Dynamic calibration of x-ray source and detector using retrieved images

Abstract

Disclosed systems include a source configured to emit a beam, a detector configured to detect the beam, and an electronic processor coupled to the source and the detector. The electronic processor is configured to control the source to emit the beam and to receive an image from the detector, the image including a shape formed by the beam, and analyze the shape to determine a geometric center for the beam. The electronic processor is configured to generate a calibration value based on the geometric center for the beam and a center point for an imaging plane of the detector. The electronic processor is configured to control the source to emit a second beam, receive a second image from the detector, the second image produced by the detector detecting the second beam, and process the second image based on the calibration value to generate a compensated image.

Description

DYNAMIC CALIBRATION OF X-RAY SOURCE AND DETECTOR USING RETRIEVED IMAGESFIELD

[0001] This application relates generally to X-ray imaging systems, and more particularly to medical X-ray imaging systems.BACKGROUND

[0002] Imaging devices utilizing X-ray-based imaging (e.g., a fluoroscope, a CT scanner, or other X-ray machine) may be used by a medical provider for diagnostic and / or therapeutic purposes. Images obtained from such imaging devices may include defects such as noise, oversaturation, and / or distortions. As such, hardware or software may be used to reduce such defects.SUMMARY

[0003] In medical imaging systems, it is important to position the beam source in front of the detector, such that they are aligned and centered with respect to each other to produce accurate images. In static imaging systems, where the source and detector do not move during a scan, inaccuracies are reduced using a preset gain calibration to correct for errors in alignment and / or centering. However, in dynamic systems, the source and detector are movable. The distance and orientation of the source and detector may change during the scan. Consequently, the source and detector may not keep their relative positions during a scan. Preset calibrations, such as those used with static imaging systems, are therefore not effective in dynamic imaging systems.

[0004] To address these problems, examples and aspects presented herein provide for the calibration of dynamic imaging systems. Using the examples presented herein, dynamic calibration values are determined and applied during operation of the dynamic imaging system to compensate for the motion of the source and detector. Using such examples, dynamic imaging systems are able to compensate for both the distance between the source and detector and the orientation of the source and detector relative to one another as those factors change during the operation of the dynamic imaging system.

[0005] In some aspects, the techniques described herein relate to a medical imaging system, the system including: a source configured to emit a beam; a detector configured to detect the beam; and an electronic processor coupled to the source and the detector, and configured to: control the source to emit the beam; receive an image from the detector, the image including ashape formed by the beam; analyze the shape to determine a geometric center for the beam; generate a calibration value based on the geometric center for the beam and a center point for an imaging plane of the detector; control the source to emit a second beam; receive a second image from the detector, the second image produced by the detector detecting the second beam; and process the second image based on the calibration value to generate a compensated image.

[0006] In some aspects, the techniques described herein relate to a method for operating a medical imaging system including a source configured to emit a beam and a detector configured to detect the beam , the method including: controlling the source to emit the beam; receiving an image from the detector, the image including a shape formed by the beam; analyzing the shape to determine a geometric center for the beam; generating a calibration value based on the geometric center for the beam and a center point for an imaging plane of the detector; controlling the source to emit a second beam; receiving a second image from the detector, the second image produced by the detector detecting the second beam; and processing the second image based on the calibration value to generate a compensated image.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views, together with the detailed description below, are incorporated in and form part of the specification, and serve to further illustrate embodiments, examples, aspects, and features of concepts that include the claimed subject matter and explain various principles and advantages of those embodiments, examples, aspects, and features.

[0008] FIG. 1 is a block diagram illustrating a medical imaging system according to various examples.

[0009] FIG. 2 illustrates a flowchart of a method performed by the medical imaging system of FIG. 1 according to various examples.

[0010] FIG. 3 schematically illustrates aspects of the operation of the medical imaging system of FIG. 1 according to various examples.

[0011] Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensionsof some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of examples, aspects, and features illustrated.

[0012] In some instances, the apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the of various embodiments, examples, aspects, and features so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.DETAILED DESCRIPTION

[0013] Before any examples are explained in detail, it is to be understood that the examples presented herein are not limited in their application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The examples are capable of other embodiments and of being practiced or of being carried out in various ways. For ease of description, the example systems presented herein may be illustrated with a single exemplar of each of its component parts. Some examples may not describe or illustrate all components of the systems. Other example embodiments may include more or fewer of each of the illustrated components, may combine some components, or may include additional or alternative components.

