CN113925523A

CN113925523A - State detection method and device of medical imaging system and CT imaging system detection

Info

Publication number: CN113925523A
Application number: CN202010608438.3A
Authority: CN
Inventors: 张笑妍; 何毅; 唐振江; 刘鑫
Original assignee: GE Precision Healthcare LLC
Current assignee: GE Precision Healthcare LLC
Priority date: 2020-06-29
Filing date: 2020-06-29
Publication date: 2022-01-14
Anticipated expiration: 2040-06-29
Also published as: CN113925523B

Abstract

The present disclosure provides a medical imaging system state detection method and apparatus and a CT imaging system detection. A medical imaging system comprising a stationary frame and a rotating portion, the rotating portion comprising a rotating base driven by a motor, characterized in that the method comprises: a data acquisition step, wherein current or power signals of the motor are acquired to obtain a first signal, and signals of the sensor are acquired to obtain a second signal; a state data acquiring step of acquiring state data which is based on the first signal and the second signal and is related to a specific state of the medical imaging system. With the state detection method and apparatus of the present disclosure, the motor in the gantry mechanism is used as a sensor for measuring the rotational resistance torque of the rotating part, which can save the cost of the CT imaging system.

Description

State detection method and device of medical imaging system and CT imaging system detection

Technical Field

The present disclosure relates to a state detection method and apparatus for a medical imaging system, and more particularly, to an electronic Computed Tomography (CT) imaging system having the state detection method and apparatus.

Background

CT imaging systems are currently in widespread clinical use due to their particular diagnostic value. Generally, a CT imaging system includes a large gantry mechanism housed within an enclosure having an annular opening through which a subject can be supported for movement. The gantry mechanism includes a rotating base on which the X-ray tube and detector assembly are mounted. With the rotation of the rotating base and the linear movement of the subject along the axial direction of the annular opening, X-ray images can be taken for subsequent analysis and diagnosis.

Typically, in addition to the X-ray tube and detector assembly, other components such as heat exchangers, generators, etc. are mounted on the rotating base. All of these components mounted on the rotating base will rotate with the rotating base in use. Ideally, a CT imaging system is capable of obtaining satisfactory high-quality images while the rotating base can be rotated uniformly and smoothly under equilibrium conditions.

However, the different weights, configurations and mounting locations of the components on the rotating base can also cause imbalance in the rotating portion of the CT gantry mechanism, which can cause the entire gantry mechanism to vibrate. The vibrations of the gantry mechanism are detrimental to the image quality, and the higher the amplitude of the vibrations, the larger the resulting image artifacts. Therefore, it is necessary to control the amplitude of the vibration of the stage mechanism within a certain range. Aiming at the unbalance of the rotating part of the CT gantry mechanism, the gantry mechanism is corrected by arranging a counterweight mechanism. Generally, the CT gantry mechanism is pre-calibrated in the factory where the CT imaging system is built and calibrated before being transported to its final installation destination. After the CT imaging system is shipped to an installation destination, or after a new component, such as an X-ray tube, is replaced, field balance corrections are also needed to ensure accurate performance of the CT imaging system. However, the balance correction system of the existing gantry mechanism is complex, a plurality of sensors are required to be arranged, the complex sensor arrangement causes high system cost, and therefore, the existing balance correction system still needs to be improved.

Disclosure of Invention

To overcome the deficiencies in the prior art, the present disclosure provides a method for detecting a state of a medical imaging system, the medical imaging system including a stationary frame and a rotating portion, the rotating portion including a rotating base driven by a motor, the method comprising: a data acquisition step, wherein a current or power signal of a motor is acquired to obtain a first signal; a state data acquiring step of acquiring state data which is based on the first signal and is related to a specific state of the medical imaging system.

According to one aspect of the disclosure, the first signal comprises a current or power fluctuation signal occurring once per revolution of the rotating base.

According to another aspect of the disclosure, the status data includes an amplitude and a phase angle of the first signal, the status data corresponding to a configuration of the counterweight mechanism on the rotating base.

According to another aspect of the disclosure, the data acquisition step further comprises: collecting a second signal output by a sensor arranged on the fixed frame; and the status data acquiring step further comprises acquiring supplemental status data based on the second signal and relating to a particular status of the medical imaging system, the supplemental status data corresponding to a configuration of the counterweight mechanism on the rotating base.

