Motion detection of gantry of computer tomography (CT) imaging system

Abstract

To improve an approach for detection a motion of a gantry of a CT imaging system.SOLUTION: A CT imaging system includes: a rotation frame for generating an X-ray radiation, transmitting the X-ray radiation, and supporting at least one component for receiving the X-ray radiation; a first motion sensor 602 configured to sense a first motion of the gantry on a first face and generate a first signal showing the first motion and having a first noise floor; a second motion sensor 602 configured to sense the first motion of the gantry on the first face simultaneously and generate a second signal showing the first motion and having a second noise floor; and a motion signal processing circuit 402 configured to generate a first coupling signal showing the first motion by coupling the first signal and the second signal, in which the first coupling signal has a third noise floor that is lower than the first noise floor and the second noise floor.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The following description relates generally to computed tomography (CT), and more particularly to detecting gantry motion in a computed tomography (CT) imaging system. [Background technology]

[0002] A computed tomography (CT) scanner includes a gantry and a rotating frame rotatably supported within the gantry by bearings. The rotating frame is configured to rotate around an examination region along a rotational axis about a center of rotation (i.e., an isocenter). The rotating frame supports components (such as at least an X-ray source, an X-ray sensitive detector array, a high-voltage generator, an X-ray collimator, and a gantry cooling system). For axial and / or helical scans, the rotating frame rotates around the examination region, the X-ray source emits X-ray radiation, and the X-rays intersect the isocenter (and the subject and / or object within the examination region) and are detected by the X-ray sensitive detector array.

[0003] The X-ray sensitive detector array generates projection data (line integrals) representative of the sensed X-ray radiation. A reconstructor reconstructs the projection data to generate volumetric image data. The voxels of the reconstructed volumetric image data are displayed as two-dimensional (2D) and / or three-dimensional (3D) CT images using grayscale values ​​corresponding to relative radiation densities. The grayscale values ​​reflect the attenuation characteristics of the scanned subject and / or object and generally indicate structure (e.g., anatomical structures within the scanned subject and / or physical structures within the scanned object).

[0004] In image space, the isocenter is used as the center of the reconstructed CT image. Therefore, movement of the isocenter during a scan can manifest as artifacts (e.g., blurring) in the reconstructed CT image, degrading the image quality and / or diagnostic quality of the CT image. This can expose the patient to additional x-ray radiation (e.g., the patient is rescanned due to poor image quality), and x-ray radiation is ionizing radiation, which can damage and / or kill tissue. Causes of such movement include imbalances in the mass supported by the rotating frame and improper mounting of the gantry relative to the examination room floor.

[0005] During manufacturing, the mass is initially balanced on the rotating frame, where components are installed in position on the rotating gantry according to an assembly procedure, the rotating frame is rotated, motion is detected with a motion detector, and one or more balance weights are attached to one or more balance weight supports to balance the mass about the axis of rotation. Mass imbalances can occur during transportation, installation at a user site, replacement of components on the rotating frame for preventive maintenance, replacement of components on the rotating frame for corrective maintenance, and over time.

[0006] Procedures exist that use motion sensors to ensure that the rotating frame is balanced. If the mass is not balanced, a rebalancing procedure can be performed to rebalance the mass. However, depending on the rotational speed of the rotating frame, the level of the motion signal may be small and fall within the noise floor of the motion sensor, making it impossible to distinguish the motion signal from noise and use it for balancing purposes. Even if the frame is balanced, other causes (such as poor mounting of the gantry to the examination room floor) may cause the gantry motion signal to fall within the noise floor of the motion sensor, making it impossible to distinguish the motion signal from noise, even if the motion is large enough to adversely affect image quality.

[0007] In view of at least the above, there remains an unresolved problem of improving approaches to detecting gantry motion in CT imaging systems. Summary of the Invention

[0008] The aspects described herein address these and other problems. This Summary introduces concepts that are described in more detail in the Detailed Description. This Summary should not be used to identify essential features of the claimed subject matter, nor does it limit the scope of the claimed subject matter.

[0009] In one aspect, a computed tomography imaging system includes a gantry and a rotating frame. The rotating frame is rotatably supported within the gantry. The rotating frame supports at least one component for generating x-ray radiation, transmitting x-ray radiation, or receiving x-ray radiation. The computed tomography imaging system further includes a first motion sensor configured to sense a first movement of the gantry in a first plane and generate a first signal indicative of the first movement. The first signal has a first noise floor. The computed tomography imaging system further includes a second motion sensor configured to simultaneously sense the first movement of the gantry in the first plane and generate a second signal indicative of the first movement. The second signal has a second noise floor. The computed tomography imaging system further includes motion signal processing circuitry configured to combine the first signal and the second signal to generate a first combined signal indicative of the first movement. The first combined signal has a third noise floor lower than the first noise floor and the second noise floor. Includes:

[0010] In another aspect, a computer-implemented method includes detecting a first movement of a gantry of a computed tomography imaging system in a first plane with a first motion sensor. The computer-implemented method further includes generating a first signal indicative of the first movement. The first signal has a first noise floor. The computer-implemented method further includes detecting the first movement of the gantry with a second motion sensor concurrently with detecting the first movement with the first motion sensor. The computer-implemented method further includes generating a second signal indicative of the first movement. The second signal has a first noise floor. The computer-implemented method further includes combining the first signal and the second signal to obtain a first combined signal. The first combined signal has a third noise floor lower than the first noise floor and the second noise floor.

[0011] In another aspect, a computer-readable medium is encoded with computer-executable instructions that, when executed by a processor, cause the processor to detect a first movement of a gantry of a computed tomography imaging system in a first plane with a first motion sensor. The computer-executable instructions further cause the processor to generate a first signal indicative of the first movement, the first signal having a first noise floor. The computer-executable instructions further cause the processor to detect the first movement of the gantry with a second motion sensor simultaneously with detecting the first movement with the first motion sensor. The computer-executable instructions further cause the processor to generate a second signal indicative of the first movement, the second signal having a first noise floor. The computer-executable instructions further cause the processor to combine the first signal and the second signal to obtain a first combined signal, the first combined signal having a third noise floor lower than the first noise floor and the second noise floor.