[0014] It should be understood that although certain figures presented herein illustrate hardware and software located within particular devices, these depictions are for illustrative purposes only. In some embodiments, the illustrated components may be combined or divided into separate software, firmware, and / or hardware. For example, instead of being located within and performed by a single electronic processor, logic and processing may be distributed among multiple electronic processors. Regardless of how they are combined or divided, hardware and software components may be located on the same computing device or may be distributed among different computing devices connected by one or more networks or other suitable communication links.

[0015] FIG. 1 illustrates an example medical imaging system 100. Such medical imaging systems are used by clinicians to acquire image data of a subject, such as a patient, for diagnostic or therapeutic purposes. Variations of the medical imaging system 100, including the illustrated example, may be used to carry out one or more aspects of one or more of the methods disclosedherein. In some embodiments, the medical imaging system 100 may be an X-ray-based imaging system (e.g., a fluoroscope, a CT scanner, or other X-ray machine).

[0016] The medical imaging system 100 includes a computing device 102, and an imaging device 112, a database 130, and / or a cloud 134. Systems according to other embodiments of the present disclosure may comprise more or fewer components than the medical imaging system 100. The computing device 102 includes an electronic processor 104, a memory 106, a communication interface 108, and a user interface 110. In some aspects, the computing device 102 may include more or fewer components than illustrated in the example.

[0017] The computing device 102 includes an electronic processor 104 (for example, a microprocessor, application specific integrated circuit, etc.), a memory 106, a communication interface 108, and a user interface 110. The electronic processor 104, the memory 106, the communication interface 108, and the user interface 110, as well as the other various modules (not illustrated) are coupled directly, by one or more control or data buses (e.g., the bus 140), or a combination thereof.

[0018] The memory 106 may be made up of one or more non-transitory computer-readable media and includes at least a program storage area and a data storage area. The program storage area and the data storage area can include combinations of several types of memory, such as readonly memory (“ROM”), random access memory (“RAM”) (for example, dynamic RAM (“DRAM”), synchronous DRAM (“SDRAM”), etc.), electrically erasable programmable readonly memory (“EEPROM”), flash memory, or any other suitable tangible, non-transitory memory for storing computer- readable data and / or instructions. The memory 106 may store information or data useful for completing, for example, any aspect of the method 200 described herein, or of any other methods. The memory 106 may store, for example, instructions and / or machine learning models that support one or more functions of the imaging device 112. For instance, the memory 106 may store content (e.g., instructions and / or machine learning models) that, when executed by the electronic processor 104, enable image processing 122, and / or imaging calibration 124. Such content may, in some embodiments, be organized into one or more applications, modules, packages, layers, or engines.

[0019] The image processing 122 enables the electronic processor 104 to process image data of an image (received from, for example, the imaging device 112, (e.g., from the detector 116), orany imaging device) for the purpose of, for example, identifying information about a subject 120 or performing techniques described herein.

[0020] The imaging calibration 124 enables the processor 104 to, among other things, analyze images received from the imaging device 112 to dynamically calibrate the operation of the imaging device 112, as described herein.

[0021] Alternatively, or additionally, the memory 106 may store other types of content or data (e.g., machine learning models, artificial neural networks, deep neural networks, etc.) that can be processed by the electronic processor 104 to carry out the various method and features described herein. Thus, although various contents of memory 106 may be described as instructions, it should be appreciated that functionality described herein can be achieved through use of instructions, algorithms, and / or machine learning models. The data, algorithms, and / or instructions may cause the electronic processor 104 to manipulate data stored in the memory 106 and / or received from or via the imaging device 112, the database 130, and / or the cloud 134.

[0022] The electronic processor 104 sends and receives information (for example, from the memory 106, the communication interface 108, and / or the user interface 110) and processes the information by executing one or more software instructions or modules, capable of being stored in the memory 106, or another non-transitory computer readable medium. The software can include firmware, one or more applications, program data, filters, rules, one or more program modules, and other executable instructions. The electronic processor 104 is configured to retrieve from the memory 106 and execute, among other things, software for performing methods as described herein.

[0023] The communication interface 108 transmits and receives information from devices external to the computing device 102, for example, components of the medical imaging system 100. The communication interface 108 receives input (for example, from the user interface 110), provides system output or a combination of both. The communication interface 108 may be used for receiving image data or other information from an external source (such as the imaging device 112, the database 130, the cloud 134, and / or any other system or component not part of the medical imaging system 100), and / or for transmitting instructions, images, or other information to an external system or device (e.g., another computing device, the imaging device 112, the database 130, the cloud 134, and / or any other system or component not part of the medical imaging system 100).

