Method and system for integrating phantom system

Abstract

Various methods and systems are provided for a tablet phantom set for an imaging system. An imaging system (200) includes a gantry (322) including a radiation source (302) and a detector (314). The housing (306) is further positioned in the gantry adjacent the radiation source. The housing includes a plate phantom set (304) that includes at least one plate phantom (324, 326). The plate phantom set is configured such that at least one plate phantom of the plate phantom set is independently movable such that one or more of the at least one plate phantom of the plate phantom set is selectively positionable in a path (312) of a radiation beam (308) between the radiation source and the detector.

Description

TECHNICAL FIELD

[0001] Embodiments of the subject matter disclosed herein relate to diagnostic medical imaging, and more particularly, to computed tomography imaging setups with integrated phantom assemblies. BACKGROUND

[0002] In computed tomography (CT) imaging systems, an electron beam generated by a cathode is directed at a target within an x-ray tube. A fan or cone shaped x-ray beam generated by the electrons colliding with the target is directed at a subject, such as a patient. After being attenuated by the object, the x-rays impinge on an array of radiation detector elements. An electrical signal is generated at each detector element, and the electrical signals generated at the detector elements are used to reconstruct an image of the object, where each electrical signal corresponds to a voxel / pixel of the image.

[0003] Image quality in terms of resolution, contrast-to-noise ratio, and other factors can depend on the alignment of each detector element within the detector array. Misalignment of the detector elements can increase the number of artifacts in the image and / or reduce the quality of the image. A calibration procedure can be periodically performed on the system to obtain projection data of a material that simulates varying human tissue densities. The calibration procedure can include performing an x-ray scan procedure on an object known as a phantom. Physical misalignment of the phantom during the calibration procedure can result in inaccurate calibration of the CT system. SUMMARY

[0004] Various methods and systems are provided for a flat panel phantom set for an imaging system. The imaging system includes a gantry including a radiation source and a detector. A housing is further positioned in the gantry adjacent to the radiation source. The housing includes a flat panel phantom set including at least one flat panel phantom. The flat panel phantom set is configured such that the at least one flat panel phantom of the flat panel phantom set is independently movable to enable one or more of the at least one flat panel phantom of the flat panel phantom set to be selectively positioned in a path of a radiation beam between the radiation source and the detector.

[0005] It should be appreciated that the above Brief Description of the Invention is provided merely for purposes of summarizing some select concepts of the detailed description that follows. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined solely by the claims that follow the detailed description. Further, the claimed subject matter is not limited to addressing any of the disadvantages that can be discussed in the Background of the Invention or any part of this disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0006] The present application will be better understood with a reading of the following description of non-limiting embodiments, the said description being produced with reference to the attached drawings in which:

[0007] Figure 1A pictorial view of an imaging system is shown in accordance with one embodiment of the present application.

[0008] Figure 2 A schematic block diagram of an imaging system is shown including a gantry, where the gantry houses a radiation source, a detector, a beam filtering device, and a housing positioned adjacent to the radiation source.

[0009] Figure 3 A configuration of an imaging system is shown Figure 2 where elements of the beam filtering device and a flat panel phantom set are housed in the housing.

[0010] Figure 4 A configuration of an imaging system is shown Figure 2 where elements of the beam filtering device are housed in the beam filtering device, and where a flat panel phantom set is positioned in the housing.

[0011] Figure 5 A configuration of an imaging system is shown Figure 4 where flat panel phantoms of a flat panel phantom set are positioned in a path of an X-ray beam emitted by a radiation source.

[0012] Figure 6 A side view of a configuration of an imaging system is shown Figure 2

[0013] Figures 7A-7B A side view of a configuration of an imaging system is shown Figure 2 where various bowtie filters of the beam filtering device and / or flat panel phantoms of the flat panel phantom set are positioned in a path of an X-ray beam.

[0014] Figures 8A-8B A configuration of an imaging system is shown Figure 2 where the beam filtering device and the housing include flat panel phantoms of a flat panel phantom set.

[0015] Figure 9 A configuration of an imaging system is shown Figure 2 where one or more flat panel phantoms of a flat panel phantom set can be moved by a single motor.

[0016] Figure 10 A side view of a configuration of an imaging system is shown Figure 2 where the housing is configured to be selectively positioned in a path of an X-ray beam via a hinge.

[0017] Figure 11 A side view of a configuration is shown Figure 10

[0018] Figure 12 A side view of a configuration is shown Figure 2 ​​configurations of imaging systems, where the housing is configured to be selectively positioned in the path of the x-ray beam via a linear track.

[0019] Figure 13 A flowchart showing a method for performing a calibration procedure of an imaging system is shown. DETAILED DESCRIPTION

[0020] The following description relates to various embodiments of x-ray imaging systems. Some imaging systems, such as computed tomography (CT) systems or photon counting computed tomography (PCCT) systems, can require relatively regular calibration, such as daily or weekly calibration scans, to offset any gain driven, for example, by hardware such as x-ray tube focal spot position changes or detector radiation reduction. In addition, PCCT or CT systems can also obtain spectral information that can generate basis material decomposition (BMD) images. Calibrating a PCCT system can therefore require obtaining calibration projection data that simulates human body materials and material thicknesses. Accordingly, phantoms for calibrating PCCT systems can include a variety of different materials, such as polyvinyl chloride (PVC) and polyethylene (PE). Multiple types of phantoms can be used for calibration purposes, including flat panel phantoms, step phantoms, columnar phantoms, etc.

[0021] Calibration using flat panel phantoms typically requires selecting different flat panels of different thicknesses, densities, and / or materials to form a single phantom to be used in a calibration scan protocol. These flat panels are placed in holes, often attached to the table via accessory slots in the front of the table. The process of forming such flat panel phantoms and positioning them within an imaging system is time consuming and prone to human error (e.g., in positioning, flat panel selection, etc.). In addition, flat panel phantoms including flat panels of multiple types of materials and densities are typically large, heavy, and physically difficult to move. Further, the large flat panels occupy storage space in a facility that might otherwise be needed for storing other materials or supplies.

[0022] Accordingly, systems and methods are provided herein that at least partially address these issues. In particular, systems and methods are provided herein for integrated phantom systems. An integrated phantom system as disclosed herein includes a flat panel phantom stored within a gantry of an imaging system. For example, the flat panel phantom set can be stored within a beam filtering device (e.g., a housing of a collimator that also stores filters, such as a bowtie filter used in diagnostic protocols) or a separate housing adjacent to a radiation source. Each flat panel phantom in the flat panel phantom set can be individually actuated to move into a field of view of an x-ray source (e.g., a path from the radiation source to the detector) based on a selected calibration protocol, thereby reducing the time spent by an operator to manually select and assemble phantoms with multiple panels. Furthermore, since the housing in which the flat panel phantom is positioned is adjacent to a radiation source of the imaging system, the field of view intersected by the phantom can be reduced, which in turn allows for a reduction in the size and overall footprint of the phantom panels. The flat panel phantom can be automatically moved into and out of the x-ray beam, which can allow for faster and more accurate placement of one or more flat panel phantoms to enable a more efficient calibration process.

[0023] The systems and methods disclosed herein will now be described by way of example with respect to the accompanying drawings, in which Figure 1 and Figure 2 An example imaging system is shown, Figures 3-12 various configurations of flat panel phantom systems integrated into Figures 1-2 imaging systems are shown, and Figure 13 a flowchart illustrating a method for flat panel selection in an integrated phantom system is shown.

[0024] Figure 1An exemplary CT system 100 is shown. In one example, the CT system 100 can be a PCCT system. In particular, the CT system 100 is configured to image a subject 112, such as a patient, an inanimate object, one or more manufactured parts, and / or a foreign object, such as a dental implant, stent, and / or contrast agent present in a body or subject placed on a couch 114. The couch 114 can be motorized and can be selectively movable. In one embodiment, the CT system 100 includes a gantry 102, which in turn can include at least one x-ray radiation source 104 configured to project an x-ray beam 106 for imaging the subject 112. The x-ray radiation source 104 includes an x-ray tube and a target. The x-ray tube generates x-rays by accelerating and focusing a beam of high-energy electrons onto a rotating target. When individual electrons hit the target, the energy released through interaction with the atoms of the target produces x-ray photons isotropically at a polychromatic spectrum, the maximum energy of which matches that of the incident electrons. The x-ray photons exit the tube through a window that defines the x-ray beam. The beam can then be collimated and conditioned using collimator leaves and one or more filters.