[0012] Those skilled in the art will recognize other aspects of the present application upon reading and understanding the accompanying description. [Brief explanation of the drawings]

[0013] This application is illustrated by way of example and not by way of limitation in the figures, in which like reference numerals refer to like elements. [Figure 1] 1 illustrates a schematic diagram of a non-limiting example of an imaging system configured for computed tomography and including a gantry motion sensing system, according to embodiments herein. [Figure 2] 1A and 1B illustrate schematic non-limiting examples of rotating frames supporting components with different masses of an imaging system and balance weights, according to embodiments herein. [Figure 3] 1 illustrates a schematic, non-limiting example of a portion of a gantry of an imaging system mounted on a support, according to embodiments herein. [Figure 4] 1A and 1B illustrate schematic, non-limiting examples of block diagrams of gantry motion sensing systems, according to embodiments herein. [Figure 5] 10 is a graphical illustration of the total noise of the sensor combination of a gantry motion sensing system as a function of the number of motion sensors, according to embodiments herein. [Figure 6] 1 illustrates a schematic diagram of a non-limiting example of a gantry motion sensing system according to embodiments herein. [Figure 7] 10 schematically illustrates another non-limiting example of a gantry motion sensing system according to embodiments herein. [Figure 8] 10 schematically illustrates yet another non-limiting example of a gantry motion sensing system according to embodiments herein. [Figure 9] 10 schematically illustrates yet another non-limiting example of a gantry motion sensing system according to embodiments herein. [Figure 10] 10 schematically illustrates another non-limiting example of a gantry motion sensing system, according to embodiments herein. [Figure 11] 1A and 1B are schematic diagrams illustrating non-limiting examples of gantry motion sensing systems installed within and on a gantry of an imaging system, according to embodiments herein. [Figure 12] 12A and 12B schematically illustrate an expanded view of the installed gantry motion sensing system of FIG. 11 according to embodiments herein. [Figure 13] 1 illustrates a non-limiting example flowchart of a computer-implemented method for balancing a mass supported by a rotating frame, according to embodiments herein. [Figure 14] FIG. 10 illustrates another non-limiting example of a flowchart of a computer-implemented method for balancing a mass supported by a rotating frame, according to embodiments herein. [Figure 15] 1 illustrates a non-limiting example of a flowchart of a computer-implemented method for installing a gantry on a support, according to embodiments herein. [Figure 16] 1 illustrates a non-limiting example of a flowchart of a computer-implemented method for installing a gantry on a support, according to embodiments herein. [Figure 17] 1 illustrates a non-limiting example flowchart of a computer-implemented method for verifying that gantry motion is within a predetermined gantry motion tolerance range through a calibration procedure, according to embodiments herein. [Figure 18] 10 illustrates another non-limiting example of a flowchart of a computer-implemented method for verifying that gantry motion is within a predetermined gantry motion tolerance range through a calibration procedure, according to embodiments herein. DETAILED DESCRIPTION OF THE INVENTION

[0014] Embodiments of the present disclosure are described by way of example with reference to the figures, in which a system, method, and / or computer-readable medium includes instructions for detecting motion of a gantry of a computed tomography (CT) imaging system with a set of motion sensors using a technique for reducing the noise floor, capable of detecting small motions that would otherwise fall within the noise floor and be indistinguishable from noise. As described in more detail below, in one example, the technique includes simultaneously detecting the same motion of the gantry using motion sensors of the set of motion sensors and then combining the motion signals output by the motion sensors to generate a combined motion signal for reducing the noise floor.

[0015] Other processing includes integrating the combined motion signal and reading out the integrated signal for further processing. In certain embodiments, the sensed motion is used to balance the weight of an object supported by the rotating frame during manufacturing and / or at a user site to rebalance the weight of an object during maintenance operations after a part has been replaced. Additionally or alternatively, the sensed motion is used to ensure that the gantry is firmly attached to the floor of the examination room. Additionally or alternatively, the sensed motion is monitored over time to ensure that the gantry motion remains within predetermined tolerances.

[0016] Referring initially to FIG. 1 , a non-limiting example of an imaging system 102 (such as a computed tomography (CT) imaging system) is shown schematically. The imaging system 102 includes a gantry 104. In some embodiments, the gantry 104 is configured to tilt. The imaging system 102 further includes a rotating frame 106. The rotating frame 106 is rotatably supported on the gantry 104, for example, via bearings (e.g., slip rings), and is configured to rotate about a rotation axis or Z-axis 110 that passes through a center of rotation / center (i.e., isocenter) of the examination region 108. A gantry controller (not shown) is configured to control the rotation of the rotating frame 106 and, if configured to tilt, the tilt of the gantry 104.

[0017] The X-ray source assembly 112 is supported by the rotating frame 106 and rotates therewith. The X-ray source assembly 112 includes an X-ray source 114 (e.g., an X-ray tube). The X-ray source 114 is configured to emit X-ray radiation having an energy in an X-ray diagnostic range (e.g., 20 keV to 150 keV). The X-ray assembly 112 may further include or be coupled to a filter 116 that provides a dose profile of the X-ray radiation and / or a collimator 118 that shapes the X-ray radiation to form a generally fan-shaped, wedge-shaped, cone-shaped, etc., beam across the examination region 108. An X-ray controller (not shown) is configured to control components of the X-ray assembly 112, such as the X-ray source 114, the collimator 118, etc.

[0018] The X-ray radiation sensitive detector array 120 includes a one-dimensional (1D) or two-dimensional (2D) array of rows of X-ray radiation sensitive detector elements 122 and is supported by the rotating frame 106 along an arc opposite the X-ray source 114 relative to the examination region 108. Each X-ray radiation sensitive detector element 122 is in electrical communication with a data acquisition system (DAS) 124. The X-ray radiation sensitive detector elements 122 may include indirect conversion detectors (such as scintillator / photodiode detectors) and / or direct conversion detectors (such as cadmium telluride (CdTe), cadmium zinc telluride (CZT), etc. detectors). A DAS controller (not shown) controls the X-ray radiation sensitive detector array 120.

[0019] Referring to FIG. 2 , a side view of the rotating frame 106 is shown schematically. In this embodiment, the rotating frame 106 supports at least the X-ray source assembly 112, the X-ray radiation sensitive detector array 120, and at least one balance weight support 202. The balance weight support 202 is configured to support one or more balance weights 204. Generally, components used to generate, emit, and / or detect X-ray radiation are of different shapes, sizes, masses, etc., and are attached to the rotating frame 106 in predetermined positions and within predetermined mechanical tolerances according to an assembly procedure. The one or more balance weights 204 are mounted on the at least one balance weight support 202 to evenly distribute the mass supported by the rotating frame 106 along the Z-axis 110.