[0024] The communication interface 108 may include one or more wired interfaces (e.g., a USB port, an Ethernet port, etc.) and / or one or more wireless transceivers or interfaces (configured, for example, to transmit and / or receive information via one or more wireless communication protocols such as 802.11a / b / g / n, Bluetooth, NFC, ZigBee, and so forth). In some embodiments, the communication interface 108 may be useful for enabling the computing device 102 to communicate with one or more other electronic processors or computing devices, whether to reduce the time needed to accomplish a computing-intensive task or for any other reason.

[0025] The computing device 102 may also include one or more user interfaces 110. The user interface 110 may be or include a keyboard, mouse, trackball, monitor, television, screen, touchscreen, and / or any other device for receiving information from a user and / or for providing information to a user. The user interface 110 may be used, for example, to receive a user selection or other user input regarding any step of any method described herein. Notwithstanding the foregoing, any required input for any step of any method described herein may be generated automatically by the medical imaging system 100 (e.g., by the electronic processor 104 or another component of the medical imaging system 100) or received by the medical imaging system 100 from a source external to the medical imaging system 100. In some embodiments, the user interface 110 may be useful to allow an operator to control the imaging device 112 and / or to modify or adjust a setting of other information displayed on the user interface 110 or corresponding thereto.

[0026] Although the user interface 110 is shown as part of the computing device 102, in some embodiments, the computing device 102 may utilize a user interface 110 that is housed separately from one or more remaining components of the computing device 102. In some embodiments, the user interface 110 may be located proximate one or more other components of the computing device 102, while in other embodiments, the user interface 110 may be located remotely from one or more other components of the computing device 102.

[0027] It should be understood that although FIG. 1 illustrates only a single electronic processor 104, memory 106, communication interface 108, and user interface 110, alternative embodiments of the computing device 102 may include multiple electronic processors, memory modules, communication interfaces, and / or user interfaces. It should also be noted that the medical imaging system 100 may include other computing devices, each including similar components as, and configured similarly to, the computing device 102. In some embodiments,portions of the computing device 102 are implemented partially or entirely on a semiconductor chip (e.g., an application specific integrated circuit (ASIC), a field-programmable gate array (“FPGA”), and the like). Similarly, the various modules and controllers described herein may be implemented as individual controllers, as illustrated, or as components of a single controller. In some aspects, a combination of approaches may be used.

[0028] Continuing with other aspects of the medical imaging system 100, the imaging device 112 may be operable to image anatomical feature(s) (e.g., bones, veins, tissue, and / or other aspects of patient anatomy), for example, of the subject 120 to yield image data (e.g., image data depicting or corresponding to the anatomical feature(s)). “Image data” as used herein refers to the data generated or captured by the imaging device 112, including in a machine-readable form, a graphical / visual form, and in any other form. In various examples, the image data may comprise data corresponding to an anatomical feature of a patient, or to a portion thereof, and / or objects such as markers, medical devices, surgical tools, and the like. The image data may be or comprise a preoperative image, an intraoperative image, a postoperative image, or an image taken independently of any surgical procedure. The imaging device 112 may be capable of taking a 2D image or a 3D image to yield the image data. The imaging device 112 may be or comprise, for example, a device utilizing X-ray-based imaging (e.g., a fluoroscope, a CT scanner, or other X- ray machine).

[0029] The imaging device 112 includes a source 114, a detector 116, a positioning system 118, and sensors 126. The imaging device 112 may also include electronic controllers (e.g., including electronic processors, memory, and input / output devices) for controlling components of the imaging device 112 as described herein. In some examples, the computing device 102 may be integrated into the imaging device 112.

[0030] The source 114 generates a beam 150 (e.g., a wave). As used herein, the term “beam” refers to a beam having a known predetermined shape, including (but not limited to) a cone. The detector 116 is configured to detect the beam 150. In some examples, the imaging device 112 is an X-ray imaging device. In such examples, the source 114 may be an X-ray source, also referred to as an emitter, that can emit X-rays toward and / or through the subject 120 to be detected by the detector 116. As is understood by one skilled in the art, the X-rays emitted by the source 114 can be emitted in a cone (e.g., the beam 150) and detected by the detector 116. The source 114 and detector 116 are generally diametrically opposed (e.g., within a gantry). In the illustratedexample, the imaging device 112 is a dynamic imaging device. The source 114 and / or the detector 116 are movable. For example, a positioning system 118 is coupled to the source 114 and the detector 116. The positioning system 118 includes controllers, motors, gears, linkages, and the like configured to (e.g., as controlled by the computing device 102) position the source 114 and the detector 116. For example, in some examples, the positioning system 118 is configured move the detector 116 in a 360° motion around the subject 120 within a gantry, with the source 114 remaining generally 180° opposed to the detector 116. In some examples, the positioning system 118 is configured to move the source 114 and the detector 116 isometrically relative to the subject 120; to tilt the source 114 and the detector 116 relative to the subject 120; to move the source 114 and the detector 116 longitudinally relative to a longitudinal axis of the subject 120; and / or to move the source 114 and the detector 116 back and forth transversely to the subject 120. In some examples, the source 114 and the detector 116 may be positionable independently of each other. The source 114 and the detector 116 may be controlled in a single, shared coordinate space, or in separate coordinate spaces. As a result, the source 114 and the detector 116 may be precisely positionable in one or more needed and specific positions and orientations.