[0025] In particular, the radiation source 104 is configured to project the x-ray beam 106 toward a detector array 108 positioned on an opposite side of the gantry 102. While a single radiation source 104 is depicted, in certain embodiments, multiple radiation sources can be employed to project multiple x-ray beams 106 to acquire projection data corresponding to the subject 112 at different energy levels. The radiation source can include an x-ray target made of graphite and metal. Figure 1

[0026] In certain embodiments, the CT system 100 further includes an image processing unit 110 configured to reconstruct an image of a target volume of the subject 112 using an iterative or analytical image reconstruction method. For example, the image processing unit 110 can reconstruct an image of the target volume of the subject 112 using an analytical image reconstruction method such as filtered back-projection (FBP). As another example, the image processing unit 110 can reconstruct an image of the target volume of the subject 112 using an iterative image reconstruction method such as advanced statistical iterative reconstruction (ASIR), conjugate gradient (CG), maximum likelihood expectation maximization (MLEM), model-based iterative reconstruction (MBIR), etc.

[0027] Figure 2 Analogous to the above-described embodiments, the image processing unit 110 can be configured to reconstruct an image of the target volume of the subject 112 using an iterative image reconstruction method such as ASIR, CG, MLEM, MBIR, etc. Figure 1 ​An exemplary imaging system 200 of the CT system 100. The imaging system 200 includes at least some of the elements of the CT system 100. In one embodiment, the system 200 includes the detector array 108. The detector array 108 also includes a plurality of detector elements 202 that together sense the x-ray beam 106 that passes through a subject 112, such as a patient, to acquire corresponding projection data. Thus, in one embodiment, the detector array 108 is fabricated in a multi-slice configuration that includes multiple rows of cells or detector elements 202. In such a configuration, an additional row or rows of detector elements 202 are arranged in a parallel configuration to acquire projection data.

[0028] The beam filtering device 240 can be mounted within the gantry 102 between the radiation source 104 and the subject 112. The beam filtering device 240 can have components that travel into and out of the beam in the z-direction while the beam is substantially in the y-direction. In some examples, the beam filtering device 240 can be configured to store one or more filters, such as a bowtie filter configured for use in a diagnostic protocol, and one or more phantom slabs configured for use in a calibration protocol. The beam filtering device 240 can perform the function of a pre-patient collimator (filtering and collimation of the beam for diagnostic imaging) and / or beam filtering for other purposes such as calibration. In some examples, the housing 242 can be positioned adjacent to and separate from the beam filtering device 240, where the beam filtering device 240 stores one or more filters, such as a bowtie filter, and the housing 242 stores one or more phantom slabs. As described herein with respect to the housing 242 for a set of phantom slabs, the beam filtering device 240 can be configured to move the one or more filters into and out of the beam based on a selected diagnostic protocol and to move the one or more phantom slabs into and out of the beam based on a selected calibration protocol. Figure 3 The housing 242 for the set of phantom slabs described herein can be positioned directly adjacent to the beam filtering device 240 within the rotating portion of the gantry 102 of the imaging system 200. In either example, the phantom slabs can be moved into and out of the beam according to a selected calibration protocol separate from one or more filters that can be moved into and out of the beam based on a selected diagnostic protocol.

[0029] In certain embodiments, the system 200 is configured to traverse different angular positions around the subject 112 to acquire desired projection data. Thus, the gantry 102 and the components mounted thereon, such as the radiation source 104, the beam filtering device 240, the housing 242, and the detector array 108, can be configured to rotate about the center of rotation 206 to acquire, for example, projection data at different energy levels. Alternatively, in embodiments where the projection angle relative to the subject 112 is varied over time, the mounted components can be configured to move along a generally curved path rather than along a segment of a circle.

[0030] In one embodiment, the system 200 includes a control mechanism 208 to control the motion of components, such as the rotation of the gantry 102 and the operation of the x-ray radiation source 104. In certain embodiments, the control mechanism 208 also includes an x-ray controller 210 configured to provide power and timing signals to the radiation source 104. Additionally, the control mechanism 208 includes a gantry motor controller 212 configured to control the rotational speed and / or position of the gantry 102 based on imaging requirements.

[0031] In certain embodiments, the control mechanism 208 also includes a data acquisition system (DAS) 214 configured to sample analog data received from the detector elements 202 and convert the analog data to digital signals for subsequent processing. The data sampled and digitized by the DAS 214 is transmitted to a computing device (also referred to as a processor) 216. In one example, the computing device 216 stores the data in a storage device 218. For example, the storage device 218 can include a hard disk drive, a floppy disk drive, a Compact Disk - Read / Write (CD-R / W) drive, a Digital Versatile Disk (DVD) drive, a flash drive, and / or a solid-state storage device.

[0032] Additionally, the computing device 216 provides commands and parameters to one or more of the DAS 214, the x-ray controller 210, and the gantry motor controller 212 for controlling system operations such as data acquisition and / or processing. In certain embodiments, the computing device 216 controls system operations based on operator input. The computing device 216 receives the operator input, which includes, for example, commands and / or scan parameters, via an operator console 220 operatively coupled to the computing device 216. The operator console 220 can include a keyboard or touch screen to allow an operator to designate commands and / or scan parameters.

[0033] While Figure 2 While one operator console 220 is illustrated, more than one operator console can be coupled to the system 200, for example, to input or output system parameters, request examinations, and / or view images. Further, in certain embodiments, the system 200 can be coupled, via one or more configurable wired and / or wireless networks, such as the Internet and / or a virtual private network, to multiple displays, printers, workstations and / or the like that are locally or remotely located, for example, within a facility or hospital or at a completely different location.

[0034] For example, in one embodiment, the system 200 includes or is coupled to a picture archiving and communication system (PACS) 224. In one example implementation, the PACS 224 is further coupled to remote systems (such as a radiology information system, a hospital information system) and / or to an internal or external network (not shown) to allow operators in different locations to supply commands and parameters and / or to gain access to image data.

[0035] The computing device 216 uses the operator-supplied and / or system-defined commands and parameters to operate a table motor controller 226, which in turn can control the examination table 114. For example, the examination table 114 can be motorized. The table motor controller 226 can actuate the motor of the examination table 114 to move the examination table 114 to properly position the subject 112 in the gantry 102 to acquire projection data corresponding to a target volume of the subject 112.

[0036] As previously mentioned, the DAS 214 samples and digitizes the projection data acquired by the detector elements 202. Subsequently, an image reconstructor 230 uses the sampled and digitized X-ray data to perform a high-speed reconstruction. While the image reconstructor 230 is illustrated as a separate entity, in certain embodiments, the image reconstructor 230 can form part of the computing device 216. Alternatively, the image reconstructor 230 can not be present in the system 200, and instead the computing device 216 can perform one or more functions of the image reconstructor 230. Further, the image reconstructor 230 can be located locally or remotely, and the image reconstructor 230 can be operatively connected to the system 100 using a wired or wireless network. In particular, one example embodiment can use computing resources in a “cloud” network cluster for the image reconstructor 230. Figure 2 While the image reconstructor 230 is illustrated as a separate entity, in certain embodiments, the image reconstructor 230 can form part of the computing device 216. Alternatively, the image reconstructor 230 can not be present in the system 200, and instead the computing device 216 can perform one or more functions of the image reconstructor 230. Further, the image reconstructor 230 can be located locally or remotely, and the image reconstructor 230 can be operatively connected to the system 100 using a wired or wireless network. In particular, one example embodiment can use computing resources in a “cloud” network cluster for the image reconstructor 230.

[0037] In one embodiment, the image reconstructor 230 stores the reconstructed images in a storage device 218. Alternatively, the image reconstructor 230 transmits the reconstructed images to the computing device 216 for generating usable patient information for diagnosis and evaluation. In certain embodiments, the computing device 216 transmits the reconstructed images and / or patient information to a display 232 that is communicatively coupled to the computing device 216 and / or the image reconstructor 230.

[0038] As described herein with respect to the system 100, the system 200 can be used to perform a variety of imaging procedures, such as computed tomography (CT), positron emission tomography (PET), single photon emission computed tomography (SPECT), and / or magnetic resonance imaging (MRI). Figures 3-13As further described, the imaging system 200 can be calibrated by executing one or more calibration scan protocols. A user can request a calibration scan protocol via operator console 220. Computing device 216 can identify the requested calibration scan protocol and determine the flat phantom corresponding to the identified calibration scan protocol. The flat phantom may include one or more flat phantoms from a set of flat phantoms housed within beam filter device 240 and / or housing 242. Computing device 216 can identify a subset of flat plates incorporated into the set of flat phantoms in housing 242 and / or beam filter device 240 of imaging system 200, forming the flat phantom corresponding to the identified calibration scan protocol. Computing device 216 can actuate one or more motors coupled to the identified subset of flat plates to move the subset of flat plates into the path of the radiation beam (e.g., X-ray beam 106). Imaging system 200 can thus acquire a calibration scan of the flat phantom.

