may attenuate the x-rays relative to the other portions of the subject 30 in a manner less conducive to reconstruction of a selected image. Thus, the pedicle screw 310, 314 or any other similarly disrupting or distorting portion, may be referred to as a distorting member. For example, the screws 310, 314 that may be formed of the metal or metal alloys may cause a metallic artifact that may disrupt image data acquisition of other portions of the subject 30 near or adjacent to the members 310, 314. Further, the greater a distance that an x-ray photon must pass through the distorting member 310, 314, the greater amount of distortion, such as due to the metal, may occur in the acquired image data at that pose of the detector and source.

[0060] Therefore, as discussed herein, a planned trajectory of the detector and source may be made to acquire the image data. The planned trajectory to acquire image data may include an appropriate or selected number of projections to achieve a selected outcome. Further, a selected distance between poses and / or number of projections may be a part of the planned trajectory. Thus, the trajectory of the scan, such as the path 300, 300’, may be planned based upon known or predetermined elements or members.

[0061] The plan can include smaller gaps or distances between certain projections (e.g., adjacent poses of the detector) when a larger amount of the screw may be in the path of the x-ray photon and larger gaps or distances between projections when there is less of the distorting member in the path of the x-ray photon. This planning and pre-known or determined pose of the elements, such as the screws 310, 314, may allow for the acquisition of an appropriate or sufficient amount of image data to generate a selected quality image reconstruction. The reduction of acquisitions in certain positions as opposed to others (e.g., those that may require additional projections for data acquisition) may allow for a total dose of radiation to the subject 30 to be within a selected range, such as nogreater than only acquiring image data at a fixed and / or even plurality of positions relative to the subject 30. For example, a selected dose may be achieved by varying distances between acquisitions, such as 0.1 degree (°) annular difference for a first set of projections and a 1.5° annual difference for a second set of acquisitions or projections. This is opposed to a fixed distance apart, such as 0.5° or 1 ° around a 360° circle.

[0062] Illustrated in Fig. 4, the detector 178 is exemplary illustrated to be at three positions 178, 178', and 178”. Thus, the reference herein to the detector 178 may refer to the pose thereof, as discussed herein. The detector 178 may be a detector of the imaging system and may be at one or more positions for imaging, such as a position as illustrated with the position of the detector 178. Each of the positions will cause x-rays to pass through one or more of the members 310, 314 for a selected distance. For example, with the detector at position 178, the center of the beam may pass through a first distance 310a of the screw 310 and a first distance 314a of the screw 314. With reference to Fig. 5, three positions of the detector, different than those in Fig. 4, illustrated as positions 1781, 178m, and 178n. The x-rays may be emitted along a beam having a central ray 274m that may pass through a distance 310c of the screw 310. The distance 310c may be greater than the distance 310a. Therefore, attenuation of the x-rays as the x-rays pass through the distance 310a may be less than the attenuation when the x-rays pass through the distance 310c of the screw 310. This determination may allow planning to be based upon the known distance through the respective members, such as the screws 310, 314.

[0063] Returning reference to Fig. 4, and the three exemplary positions of the detector 178, 178’, 178” are related poses or positions of the source assembly 174, 174', 174”. Each of the source poses have respective source emitter poses 250, 250', 250”.Similarly, each of the source poses when emitting x-rays for generating a projection orimage data projection will include x-rays within a cone or beam poses respectively 270, 270’, and 270”. Each of the respective cones poses 270, 270', 270” may have the central ray or axis poses 274, 274' and 274”. Thus, while a single imaging module 198 may include the detector 178 and the source 174, it and the portions may be moved to one or many poses relative to the subject to emit and detect the beam thereat.

[0064] The entire volume of each of the cone poses may be analyzed for impingement or pass through of the members 310, 314. The analysis may allow for the evaluation or determination of a value related to the amount or distance the photon passes through the member. Herein, the central vector or axis 274, is discussed for simplicity and clarity of the current discussion but it is understood that each of the cones or beams may have a plurality of axes from the source 250 to the detector 178.

[0065] The source assembly when at the source pose 174 may emit the beam 270 that passes through the subject 30 and portions therein, such as the screws through 310, 314 before being detected at the detector pose 178. With exemplary discussion of the central axis 274, it may pass through the screw 310 for the distance 310a and pass through the second screw 314 for the distance 314a before reaching the detector pose 178. The detector pose 178 of the detector may be known or selected for planning image data acquisition in the distances 310a, 314a may also be known or determined. The distances of the photon passing through the respective screws 310, 314 may be determined during a planning phase based upon a known pose of the screws 310, 314 within the subject 30 and relative to the imaging system 80. The distances 310a, 314a may, therefore, be known or predetermined during a planning phase for image data acquisition of the subject 30 and the various portions therein.