[0031] The source 114 may include one or more sources of X-rays for imaging the subject 120. In various examples, the source 114 may include a single source (e.g., an X-ray tube) that may be powered by more than one power source to generate and / or emit X-rays at different energy characteristics. Further, more than one X-ray source may be the source 114 that may be powered to emit X-rays with differing energy characteristics at selected times. X-rays can be emitted from the X-ray tube of the source 114 generally in a cone shape (e.g., the beam 150) towards the detector 116 and generally in a direction substantially perpendicular from the source 114.

[0032] The detector 116 is configured to detect the beam 150. In one example, the detector 116 senses the X-rays of the beam 150 and converts the X-rays into electrical charges, which are processed to produce an image. The detector 116 may be configured for either direct or indirect conversion. In some examples, the detector 116 includes software and / or hardware for processing the electrical charges. In other examples, the software and / or hardware for processing the electrical charges is separate from and coupled to the detector 116. The electrical charges are processed to produce image data, which includes a plurality of pixels making up the image. Insome examples, each of the pixels includes values describing the pixel (e.g., coordinates, intensity values, etc.). Image data collected by the imaging device 112 can be transferred to the computing device 102 for navigation, display, reconstruction, and the like.

[0033] In the illustrated example, the imaging device 112 includes one or more sensors 126, which are configured to provide sensor output. The sensors 126 may include a position sensor, a proximity sensor, a magnetometer, or an accelerometer. In some examples, the sensors 126 may include a linear encoder, a rotary encoder, or an incremental encoder. The sensors 126 are positioned to sense movement and / or positions of the source 114, the detector 116, and / or components of the positioning system 118. Sensor output or output data from the sensors 126 may be provided to the electronic processor 104 of the computing device 102. Output data from the sensor(s) 126 may also be used to determine position information for the source 114 and the detector 116. For example, sensor output or output data from the sensors 126 may be used to calculate positions in space of the source 114 and the detector 116 relative to one or more coordinate systems.

[0034] The database 130 may store information relating to a coordinate system for the imaging device 112. The database 130 may additionally or alternatively store, for example, one or more imaging plans (including, for example, pose information about a subject 120 and / or image information about the subject’s anatomy; one or more images created by the imaging device 112; calibration information for the imaging device 112; and / or any other useful information. The database 130 may be configured to provide any such information to the computing device 102 or to any other device of the medical imaging system 100 or external to the medical imaging system 100, whether directly or via the cloud 134. In some embodiments, the database 130 may be or comprise part of a hospital image storage system, such as a picture archiving and communication system (PACS), a health information system (HIS), and / or another system for collecting, storing, managing, and / or transmitting electronic medical records including image data.

[0035] The cloud 134 may be or represent the Internet or any other wide area network. The computing device 102 may be connected to the cloud 134 via the communication interface 108, using a wired connection, a wireless connection, or both. In some embodiments, the computing device 102 may communicate with the database 130 and / or an external device (e.g., a computing device) via the cloud 134.

[0036] The medical imaging system 100 or similar systems may be used, for example, to carry out one or more aspects of the method 200 described herein. The medical imaging system 100 or similar systems may also be used for other purposes.

[0037] FIG. 2 is a flowchart of an example method for operating a medical imaging including a source configured to emit a beam and a detector configured to detect the beam (e.g., the medical imaging system 100). Although the method 200 is described in conjunction with the medical imaging system 100 as described herein, the method 200 could be used with other systems and devices. In addition, the method 200 may be modified or performed differently than the example provided. In particular, the method 200 is applicable to imaging systems, which are not used for medical scanning.

[0038] As an example, the method 200 is described as being performed by the computing device 102, and, in particular, the electronic processor 104. However, it should be understood that, in some examples, portions of the method 200 may be performed by other components of the medical imaging system 100, such as, for example, one or more components of the imaging device 112.