[0039] Figure 3 It shows Figure 2 The imaging system 200 is configured 300, wherein the rack 102 houses the radiation source 104, the beam filter 240, the housing 242, and the detector array 108. Figure 3 In the illustrated configuration, housing 242 and beam filter 240 are combined into a single housing 306, which includes elements of beam filter 240 and elements of housing 242. For example, a flat phantom assembly 304 is positioned within the single housing 306 of the imaging system 200, as further described herein. Additionally, in this illustrated example, one or more example bowtie filters 320 are positioned within the single housing 306. One or more example bowtie filters 320 may alternatively be positioned within beam filter 240, as relative to... Figures 4-12 Further described. In this illustrative example, the phantom of the flat phantom assembly 304 and other filters (e.g., bowtie filters) of the imaging system 200 are moved parallel to the x-axis. Alternatively, the flat phantom assembly 304 and the individual housing 306 may be positioned such that the flat phantom assembly 304 is moved parallel to the z-axis. Figure 3 Includes axis system 299, where the x-axis is the horizontal axis, the y-axis is the vertical (e.g., gravity) axis, and the z-axis is the vertical axis (e.g., entering / exiting the rack).

[0040] The configuration 300 of the imaging system 200 includes an X-ray source 302 (e.g., Figures 1-2 The X-ray source 302 is configured to emit an X-ray beam (e.g., X-ray beam 106) 308. The X-ray beam 308 travels along path 312 from the X-ray source 302 to the detector 314 (e.g., detector array 108) of the imaging system 200. The detector 314 is positioned within a gantry housing 322 (e.g., [missing information - likely a specific type of housing]).Figure 1 and Figure 2 The detector 314 is located within the rotating portion 334 of the frame housing 322 (102). The detector 314 is positioned on the side of the frame housing 322 opposite to the X-ray source 302 via a hole 316. The rotating portion 334 also houses the X-ray source 302 and a single housing 306 containing a flat body module 304. The single housing 306 is positioned adjacent to the X-ray source 302 within the rotating portion 334 such that the single housing 306 is in the path 312 of the X-ray beam 308.

[0041] exist Figure 3 In the example, the single housing 306 is made of metal (e.g., aluminum). Alternatively, the housing may be made of an X-ray transparent material. The single housing 306 includes a first gap 336 on a first side 390 adjacent to the X-ray source 302 and a second gap 338 on a second side 392 opposite to the first side 390. The first gap 336 and the second gap 338 are aligned (e.g., along the y-axis) such that the X-ray beam 308 passes through the first gap 336 and the second gap 338. The single housing 306 includes a collimator configured to align and / or narrow the X-ray beam 308. For example, the single housing 306 may include one or more bowtie filters 320. When positioned in the path 312 of the X-ray beam 308, the one or more bowtie filters 320 are configured to alter one or more configurations of the X-ray beam, such as reducing the amount of radiation delivered to the periphery of the patient. In some examples, a bowtie filter 320 is positioned in the path of the X-ray beam 308. In some examples, more than one filter (e.g., another bowtie filter 320, different filters) may be positioned in the path of the X-ray beam 308 together with one of the example bowtie filters 320. The bowtie filter 320 is positioned within a single housing 306 at a first side 390 of the single housing 306. The bowtie filter 320 can be configured for use in diagnostic imaging protocols and can be moved during diagnostic protocols to intersect or not intersect with the X-ray beam 308. In contrast, the flat phantom assembly 304 can be configured for use in calibration protocols and can be moved during calibration scans to intersect or not intersect with the X-ray beam 308.

[0042] exist Figure 3In the illustrated embodiment, a flat phantom set 304 is positioned within a single housing 306. The flat phantom set 304 includes a plurality of phantom plates. As described herein, a flat phantom is a piece of material configured to simulate a specific density of human tissue (e.g., bone, blood, brain matter, etc.). Using known parameters of the plates and a set of plates forming a selected flat phantom, calibration of the imaging system 200 can be performed by comparing various outputs of a calibration scan with a standard. The flat phantom set 304 may include a first flat phantom 324 having a first thickness, wherein the first thickness is parallel to the direction of path 312 (e.g., parallel to the y-axis). The first flat phantom 324 is formed of a first material. The flat phantom set 304 may also include a second flat phantom 326 having a second thickness, wherein the second thickness is parallel to the direction of path 312 (e.g., parallel to the y-axis). The second flat phantom 326 is formed of a second material. The second thickness may differ from the first thickness. The second material may differ from the first material. The flat phantom assembly 304 may include additional flat plates, wherein each flat plate may be formed of a material that is the same as and / or different from the first material and / or the second material. Figure 3 In the example, the plate phantom set 304 includes six phantom plates. Different combinations of the six available plates can be pre-programmed as plate phantoms in the system, whereby the selection of a first plate phantom can trigger the selection of a first subset of available plates. Additional plates can each have a thickness parallel to the y-axis, which is greater than, less than, and / or equal to a first thickness and / or a second thickness. Each plate in the additional plates can have a different thickness. The space between the plates of the plate phantom set 304 (e.g., between the first plate phantom 324 and the second plate phantom 326 along the y-axis) allows multiple plates to be stacked along the y-axis in the path 312 of the X-ray beam 308 to create a single filtered phantom. Relative to Figure 5 and Figure 7B Example combinations of flat phantoms are described.

[0043] The flat panel phantom assembly 304 is positioned at a second side 392 of a single housing 306 opposite the first side 390. The single housing 306 is oriented such that the bowtie filter 320 is close to the X-ray source 302 (e.g., there are no components of the single housing 306 between the bowtie filter 320 and the X-ray source 302). Alternatively, the flat panel phantom assembly 304 and the bowtie filter 320 can be stacked vertically relative to the y-axis. The flat panel phantom assembly 304 can be positioned away from the X-ray source 302, wherein the walls of the bowtie filter 320 and the single housing 306 at the first side 390 of the single housing 306 are between the flat panel phantom assembly and the X-ray source. Therefore, the flat panel phantom assembly 304 can be incorporated into the same housing as the bowtie filter, thereby allowing the flat panel to be stored within the imaging system rather than outside the imaging system.

[0044] Additionally, by positioning the plate phantom set 304 closer to the X-ray source 302 than the detector 314 (e.g., on the same side of the aperture 316 as the X-ray source 302, opposite the detector), the size of each plate in the plate phantom set 304 can be reduced compared to a conventional plate phantom. For example, in a conventional calibration procedure for calibrating an imaging system (e.g., imaging system 200), one or more plate phantoms can be positioned in the path 312 of the X-ray beam 308 by placing one or more plates on an imaging surface (e.g., inspection table 114). The imaging surface is inserted into the aperture 316. Figure 3 As shown, the width of the X-ray beam 308 in aperture 316 is greater than the width of the X-ray beam 308 outside aperture 316 closer to X-ray source 302. For example, the first width 332 of the X-ray beam 308 in aperture 316 is greater than the second width 330 of the X-ray beam 308 passing through a single housing 306. In order to image the entire selected plate phantom (e.g., such that the X-ray beam 308 received by detector 314 passes through the plate phantom), the plates moved to intersect the X-ray beam 308 are configured to have a width at least equal to and / or greater than the width of the X-ray beam 308 at the position where the phantom is positioned within the X-ray beam 308 (e.g., parallel to the x-axis). Thus, by positioning the plate phantom set 304 and its plates closer to X-ray source 302, the width of each plate can be smaller than the width of the plate phantom positioned further along the path 312 of X-ray beam 308 (e.g., closer to detector 314), while achieving the same desired filtering. Therefore, the area and weight occupied by each phantom and the phantom set 304 can be reduced. Furthermore, since the phantom set 304 is stored in a single housing 306 integrated into the imaging system 200, the complexity, space, and operational requirements for storing the phantom set 304 can be reduced and / or eliminated. Additionally, as shown in Figures 7 to... Figure 13 As described, during different calibration procedures of the imaging system 200, one or more flat phantoms of the flat phantom set 304 can be automatically moved into and / or out of the X-ray beam 308. This further reduces the need for the user to manually move and / or adjust the positioning of one or more flat phantoms in the path 312 of the X-ray beam 308 (e.g., on the inspection table 114). Therefore, the time spent performing calibration procedures can be reduced. Additionally, the accuracy of imaging system calibration can be improved by automatically positioning the flat phantoms in the X-ray beam 308 in response to the selection of one or more calibration procedures.