[0066] With continuing reference to Fig. 4, the detector 178 may be at the detector position 178'. Therefore, the source may be at source position 174' having the emitter position 250' that may emit the beam at the beam pose 270' with the central axis pose 274’. The ray 274’ may pass through the first screw 310 for a distance 310b and the second screw 314 for a distance 314b. Again, these distances may also be known or determined based upon known or determined or planned detector position 178' relative to the positions of the screws 310, 314. The third source position detector 174", third detector pose 178" may emit the beam pose 270” along the central axis pose 274”. The central axis pose 274" may pass through the second screw 314 only for the distance 314c. Therefore, the three exemplary poses illustrated in Fig. 4 may have the known or determined x-ray pass through lengths 310a, 310b, 314a, 314b, 314c for each of the three positions of the detector poses 178, 178' and 178". These lengths alone or parameters related thereto may be values of distortion. The value of distortion may also relate to a weighted amount, such as an angle of incidence with the member, the material of the member relative to different material of another member, etc.

[0067] Three exemplary poses of the detector are detector poses 178m, 170n, 178I illustrated in Fig. 5 that are 314 in poses different than that illustrated in Fig 4. Accordingly, the respective poses of the detector are positioned such that the respective cones or x- ray beams poses 270m, 270n, 278I with respective central axes or ray poses 270m, 270n, 270I pass through or interact with the respective screws 310, 314 in alternate or different amounts than those illustrated in Fig. 4.

[0068] As illustrated in Fig. 5, the detector poses 178m, 1781 are substantially opposed to one another. Therefore, each of the respective ray poses 274m, 2741 pass generally a distance 310c through the screw 310. The distance 310c may generally begreater than any of the distances 310a, 310b, 314a, 314b, or 314c. Therefore, an attenuation of the x-ray through the screw 310 due to passing through the distant 310c may be greater than that of any of the poses illustrated in Fig. 4.

[0069] The detector pose 178n is opposed to the x-ray source pose 174n that may generate the beam pose 270n and generally pass along the central axis pose 274n. This may define a ray pose 274n that will pass the distance 314d through the screw 314. Again, the distance 314d may be greater than any of those illustrated in Fig. 4. Further the distance 314d may be greater than that of the distance 310c. Regardless, the various distances may be known or determined due to possible positions or poses of the detector and source 178, 174, respectively relative to the subject of 30 that may include the screws 310, 314.

[0070] In the examples in Fig. 4, a distortion value or value related to the pose of the member 310, 314 may be less than any of the values for the members 310, 314 illustrated in Fig. 5. This may be determined or evaluated, as discussed herein. The values may be used to assist in determining a specific number and position of poses of the imaging module 198 to generate selected image data.

[0071] The detector 178, therefore, may be positioned relative to the subject 30 in various poses that may be around the subject such as generally in a circle 300 (as illustrated in Fig. 3) or in a non-circular trajectory 300’ which may include movement relative to the subject 30 in any appropriate axes or directions allowed by the imaging system 80, discussed above. Thus, the detector 178 may be positioned relative to the subject to achieve a selected image data acquisition. As discussed above, the positioning of the imaging system, including the detector 178, may be planned to achieve image data acquisition of the subject 30 in an appropriate manner and amount to allow for a selectedreconstruction of an image while maintaining a selected dose of radiation to the subject 30. Thus, the path, such as the path 300 and 300’, may be planned and selected poses of the detector 178 may be planned to achieve an appropriate image data acquisition.

[0072] The plan may be based upon the known pose of the screws is 310, 314, which may be known for various reasons such as or real time- or pre-determined, recalled, etc. The pose of the screws 310, 314 in the subject may be determined by positioning information regarding the screws 310, 314 during a selected procedure. Pose information may be determined from the navigation system 26, the robotic system 20, or other appropriate systems. Briefly, the discussion herein regarding the screws 310, 314 may relate to any appropriate member that may be positioned in the subject 30. The discussion and exemplary illustration of the screws 310, 314 is merely for clarity of the current discussion and appropriate disclosure of the system and method.

[0073] In various embodiments, as discussed above, the instrument 68 may be used to position one or more of the screws 310, 314 in the subject 30. The pose of the screws 310, 314, therefore, may be known due to tracking of the instrument 68. In various embodiments, the screws 310, 314 may also be directly tracked, such as with the inclusion of a tracking device on their respective screws 310, 314. The tracked pose of the instrument 68 may be known or made relative to the patient tracker 58 such that the navigation system 26 is able to know or determine the pose of the screws 310, 314 relative to the subject 30. The pose may then be stored, retrieved or recalled for various purposes.

[0074] In various embodiments, the robotic system 20 may also be used to position or guide an instrument to position the screws 310, 314. Therefore, the robotic system 20 may also be used to know or determinate a pose of the screws 310, 314 in the subject 30.

[0075] As the pose of the screws 310, 314 may be known relative to the subject in an appropriate manner, as discussed above, the pose of the detector 178 or any appropriate portion of the imaging system 80 may also be known relative to the subject 30. The imaging system 80 may be tracked relative to the subject 30 at any appropriate time. Thus, the pose of the image data acquisition portions relative to the subject 30 may be know.