[0039] At block 210, the electronic processor 104 controls the source 114 to emit a beam 150 (e.g., an X-ray beam). In some aspects, prior to controlling the source 114 to emit the beam 150, the electronic processor 104 controls the positioning system 118 to position the detector 116 within a threshold distance of the source 114. As noted, the beam 150 is generally cone-shaped. As illustrated in FIG. 3, the plane of the cone (defined by the intersection of the imaging plane of the detector 116 and the beam 150) forms a shape 152 at the detector 116. The X-rays of the beam 150, as detected by the detector 116, produce an image including the shape 152 (sometimes referred to as a “blob”). As the distance between the source 114 and the detector 116 changes, the plane of the cone varies in size. In some aspects, the threshold distance between the source 114 and the detector 116 is the distance, beyond which the entire shape 152 formed by the plane of the cone would not fit within the sensing area of the detector 116. The threshold distance is set such that the entire shape 152 is visible in an image produced by the detector 116.

[0040] At block 220, the electronic processor 104 receives an image from the detector 116. The image includes the shape 152, formed by the beam 150. In some instances, the electronic processor 104 receives the image. In other instances, the electronic processor receives image data, which it converts to an image. In some aspects, the image data (or the image) includes aplurality of pixels making up the image. Each pixel is defined by data (for example, position data and an intensity value). In some instances, the electronic processor 104 analyzes the image to extract the shape 152 based on the plurality of pixels and a threshold intensity value. For example, the shape 152 may be extracted by selecting only those pixels exceeding a predetermined intensity value. For example, the pre-determined intensity value may be selected to produce a shape 152 with more defined edges.

[0041] In some instances, the shape 152 is a two-dimensional shape. In some instances, the electronic processor 104 is configured to extract a three-dimensional shape from the image.

[0042] At block 230, the electronic processor 104 analyzes the shape 152 to determine a geometric center for the beam 150. For example, the electronic processor 104 may analyze the dimensions of the shape to determine a center point for the shape and combine this with a distance between the source 114 and the detector 116 to determine a center point for the beam 150. In another example, the electronic processor 104 may determine the geometric center for the beam by fitting the received image to a mathematical model of the beam 150 (e.g., using Gaussian curve fitting). As used herein, the term “mathematical model of the beam” means a mathematical model of the expected (intensity) image created by the beam 150 and received by the detector 116, given a specific positioning of the X-ray source 114 and detector 116.

[0043] At block 240, the electronic processor 104 generates a calibration value based on the geometric center for the beam 150 and a center point for an imaging plane of the detector 116. For example, the electronic processor 104 may determine a center point for the imaging plane of the detector 116 based on a priori knowledge of the imaging plane’s dimensions and the position of the detector 116 relative to the source 114 (e.g., as reported by the positioning system 118, determined from readings from the sensors 126, or combinations of both). By comparing the geometric center of the beam 150 to the center point for the imaging plane, the electronic processor 104 may determine a dimensional offset between the two and use that as the calibration value.

[0044] In some instances, the calibration value may be one or more values. For example, the electronic processor 104 may analyze the shape 152 to generate the calibration value or another aspect to the calibration value. In some instances, the electronic processor 104 may analyze the shape 152 to determine an eccentricity for the shape 152 and generate the calibration value based on the eccentricity for the shape 152. For example, the when the source 114 and the detector 116are not parallel, the shape 152 may vary from a circular form. The variance (eccentricity) may be used to determine the extent to which the source 114 and the detector 116 are not parallel. In some aspects, the electronic processor 104 analyze the shape 152 to determine a symmetricity for the shape 152 and generate the calibration value based further on the symmetricity for the shape. The extent to with the shape lacks symmetricity is another indicator of the extent to which the source 114 and the detector 116 are not parallel.

[0045] In some instances, the calibration value may include information relating to the variances from both center and parallel orientation.

[0046] When the electronic processor 104 has generated a calibration value, the calibration value can be used to operate the imaging device 112. For example, in some instances, the electronic processor 104 may operate the positioning system 118 to position the source 114 and the detector 116 during a scan based on an operator input and the calibration value. For example, the electronic processor 104 may receive instructions via the user interface 110 to position the source 114 and the detector 116 and may control the positioning system 118 to modify the positioning based on offsets in the calibration value to compensate for the source 114 and the detector 116 being off center or out of parallel.

[0047] Alternatively, or in addition, the electronic processor 104 may use the calibration value to process images produced by the imaging device 112. For example, at block 250, the electronic processor 104 controls the source 114 to emit a second beam (e.g., as part of a patient scan).

[0048] At block 260, the electronic processor 104 receives a second image from the detector 116, the second image having been produced by the detector 116 detecting the second beam. The second image may be, for example, a scan of a portion of a subject’s anatomy. However, the image may be affected by the source 114 and the detector 116 being off center, out or parallel, or both.