[0045] Figure 3The illustrated geometric configuration of a single housing 306, including a flat phantom assembly 304 and one or more bowtie filters 320, can be implemented in a CT imaging system having a typically small detector 314 span in the x-direction. In this illustrated configuration, the bowtie 320 and flat phantom assembly 304 are moved in the x-direction to intersect with the X-ray beam 308. In other configurations, the bowtie 320 and flat phantom assembly 304 are moved in the z-direction to intersect with the X-ray beam 308. Due to the availability of physical space on a CT imaging system, moving the bowtie 320 and flat phantom assembly 304 in the z-direction may be preferred for medium to large coverage detectors 314, as physical space on gantry 102 may not be available for the required size where the bowtie 320 and flat phantom assembly 304 completely surround the X-ray beam 308.

[0046] As relative to Figures 4-12 Further described, one or more plate phantoms in the plate phantom set 304 can be independently positioned in and / or removed from the path 312 of the X-ray beam 308. The plate phantoms in the plate phantom set 304... Figure 3 The middle is shown positioned on either side of the X-ray beam 308 (e.g., not positioned within the X-ray beam). One or more motors ( Figure 3 (Not shown) One or more plates (of the plates in the plate phantom set 304) can be coupled to the bowtie filter 320, wherein one or more motors are configured to independently move the plates (e.g., plate phantom, bowtie filter, etc.) into and / or out of the path 312 of the X-ray beam 308. In this way, the imaging system 200 includes a single retainer (e.g., housing 306) that houses the plate phantom (e.g., plate phantom set 304) and the patient precollimator (e.g., bowtie filter 320) for calibrating the imaging system 200.

[0047] Figure 4 It shows Figures 2-3 The imaging system 200 is configured in a configuration 400, wherein elements of the beam filter 240 (e.g., one or more bowtie filters 320) are housed within the beam filter 240, and a planar body assembly 304 is housed within a housing 242. The housing 242 is a structure separate from the beam filter 240 in the configuration 400. The configuration 400 may include […]. Figures 2-3 The imaging system 200 has at least some of the same components, these components in Figure 4The beam filter 240 is marked and will not be repeated for brevity. The beam filter 240 includes a first gap 436 on a first side 390 adjacent to the X-ray source 302. The housing 242 includes a second gap 438 on a second side 392 opposite to the first side 390. Both the housing 242 and the beam filter 240 include a third gap 440 at corresponding faces of the housing 242 and the beam filter 240 facing each other. The first gap 436, the second gap 438, and the third gap 440 are aligned (e.g., along the y-axis) such that the X-ray beam 308 passes through the first gap 436, the second gap 438, and the third gap 440. The housing 242 can be rigidly positioned in the path 312 of the X-ray beam 308. For example, the housing 242 can be coupled to the beam filter 240 via welding, bolts, clamps, and / or other rigid fasteners. In other examples, housing 242 may be rigidly coupled to another portion of the rotating portion 334 of rack housing 322 to rigidly position housing 242 within the path 312 of X-ray beam 308. In further examples, such as relative to Figures 9-12 As described herein, housing 242 can be selectively coupled to beam filter device 240. Beam filter device 240 is positioned between housing 242 and X-ray source 302. As described herein with respect to Figures 7 to 10. Figure 13 Furthermore, during the calibration operation of the imaging system 200, the flat panel of the flat phantom assembly 304 can be independently and selectively positioned within the path 312 of the X-ray beam 308. Therefore, the X-ray beam 308 can pass through the bowtie filter 320 before passing through one or more filters of the flat phantom assembly 304.

[0048] Figure 5 It shows Figure 4 The configuration of 400 is view 500. In Figure 5 In view 500, the plate phantom of plate phantom set 304 is positioned in path 312 of X-ray beam 308. Figure 5 In the example, the plate phantom set 304 includes four plates. Each of the first plate phantom 324, the second plate phantom 326, the third plate phantom 524, and the fourth plate phantom 526 of the plate phantom set 304 may have the same width perpendicular to the path 312 of the X-ray beam 308 (e.g., parallel to the x-axis). The width of each plate phantom is configured to be at least equal to or greater than the width of the X-ray beam 308 at the position of the plate phantom. For example, the first width 530 of the first plate phantom 324 is greater than the second width 532 of the X-ray beam 308 at the position of the first plate phantom 324. In this way, the first plate phantom 324 is completely positioned in the path 312 of the X-ray beam 308 such that the entire X-ray beam 308 passes through the first plate phantom 324 along the path 312 from the X-ray source 302 to the detector 314.

[0049] As relative to Figure 3 As described, one or more plates in the plate phantom set 304 can be formed of the same or different materials. Furthermore, one or more plate phantoms in the plate phantom set 304 can have the same or different thicknesses along the path 312 parallel to the X-ray beam 308 (e.g., parallel to the y-axis). Therefore, different plates can be selected or predetermined as part of a given plate phantom.

[0050] As shown in Figure 7 to... Figure 13 Furthermore, during the calibration operation of the imaging system 200, the plates of the flat phantom set 304 can be independently and selectively positioned within the path 312 of the X-ray beam 308. For example, one or more plates of the flat phantom set 304 can be simultaneously positioned within the path 312 of the X-ray beam 308, such as... Figure 5 As shown. The bow tie 320 and the plate set 304 move in the z-direction to enter and exit the X-ray beam 308. Due to the physical space constraints on the rotating gantry 102, this z-direction movement configuration of the bow tie 320 and the plate set 304 is preferred for detector 314 with medium to large x-direction coverage.

[0051] Figure 6 It shows Figure 2 A side view 600 showing the configuration of the imaging system 200. For clarity, some elements of the imaging system 200 are excluded from the side view 600. (Relative to...) Figures 3-5 Some components of the described imaging system 200 are included Figure 6 The configuration is described in detail here, and for the sake of simplicity, it will not be repeated. Figure 6 Side view 600 shows a first plate phantom 324, a second plate phantom 326, a third plate phantom 524, and a fourth plate phantom 526 of a plate phantom set 304. The plate phantom set 304 may also include a fifth plate phantom 624, a sixth plate phantom 626, and a seventh plate phantom 628. Each plate phantom in the plate phantom set 304 may have a different thickness along the path 312 of the X-ray beam 308 (e.g., parallel to the y-axis). Furthermore, one or more plates in the plate phantom set 304 may be formed from different materials configured to simulate different human tissues.

[0052] Each plate in the plate may have a corresponding motor and drive shaft. The motor can actuate the drive shaft of the plate based on a selected calibration scan protocol to move the plate to intersect with path 312, as will be further described below. Configuration 400 includes one or more bowtie filters 320. Figure 6As shown, beam filtering device 240 may include three bowtie filters 320 and two apertures 618. The apertures 618 function to increase or decrease the coverage of the X-ray beam 308 in the z-direction. The collimator apertures 618 are configured to guide the X-ray beam 308 from the X-ray source 302 to the detector 314 along path 312. As noted, the bowtie filters 320 may be configured to change the shape or size of the X-ray beam 308 as it passes through the subject during diagnostic imaging. In other examples, beam filtering device 240 may include more or fewer bowtie filters 320 and / or apertures 618 than illustrated. The bowtie filters 320 are positioned at a first side 390 of beam filtering device 240, and the apertures 618 are positioned at a second side 392 of beam filtering device 240. The apertures 618 may be movably positioned in beam filtering device 240, for example, using a drive system such as a motor and drive shaft (not shown). Each bowtie filter in the bowtie filter array can be coupled to a drive system including a motor and a drive shaft. For example, each bowtie filter in the bowtie filter array 320 can be mounted on the drive shaft of a motor configured to selectively and / or independently move the bowtie filter array 320 into and / or out of the path 312 of the X-ray beam 308. For example, a first motor 602 can have a first drive shaft 606 extending therefrom. A first bowtie filter array 320a can be mounted on and / or coupled to the first drive shaft 606. The first motor 602 can be actuated to selectively move the first bowtie filter array 320a into and / or out of the path 312 of the X-ray beam 308. A second motor 604 can have a second drive shaft 608 extending therefrom. A second bowtie filter array 320b and a third bowtie filter array 320c can be mounted on and / or coupled to the second drive shaft 608. The second motor 604 can be actuated to selectively move the second bowtie filter 320b and / or the third bowtie filter 320c into and / or out of the path 312 of the X-ray beam 308.