[0020] Returning to FIG. 1 , the gantry 104 is mounted to a support 126. In this example, the support 126 is the floor of an examination room. Referring to FIG. 3 , an example of a bottom 300 of the gantry 104 mounted to the floor 126 is shown schematically. In this example, a mounting bracket 302 for the gantry 104 is disposed on the surface of the floor 126. A plurality of mounting elements 304 are fixed to and / or integrated into the support 126. For each mounting element 304, a trunk 306 extends from the floor 126, through an opening in the mounting bracket 302, and into the mounting bracket 302. A locking mechanism 308 engages the trunk 306, locking the mounting bracket 302 (and therefore the gantry 104) to the floor 126.

[0021] 1, gantry 104 includes gantry motion sensing system 128. Gantry motion sensing system 128 is configured to sense specific movements of gantry 104 (e.g., gantry movement in the X direction, gantry movement in the Z direction). Generally, gantry motion sensing system 128 uses multiple motion sensors in a set of motion sensors to simultaneously detect the same gantry movement and then combines the motion signals generated by the multiple motion sensors to reduce the noise floor and detect small movements that would otherwise be lost within the noise floor and not be easily detected using the techniques described herein.

[0022] In one example, the sensed motion is used during manufacturing to balance the mass supported by the rotating frame. In another example, the sensed motion is used at a user site to rebalance the mass, for example, during inspection after a part has been replaced. Additionally or alternatively, the sensed motion is used to ensure that the gantry is securely attached to the floor of the examination room. Additionally or alternatively, the sensed motion is monitored over time to ensure that the gantry motion remains within a predetermined tolerance. Additionally or alternatively, the sensed motion is used in other ways.

[0023] Referring to FIG. 4, an example block diagram of the gantry motion sensing system 128 is shown. The gantry motion sensing system 128 includes a set of motion sensors 402. In one embodiment, the set of motion sensors 402 includes a set of acceleration sensors configured to detect gantry motion in at least two axes / planes, e.g., along the X and Z directions. The gantry motion sensing system 128 further includes motion signal processing circuitry 404. In one embodiment, the motion signal processing circuitry 404 is configured to combine signals generated by the set of accelerometers to generate an acceleration signal indicative of gantry motion. Further processing includes integrating the combined signals to determine a velocity signal indicative of gantry motion. In some embodiments, further processing includes integrating the velocity signal to determine a displacement signal indicative of gantry motion. In another embodiment, the velocity signal is read and further processed by other hardware and / or software to determine the displacement signal.

[0024] In one example, the set of accelerometers includes at least two accelerometers configured to sense gantry motion in the same plane (e.g., X or Z), and the motion signal processing circuitry 404 includes corresponding circuitry that averages the motion signals generated by the at least two accelerometers. In one example, the averaging is based on a statistical analysis approach (such as a root-sum-of-squares / square-root-sum-of-squares approach). With respect to noise, such an approach reduces the noise floor of the set of accelerometers compared to the individual accelerometers of the set, as shown in Equation 1.

number

Equation

[0025] Referring to FIG. 5, a graphical representation showing the relationship between the noise floor of a set of n acceleration sensors and the number n of acceleration sensors is shown. In FIG. 5, the first axis 502 represents the magnitude of the signal, and the second axis 504 represents the noise. Plot 506, plot 508, and plot 510 show the total noise for n = i, plot 512 shows the total noise for n = j, and plot 514 shows the total noise for n = k. Here, i, j, and k are positive integers, and i < j and j < k. From FIG. 5, as n increases from i to j and then to k, the noise floor of a set of n acceleration sensors decreases. In a non-limiting example, examples of n include 2, 16, 30, values greater than, values less than, or values between those values.

[0026] Returning to FIG. 1, the subject / object support 130 includes a top plate 132 movably coupled to the frame / base 134. In one embodiment, the top plate 132 is slidably coupled to the frame / base 134 via bearings or the like, and is moved in and out of the inspection area 108 along the frame / base 134 by a drive system (not shown) including a controller, a motor, a lead screw, and a nut (or other drive system). The top plate 132 is configured to support an object or a subject within the inspection area 108 and to carry in, scan, and / or carry out the subject or object. The drive system is controlled by a table controller (not shown).

[0027] For helical scanning, the rotating frame 106 rotates in coordination with the top plate 132, which moves along the Z-axis 110, and the active x-ray detector elements 122 of the x-ray radiation-sensitive detector array 120 detect x-ray radiation over successive arcuate intervals (integration periods) with each rotation and generate respective signals. For axial (step-and-shoot) scanning, the top plate 132 is positioned at a stationary position during each integration period and moves between integration periods. For each arcuate interval, the data acquisition electronics 124 processes the respective signals and generates projection data.

[0028] The reconstructor 136 reconstructs the projection data to generate volumetric (3D) image data for helical scans and / or individual axial (2D) images for axial step-and-shoot scans (the axial 2D images can be combined to generate the volumetric image data). The volumetric image data and / or 2-D slices of the volumetric image data and / or the individual axial images can be presented visually, recorded on film, etc. Examples of suitable reconstruction algorithms include filtered backprojection (FBP), advanced statistical iterative reconstruction (ASIR), conjugate gradient (CG), maximum likelihood expectation maximization (MLEM), model-based iterative reconstruction (MBIR), and / or other reconstruction algorithms.

[0029] Computing system 138 serves as an operator console for system 102. Computing system 138 may include a computer, a workstation, etc. Computing system 138 includes input / output (I / O) 140. Input devices 142 include a keyboard, a mouse, a touch screen, a microphone, etc. The input devices 142 electronically communicate with computing system 138 through I / O 140 and / or in other ways. Output devices 144 include a human-readable device (e.g., a display monitor). The output devices 144 electronically communicate with computing system 138 through I / O 140 and / or in other ways.

[0030] The remote resources 146 include one or more of a server, a workstation, a radiology information system (RIS), a hospital information system (HIS), an electronic medical record (EMR), a picture archiving and communication system (PACS), one or more other CT scanners, cloud processing resources (cloud processing resources include shared remote data storage and / or computing power, including processing resources distributed across multiple locations / data centers), etc. The remote resources 146 communicate electronically with the computing system 138 via the I / O 140 and / or by other means.

[0031] Computing system 138 also includes at least one processor 148 (e.g., microprocessor (μP), central processing unit (CPU), graphics processing unit (GPU), etc.) and computer-readable medium 150 ("memory") (including non-transitory media, but excluding transitory media (signals, carrier waves, etc.)). Computer-readable medium / memory 150 includes at least a gantry motion assessment module 152. As described in more detail below, in one embodiment, gantry motion assessment module 152 is configured to process motion signals from gantry motion sensing system 128 in connection with, for example, balancing the mass supported by rotating frame 106, ensuring proper installation of gantry 104 in the examination room, monitoring gantry movement over time, etc.