[0049] In such instances, at block 270, the electronic processor 104 processes the second image based on the calibration value to generate a compensated image. For example, the electronic processor 104 may generate a gain calibration value by applying the calibration value to a mathematical model for the beam(e.g., a Gaussian output model). The electronic processor 104 may then process the second image based on the gain calibration value and one or both of adistance between the source and the detector and an orientation of the detector relative to the source to produce the compensated image.

[0050] With regard to the processes, systems, methods, heuristics, etc. described herein, it should be understood that, although the steps of such processes, etc. have been described as occurring according to a certain ordered sequence, such processes could be practiced with the described steps performed in an order other than the order described herein. It further should be understood that certain steps could be performed simultaneously, that other steps could be added, or that certain steps described herein could be omitted. In other words, the descriptions of processes herein are provided for the purpose of illustrating certain implementations and should in no way be construed to limit the claims.

[0051] Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided would be apparent upon reading the above description. The scope should be determined, not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur in the technologies discussed herein, and that the disclosed systems and methods will be incorporated into such future embodiments. In sum, it should be understood that the application is capable of modification and variation.

[0052] All terms used in the claims are intended to be given their broadest reasonable constructions and their ordinary meanings as understood by those knowledgeable in the technologies described herein unless an explicit indication to the contrary in made herein. In particular, use of the singular articles such as “a,” “the,” “said,” et cetera, should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary.

[0053] Unless explicitly stated otherwise, each numerical value and range should be interpreted as being approximate as if the word “about” or “approximately” preceded the value or range.

[0054] Reference herein to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the disclosure. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment, norare separate or alternative embodiments necessarily mutually exclusive of other embodiments. The same applies to the term “implementation.”

[0055] Unless otherwise specified herein, the use of the ordinal adjectives “first,” “second,” “third,” etc., to refer to an object of a plurality of like objects merely indicates that different instances of such like objects are being referred to, and is not intended to imply that the like objects so referred-to have to be in a corresponding order or sequence, either temporally, spatially, in ranking, or in any other manner. Specific embodiments of the present disclosure are now described with reference to the figures, wherein like reference numbers indicate identical or functionally similar elements. The terms “distal” and “proximal” are used in the following description with respect to a position or direction relative to the treating clinician. “Distal” or “distally” are a position distant from or in a direction away from the clinician. “Proximal” and “proximally” are a position near or in a direction toward the clinician.

[0056] Unless otherwise specified herein, in addition to its plain meaning, the conjunction “if’ may also or alternatively be construed to mean “when” or “upon” or “in response to determining” or “in response to detecting,” which construal may depend on the corresponding specific context. For example, the phrase “if it is determined” or “if [a stated condition] is detected” may be construed to mean “upon determining” or “in response to determining” or “upon detecting [the stated condition or event]” or “in response to detecting [the stated condition or event].”

[0057] Also, for purposes of this description, the terms “couple,” “coupling,” “coupled,” “connect,” “connecting,” or “connected” refer to any manner known in the art or later developed in which energy is allowed to be transferred between two or more elements, and the interposition of one or more additional elements is contemplated, although not required. Conversely, the terms “directly coupled,” “directly connected,” et cetera, imply the absence of such additional elements. The same type of distinction applies to the use of terms “attached” and “directly attached,” as applied to a description of a physical structure. For example, a relatively thin layer of adhesive or other suitable binder can be used to implement such “direct attachment” of the two corresponding components in such physical structure.

[0058] The described embodiments are to be considered in all respects as only illustrative and not restrictive. In particular, the scope of the disclosure is indicated by the appended claims ratherthan by the description and figures herein. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

[0059] The functions of the various elements shown in the figures, including any functional blocks labeled as “processors” and / or “controllers,” may be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software. When provided by a processor, the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared. Moreover, explicit use of the term “processor” or “controller” should not be construed to refer exclusively to hardware capable of executing software, and may implicitly include, without limitation, digital signal processor (DSP) hardware, network processor, application specific integrated circuit (ASIC), field programmable gate array (FPGA), read only memory (ROM) for storing software, random access memory (RAM), and nonvolatile storage. Other hardware, conventional and / or custom, may also be included. Similarly, any switches shown in the figures are conceptual only. Their function may be carried out through the operation of program logic, through dedicated logic, through the interaction of program control and dedicated logic, or even manually, the particular technique being selectable by the implementer as more specifically understood from the context.