[0053] In a similar sense, each plate of the phantom set 304 can be individually coupled to a drive system comprising a motor with a drive shaft configured to move the corresponding plate to intersect path 312 based on a selected protocol. For example, a first protocol could indicate that a first phantom set will be imaged for calibration scanning. The first phantom set may include a first subset of the plates of the phantom set 304. When the first protocol is selected, the corresponding drive system for the first subset of plates can actuate the first subset of plates to move into path 312, while other plates of the phantom set 304 not included in the first subset are not actuated to move. In this way, the first phantom set can be imaged according to the selected calibration scanning protocol for calibration of the imaging system. When a second, different calibration protocol is selected, its different drive system can actuate a second subset of the phantom set 304 to move into path 312, wherein the second subset of plates forms a second phantom set corresponding to the selected second calibration protocol.

[0054] In some examples, the bowtie filter may be included in the selected calibration protocol, and therefore the motors corresponding to the bowtie filter and their drive shafts (e.g., first motor 602 and second motor 604, and first drive shaft 606 and second drive shaft 608) may be actuated during the calibration protocol. In other examples, the bowtie filter may not be included in the selected calibration protocol, and therefore may not be actuated to move into the path during calibration scans. Similarly, the motors and drive shafts corresponding to the flat phantom set 304 may not be actuated during diagnostic imaging protocols, since the phantom is intended for calibration purposes rather than diagnostic purposes.

[0055] Figure 7A and Figure 7B The imaging system 200 is shown. Figure 6 The side view 700 of the configuration shown. For clarity, it can be seen from... Figure 7A and Figure 7B Some component markings are excluded in one or more side views 700. It should be understood that... Figure 7A and Figure 7B Each side view 700 includes the same elements. In side view 700, various combinations of bowtie filters and / or flat phantoms selectively positioned in the path 312 of the X-ray beam 308 are shown. Figure 7A and Figure 7BThe views illustrate the paths through which the plates of the plate phantom set 304 and the bow-tie filter 320 can be independently moved into and / or out of the X-ray beam 308, thereby allowing the plates to be used alone and / or in combination with other plate phantoms and / or bow-tie filters 320. The plates and bow-tie filters 320 are described herein as being moved into and / or out of the X-ray beam 308 by a motor having a drive shaft. Other types of drive mechanisms may be used to selectively and independently move the filters into and / or out of the X-ray beam 308 without departing from the scope of this disclosure.

[0056] In first view 702, first motor 602 is actuated to extend first drive shaft 606 and position first bowtie filter 320a in the path 312 of X-ray beam 308. Motors coupled to the plates of plate matrix assembly 304 are not actuated, so none of the plates in plate matrix assembly 304 are positioned in the path 312 of X-ray beam 308. First view 702 may be an example of the configuration of imaging system 200 during a routine diagnostic imaging procedure (e.g., not a calibration procedure for the imaging system). By positioning the first bowtie filter 320a in the path 312 of X-ray beam 308, the first bowtie filter 320a can be used to change the size, shape, or configuration of the beam during a diagnostic scan performed by the imaging system.

[0057] The imaging system 200 may include a third motor 712 from which a third drive shaft 705 extends. A fifth plate phantom 624 is positioned on and / or coupled to the third drive shaft 705. In the second view 704, the third motor 712 is actuated to extend the third drive shaft 705 and position the fifth plate phantom 624 in the path 312 of the X-ray beam 308. The motors of the other plates coupled to the plate phantom set 304 are not actuated, therefore the first plate phantom 324, the second plate phantom 326, the third plate phantom 524, the fourth plate phantom 526, the sixth plate phantom 626, and the seventh plate phantom 628 are not positioned in the X-ray beam 308. Furthermore, the first motor 602 and the second motor 604 are not actuated, therefore the first bowtie filter 320a, the second bowtie filter 320b, and the third bowtie filter 320c are not positioned in the X-ray beam 308. Therefore, second view 704 illustrates an example configuration in which a single plate is positioned within X-ray beam 308. Second view 704 is realized when the first calibration procedure of imaging system 200 is performed.

[0058] The imaging system 200 may further include a fourth motor 714 from which a fourth drive shaft 716 extends. A sixth plate phantom 626 is positioned on and / or coupled to the fourth drive shaft 716. In the third view 706, the fourth motor 714 is actuated to extend the fourth drive shaft 716 and position the sixth plate phantom 626 in the path 312 of the X-ray beam 308. Additionally, the third motor 712 is actuated to extend the third drive shaft 705 and position the fifth plate phantom 624 in the path 312 of the X-ray beam 308. The motors of the other plate phantoms coupled to the plate phantom set 304 are not actuated, therefore the first plate phantom 324, the second plate phantom 326, the third plate phantom 524, the fourth plate phantom 526, and the seventh plate phantom 628 are not positioned in the X-ray beam 308. Furthermore, since the first motor 602 and the second motor 604 are not actuated, the first bowtie filter 320a, the second bowtie filter 320b, and the third bowtie filter 320c are not positioned within the X-ray beam 308. Therefore, third view 706 illustrates an example configuration in which multiple plates forming a single plate phantom are positioned within the X-ray beam 308. In the example of third view 706, the phantom plates positioned within the X-ray beam 308 are housed on the same side of the housing 242 (e.g., on the first side 790 of the X-ray beam 308) and extend from there. Third view 706 can be realized when a second calibration procedure of the imaging system 200 is performed, wherein the second calibration procedure differs from the first calibration procedure using second view 704.

[0059] The imaging system 200 may include a fifth motor 718 from which a fifth drive shaft 720 extends. A seventh plate phantom 628 is positioned on and / or coupled to the fifth drive shaft 720. In the fourth view 708, the fifth motor 718 is actuated to extend the fifth drive shaft 720 and position the seventh plate phantom 628 in the path 312 of the X-ray beam 308. Additionally, a third motor 712 is actuated to extend a third drive shaft 705 and position the fifth plate phantom 624 in the path 312 of the X-ray beam 308. The motors of the other plates coupled to the plate phantom set 304 are not actuated, therefore the first plate phantom 324, the second plate phantom 326, the third plate phantom 524, the fourth plate phantom 526, and the sixth plate phantom 626 are not positioned in the X-ray beam 308. Furthermore, since the first motor 602 and the second motor 604 are not actuated, the first bowtie filter 320a, the second bowtie filter 320b, and the third bowtie filter 320c are not positioned within the X-ray beam 308. Therefore, fourth view 708 illustrates an example configuration in which multiple plates forming a plate phantom are positioned within the X-ray beam 308. In the example of fourth view 708, the plates positioned within the X-ray beam 308 are housed on and extend from opposite sides of the housing 242 (e.g., the first side 790 and the second side 792 of the X-ray beam 308, the second side being opposite to the first side 790 relative to the z-axis). Fourth view 708 can be realized when a third calibration procedure of the imaging system 200 is performed, wherein the third calibration procedure differs from the first calibration procedure using second view 704 and the second calibration procedure using third view 706.

[0060] By independently and selectively positioning one or more plates of the plate phantom set 304 within the path of the X-ray beam, different combinations of plates can be used to perform calibration procedures and / or diagnostic imaging procedures. Different combinations can form different plate phantoms with varying materials, densities, and thicknesses, and different configurations, these plate phantoms being configured to simulate different types of human tissue. For example, a first plate phantom may include a selected set of plates configured to mimic a specific configuration of the human torso, while a second plate phantom may include a different selected set of plates configured to mimic another configuration of the human brain. In this way, the same set of plates can be used to select different plate phantoms available to the system, without requiring multiple identical plates to form different individual plate phantoms outside the imaging system.

[0061] Figure 8A and Figure 8B It shows Figure 2 The imaging system 200 is configured 800, wherein the beam filter 240 and housing 242 include a flat phantom of a flat phantom assembly 304. Relative to Figure 3Some of the components of the imaging system 200 described in Figure 7 are included. Figures 8A-8B The configuration is described herein, and for the sake of brevity, will not be repeated. Configuration 800 provides further illustration of how the plates of the plate phantom set 304 and the bow-tie filter 320 can be independently moved into and / or out of the X-ray beam 308, thereby allowing the plates to be used alone and / or in combination with other plates and / or bow-tie filters 320 (as a plate phantom). The plates and bow-tie filters 320 are described herein as being moved into and / or out of the X-ray beam 308 by a motor having a drive shaft. Other types of drive mechanisms may be used to selectively and independently move the filters into and / or out of the X-ray beam 308 without departing from the scope of this disclosure.