[0032] In one example, this includes providing notifications, messages, warnings, etc. regarding gantry motion. For example, in one example, gantry motion assessment module 152 provides a value for motion in a plane along with a predetermined range of allowable motion in that plane. In another example, gantry motion assessment module 152 processes to display a pop-up window or the like on a display monitor of output device 144 with an indicator (text, graph, etc.) indicating the sensed motion relative to the predetermined range. Additionally or alternatively, gantry motion assessment module 152 processes to send a text message, email, etc. to service staff and / or the manufacturer in response to the sensed motion falling outside the predetermined range. Other notifications, messages, warnings, etc. are also contemplated herein.

[0033] 6, an example of a gantry motion sensing system 128 (FIG. 1) is shown schematically. The set of motion sensors 402 (FIG. 4) includes motion sensors MS 1,1 , ..., motion sensor MS N,1 , ..., motion sensor MS 1,M , ..., and a motion sensor MS N,M where N is an integer greater than or equal to 1 and M is an integer greater than or equal to 1, such that when M equals 1, N is greater than 1 and when N equals 1, M is greater than 1. In this example, each motion sensor in the array of N x M motion sensors 602 is a multi-axis motion sensor, with at least one axis assigned to sense gantry motion in one axis / plane (e.g., X or Z direction), another axis assigned to sense gantry motion in another axis / plane (e.g., X or Z direction), and so on. As an example, motion sensor MS 1,1 , ..., MS N,M includes a multi-axis accelerometer using microelectromechanical systems (MEMS) packaged on an integrated chip (IC).

[0034] The motion signal processing circuit unit 404 (FIG. 4) includes averaging circuits AC1, . . . and AC K, ..., and a processor AC1 that samples only the output acceleration values ​​of each motion sensor in the array of N by M motion sensors 602 that correspond to the axis / plane assigned to the averaging circuit AC1. K is the average circuit AC of each motion sensor in the array 602 of N×M motion sensors. K Only the output acceleration values ​​corresponding to the axis / plane assigned to the averaging circuits AC1, ..., and AC K are configured to simultaneously sample the outputs of the array of N×M motion sensors 602. Each averaging circuit of the K averaging circuits 604 is configured to determine an average of samples of acceleration values ​​of a corresponding motion sensor in the array of N×M motion sensors 602, for example, based on a square root of the sum of squares / square root of the sum of squares approach and / or other approaches. In one embodiment, averaging circuits AC1, ..., and AC K includes MEMS-based devices mounted on ICs.

[0035] The motion signal processing circuit unit 404 includes integrating circuits IC1, . . . and integrating circuit IC K The integrator circuit IC1 integrates the output of the averaging circuit AC1, ..., and the integrator circuit IC K is the averaging circuit AC K In one example, integrator circuits IC1, ..., and IC K includes MEMS-based devices mounted on ICs.

[0036] The gantry motion sensing system 128 further includes readout electronics 608. The readout electronics 608 receives the signals integrated by integrator circuits IC1, ..., and IC2. KIn one embodiment, the readout electronics 608 is part of and / or electrically connected to an electromechanical connector, such as the socket (e.g., a "female" socket including an outer housing and receptacle contacts) of a plug and socket connector pair. In this example, the complementary electromechanical connector may include the plug (e.g., a "male" plug including an outer housing and conductive pins) of a plug and socket connector pair.

[0037] In this example, the array of N×M motion sensors 602, the K averaging circuits 604, the K integrating circuits 606, and the readout electronics 608 are disposed on a common substrate 610, such as a circuit board (e.g., a printed circuit board (PCB), a printed wiring board (PWB), etc.). In this example, the integrated signals are further processed remotely from the common substrate 610, e.g., to determine displacement values ​​for motion in the axis / plane assigned to the averaging circuit AC1, ..., and displacement values ​​for motion in the axis / plane assigned to the averaging circuit AC1. In one example, other hardware components and / or software within the gantry 104 determine the displacement values. Additionally or alternatively, other hardware components and / or software external to the gantry 104 (e.g., hardware components and / or software within the operator console 138) determine the displacement values. For example, in one example, the gantry motion estimation module 152 is configured to determine the displacement values ​​from signals read out from the common substrate 610.

[0038] 7 shows a schematic diagram of a variation of the gantry motion sensing system 128 (FIG. 1). In this embodiment, the gantry motion sensing system 128 includes integrating circuits IC1, ..., and integrating circuit IC K For purposes of illustration and clarity, the set of K integrator circuits 606 includes integrator circuits IC1, ..., and the set of K integrator circuits 606 includes integrator circuits IC K are the speed circuits VC1, ..., and the speed circuit VC K, and the integrator circuits IC1, ..., of the second set of K integrator circuits 702, and the integrator circuit IC K are the displacement circuits DC1, ..., and the displacement circuit DC K It is called.

[0039] The displacement circuit DC1 of the second set of K integrator circuits 702 integrates the output of the velocity circuit IC1 of the set of K integrator circuits 606 to generate a displacement value for motion in the axis / plane assigned to the averaging circuit AC1, ..., and the displacement circuit IC K The set of K integrating circuits 606 integrates the output of the velocity circuit IC1 and the averaging circuit AC K The readout electronics 608 generates displacement values ​​for movement in the axis / plane assigned to the displacement circuits IC1, ..., and integrator circuit IC of a second set of K integrator circuits 702. K In another embodiment, the velocity and displacement calculations are performed within the same IC.

[0040] 8 schematically illustrates another variation of gantry motion sensing system 128 (FIG. 1). In this example, gantry motion sensing system 128 includes a circuit board 802 for motion in one axis / plane (e.g., X or Z) and a circuit board 804 for motion in another axis / plane (e.g., the other of the X and Z directions). Circuit board 802 includes a set of motion sensors 806, motion signal processing circuitry 808 (e.g., averaging and integrating circuits, etc.), and readout electronics 810. Circuit board 804 includes a set of motion sensors 812, motion signal processing circuitry 814 (e.g., averaging and integrating circuits, etc.), and readout electronics 816.