[0076] In various embodiments, the robotic system 20 may be fixed relative to the imaging system during a procedure and thus the pose of the imaging system 80, including the detector 178 may be known relative to the robotic system 20. Further, the imaging system 80 may be tracked with various tracking devices, as discussed above including the imaging device tracking device 62, to allow for a navigated pose of the imaging system 80 such as during image data acquisition. Thus, the navigation system 26 may be used to determine a pose of the imaging system 80, or at least a portion thereof, such as the detector 178, at various times.

[0077] The screws 310, 314 may be positioned in the subject 30. The pose of the screws 310, 314 may be known due to tracking the instrument 68, tracking the screws directly, determining or knowing a pose of the end effector 44 of the robotic system 20, or other appropriate mechanisms. Thus, the navigation system 26 may be used to determine, retrieve or recall the pose of the screws 310, 314 to assist in planning a positioning of the detector 178 to acquire a selected or appropriate image data. The planning may include a total or complete trajectory and number of projection positions of the detector 178 to acquire appropriate or selected image data. Thus, the navigation system, or any appropriate processing system, may acquire or determine the pose of thescrews 310, 314 for an image data acquisition of the subject 30 with the screws 310, 314 positioned in the subject 30.

[0078] An appropriate processing module, such as the processing module 102 of the navigation system 26, the processing module of 97 of the imaging system 80, or any other appropriate processing module may be used to determine or calculate the trajectory 300’ of the imaging system. The trajectory 300’ may include a selected number of poses of the source assembly 174 and / or the detector 178 to acquire the appropriate image data of the subject 30. As discussed above, the known length of the image cone rays 274 through the respective screws may be used to assist in determining the appropriate trajectory, such as an optimal trajectory that may minimize the dose of radiation to the subject while acquiring image data appropriate or required for a selected reconstruction, such as the quality thereof. A quality of the image reconstruction may include a clarity, confidence level, selected amount of distortion tolerance, or the like.

[0079] As discussed above, the imaging system 80 may include various portions, such as the source assembly 174 and the detector assembly 178. The source and detector assembly 174, 178 may be operated as the source detector unit 198. Generally, the source detector unit 198 may be operated as a unit to acquire image data of the subject 30. Thus, the imaging unit 198 may be moved relative to the subject 30 in a selected manner to acquire image data thereof. The imaging unit 198 may move as a fixed unit and / or the detector 178 may move relative to the source unit 174 or vice versa. Nevertheless, the imaging unit 198 may move in a selected trajectory to acquire a selected amount or appropriate amount of image data of the subject 30 for reconstruction of a selected image, such as for the image 108 for display for selected purpose. As discussed above, members may be positioned relative to the subject 30, such as within the subject30, and may include the screws 310, 314. The screws 310, 314 or any other member may be an interfering or distorting member.

[0080] The imaging system 80 including the imaging unit 198 may, therefore, be used in a selected process to acquire image data of the subject 30 and / or reconstructing an image of the subject 30. A process 400 is illustrated in Fig. 6. The process 400 may include portions that are executed by a processor assembly or module and may be included in instructions that are executed thereby. Therefore, the process 400 may include portions of an algorithm or may be included in an algorithm to allow for acquiring image data of the subject 30 even when there are interfering members therein. Particularly, when the interference or distorting members are within the path of an imaging beam, such as an x-ray beam. The process 400 may also include various manual inputs and / or selections as discussed herein. The process 400 may be entirely automatic, including instructions executed by a processor module, manual, or combinations thereof.

[0081] The process 400 may begin in start block 410. The start block 410 may allow the beginning of the process 400 and may initiate the process, such as initiating operation of processor module, selecting various inputs, or the like. The start block 410 may include selecting the subject, selecting a portion of the subject to be imaged, or other appropriate selection processes. The process 400 may include retrieving or recalling a pose of the distorting members in block 414. As discussed above, the distorting members may include the screws 310, 314 or other appropriate members. Distorting members may be positioned within the subject 30 such as with a navigated procedure including the navigating with one or more of the tracking systems and / or with the robotic system 20. The navigation or tracking may allow the pose of the distorting members to be known, retrieved or recalled. In various embodiments, the distorting members may be trackedwhile placed and the pose may be retrieved, recalled or accessed from a navigation memory for performing an imaging planning procedure, including in the process 400.

[0082] Further, various other inputs or predetermined information may be used to retrieve or recall the pose. For example, the user 72 may input a pose of the distorting members. It is understood, however, that various inputs may be more efficient or more precise. For example, the tracked pose of the instruments used to perform a procedure may allow for a substantially precise determination of the pose of the implants or distorting numbers, such as with millimeter accuracy. The user 72 may determine the accurate pose of the instruments or distorting member with appropriate measuring or calibration systems, but may require additional steps other than the tracking of the navigated procedure.