[0062] The flat plates of the flat phantom assembly 304 are positioned within a beam filtering device 240, which also houses a bowtie filter 320 and an aperture 618. In addition to the first bowtie filter 320, an eighth flat plate 824 is coupled to the first drive shaft 606 of a first motor 602. In addition to the second bowtie filters 320b and 320c, a ninth flat plate 826 is coupled to the second drive shaft 608 of a second motor 604. In the first view 802, neither the first motor 602 nor the second motor 604 is actuated, therefore the first bowtie filters 320a, 320b, 320c, eighth flat plate 824, and ninth flat plate 826 are positioned within the X-ray beam 308. Each of the first motor 602 and the second motor 604 can be independently actuated to extend their drive shafts (e.g., first drive shaft 606 and second drive shaft 608, respectively) to independently position each of the filters and plates mounted thereon within the X-ray beam 308. For example, in the second view 804, the second motor 604 is actuated. The second motor 604 extends the second drive shaft 608 to a first position, such that the ninth plate 826 is positioned within the X-ray beam 308. When the second drive shaft 608 is in the first position, the second bowtie filter 320b and the third bowtie filter 320c are not positioned within the X-ray beam 308. In the second view 804, the second bowtie filter 320b and the third bowtie filter 320c are positioned on a second side 792 of the X-ray beam 308 (e.g., on the same side as the first bowtie filter 320a and the eighth plate 824). An extension of the second drive shaft 608 (e.g., parallel to the z-axis) can be adjusted to another position via actuation of the second motor 604 to alternately position the third bowtie filter 320c or the second bowtie filter 320b within the X-ray beam 308. In this way, with the flat plate and bowtie filters aligned on the same drive shaft and within the same housing, the number of system components and complexity can be reduced.

[0063] In third view 806 and fourth view 808, housing 242 is coupled to beam filter device 240, and additional plates of plate body assembly 304 are positioned in housing 242, as relative to... Figures 4-7B In the third view 806, none of the motors on which the plate and / or one or more bow-tie filters are positioned are actuated, so no plate or bow-tie filter is positioned in the path 312 of the X-ray beam 308. In the fourth view 808, the second motor 604 is actuated to extend the second drive shaft 608 and position the ninth plate 826 in the X-ray beam 308. Additionally, the fourth motor 714 is actuated to extend the fourth drive shaft 716 and position the sixth plate phantom 626 in the path 312 of the X-ray beam 308. In this way, the plate positioned in the beam filter device 240 and the plate positioned in the housing 242 extend into the path 312 of the X-ray beam 308. Therefore, a plate phantom including both the plate in the beam filter device and the plate in the phantom housing can be imaged in a calibration scan without having to assemble the plate phantom independently outside the imaging system.

[0064] Figure 9 It shows Figure 2 The imaging system 200 is configured 900, wherein the housing 242 is configured to be selectively positioned within the path 312 of the X-ray beam 308. Relative to Figures 3-8B Some components of the described imaging system 200 are included Figure 6 The configuration is described in detail here, and for the sake of simplicity, it will not be repeated. Figure 9 In the example, beam filtering device 240 includes an aperture 618, a plate, and a bowtie filter. An eighth plate 824 and a first bowtie filter 320a can be positioned on a first drive shaft 606 of a first motor 602. A second bowtie filter 320b and a third bowtie filter 320c can be coupled to a second drive shaft 608 of a second motor 604.

[0065] In the first view 902, no motor or drive shaft is actuated, and therefore no bowtie filter or plate is positioned to intersect the beam. In the second view 904, a fifth motor 908, to which the tenth plate 910 and eleventh plate 912 are coupled, is actuated to extend the fifth drive shaft 914 to a first position. In the first position, the eleventh plate 912 may intersect the X-ray beam, but the tenth plate 910 may not intersect the X-ray beam.

[0066] In the third view 906, the fifth motor 908 is actuated to extend the fifth drive shaft 914 to a second position. In the second position, the tenth plate 910 may intersect with the X-ray beam 308, but the eleventh plate 912 may not intersect with the X-ray beam. In this way, by utilizing the different positions of the drive shaft, a single drive shaft can be coupled to multiple plates, and selected plates can be selectively positioned to intersect with the beam based on the position corresponding to the plate.

[0067] Figure 10 It shows Figure 2 A side view of the imaging system configuration 1000, wherein the housing is configured to be selectively positioned within the path 312 of the X-ray beam 308. In configuration 1000, a flat phantom assembly 304 can be integrated into the housing 242. The housing 242 can be coupled to the beam filter device 240 via a hinge 1002. By pivoting the housing 242 about the hinge 1002, the housing 242 can be rotated from a first position 1004 to a second position 1006. In the first position 1004, the flat phantom assembly 304 is not positioned within the aperture and therefore does not intersect with the X-ray beam. However, when rotated to the second position 1006, the flat phantom assembly 304 can be positioned to intersect with the X-ray beam. In this example, the flat phantom within the assembly can be manually selected because when in the second position 1006, the entire assembly can be imaged. In some examples, pivoting housing 242 about hinge 1002 may additionally include removing the scan window before moving housing into path 312 of X-ray beam 308.

[0068] Figure 11 It shows Figure 10 Side view 1100 of configuration 1000. In side view 1100, the beam filter device 240 is separated from the housing 242, similar to that described above. The housing 242 may be a hinged or rotating component stored in a rotating frame during diagnostic protocols. In some examples, when in the illustrated configuration 1000, the housing 242 may be fixedly coupled to the beam filter device 240 using fasteners 1102. When a calibration protocol is selected, the housing 242 may be rotated to be adjacent to the beam filter device 240. The motor and drive shaft may then actuate a different plate to move to intersect with the beam, as previously described. In this way, the plate may be inconspicuous during diagnostic procedures, thereby reducing the possibility of artifacts or other interference, and can be moved to a position for the calibration protocol. In some examples of configuration 1000, the imaging system 200 includes a scanning window 1108. The scanning window 1108 may be removed before the housing 242 is moved into the path 312 of the radiation beam by pivoting the housing 242 around the hinge 1002.

[0069] Figure 12 It shows Figure 2The imaging system is configured 1200 in which housing 242 is configured to be selectively positioned within path 312 of X-ray beam 308. In configuration 1200, a sliding mechanism is available to move housing 242 to a position for calibration protocols. As an example, the sliding mechanism may include housing motor 1202 and housing drive shaft 1204, which are configured to move housing 242 along track 1206 perpendicular to the path of the radiation beam; however, it should be understood that other sliding mechanisms are contemplated.

[0070] Figure 13 A flowchart illustrating a method 1300 for performing a calibration scan of the illustrated flat phantom is shown. Method 1300 can be executed by one or more processors based on instructions stored in non-transitory memory. For example, method 1300 can be executed according to instructions stored in memory and executed by one or more processors of the computing device 216 of the imaging system 200 described above.

[0071] At 1302, method 1300 includes receiving a calibration scan request. In some examples, receiving a calibration scan request may include receiving user input to an operator console. For example, a user may click on an element to start a calibration scan.

[0072] At 1304, method 1300 includes identifying the calibration scan protocol. The calibration scan protocol can also be selected by the user. For example, the user can select the desired calibration protocol from a drop-down menu of available calibration protocols. It is worth noting that available calibration protocols may not include diagnostic protocols; for example, calibration protocols may have different radiation doses, beam configurations, etc.

[0073] At 1306, method 1300 includes determining a flat phantom corresponding to the identified calibration scan protocol. Each available calibration scan protocol may correspond to a specific flat phantom. Each flat phantom may include a subset of flat plates from a set of flat phantoms (e.g., set 304 described above). The set of flat phantoms may include various different flat plates with different densities and thicknesses and formed of different materials. In some examples, the set of flat phantoms may include more than one of the same flat plates. As described above, the set of flat phantoms may be integrated into an imaging system. For example, the set of flat phantoms may be incorporated into a beam filter that also houses filters used during diagnostic scan protocols, such as bowtie filters. In another example, the set of flat phantoms may be incorporated into a separate phantom housing located elsewhere in the imaging system (e.g., adjacent to the beam filter, within a gantry, etc.). Thus, the set of flat phantoms may include various combinations and sub-combinations of flat plates to form different flat phantoms.