[0060] As used in this application, the term “circuitry” may refer to one or more or all of the following: (a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry); (b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions); and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.” This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claimelement, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0061] It should be appreciated by those of ordinary skill in the art that any block diagrams herein represent conceptual views of illustrative circuitry embodying the principles of the disclosure. Similarly, it will be appreciated that any flow charts, flow diagrams, state transition diagrams, pseudo code, and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.

[0062] The following paragraphs provide various examples and alternatives disclosed herein.

[0063] Example 1. A medical imaging system, the system comprising: a source configured to emit a beam; a detector configured to detect the beam; and an electronic processor coupled to the source and the detector, and configured to: control the source to emit the beam; receive an image from the detector, the image including a shape formed by the beam; analyze the shape to determine a geometric center for the beam; generate a calibration value based on the geometric center for the beam and a center point for an imaging plane of the detector; control the source to emit a second beam; receive a second image from the detector, the second image produced by the detector detecting the second beam; and process the second image based on the calibration value to generate a compensated image.

[0064] Example 2. The medical imaging system of example 1, further comprising: a positioning system for positioning the source and the detector relative to each other; wherein the electronic processor is coupled the positioning system and further configured to: operate the positioning system to position the source and the detector based on an operator input and the calibration value.

[0065] Example 3. The medical imaging system of any one of examples 1 and 2, wherein the electronic processor is further configured to: generate a gain calibration value by applying the calibration value to a mathematical model for the beam; and process the second image based on the gain calibration value and one or both of a distance between the source and the detector and an orientation of the detector relative to the source.

[0066] Example 4. The medical imaging system of any one of examples 1-3, further comprising: a positioning system for positioning the source and the detector relative to eachother; wherein the electronic processor is coupled the positioning system and further configured to: prior to controlling the source to emit the beam, control the positioning system to position the detector within a threshold distance of the source.

[0067] Example 5. The medical imaging system of any one of examples 1-4, wherein the electronic processor is further configured to: analyze the shape to determine an eccentricity for the shape; and generate the calibration value based further on the eccentricity for the shape.

[0068] Example 6. The medical imaging system of any one of examples 1-5, wherein the electronic processor is further configured to: analyze the shape to determine a symmetricity for the shape; and generate the calibration value based further on the symmetricity for the shape.

[0069] Example 7. The medical imaging system of any one of examples 1-6, wherein the electronic processor is further configured to: determine the geometric center for the beam by fitting the image to a mathematical model of the beam.

[0070] Example 8. The medical imaging system of any one of examples 1-7, wherein: the image includes a plurality of pixels, each having an intensity value; and the electronic processor is further configured to analyze the image to extract the shape based on the plurality of pixels and a threshold intensity value.

[0071] Example 9. The medical imaging system of any one of examples 1-8, wherein the beam and the second beam are X-ray beams.

[0072] Example 10. The medical imaging system of any one of examples 1-9, wherein the shape is a two-dimensional shape.

[0073] Example 11. A method for operating a medical imaging system including a source configured to emit a beam and a detector configured to detect the beam , the method comprising: controlling the source to emit the beam; receiving an image from the detector, the image including a shape formed by the beam; analyzing the shape to determine a geometric center for the beam; generating a calibration value based on the geometric center for the beam and a center point for an imaging plane of the detector; controlling the source to emit a second beam; receiving a second image from the detector, the second image produced by the detector detecting the second beam; and processing the second image based on the calibration value to generate a compensated image.

[0074] Example 12. The method of example 11, further comprising: operating a positioning system for positioning the source and the detector relative to each other to position the source and the detector based on an operator input and the calibration value.

[0075] Example 13. The method of any one of examples 11 and 12, further comprising: generating a gain calibration value by applying the calibration value to a mathematical model for the beam; and processing the second image based on the gain calibration value and one or both of a distance between the source and the detector and an orientation of the detector relative to the source.

[0076] Example 14. The method of any one of examples 11-13, further comprising: prior to controlling the source to emit the beam, positioning the detector within a threshold distance of the source.

[0077] Example 15. The method of any one of examples 11-14, further comprising: analyzing the shape to determine an eccentricity for the shape; and generating the calibration value based further on the eccentricity for the shape.

[0078] Example 16. The method of any one of examples 11-15, further comprising: analyzing the shape to determine a symmetricity for the shape; and generating the calibration value based further on the symmetricity for the shape.

[0079] Example 17. The method of any one of examples 11-16, further comprising: determining the geometric center for the beam includes fitting the image to a mathematical model of the beam.

[0080] Example 18. The method of any one of examples 11-17, wherein: the image includes a plurality of pixels, each having an intensity value; and the method further comprises analyzing the image to extract the shape based on the plurality of pixels and a threshold intensity value.