[0083] The recalled pose of the distorting member allows for the pose of the distorting members to be used for the process 400. The imaging system 80, as discussed above, may also be tracked such that the pose of one or more portions of the imaging module 198 may be tracked or determined during the acquisition of image data. In other words, the pose of the imaging module 198 may be determined during imaging and / or selected during planning of an imaging trajectory for imaging the subject 30.

[0084] As discussed above, the imaging module 198 may move in a trajectory relative to the subject, for example, including the circular trajectory 300 or non-circular trajectory 300’. The trajectory may include any appropriate movement of the imaging system 80, including the imaging module 198, relative to the subject 30. Further, as discussed above, projections may be acquired at any appropriate pose of the imaging module 198 relative to the subject 30. The trajectory of the imaging system may be understood to include all of the movements selected to acquire an appropriate or selectedamount of image data of the subject 30. Generally, the trajectory may include a movement and a projection position determination to acquire image data for a selected image reconstruction, such as the selected portion of the subject 30 including one or more vertebrae thereof.

[0085] The process 400 may also include determination of all possible positions of an imaging system, including the imaging module 198 relative to the subject 30 for a selected image data reconstruction. In various embodiments, all possible positions may include those for a selected or standard image data acquisition for a selected reconstruction. For example, a standard trajectory may be determined to image a selected vertebra, assuming that no distorting objects are present. This standard trajectory may include selected spacing between projections, such as fixed or identical spacing. In various embodiments, however, a determination of all possible positions may include the determination of all possible positions of the imaging module 198 relative to the subject 30 given an initial or range of movement of the imaging system relative to the subject 30. The determination of all the possible positions allows for a predetermination of a position of the imaging system, such as of the central axis 274 of each of the possible positions of the imaging module 198 relative to the subject 30.

[0086] As discussed above, the central axis 274 may be used either alone or with other rays or vectors of the beam 270 from the source 174 to the detector 178 of the imaging module 198. As the central axis 274 is an example, a distance that the axis extends through the distorting member may be determined ray and may be determined given the retrieved or recalled pose of the distorting members from block 414 relative to the known axis position at each possible position in the trajectory. As discussed and illustrated above, for example as is illustrated in Fig. 4, the central axis 274 may be usedto determine a distance of a passage of the x-rays through one or more of the distorting members at one or more of the poses of the imaging module 198.

[0087] In various embodiments, the distance may be understood or identified as a ray along the central axis 274 from the source to the detector through each of the distorting members. Accordingly, an evaluation of a ray length at a selected number including all of the possible positions through to the distorting members may be made in block 424. As all of the possible positions of the imaging system 198 may be known, a distance of the ray, such as along the central axis 274, through the distorting members may be determined at each position. The determined position of the imaging module 198 and the various geometries relative thereto, such as the central axis 274, may be used in combination with the retrieved or recalled pose of the distorting members to evaluate the ray length at each of the possible positions. Therefore, the processing module, such as of the imaging system 80, therefore, including the processing module 97, may determine and calculate all of the ray lengths and evaluate them in block 424. An evaluation of the ray length may be a determination of a total ray length through one or more of the distorting members at each of the possible positions. The evaluating of the ray lengths may allow a determination of a value, such as a distortion value at each pose of the imaging module 198. The distortion value may be used in further processing of a plan for imaging the subject 30 with the distorting member, such as one or more of the screws 310, 314, present. The distortion value, therefore, may be understood to relate to a distance a photon may pass through the distorting member at each pose and the distortion value may relate thereto. In various embodiments, the distortion value may be normalized to a range, such as zero to one. In various embodiments, the distortion value may be normalized to a value within in another range. It may depend on the way one decides toimplement the subject disclosure. Thus, the distortion values may be identified as any appropriate value and may relate to an implementation and, therefore, the type and or amount of specific distortion experienced.

[0088] An evaluation of the ray length, including the distortion value, may then be saved for later retrieve or recall and / or processed in the process 400. The evaluation of the ray length may be used to evaluate a selected trajectory of the imaging module 198, as discussed further herein, according to the process 400.

[0089] Thus, a retrieval or recall or a determination of a minimum number of projections and / or trajectory to achieve a selected image reconstruction may be made in block 430. As discussed above, a selected trajectory may be used to determine to acquire imaging of the subject 30 for a selected reconstruction. For example, to reconstruct a vertebrae, or a plurality of vertebrae in an image, a selected number of projections to acquire a selected image data may be determined. The number of projections and image data may be determined or predetermined to allow for a generation or reconstruction of an image having an appropriate accuracy, detail, or the like. The predetermined trajectory, including predetermined projections positions and a path of the imaging module 198, may be retrieved, recalled or determined in block 430.