[0074] Therefore, determining the plate phantom corresponding to the identified calibration protocol may include identifying a subset of the plates in the set of plate phantoms integrated into the imaging system, as indicated at 1308. The subset of plates may form the plate phantom to be imaged in the calibration scan. For example, for a first calibration scan protocol, a first subset of plates including a first plate, a second plate, and a third plate may form a first plate phantom corresponding to the first calibration scan protocol. For a second calibration scan protocol, a second subset of plates including a first plate, a second plate, and a fourth plate may form a second plate phantom corresponding to the second calibration scan protocol. When the identified calibration scan protocol is the first calibration scan protocol, a first subset of plates can be identified. When the identified calibration scan protocol is the second calibration scan protocol, a second subset of plates can be identified. Because the calibration scan protocol is used to calibrate the imaging system, filters configured for diagnostic protocols, such as bowtie filters, may not be identified.

[0075] At 1310, method 1300 includes moving a subset of the plate into the path of the X-ray beam. (See Figure 8 to...) Figure 10 As described, each plate can be coupled to a drive shaft of a motor. The motor can actuate the drive shaft to move the corresponding plate to a position intersecting the beam. In some examples, multiple plates can be coupled to the same drive shaft, in which case the motor can actuate the drive shaft to a specific position corresponding to a selected plate. Therefore, the motor corresponding to each plate within a subset of plates can be actuated to move each plate in the subset to a position intersecting the beam. The motor corresponding to a plate not in a subset of plates can be left unacted, and therefore the plates not in a subset of plates can remain unmoved and can remain outside the path of the beam.

[0076] For example, if a first calibration scan protocol is identified, the first, second, and third plates can be actuated to move to intersect the beam without moving the fourth plate. If a second calibration scan protocol is identified, the first, second, and fourth plates can be actuated to move to intersect the beam without moving the third plate. In this way, the intended plates of a phantom phantom designed for imaging in a calibration scan can be moved to intersect the beam.

[0077] As described herein, intersection with the radiation beam can include perpendicular intersection, whereby the plate moves linearly in a direction perpendicular to the path of the radiation beam. In some examples, the drive shaft can be rotated to position the plate within the path of the radiation beam.

[0078] Furthermore, when identifying calibration scan protocols, filters designed for diagnosing the protocol (such as bowtie filters) may not be actuated to move to a position intersecting the beam. In some examples, the bowtie filter may be coupled to the same drive shaft as the plate of the identified subset. In such examples, the drive shaft may be moved to a corresponding position that includes both the plate intersecting the beam and the bowtie filter not intersecting the beam.

[0079] At 1312, method 1300 includes acquiring a calibration scan of the plate phantom according to the identified calibration scan protocol. When a subset of the plate is positioned within the beam path, a calibration scan can be acquired such that X-rays pass through the plate phantom to image it. The output image of the plate phantom can be used for calibration purposes of the imaging system (e.g., compared with known standards to assess drift or other common systematic errors).

[0080] Therefore, the technical advantage of the system and method presented in this paper is that the flat panel can be integrated and stored within the imaging system itself. Thus, the flat panel does not need to be stored elsewhere, thereby reducing the space occupied by the flat panel. Furthermore, since the integrated phantom system can automatically and independently move the individual flat panels of the selected flat panel phantom to their appropriate positions without user assistance, operator time is reduced. The automatic placement of the flat panel phantom also improves calibration accuracy by reducing human error during placement.

[0081] Furthermore, because the housing in which the phantom plate set is positioned can be located closer to the X-ray source of the imaging system, the size (e.g., width) of each plate can be reduced, since the width of the X-ray beams that intersect with it is narrower closer to the X-ray source than at the isocenter where a manually placed phantom is typically positioned. Reducing the size of the plates can increase the space efficiency of storage within the system.

[0082] This disclosure also provides support for an imaging system comprising: a gantry including a radiation source and a detector; a housing positioned adjacent to the radiation source within the gantry; and a flat panel phantom assembly positioned within the housing, wherein the phantom assembly includes at least one flat panel phantom, and wherein the phantom assembly is configured such that the at least one flat panel phantom of the phantom assembly is independently movable, such that one or more of the at least one flat panel phantom of the phantom assembly can be selectively positioned in the path of a radiation beam between the radiation source and the detector. In a first example of the system, the housing includes a collimator configured to align and / or narrow the radiation beam, and wherein the housing includes one or more bowtie filters and an aperture. In a second example of the system, optionally including a first example, the one or more bowtie filters are positioned at a first end within the housing, the phantom assembly is positioned at a second end of the housing, and the aperture is positioned between the one or more bowtie filters and the phantom assembly. In a third example of the system, optionally including one or both of the first and second examples, the one or more bowtie filters are positioned at a first end within the housing, the flat panel model is positioned horizontally aligned with the one or more bowtie filters, and the aperture is positioned at a second end of the housing, vertically aligned with the one or more bowtie filters. In a fourth example of the system, optionally including one or more or each of the first to third examples, the at least one flat panel model includes a first flat panel model and a second flat panel model, and the system further includes at least one motor configured to selectively position one or more of the selected bowtie filters, the first flat panel model, and the second flat panel model within the path of the radiation beam. In a fifth example of the system, optionally including one or more or each of the first to fourth examples, the system further includes: a motor coupled to at least one of the one or more bowtie filters, wherein the motor is configured to move a selected bowtie filter among the one or more bowtie filters to selectively position the selected bowtie filter among the one or more bowtie filters in the path of the radiation beam.In a sixth example of the system, optionally including one or more or each of the first to fifth examples, the at least one flat phantom includes a first flat phantom and a second flat phantom. The system further includes a first motor coupled to the first flat phantom, wherein the first motor is configured to selectively position the first flat phantom within the path of the radiation beam between the radiation source and the detector, and wherein a first width of the first flat phantom is approximately equal to the width of the radiation beam in which the first flat phantom is selectively positioned. In a seventh example of the system, optionally including one or more or each of the first to sixth examples, the system further includes a second motor coupled to the second flat phantom, wherein the second motor is configured to move the second flat phantom to selectively position the second flat phantom within the path of the radiation beam between the radiation source and the detector, and wherein a second width of the second flat phantom is approximately equal to the width of the radiation beam in which the second flat phantom is selectively positioned. In an eighth example of the system, optionally including one or more or each of the first to seventh examples, the housing is rigidly coupled to a beam filter device, wherein the beam filter device is positioned between the housing and the radiation source. In a ninth example of the system, optionally including one or more or each of the first to eighth examples, the housing is configured to be selectively positioned in the path of the radiation beam and configured to move into and out of the path of the radiation beam by pivoting about a hinge. In a tenth example of the system, optionally including one or more or each of the first to ninth examples, the housing is configured to be selectively positioned in the path of the radiation beam and configured to move into and out of the path of the radiation beam by moving linearly along a track. In an eleventh example of the system, optionally including one or more or each of the first to eleventh examples, the at least one plate phantom includes a first plate phantom, a second plate phantom, and a third plate phantom of the plate phantom set, wherein the third plate phantom is movable independently relative to the first and second plate phantoms to selectively position the third plate phantom within the path of the radiation beam. In a twelfth example of the system, optionally including one or more or each of the first to eleventh examples, the at least one plate phantom includes a first plate phantom and a second plate phantom, wherein the first plate phantom is formed of a first material, and the second plate phantom is formed of a second material different from the first material.In the thirteenth example of the system, optionally including one or more or each of the first to twelfth examples, the at least one flat body mold includes a first flat body mold and a second flat body mold, wherein the first flat body mold has a first thickness and the second flat body mold has a second thickness different from the first thickness.

[0083] This disclosure also provides support for a method for calibrating an imaging system, the method comprising: identifying a requested calibration scan protocol; determining a planar phantom corresponding to the identified calibration scan protocol; identifying a subset of planar plates of a planar phantom set incorporated into a housing of the imaging system, the subset of planar plates forming the planar phantom corresponding to the identified calibration scan protocol; moving the subset of planar plates into the path of a radiation beam; and acquiring a calibration scan of the planar phantom. In a first example of the method, the subset of planar plates includes a first planar phantom, and wherein moving the first planar phantom includes actuating a first motor coupled to the first planar phantom via a first axis operable to move the first planar phantom in a direction perpendicular to the path of the radiation beam. In a second example of the method, optionally including the first example, the method further comprises: moving the housing into the path of the radiation beam by pivoting the housing about a hinge and / or translating the housing linearly along an orbit perpendicular to the path of the radiation beam, wherein the set of planar phantoms is positioned within the housing. In a third example of the method, optionally including one or both of the first and second examples, the method further includes: removing the scanning window before moving the housing into the path of the radiation beam by pivoting the housing about the hinge.