[0081] Example 19. The method of any one of examples 11-18, wherein the beam is an X-ray beam.

[0082] Example 20. The method of any one of examples 11-19, wherein the shape is a two- dimensional shape.

[0083] Various features and advantages of the embodiments presented herein are set forth in the following claims.

Claims

CLAIMSWhat is claimed is:

1. A medical imaging system (100), the system comprising: a source (114) configured to emit a beam (150); a detector (116) configured to detect the beam (150); and an electronic processor (104) coupled to the source (114) and the detector (116), and configured to: control the source (114) to emit the beam (150); receive an image from the detector (116), the image including a shape (152) formed by the beam (150); analyze the shape (152) to determine a geometric center for the beam (150); generate a calibration value based on the geometric center for the beam (150) and a center point for an imaging plane of the detector (116); control the source (114) to emit a second beam (150); receive a second image from the detector (116), the second image produced by the detector (116) detecting the second beam (150); and process the second image based on the calibration value to generate a compensated image.

2. The medical imaging system (100) of claim 1, further comprising: a positioning system (118) for positioning the source (114) and the detector (116) relative to each other; wherein the electronic processor (104) is coupled the positioning system (118) and further configured to: operate the positioning system (118) to position the source (114) and the detector (116) based on an operator input and the calibration value.

3. The medical imaging system (100) of claim 1 or 2, wherein the electronic processor (104) is further configured to: generate a gain calibration value by applying the calibration value to a mathematical model for the beam (150); and process the second image based on the gain calibration value and one or both of a distance between the source (114) and the detector (116) and an orientation of the detector (116) relative to the source (114).

4. The medical imaging system (100) of any one of claims 1-3, further comprising: a positioning system (118) for positioning the source (114) and the detector (116) relative to each other; wherein the electronic processor (104) is coupled the positioning system (118) and further configured to: prior to controlling the source (114) to emit the beam (150), control the positioning system (118) to position the detector (116) within a threshold distance of the source (114).

5. The medical imaging system (100) of any one of claims 1-4, wherein the electronic processor (104) is further configured to: analyze the shape (152) to determine an eccentricity for the shape (152); and generate the calibration value based further on the eccentricity for the shape (152).

6. The medical imaging system (100) of any one of claims 1-5, wherein the electronic processor (104) is further configured to: analyze the shape (152) to determine a symmetricity for the shape (152); and generate the calibration value based further on the symmetricity for the shape (152).

7. The medical imaging system (100) of any one of claims 1-6, wherein the electronic processor (104) is further configured to: determine the geometric center for the beam (150) by fitting the image to a mathematical model of the beam (150).

8. The medical imaging system (100) of any one of claims 1-7, wherein: the image includes a plurality of pixels, each having an intensity value; and the electronic processor (104) is further configured to analyze the image to extract the shape (152) based on the plurality of pixels and a threshold intensity value.

9. The medical imaging system (100) of any one of claims 1-8, wherein the beam (150) and the second beam (150) are X-ray beams.

10. The medical imaging system (100) of any one of claims 1-9, wherein the shape (152) is a two-dimensional shape (152).

11. A method (200) for operating a medical imaging system (100) including a source (114) configured to emit a beam (150) and a detector (116) configured to detect the beam (150) , the method (200) comprising: controlling the source (114) to emit the beam (150);receiving an image from the detector (116), the image including a shape (152) formed by the beam (150); analyzing the shape (152) to determine a geometric center for the beam (150); generating a calibration value based on the geometric center for the beam (150) and a center point for an imaging plane of the detector (116); controlling the source (114) to emit a second beam (150); receiving a second image from the detector (116), the second image produced by the detector (116) detecting the second beam (150); and processing the second image based on the calibration value to generate a compensated image.

12. The method (200) of claim 11, further comprising: operating a positioning system (118) for positioning the source (114) and the detector (116) relative to each other to position the source (114) and the detector (116) based on an operator input and the calibration value.

13. The method (200) of claim 11 or 12, further comprising: generating a gain calibration value by applying the calibration value to a mathematical model for the beam (150); and processing the second image based on the gain calibration value and one or both of a distance between the source (114) and the detector (116) and an orientation of the detector (116) relative to the source (114).

14. The method (200) of any one of claims 11-13, further comprising: prior to controlling the source (114) to emit the beam (150), positioning the detector (116) within a threshold distance of the source (114).

15. The method (200) of any one of claims 11-14, further comprising: analyzing the shape (152) to determine an eccentricity for the shape (152) and a symmetricity for the shape (152); and generating the calibration value based further on one or both of: the eccentricity for the shape (152) and the symmetricity for the shape (152).

Images