[0090] A plan for a trajectory accounting for the distorting members may include a selection of a spatial position or position difference between the imaging module positions and a path may be made in block 440. The planned trajectory may be based upon the evaluated ray length, including the distortion value. The selection of the spatial position or difference may include a sub-process 450 where a selection of a smaller imaging position difference between projections may be selected when a ray length or distortion value is greater through a distorting value threshold in block 454. Thus, a greater number orgreater density of projections may be determined to be acquired within a range of imaging module positions. For example, the ray length may be greater than a selected threshold. The threshold may be any appropriate number such as 1 mm, 10mm, 2cm, or any appropriate distance. Also, the threshold may be a dimensionless or other dimension number for the distorting value as discussed above. Nevertheless, the ray length at any particular position may be determined to be greater than or over a selected threshold.

[0091] A larger imaging system position difference between projections may be selected when the ray length is smaller or less than a selected threshold in block 458. That is, the distance between projections may be greater when the ray length of distortion number is less than a threshold. It is also understood that a plurality of thresholds may be selected and a plurality of differences in positions for image data projections may be included in the sub-process 450. A single threshold is merely an example.

[0092] As illustrated in Fig. 5, the distance 314d may be greater than the threshold. Therefore, for any projections that include the distance 314d an adjacent projection may be acquired at a selected projections distance that may be smaller than other imaging module distance differences. For example, a 0.5° may be a selected distance difference for the ray length 314d. For the ray length 314c, as illustrated in Fig. 4, however, the position difference to an adjacent or next image projection may be 1 °, 1.5°, or the like. Therefore, a varying ray length may be used to determine or select a differing space to a next projection.

[0093] In various embodiments, the trajectory or difference in image projections may be based upon a total x-ray dosage to the subject 30. Thus, if a trajectory is selected to have a selected maximum dosage to the subject 30, distances or differences between each of the projections may be altered to achieve the selected radiation dosage.Therefore, the trajectory may be used to achieve an optimum dosage to the subject while achieving an optimum or best possible image data acquisition for an image reconstruction. It is understood, however, various inputs may be used to alter the dosage and / or selected image reconstruction of a selected region or volume of the subject 30 based upon various inputs, service inputs of this user 72.

[0094] The process 400 may output the imaging module trajectory including the projection spacing or differential in block 470. As discussed above, the output trajectory may be based upon the selected trajectory to acquire the image data that is retrieved or recalled in block 430 and a selected spatial difference from block 440 including the subprocess 450. The output imaging module trajectory may be reviewed by the user 72 and various augmentations and / more inputs may be provided by the user 72. For example, the user 72 may select to increase projection distances in various regions and decrease them and others to achieve a selected image reconstruction based upon the acquired image data.

[0095] The output imaging module and trajectory may be optionally used to operate an imaging system to achieve the selected trajectory and selected projection spacing in block 474. It is understood that operating the imaging system of block 474 is optional and that outputting the imaging module trajectory in block 470 may be used for various purposes, such as planning a procedure, planning image data acquisition at an appropriate time, or other purposes. Therefore, operating the imaging system block 470 is not required but the imaging system may be operated to acquire the image data according to the output imaging module trajectory from block 470. If image data is acquired it may be saved in block 478, such as in the appropriate memory module for various purposes, such as later retrieve, recall and / or reconstruction.

[0096] An image, such as the image 108, may be reconstructed in block 482. The reconstructed image may be based upon the image data acquired with the imaging system at the trajectory as discussed above. The reconstruction image may then be output in block 486. Outputting the image reconstruction in block 486 may be any appropriate output such as displaying the image, saving the image, further processing the image according to various non-processes, or the like. The process 400 may then end in block 500.

[0097] Thus, the process 400 may be used to select the trajectory of the imaging module 198 to achieve a selected image data acquisition of the subject 30. The distorting objects, such as one or more of the screws 310, 314 or any appropriate distorting member may be evaluated and analyzed in the subject 30 to acquire image data to achieve an optimal image reconstruction even with the distorting objects present in the trajectory of using module 198. In other words, the process 400 may be used to image the subject 30 even when the distorting member is present to achieve a selected image reconstruction that may be understood to be a best or optimal image reconstruction based upon the acquired image data. The process 400 may be understood to determine an optimal trajectory of the imaging system based on the known pose of the distorting members.

[0098] The following Examples disclose various embodiments of the invention.

[0099] Example 1 - A system for generating an image of a subject in a volume having a distorting member in the volume, comprising: operating a processor module to execute instructions to: retrieve or recall a pose of a distorting member; evaluate the retrieved or recalled pose of the distorting member; retrieve or recall a selected trajectory for acquiring image data of the subject to generate a selected image, wherein the trajectory includes at least a first imaging assembly position of an imaging assembly foracquiring a first projection; evaluate a value related to the amount of the distorting member is in the first projection based on the evaluated pose of the distorting member and the first imaging assembly position; determine a second imaging assembly position as a differential from the first imaging assembly position based on the evaluated value, wherein the differential is based on the evaluated value relative to a threshold; output at least one of the second imaging assembly position or the differential from the first imaging assembly position to operate an imaging system.