[0041] The functionality of motion sensor set 806, motion signal processing circuitry 808, readout electronics 810, motion sensor set 812, motion signal processing circuitry 814, and readout electronics 816 is substantially similar to the functionality described in connection with motion sensor set 602, set of averaging circuitry 604, and readout electronics 608 of Figure 6, except that each circuit board 802 and 804 is configured for a single axis / plane, allowing the use of single-axis sensors or a single axis of a multi-axis sensor on each circuit board 802 and 804. Circuit boards 802, ..., and circuit board 804 are mounted on a common substrate 818.

[0042] 9 schematically illustrates another variation of gantry motion sensing system 128 (FIG. 1). In this example, gantry motion sensing system 128 is substantially similar to the variation described in connection with FIG. 9, except that common board 818 is omitted and each circuit board, circuit board 802, ..., and circuit board 804, is individually mounted on gantry 104.

[0043] FIG. 10 schematically illustrates another variation of the gantry motion sensing system 128 (FIG. 1). In this embodiment, the gantry motion sensing system 128 is substantially similar to the variation described in connection with FIG. 6, except that the motion signal processing circuitry 404 is omitted. As described herein, in one embodiment, each motion sensor in the array of N×M motion sensors 602 is a multi-axis motion sensor, with at least one axis assigned to sense gantry motion in one axis / plane, another axis assigned to sense gantry motion in another axis / plane, and so on, such that the motion sensors in the array of N×M motion sensors 602 output acceleration values ​​corresponding to the detected gantry motion. In this example, readout electronics 608 reads out the acceleration signals. Other processing (such as integrating the acceleration signals to determine displacement values ​​corresponding to gantry motion) is performed off-board 610.

[0044] FIG. 11 schematically illustrates an exemplary location of the gantry motion sensing system 128 ( FIG. 1 ) within the gantry 104. Typically, for an imaging system 102 mounted on a floor 126 ( FIG. 3 ), a higher position of the gantry 104 relative to the support 126 experiences more movement than a lower position of the gantry 104 because the gantry / floor surface is the pivot point. FIG. 11 illustrates the interior of the imaging system 102, e.g., with the front cover open or removed. In FIG. 11 , the gantry motion sensing system 128 is mounted within the gantry 104 near the top 1102 of the gantry 104. Additionally, the gantry motion sensing system 128 may be mounted within the gantry 104 near the rotating frame 106 to facilitate communication of X and / or Z movement of the rotating frame 106 to the gantry motion sensing system 128.

[0045] Figure 12 shows an expanded view of the gantry motion sensing system 128 shown in Figure 11. In this embodiment, the gantry motion sensing system 128 is housed in a container 1202, which is attached to the gantry 104 by fasteners 1204 and 1206 (screws, nuts and bolts, rivets, etc.) via a mounting plate 1208 on the container 1202. The electromechanical connector 1214 is complementary to and connects to the electromechanical connector of the readout electronics 608. The electromechanical connector 1210 includes a cable 1214 for transmitting motion signals from the gantry motion sensing system 128. In one embodiment, the cable 1214 is at least part of a communication path to the operator console 138 (Figure 1), for transmitting the motion signals, for example, for processing by the gantry motion assessment module 152 and / or others.

[0046] As described herein, the motion signals can be used to balance and / or rebalance a mass supported by the rotating gantry 106. An exemplary approach is described in U.S. Pat. No. 6,890,100 B2 to Reznicek et al., entitled "CT Gantry Balance System," filed May 10, 2005, and incorporated herein by reference in its entirety. In this approach, signals from multiple sensors are transmitted to a balance sensor buffer board, then to a sub-board containing filters, then to an analog-to-digital converter, and then to a microprocessor having firmware that performs certain calculations. The output of the microprocessor is transmitted to a monitor and / or printer, which provides balancing calculations and instructions based on the algorithms disclosed herein.

[0047] Another exemplary technique for balancing and / or rebalancing the mass supported by the rotating gantry 106 is described in U.S. Pat. No. 6,748,806 B2 to Halsmer, entitled "Dynamic balancing system for computed tomography gantry," filed August 28, 2003, and incorporated herein by reference in its entirety. This technique utilizes signals from multiple sensors to move weights to balance the gantry. In one embodiment, the weights can be moved manually by directly controlling signals on leads, such as through a control panel. In another example, an automatic balancing procedure is used, in which a balance controller uses signals from sensors and motors to control weights in a motorized weight unit. Other techniques are also contemplated herein.

[0048] As described herein, additionally or alternatively, the motion signals can be used to identify and correct insufficient or improper mounting of the gantry 104 relative to the support 126 (e.g., the examination room floor), identify other imbalances that occur over time, and the like. In one embodiment, this is accomplished by a gantry motion assessment module 152 ( FIG. 1 ) in the operator console 138 ( FIG. 1 ). For example, at predetermined intervals (e.g., scheduled intervals, predetermined intervals, on-demand intervals, etc.), the gantry motion assessment module 152 can evaluate signals from the gantry motion sensing system 128. For example, the gantry motion assessment module 152 can compare the detected motion with a predetermined range of acceptable motion. In this example, if the motion falls outside the predetermined range, the gantry motion assessment module 152 can notify appropriate personnel. In one example, the notification can indicate areas of the CT imaging system 102 that are believed to be contributing to the motion. This can include utilizing a lookup table, database, data structure, etc. that maps motion values ​​to possible areas.

[0049] 13 illustrates a non-limiting example flowchart of a computer-implemented method for balancing a mass supported by rotating frame 106, according to one aspect of the present disclosure. It should be understood that the order of operations in the method is not limiting. As such, other orders are contemplated herein. Additionally, one or more operations may be omitted and / or one or more additional operations may be included.

[0050] In step 1302, the imaging system 102 is assembled. In one embodiment, this includes installing the rotating frame 106 on the gantry 104, installing the X-ray source assembly 112 on the rotating frame 106, installing the X-ray radiation-sensitive detector array 120 on the rotating frame 106, installing at least one balance weight support 202 on the rotating frame 106, installing the gantry motion sensing system 128, etc., as described herein and / or otherwise. In step 1304, the imaging system 102 is operated to rotate the rotating frame 106. In step 1306, multiple motion sensors of the gantry motion sensing system 128 detect the same motion of the gantry 104, as described herein and / or otherwise.

[0051] In step 1308, the gantry motion sensing system 128 processes the detected motion as described herein and / or otherwise to reduce the noise floor of the motion sensors. In step 1310, the processed motion signals are further processed as described herein and / or otherwise, and the processed motion signals are used to adjust one or more balance weights 204 in at least one balance weight support 202 to balance the mass supported by the rotating frame 106. For example, the processed motion signals can be used as described in U.S. Pat. No. 6,890,100 B2 and / or U.S. Pat. No. 6,748,806 B2 and / or can be used in other ways to balance the mass supported by the rotating frame 106.