According to another aspect of the disclosure, the status data acquiring step includes:

extracting a fluctuation signal appearing once per rotation of the rotary base from the first signal or the second signal; and calculating an amplitude and a phase angle associated with a particular state of the medical imaging system based on the extracted fluctuation signal.

According to still another aspect of the present disclosure, the status data acquiring step further includes: processing the first signal or the second signal using one of fourier transform and least square method when the first signal or the second signal is obtained by sampling at equal time intervals; and processing the first signal or the second signal using a least squares method when the first signal or the second signal is obtained by sampling at unequal time intervals.

According to still another aspect of the present disclosure, the method controls the motor to rotate the spin base at a constant rotation speed, wherein the constant rotation speed is close to or equal to a rated maximum rotation speed of the spin base, and the data collecting step is performed under the condition that the spin base is rotated at the constant rotation speed.

In addition, the present disclosure also provides a status detecting apparatus of a medical imaging system, the medical imaging system including a fixed frame and a rotating part, the rotating part including a rotating base driven by a motor and a rotating part mounted thereon, the status detecting apparatus including: a data acquisition module configured to acquire a current or power signal of the motor to obtain a first signal; a status data acquisition module configured to acquire status data based on the first signal and relating to a particular status of the medical imaging system.

According to yet another aspect of the present disclosure, the data acquisition module is further configured to acquire a second signal output by a sensor disposed on the fixed frame; and, the status data acquisition module is configured to acquire a supplemental status parameter based on the second signal and related to a particular status of the medical imaging system, the supplemental status parameter corresponding to a configuration of the counterweight mechanism on the rotating base.

According to yet another aspect of the disclosure, the status data acquisition module is further configured for: extracting a fluctuation signal appearing once per rotation of the rotary base from the first signal or the second signal; and calculating an amplitude and a phase angle associated with a particular state of the medical imaging system based on the extracted fluctuation signal.

According to still another aspect of the present disclosure, the state detecting device further includes: a motor control module configured to control the motor to rotate the rotating base of the gantry mechanism at a constant rotational speed, wherein the constant rotational speed is near or equal to a nominal maximum rotational speed of the rotating base.

According to yet another aspect of the disclosure, the first signal may further include a current or power ripple signal that occurs multiple times per revolution of the rotating base, and the second signal may further include a ripple signal that occurs multiple times per revolution of the rotating base.

The present disclosure also provides a CT imaging system, comprising: the rotary part comprises a rotary base driven by a motor and a rotary part on the rotary base; at least one counterbalance mechanism comprising at least one counterbalance weight that is adjustable; a state detection device comprising a data acquisition module configured to acquire a current or power signal of the motor to obtain a first signal and a state data acquisition module configured to acquire state data based on the first signal and related to a particular state of the CT imaging system, the state data indicating an adjustment of the at least one counterweight.

In accordance with another aspect of the present disclosure, the CT imaging system further includes a sensor disposed on the fixed frame. Preferably, the sensor is selected from the group consisting of an acceleration sensor, a velocity sensor, and a displacement sensor, and is provided at an upper portion or a middle portion of the fixed frame of the stage mechanism, or the sensor is selected from the group consisting of a strain sensor and a piezoelectric sensor, and is provided at a lower portion of the fixed frame of the stage mechanism.

According to yet another aspect of the present disclosure, the data acquisition module further acquires signals of the sensor to obtain second signals, and the status data acquisition module further acquires a supplemental status parameter based on the second signals and related to a particular status of the CT imaging system, the supplemental status parameter corresponding to a configuration of the counterweight mechanism on the rotating base.

According to still another aspect of the present disclosure, the CT imaging system further includes a first test block and a second test block, the first test block and the second test block have a preset weight and a preset installation position, respectively, and the first signal includes a fluctuation signal that appears once per rotation of the rotating base under the condition that the first test block and the second test block are not installed and the first test block and the second test block are installed, respectively.

According to yet another aspect of the present disclosure, the rotating portion further comprises an X-ray tube mounted on the rotating base, the X-ray tube being disposed at a 0 degree position around a central axis of the rotating portion, a rotation angle between the first weight mechanism and the second weight mechanism being disposed at a difference of 80 degrees to 120 degrees around the central axis, wherein the second weight mechanism is disposed at a position rotated about 180 degrees with respect to the 0 degree position.