[0084] This disclosure also provides support for an imaging system comprising: a gantry including an aperture configured to receive an imaging subject; a radiation source positioned within the gantry and configured to emit a radiation beam; a detector positioned within the gantry opposite the radiation source; a housing located adjacent to the radiation source within the gantry, wherein a first plate phantom and a second plate phantom are positioned within the housing; a first drive system configured to move the first plate phantom into and out of the path of the radiation beam; a second drive system configured to move the second plate phantom into and out of the radiation beam; and a computing device having instructions stored in a non-transitory memory, the instructions, when executed by a processor, causing the processor to: identify a calibration scan protocol and actuate one or more of the first and second drive systems to move the first plate phantom and / or the second plate phantom into the path of the radiation beam, respectively, based on the identified calibration scan protocol, and to perform a calibration procedure. In a first example of the system, the housing includes at least one bowtie filter and an aperture, wherein the aperture is positioned between the at least one bowtie filter and the first flat panel model and the second flat panel model.

[0085] Figures 1-12An example configuration for the relative positioning of the various components is shown. In at least one example, if such components are shown to be in direct contact or directly coupled, they may be referred to as being in direct contact or directly coupled, respectively. Similarly, in at least one example, components shown to be adjacent to or next to each other may be referred to as being adjacent to or next to each other, respectively. For example, components placed in coplanar contact with each other may be referred to as being in coplanar contact. As another example, in at least one example, components positioned to be spaced apart from each other and having only space between them without other components may be described and referenced as such. As yet another example, components shown to be above / below each other, on opposite sides of each other, or on the left / right side of each other may be described and referenced relative to each other. Furthermore, as shown, in at least one example, the topmost component or the point of the component may be referred to as the “top” of the component, and the bottommost component or the point of the component may be referred to as the “bottom” of the component. As used herein, top / bottom, upper / lower, above / below may be relative to the vertical axis of the figure and may be used to describe the position of the components in the figure relative to each other. Therefore, in one example, an element shown above other elements is vertically positioned above them. Similarly, the shapes of the elements depicted in the figures can be described as having those shapes (e.g., circular, straight, planar, curved, rounded, chamfered, angled, etc.). Furthermore, in at least one example, elements shown intersecting each other can be described as intersecting elements or intersecting with each other. Additionally, in one example, an element shown as being inside or outside another element can be described and referred to as such.

[0086] As used herein, elements or steps listed in the singular and beginning with the word "a" or "an" should be understood to not exclude a plurality of said elements or steps unless such exclusion is explicitly stated. Furthermore, references to "one embodiment" of the invention are not intended to be construed as excluding the existence of additional embodiments that also include the referenced features. Moreover, unless explicitly stated to the contrary, embodiments that "comprise," "include," or "have" elements or multiple elements having a particular characteristic may include additional such elements that do not have that characteristic. The terms "comprise" and "in" are used as concise linguistic equivalents to the corresponding terms "comprising" and "wherein". Furthermore, the terms "first," "second," and "third," etc., are used merely as notations and are not intended to impose numerical requirements or a particular order of position on their objects.

[0087] This written description uses examples to disclose the invention, including the best mode, and also enables those skilled in the art to practice the invention, including making and using any device or system and performing any incorporated methods. The scope of patentability of the invention is defined by the claims, but may include other examples that would occur to those skilled in the art. Such other examples are intended to fall within the scope of the claims if they have structural elements that are not indistinguishable from the literal language of the claims, or if they include equivalent structural elements that have minor differences from the literal language of the claims.

Claims

1. An imaging system (200), the imaging system comprising: a gantry (322) including a radiation source (302) and a detector (314); a housing (306) positioned adjacent the radiation source within the gantry; a flat panel phantom set (304) positioned in the housing, wherein the flat panel phantom set includes at least one flat panel phantom (324, 326), and wherein the flat panel phantom set is configured such that the at least one flat panel phantom of the flat panel phantom set is independently movable to enable one or more of the at least one flat panel phantom of the flat panel phantom set to be selectively positioned in a path (312) of a radiation beam (308) between the radiation source and the detector.

2. The imaging system of claim 1, wherein the housing includes a collimator configured to collimate and / or narrow the radiation beam, and wherein the housing includes one or more bowtie filters (320) and an aperture (618).

3. The imaging system of claim 2, wherein the one or more bowtie filters are positioned in the housing at a first end (390), the flat panel phantom set is positioned at a second end (392) of the housing, and the aperture is positioned between the one or more bowtie filters and the flat panel phantom set.

4. The imaging system of claim 2, wherein the one or more bowtie filters are positioned in the housing at a first end (390), the flat panel phantom set is positioned in horizontal alignment with the one or more bowtie filters, and the aperture is positioned at a second end (392) of the housing in vertical alignment with the one or more bowtie filters.

5. The imaging system of claim 2, wherein the at least one flat panel phantom includes a first flat panel phantom (324) and a second flat panel phantom (326), the imaging system further comprising at least one motor (602, 604), wherein at least one motor is configured to selectively position one or more of a selected one of the one or more bowtie filters, the first flat panel phantom, and the second flat panel phantom in the path of the radiation beam.

6. The imaging system of claim 2, further comprising a motor (602) coupled at least one of the one or more bowtie filters, wherein the motor is configured to move a selected one of the one or more bowtie filters to selectively position the selected one of the one or more bowtie filters in the path of the radiation beam.

7. The imaging system of claim 1, wherein the at least one flat panel phantom comprises a first flat panel phantom (705) and a second flat panel phantom (716), the imaging system further comprising a first motor coupled to the first flat panel phantom, wherein the first motor is configured to selectively position the first flat panel phantom in the path of the radiation beam between the radiation source and the detector, and wherein a first width (530) of the first flat panel phantom is approximately equal to a width (532) of the radiation beam in which the first flat panel phantom is selectively positioned.

8. The imaging system of claim 7, the imaging system further comprising a second motor (714) coupled to the second flat panel phantom (716), wherein the second motor is configured to move the second flat panel phantom to selectively position the second flat panel phantom in the path of the radiation beam between the radiation source and the detector, and wherein a second width of the second flat panel phantom is approximately equal to a width of the radiation beam in which the second flat panel phantom is selectively positioned.

9. The imaging system of claim 1, wherein the housing (242) is rigidly coupled to a beam filtering device (240), and wherein the beam filtering device is positioned between the housing and the radiation source.

10. The imaging system of claim 1, wherein the housing is configured to be selectively positioned in the path of the radiation beam and is configured to be moved into and out of the path of the radiation beam by pivoting about a hinge (1002).

11. The imaging system of claim 1, wherein the housing is configured to be selectively positioned in the path of the radiation beam and is configured to be moved into and out of the path of the radiation beam by linearly moving along a track (1206).

12. The imaging system of claim 1, wherein the at least one flat panel phantom comprises a first flat panel phantom (324), a second flat panel phantom (326), and a third flat panel phantom (524) of the set of flat panel phantoms, wherein the third flat panel phantom is independently movable relative to the first flat panel phantom and the second flat panel phantom to selectively position the third flat panel phantom in the path of the radiation beam.

13. The imaging system of claim 1, wherein the at least one flat panel phantom comprises a first flat panel phantom (324) and a second flat panel phantom (326), wherein the first flat panel phantom is formed of a first material and the second flat panel phantom is formed of a second material different from the first material.

14. The imaging system of claim 1, wherein the at least one flat panel phantom comprises a first flat panel phantom and a second flat panel phantom, wherein the first flat panel phantom has a first thickness and the second flat panel phantom has a second thickness different from the first thickness.

15. A method (1300) for calibrating an imaging system (200), the method comprising: identifying (1304) a requested calibration scan protocol; determining (1306) a flat panel phantom corresponding to the identified calibration scan protocol; identifying (1308) a subset of flats of a set of flat panels incorporated into a housing of the imaging system, the subset of flats forming the flat panel phantom corresponding to the identified calibration scan protocol; moving (1310) the subset of flats into a path of a radiation beam; and acquiring (1312) a calibration scan of the flat panel phantom. ​

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