[0052] 14 illustrates another non-limiting example flowchart of a computer-implemented method for balancing a mass supported by a rotating frame 104, according to an aspect of the present disclosure. It should be understood that the order of operations in the method is not limited to this order. As such, other orders are contemplated herein. Additionally, one or more operations may be omitted and / or one or more additional operations may be included.

[0053] In step 1402, the imaging system 102 is assembled. In one embodiment, this includes mounting the rotating frame 106 to the gantry 104, mounting the X-ray source assembly 112 to the rotating frame 106, mounting the X-ray radiation sensitive detector array 120 to the rotating frame 106, mounting at least one balance weight support 202 to the rotating frame 106, mounting the accelerometers of the gantry motion sensing system 128, etc., as described herein and / or otherwise. In step 1404, the imaging system 102 is operated to rotate the rotating frame 106. In step 1406, the multiple accelerometers detect the same movement of the gantry 104 and output acceleration signals indicative of the detected gantry movement.

[0054] In step 1408, the gantry motion sensing system 128 processes the acceleration signals, as described herein and / or otherwise, to reduce the noise floor of the series of acceleration signals and generate a combined acceleration signal. In step 1410, the gantry motion sensing system 128 integrates the acceleration signals, as described herein and / or otherwise, to generate a velocity signal indicative of gantry motion. In step 1412, the operator console 138 processes the velocity signal, as described herein and / or otherwise, to generate a displacement value indicative of gantry motion. In step 1412, the displacement value is used to adjust one or more balance weights 204 on at least one balance weight support 202 to balance the mass supported by the rotating frame 106.

[0055] 15 illustrates a non-limiting example flowchart of a computer-implemented method for installing the gantry 104 on the support 126, according to one aspect of the present disclosure. It should be understood that the order of operations in the method is not limited to this order. As such, other orders are contemplated herein. Furthermore, one or more operations may be omitted and / or one or more additional operations may be included.

[0056] In step 1502, the imaging system 102 is installed. In step 1504, the gantry is attached to a support 126 (such as the floor of an examination room) as described herein and / or otherwise. In step 1506, the imaging system 102 is operated to rotate the rotating frame 106. In step 1508, multiple motion sensors of the gantry motion sensing system 128 detect the same motion of the gantry 104 as described herein and / or otherwise.

[0057] In step 1510, the gantry motion sensing system 128 processes the detected motion as described herein and / or otherwise to reduce the noise floor of the motion sensors and generate a combined motion signal. In step 1512, the combined motion signal is used to verify that the gantry 104 is properly attached to the examination room floor. If necessary (e.g., if this verification cannot be performed), the gantry 104 is reinstalled on the examination room floor 126.

[0058] 16 illustrates another non-limiting example flowchart of a computer-implemented method for installing the gantry 104 on the support 126, according to an aspect of the present disclosure. It should be understood that the order of operations in the method is not limited to this order. As such, other orders are contemplated herein. Furthermore, one or more operations may be omitted and / or one or more additional operations may be included.

[0059] In step 1602, the imaging system 102 is assembled. In one embodiment, this step includes mounting the gantry 104 to a support 126 (e.g., an examination room floor) as described herein and / or otherwise. In step 1604, the imaging system 102 is operated to rotate the rotating frame 106. In step 1606, multiple accelerometers of the gantry motion sensing system 128 detect the same movement of the gantry 104 and output acceleration signals indicative of the detected gantry movement as described herein and / or otherwise. In step 1608, the gantry motion sensing system 128 processes the acceleration signals to reduce the noise floor of the acceleration signals, producing a combined acceleration signal, as described herein and / or otherwise.

[0060] In step 1610, the gantry motion sensing system 128 integrates the combined acceleration signal, as described herein and / or otherwise, to generate a velocity signal indicative of gantry motion. In step 1612, the operator console 138 processes the velocity signal, as described herein and / or otherwise, to generate a displacement value indicative of gantry motion. In step 1614, the displacement value is used to adjust one or more balance weights 204 in at least one balance weight support 202 to balance the mass supported by the rotating frame 106. In step 1616, the displacement value is used to verify that the gantry 104 is properly seated on the support 126. If necessary (e.g., if this verification cannot be performed), the gantry 104 is re-seated on the examination room floor 126.

[0061] 17 illustrates a non-limiting example flowchart of a computer-implemented method for verifying that gantry motion is within a predetermined acceptable range of gantry motion through a calibration procedure, according to one aspect of the present disclosure. It should be understood that the order of operations in the present method is not intended to be limiting. Thus, other orders are contemplated herein. Furthermore, one or more operations may be omitted and / or one or more additional operations may be included.

[0062] In step 1702, imaging system 102 operates according to a calibration procedure. In step 1704, multiple motion sensors of gantry motion sensing system 128 detect the same motion of gantry 104, as described herein and / or otherwise. In step 1706, gantry motion sensing system 128 processes the detected motion and generates a combined motion signal, as described herein and / or otherwise, to reduce the noise floor of the motion sensors. In step 1708, the combined motion signal is used, as described herein and / or otherwise, to verify that the gantry motion is within a predetermined allowable gantry motion range.

[0063] 18 illustrates another non-limiting example flowchart of a computer-implemented method for verifying that gantry motion is within a predetermined acceptable range of gantry motion through a calibration procedure, according to an aspect of the present disclosure. It should be understood that the order of operations in the present method is not limited thereto. Thus, other orders are contemplated herein. Furthermore, one or more operations can be omitted and / or one or more additional operations can be included.

[0064] In step 1802, imaging system 102 operates according to a calibration procedure. In step 1804, multiple accelerometers of gantry motion sensing system 128 detect the same movement of gantry 104, as described herein and / or otherwise, and output acceleration signals indicative of the detected gantry movement. In step 1806, gantry motion sensing system 128 processes the acceleration signals, as described herein and / or otherwise, to reduce the noise floor of the acceleration signals, to generate a combined acceleration signal.

[0065] In step 1808, the gantry motion sensing system 128 integrates the combined acceleration signal, as described herein and / or otherwise, to generate a velocity signal indicative of gantry motion. In step 1810, the operator console 138 processes the velocity signal, as described herein and / or otherwise, to generate a displacement value indicative of gantry motion. In step 1812, the displacement value is used, as described herein and / or otherwise, to verify that the gantry motion is within a predetermined allowable gantry motion range.