[0100] Example 2 - The system of Example 1 , further comprising: a tracking system configured to track a position of the distorting member during a positioning of the distorting member in the subject; a memory system configured to store the tracked pose of the distorting member; wherein the retrieved or recalled pose of the distorting member is retrieved or recalled from the memory system.

[0101] Example 3 - The system of Example 1 , further comprising: a robotic system having an end effector; a memory system configured to store a pose of the end effector; wherein the distorting member is guided into the subject with the end effector.

[0102] Example 4 - The system of Example 1 , wherein the evaluation of the value related the amount of the distorting member is in the first projection based on the evaluated pose of the distorting member and the first imaging assembly position comprises: operating the processor module to execute further instructions to determine a first ray length of at least a first portion of a beam emitted at the first imaging assembly position.

[0103] Example s - The system of Example 1 , further comprising: an imaging system including the imaging assembly; wherein the selected trajectory for acquiring image data of the subject to generate the selected image includes a plurality of positionsof the imaging assembly relative to the subject to acquire the first projection and the second projection.

[0104] Example 6 - The system of Example 5, wherein the evaluated value related to the amount of the distorting member is in the first projection based on the evaluated pose of the distorting member and the first position comprises: the processor module executing instructions to determine a plurality of ray lengths including at least one ray length for at least a portion of a beam at each of the plurality of positions of the imaging assembly.

[0105] Example 7 - A method for generating an image of a subject in a volume having a distorting member in the volume, comprising: evaluating a pose of a distorting member; retrieving or recalling a selected trajectory for acquiring image data of the subject to generate a selected image, wherein the trajectory includes at least a first position for acquiring a first projection and a second position for acquiring a second projection; and evaluating a value related to the amount of the distorting member is in each of the first projection and the second projection based on the evaluated pose of the distorting member and the first position and the second position.

[0106] Example 8 - The method of Example 7, further comprising retrieving or recalling the pose of the distorting member.

[0107] Example 9 - The method of Example 8, further comprising tracking a position of the distorting member during implantation of the distorting member; wherein the retrieving or recalling of the pose of the distorting member includes retrieving or recalling the tracked position of the distorting member during implantation of the distorting member.

[0108] Example 10 - The method of Example 9, wherein tracking the position of the distorting member during implantation of the distorting member comprises tracking a tracking device pose associated with the distorting member.

[0109] Example 11 - The method of Example 9, wherein tracking the position of the distorting member during implantation of the distorting member comprises determining a pose of at least an end effector of a robotic system.

[0110] Example 12 - The method of Example 7, wherein the first position includes a first detector pose of an imaging system relative to the subject and the second position includes a second detector pose of the imaging system relative to the subject.

[0111] Example 13 - The method of Example 12, further comprising determining a first source position relative to the first detector pose; and determining a second source position relative to the second detector pose.

[0112] Example 14 - The method of Example 13, wherein evaluating the value related to the amount of the distorting member in each of the first projection and the second projection based on the evaluated pose of the distorting member and the first position and the second position comprises: determining a first ray length of at least a first portion of a beam from the first source position to the first detector pose; determining a second ray length of at least a second portion of the beam from the second source position to the second detector pose.

[0113] Example 15 - The method of Example 14, wherein the first portion and the second portion are the same portion of the beam at the first source position and the second source position.

[0114] Example 16 - The method of Example 15, wherein the portion includes a central axis of the beam.

[0115] Example 17 - The method of Example 7, wherein retrieving or recalling the selected trajectory for acquiring image data of the subject to generate the selected image includes a plurality of positions including at least the first position for acquiring the first projection and the second position for acquiring the second projection.

[0116] Example 18 - The method of Example 17, wherein evaluating the value related to the amount of the distorting member in each of the first projection and the second projection based on the evaluated pose of the distorting member and the first position and the second position comprises determining a plurality of ray lengths including at least one ray length for at least a portion of a beam from each source position of the plurality of source positions to each detector position of the plurality of detector poses.

[0117] Example 19 - The method of Example 17, further comprising determining a third position differential from either of the first position or the second position based on the evaluated value; wherein the evaluated value above a threshold will result in a larger third position differential than the evaluated value below the threshold.

[0118] Example 20 - A method for generating an image of a subject in a volume having a distorting member in the volume, comprising: evaluating a pose of the distorting member; retrieving or recalling a selected trajectory for acquiring image data of the subject to generate a selected image, wherein the trajectory includes at least a first imaging assembly position of an imaging assembly for acquiring a first projection; evaluating a value related to the amount of the distorting member is in the first projection based on the evaluated pose of the distorting member and the first imaging assembly position; determining a second imaging assembly position as a differential from the first imaging assembly position based on the evaluated value, wherein the differential is based on the evaluated value relative to a threshold; and outputting at least one of the second imagingassembly position or the differential from the first imaging assembly position to operate an imaging system.