[0066] The foregoing may be implemented by computer-readable instructions encoded on or embedded in a computer-readable storage medium, which, when executed by a computer processor, cause the processor to perform the described operations or functions. Additionally or alternatively, at least one computer-readable instruction of the plurality of computer-readable instructions may be implemented by a signal, carrier wave, or other transitory medium that is not a computer-readable storage medium.

[0067] As used herein, elements or steps described in the singular and preceded by the words "a" or "an" should be understood not to exclude a plurality of such elements or steps, unless the exclusion of a plurality of such elements or steps is expressly stated. Furthermore, references to "one embodiment" of the invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Furthermore, unless expressly stated to the contrary, embodiments "comprising," "including," or "having" an element or elements having a particular characteristic may include additional such elements that do not have that characteristic. The terms "including" and "in which" are used as shorthand for the terms "comprising" and "wherein," respectively. Terms such as "first," "second," and "third" are used merely as labels, and are not intended to impose numerical requirements or a specific positional order on the objects of these terms.

[0068] Various embodiments and / or components (e.g., modules, or components and controllers within modules) may also be implemented as part of one or more computers or processors. The computer or processor may include a computing device, an input device, a display unit, and an interface, for example, for accessing the Internet. The computer or processor may include a microprocessor. The microprocessor may be connected to a communication bus. The computer or processor may also include memory. Memory may include random access memory (RAM) and read-only memory (ROM). The computer or processor may further include a storage device, which may be a hard disk drive or a removable storage drive (such as a floppy disk drive or optical disk drive). The storage device may also be other similar means for loading computer programs or other instructions into the computer or processor.

[0069] As used herein, the terms "computer" or "module" may include any processor-based or microprocessor-based system, including systems that use microcontrollers, reduced instruction set computers (RISC), application specific integrated circuits (ASIC), logic circuits, and other circuits or processors capable of performing the functions described herein. The above examples are illustrative only and are thus not intended to limit in any way the definition and / or meaning of the term "computer." A computer or processor executes a set of instructions stored in one or more memory elements to process input data. The memory elements may also store data or other information as desired or needed. The memory elements may be in the form of information sources or physical memory elements within a processing machine.

[0070] The set of instructions may include various commands that instruct a computer or processor as a processing machine to perform certain operations, such as the methods and processes in various embodiments of the present invention. The set of instructions may be in the form of a software program. The software may be in various forms (e.g., system software or application software). Furthermore, the software may be in the form of a collection of individual programs or modules, or in the form of a program module within a larger program or portion of a program module. The software may also include modular programming in the form of object-oriented programming. The processing of input data by the processing machine may be performed in response to operator commands, in response to results of previous processing, or in response to requests made by other processing machines.

[0071] As used herein, the terms "software" and "firmware" are used interchangeably and include any computer program stored in memory (e.g., RAM memory, ROM memory, EPROM memory, EEPROM memory, and non-volatile RAM (NVRAM) memory) and executed by a computer. The above memory types are merely exemplary and thus do not limit the types of memory that can be used to store computer programs.

[0072] It should be understood that the above description is illustrative and not intended to be limiting. For example, the above-described embodiments (and / or aspects of the embodiments) can be used in combination with each other. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the various embodiments of the invention without departing from the scope of the invention. The dimensions and types of materials set forth herein are intended to define the parameters of the various embodiments of the invention, but are by no means limited to these embodiments, which are exemplary. Many other embodiments will be apparent to those skilled in the art upon review of the above description.

[0073] This specification uses examples to disclose various embodiments of the invention, including the best mode, and also to enable those skilled in the art to practice various embodiments of the invention (e.g., make and use devices or systems, and perform incorporated methods). The patentable scope of various embodiments of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ insubstantially from the literal language of the claims.

[0074] The embodiments of the present disclosure illustrated in the drawings and described above are merely exemplary embodiments and are not intended to limit the scope of the claims (including equivalents thereto). Various modifications are possible and will be apparent to those skilled in the art. Any combination of non-mutually exclusive features described herein is intended to be within the scope of the present disclosure. That is, features of the described embodiments may be combined with any appropriate aspect described above, and any feature of one aspect may be combined with any other appropriate aspect. Similarly, features described in a dependent claim may be combined with non-mutually exclusive features of other dependent claims, particularly if the dependent claims depend on the same independent claim. Although single claim dependency may be used as a practice in some jurisdictions requiring single claim dependency, this should not be interpreted to mean that features of multiple dependent claims are mutually exclusive. [Explanation of symbols]

[0075] 108 Inspection Area 110 Z axis 114 X-ray source 116 filters 118 Collimator 120 X-ray radiation sensitive detector array 122 X-ray radiation sensitive detector elements 128 Gantry Motion Sensing System 130 Object support 132 Top plate 134 Base 136 Constructor 142 Input Devices 144 Output Devices 146 Remote Resources 148 processors 152 Gantry Motion Evaluation Module 202 Balance weight support 204 Balance Weight 300 bottom 302 Mounting Bracket 304 Mounting Elements 306 Trunk 308 Fixing mechanism 402 sets 404 Motion signal processing circuit section 502 First Axis 504 Second Axis 506 plots 508 plots 510 plots 512 plots 514 plots 606 Integral circuit 608 Readout electronic circuit section 702 Second Set 802 Circuit Board 804 Circuit Board 806 sets 808 Motion signal processing circuit section 810 Readout electronic circuit unit 812 sets 814 Motion signal processing circuit section 816 Readout electronic circuit unit 818 Common Board 1102 Upper 1202 Container 1204 Fasteners 1208 Mounting plate 1210 Electromechanical Connectors 1302 steps 1304 steps 1306 steps 1308 steps 1310 steps 1402 steps 1404 steps 1406 steps 1408 steps 1410 steps 1412 steps 1502 steps 1504 steps 1506 steps 1508 steps 1510 steps 1512 steps 1602 steps 1604 steps 1606 steps 1608 steps 1610 steps 1612 steps 1614 steps 1616 steps 1702 steps 1704 steps 1706 steps 1708 steps 1802 steps 1804 steps 1806 steps 1808 steps 1810 steps 1812 steps

Claims

1. 1. A computed tomography imaging system, comprising: Gantry, a rotating frame rotatably supported within the gantry, the rotating frame supporting at least one component for generating, transmitting, or receiving x-ray radiation; a first motion sensor configured to sense a first movement of the gantry in a first plane and to generate a first signal indicative of the first movement, the first signal having a first noise floor; a second motion sensor configured to simultaneously sense a first movement of the gantry in the first plane and generate a second signal indicative of the first movement, the second signal having a second noise floor; and motion signal processing circuitry configured to combine the first signal and the second signal to generate a first combined signal indicative of the first motion, the first combined signal having a third noise floor lower than the first noise floor and the second noise floor; 1. A computed tomography imaging system comprising:

2. 2. The computed tomography imaging system of claim 1, wherein the motion signal processing circuitry averages a combination of the first signal and the second signal using a square root of the sum of squares algorithm to generate the first combined signal.