[0119] Example 21 -The method of Example 20, wherein retrieving or recalling the selected trajectory for acquiring image data of the subject to generate a selected image further includes a second imaging assembly position for acquiring a second projection; and evaluating the value related to the amount of the distorting member for each of the first projection and the second projection based on the evaluated pose of the distorting member and the first imaging assembly position and the second imaging assembly position.

[0120] Example 22 - The method of Example 21 , further comprising tracking a position of the distorting member during implantation of the distorting member; wherein the retrieving or recalling the pose of the distorting member includes at least one of (1) retrieving or recalling the tracked position of the distorting member during implantation of the distorting member or (2) determining a pose of at least an end effector of a robotic system.

[0121] Example 23 - The method of Example 21 , wherein the first position includes a first detector pose of an imaging system relative to the subject and the second position includes a second detector pose of the imaging system relative to the subject.

[0122] Example 24 - The method of Example 23, further comprising determining a first source position relative to the first detector pose; and determining a second source position relative to the second detector pose.

[0123] Example 25 - The method of Example 24, wherein evaluating the value related to the amount of the distorting member in each of the first projection and the second projection based on the evaluated pose of the distorting member and the firstposition and the second position comprises determining a first ray length of at least a first portion of a beam from the first source position to the first detector pose; and determining a second ray length of at least a second portion of the beam from the second source position to the second detector pose.

[0124] Example 26 - The method of Example 21 , wherein retrieving or recalling the selected trajectory for acquiring image data of the subject to generate the selected image includes a plurality of positions including at least the first position for acquiring the first projection and the second position for acquiring the second projection.

[0125] Example 27 - The method of Example 26, wherein evaluating the value related to the amount of the distorting member in each of the first projection and the second projection based on the evaluated pose of the distorting member and the first position and the second position comprises determining a plurality of ray lengths including at least one ray length for at least a portion of a beam from each source position of the plurality of source positions to each detector position of the plurality of detector poses.

[0126] Example 28 - The method of Example 26, further comprising determining a third position differential from either of the first position or the second position based on the evaluated value; wherein the evaluated value above a threshold will result in a larger third position differential than the evaluated value below the threshold.

[0127] Example embodiments are provided so that this disclosure will be thorough and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should beconstrued to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0128] Instructions may be executed by a processor and may include software, firmware, and / or microcode, and may refer to programs, routines, functions, classes, data structures, and / or objects. The term shared processor circuit encompasses a single processor circuit that executes some or all code from multiple modules. The term group processor circuit encompasses a processor circuit that, in combination with additional processor circuits, executes some or all code from one or more modules. References to multiple processor circuits encompass multiple processor circuits on discrete dies, multiple processor circuits on a single die, multiple cores of a single processor circuit, multiple threads of a single processor circuit, or a combination of the above. The term shared memory circuit encompasses a single memory circuit that stores some or all code from multiple modules. The term group memory circuit encompasses a memory circuit that, in combination with additional memories, stores some or all code from one or more modules.

[0129] The apparatuses and methods described in this application may be partially or fully implemented by a processor (also referred to as a processor module) that may include a special purpose computer (i.e., created by configuring a processor) and / or a general purpose computer to execute one or more particular functions embodied in computer programs. The computer programs include processor-executable instructions that are stored on at least one non-transitory, tangible computer-readable medium. The computer programs may also include or rely on stored data. The computer programs may include a basic input / output system (BIOS) that interacts with hardware of the specialpurpose computer, device drivers that interact with particular devices of the special purpose computer, one or more operating systems, user applications, background services and applications, etc.

[0130] The computer programs may include: (i) assembly code; (ii) object code generated from source code by a compiler; (iii) source code for execution by an interpreter; (iv) source code for compilation and execution by a just-in-time compiler, (v) descriptive text for parsing, such as HTML (hypertext markup language) or XML (extensible markup language), etc. As examples only, source code may be written in C, C++, C#, Objective-C, Haskell, Go, SQL, Lisp, Java®, ASP, Perl, Javascript®, HTML5, Ada, ASP (active server pages), Perl, Scala, Erlang, Ruby, Flash®, Visual Basic®, Lua, or Python®.

[0131] Communications may include wireless communications described in the present disclosure can be conducted in full or partial compliance with IEEE standard 802.11-2012, IEEE standard 802.16-2009, and / or IEEE standard 802.20-2008. In various implementations, IEEE 802.11-2012 may be supplemented by draft IEEE standard 802.11ac, draft IEEE standard 802.11ad, and / or draft IEEE standard 802.11ah.

[0132] A processor, processor module, module or ‘controller’ may be used interchangeably herein (unless specifically noted otherwise) and each may be replaced with the term ‘circuit.’ Any of these terms may refer to, be part of, or include: an Application Specific Integrated Circuit (ASIC); a digital, analog, or mixed analog / digital discrete circuit; a digital, analog, or mixed analog / digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor circuit (shared, dedicated, or group) that executes code; a memory circuit (shared, dedicated, or group) that stores code executed by the processor circuit; other suitable hardware components that provide thedescribed functionality; or a combination of some or all of the above, such as in a system- on-chip.

[0133] Instructions may be executed by one or more processors or processor modules, such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Accordingly, the term “processor” or “processor module” as used herein may refer to any of the foregoing structure or any other physical structure suitable for implementation of the described techniques. Also, the techniques could be fully implemented in one or more circuits or logic elements.

[0134] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

CLAIMSWhat is claimed is:1 . A system for generating an image of a subject in a volume having a distorting member in the volume, comprising: operating a processor module to execute instructions to: recall a pose of a distorting member; evaluate the recalled pose of the distorting member; recall a selected trajectory for acquiring image data of the subject to generate a selected image, wherein the trajectory includes at least a first imaging assembly position of an imaging assembly for acquiring a first projection; evaluate a value related to the amount of the distorting member is in the first projection based on the evaluated pose of the distorting member and the first imaging assembly position; determine a second imaging assembly position as a differential from the first imaging assembly position based on the evaluated value, wherein the differential is based on the evaluated value relative to a threshold; output at least one of the second imaging assembly position or the differential from the first imaging assembly position to operate an imaging system.

2. The system of Claim 1 , further comprising: a tracking system configured to track a position of the distorting member during a positioning of the distorting member in the subject; a memory system configured to store the tracked pose of the distorting member;wherein the recalled the pose of the distorting member is recalled from the memory system.

3. The system of Claim 1 , further comprising: a robotic system having an end effector; a memory system configured to store a pose of the end effector; wherein the distorting member is guided into the subject with the end effector.

4. The system of Claim 1 , wherein the evaluation of the value related the amount of the distorting member is in the first projection based on the evaluated pose of the distorting member and the first imaging assembly position comprises: operating the processor module to execute further instructions to determine a first ray length of at least a first portion of a beam emitted at the first imaging assembly position.

5. The system of Claim 1 , further comprising: an imaging system including the imaging assembly; wherein the selected trajectory for acquiring image data of the subject to generate the selected image includes a plurality of positions of the imaging assembly relative to the subject to acquire the first projection and the second projection.

6. The system of Claim 5, wherein the evaluated value related to the amount of the distorting member is in the first projection based on the evaluated pose of the distorting member and the first position comprises: the processor module executing instructions to determine a plurality of ray lengths including at least one ray length for at least a portion of a beam at each of the plurality of positions of the imaging assembly.

7. A method for generating an image of a subject in a volume having a distorting member in the volume, comprising: evaluating a pose of the distorting member; recalling a selected trajectory for acquiring image data of the subject to generate a selected image, wherein the trajectory includes at least a first imaging assembly position of an imaging assembly for acquiring a first projection; evaluating a value related to the amount of the distorting member is in each of the first projection based on the evaluated pose of the distorting member and the first imaging assembly position; determining a second imaging assembly position as a differential from the first imaging assembly position based on the evaluated value, wherein the differential is based on the evaluated value relative to a threshold; and outputting at least one of the second imaging assembly position or the differential from the first imaging assembly position to operate an imaging system.

8. The method of Claim 7, wherein recalling the selected trajectory for acquiring image data of the subject to generate a selected image further includes a second imaging assembly position for acquiring a second projection; and evaluating the value related to the amount of the distorting member for each of the first projection and the second projection based on the evaluated pose of the distorting member and the first imaging assembly position and the second imaging assembly position.

9. The method of Claim 8, further comprising: tracking a position of the distorting member during implantation of the distorting member;wherein the recalling the pose of the distorting member includes at least one of (1) recalling the tracked position of the distorting member during implantation of the distorting member or (2) determining a pose of at least an end effector of a robotic system.

10. The method of Claim 8, wherein the first position includes a first detector pose of an imaging system relative to the subject and the second position includes a second detector pose of the imaging system relative to the subject.11 . The method of Claim 10, further comprising, determining a first source position relative to the first detector pose; and determining a second source position relative to the second detector pose.

12. The method of Claim 11 , wherein evaluating the value related to the amount of the distorting member in each of the first projection and the second projection based on the evaluated pose of the distorting member and the first position and the second position comprises: determining a first ray length of at least a first portion of a beam from the first source position to the first detector pose; determining a second ray length of at least a second portion of the beam from the second source position to the second detector pose.

13. The method of Claim 8, wherein recalling the selected trajectory for acquiring image data of the subject to generate the selected image includes a plurality of positions including at least the first position for acquiring the first projection and the second position for acquiring the second projection.

14. The method of Claim 13, wherein evaluating the value related to the amount of the distorting member in each of the first projection and the second projection basedon the evaluated pose of the distorting member and the first position and the second position comprises: determining a plurality of ray lengths including at least one ray length for at least a portion of a beam from each source position of the plurality of source positions to each detector position of the plurality of detector poses.

15. The method of Claim 13, further comprising: determining a third position differential from either of the first position or the second position based on the evaluated value; wherein the evaluated value above a threshold will result in a larger third position differential than the evaluated value below the threshold.

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