3. the first combined signal is a first acceleration signal, and the motion signal processing circuitry is further configured to process the first acceleration signal to generate a first velocity signal; readout electronics configured to read out the first velocity signal; The computed tomography imaging system of claim 1 , comprising:

4. a processor configured to execute computer instructions in a memory, the computer instructions causing the processor to process the first velocity signal such that a displacement value corresponding to movement of the gantry is determined. The computed tomography system of claim 3 , comprising:

5. 5. The computed tomography imaging system of claim 4, wherein the rotating frame further comprises a balance weight support configured to support one or more balance weights that balance a total mass supported by the rotating gantry based on the displacement value.

6. The computed tomography imaging system of claim 4 , wherein the gantry includes a mounting bracket configured to be mounted to an examination room floor according to a mounting procedure based on the displacement values.

7. the first motion sensor is further configured to sense a second first movement of the gantry in a second plane and generate a third signal indicative of the second movement, the third signal having a fourth noise floor; the second motion sensor is further configured to sense the second motion of the gantry in the second plane and generate a fourth signal indicative of the second motion, the fourth signal having a fifth noise floor; 2. The computed tomography imaging system of claim 1, wherein the motion signal processing circuitry is further configured to combine the third signal and the fourth signal to generate a second combined signal, the second combined signal having a sixth noise floor that is lower than the fourth noise floor and the fifth noise floor.

8. The computed tomography imaging system of claim 1 , wherein the first motion sensor and the second motion sensor are mounted to the gantry.

9. The computed tomography system of claim 1 , further comprising a circuit board configured to carry the first motion sensor, the second motion sensor, and the motion signal processing circuitry.

10. The computed tomography imaging system of claim 1 , wherein the first motion sensor comprises a first accelerometer and the second motion sensor comprises a second accelerometer.

11. 1. A computer-implemented method comprising: detecting a first movement of a gantry of a computed tomography imaging system in a first plane with a first motion sensor; generating a first signal indicative of the first movement, the first signal having a first noise floor; detecting the first movement of the gantry with a second motion sensor simultaneously with detecting the first movement with the first motion sensor; generating a second signal indicative of the first movement, the second signal having a first noise floor; and Combining the first signal and the second signal to obtain a first combined signal, the first combined signal having a third noise floor lower than the first noise floor and the second noise floor. A computer-implemented method comprising:

12. detecting a second movement of the gantry in a second plane with the first movement sensor; generating a third signal indicative of the second movement, the third signal having a fourth noise floor; detecting a second movement of the gantry with a second motion sensor simultaneously with detecting the second movement with the first motion sensor; generating a fourth signal indicative of the second movement, the fourth signal having a fifth noise floor; and Combining the third signal and the fourth signal to obtain a second combined signal, the second combined signal having a sixth noise floor that is lower than the fourth noise floor and the fifth noise floor. The computer-implemented method of claim 11 further comprising:

13. 13. The computer-implemented method of claim 12, wherein combining the first signal and the second signal comprises averaging the combination of the first signal and the second signal using a square root of the sum of squares algorithm, and combining the third signal and the fourth signal comprises averaging the combination of the third signal and the fourth signal using a square root of the sum of squares algorithm.

14. the first combined signal is a first acceleration signal, and the second combined signal is a second acceleration signal; integrating the first acceleration signal to generate a first velocity signal; integrating the second acceleration signal to generate a second velocity signal; and Reading out the first speed signal and the second speed signal.

14. The computer-implemented method of claim 13, further comprising:

15. integrating the first velocity signal to determine a first displacement value corresponding to movement of the gantry in the first plane; and integrating the second velocity signal to determine a second displacement value corresponding to movement of the gantry in the second plane.

15. The computer-implemented method of claim 14, further comprising:

16. A computer-readable medium having computer-executable instructions encoded thereon, the computer-executable instructions, when executed by a processor, causing the processor to: detecting a first movement of a gantry of a computed tomography imaging system in a first plane with a first motion sensor; generating a first signal indicative of the first movement, the first signal having a first noise floor; detecting the first movement of the gantry with a second motion sensor simultaneously with detecting the first movement with the first motion sensor; generating a second signal indicative of the first movement, the second signal having a first noise floor; and Combining the first signal and the second signal to obtain a first combined signal, the first combined signal having a third noise floor lower than the first noise floor and the second noise floor. A computer-readable medium for causing the computer to execute the method.

17. The computer-executable instructions further cause the processor to: detecting a second movement of the gantry in a second plane with the first movement sensor; generating a third signal indicative of the second movement, the third signal having a fourth noise floor; detecting the second movement of the gantry with a second motion sensor simultaneously with detecting the second movement with the first motion sensor; generating a fourth signal indicative of the second movement, the fourth signal having a fifth noise floor; and Combining the third signal and the fourth signal to obtain a second combined signal, the second combined signal having a sixth noise floor that is lower than the fourth noise floor and the fifth noise floor.

17. The computer-readable medium of claim 16, wherein the computer-readable medium causes execution of the following:

18. The computer-executable instructions further cause the processor to: combining the first signal and the second signal by averaging the combination of the first signal and the second signal using a square root sum of squares algorithm; and combining the third signal and the fourth signal by averaging the combination of the third signal and the fourth signal using a square root sum of squares algorithm; 20. The computer-readable medium of claim 17, wherein the computer-readable medium causes execution of the following:

19. The first combined signal is a first acceleration signal and the second combined signal is a second acceleration signal, and the computer-executable instructions further include causing the processor to: integrating the first acceleration signal to generate a first velocity signal; integrating the second acceleration signal to generate a second velocity signal; and reading out the first speed signal and the second speed signal; 20. The computer-readable medium of claim 18, wherein the computer-readable medium causes execution of the following:

20. The computer-executable instructions further cause the processor to: integrating the first velocity signal to determine a first displacement value corresponding to movement of the gantry in the first plane; and integrating the second velocity signal to determine a second displacement value corresponding to movement of the gantry in the second plane.

20. The computer-readable medium of claim 19,

Images