According to yet another aspect of the present disclosure, the at least one weight mechanism includes a first weight mechanism and a second weight mechanism; and the status data acquisition module is further configured for: processing the first signal or the second signal using one of fourier transform and least square method when the first signal or the second signal is obtained by sampling at equal time intervals; when the first signal or the second signal is obtained by sampling at unequal time intervals, processing the first signal or the second signal by using a least square method; extracting a fluctuation signal appearing once per rotation of the rotary base from the processed first signal and second signal; calculating an amplitude and a phase angle associated with a particular state of the CT imaging system based on the extracted fluctuation signal; and when the calculated amplitude does not meet the preset value, calculating a new configuration of the first counterweight mechanism and the second counterweight mechanism arranged at different positions on the rotating part of the gantry mechanism according to the amplitude and the phase angle.

By adopting the detection state detection method disclosed by the invention, the original motor of the rack mechanism in the CT imaging system is used for realizing the state monitoring of the system. Especially, in the process of monitoring the balance state, the motor replaces a sensor specially arranged for measuring the rotation resistance moment of the gantry mechanism originally, so that the cost of the CT imaging system can be saved. Further, since the motor can reflect the magnitude of the resisting moment more accurately, high-precision balance correction can be realized.

Drawings

The disclosure may be better understood by describing exemplary embodiments thereof in conjunction with the following drawings, wherein like reference numerals are used to refer to the same or similar parts throughout, and in which:

FIG. 1 illustrates a perspective view of a conventional CT imaging system;

FIG. 2 illustrates a front view of a CT gantry mechanism with a cover of the CT gantry mechanism removed to show its internal structure, in accordance with a preferred embodiment of the present disclosure;

FIG. 3 illustrates an exploded perspective view of a first counterweight mechanism for use in a CT gantry mechanism, according to a preferred embodiment of the present disclosure;

FIG. 4 illustrates an exploded perspective view of a second counterweight mechanism for use in a CT gantry mechanism, according to a preferred embodiment of the present disclosure;

FIG. 5 shows a schematic diagram of a time-domain sampled signal according to a preferred embodiment of the present disclosure;

FIG. 6 shows a schematic diagram of a processed frequency domain signal according to a preferred embodiment of the present disclosure;

FIGS. 7A and 7B illustrate a flow chart of a two-plane balancing method according to a preferred embodiment of the present disclosure;

FIGS. 8A and 8B illustrate a flow chart of a static balancing method according to a preferred embodiment of the present disclosure; and

fig. 9 shows a schematic block diagram of a control device according to a preferred embodiment of the present disclosure.

List of reference numerals

10 CT imaging system

12 scanning bed

20 rack mechanism

21 opening of the stand

30 rotating base

31 first counter weight mechanism

311 first counter weight base

312 first balancing weight

32 second counter weight mechanism

321 second counterweight base

322 second counter weight

323 shim

35 Detector Assembly

36X-ray tube

40 fixed frame

50 electric machine

51 Motor controller

60 sensor

100 flow chart

200 flow chart

400 state detection device

410 data acquisition module

420 state data processing module

450 motor control module

Detailed Description

In the following description of the embodiments of the present disclosure, it is noted that in the interest of brevity and conciseness, not all features of an actual implementation may be described in detail in this specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions are made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be further appreciated that such a development effort might be complex and tedious, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure, and it will be appreciated that such a development effort might be complex and tedious.

Unless otherwise defined, technical or scientific terms used in the claims and the specification should have the ordinary meaning as understood by those of ordinary skill in the art to which this disclosure belongs. The use of "first," "second," and similar terms in the description and claims of the present disclosure are not intended to indicate any order, quantity, or importance, but rather are used to distinguish one element from another. The terms "a" or "an," and the like, do not denote a limitation of quantity, but rather denote the presence of at least one. The word "comprise" or "comprises", and the like, means that the element or item listed before "comprises" or "comprising" covers the element or item listed after "comprising" or "comprises" and its equivalent, and does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, nor are they restricted to direct or indirect connections.

FIG. 1 illustrates a conventional CT imaging system, generally designated by the reference numeral 10. The CT imaging system 10 generally includes a couch 12 for positioning a subject and a gantry mechanism 20. The stage opening 21 of the stage mechanism 20 is formed in the X-Y plane and can rotate about the Z axis. An X-ray generating device 36, such as an X-ray tube, and a detector assembly 35 are located on the gantry mechanism 20 opposite each other. The imaging system 10 is capable of taking X-ray images of a subject as the couch 12 supports the subject for movement in a Z-axis direction, either completely or partially, through the gantry opening 21 of the gantry mechanism 20.

Fig. 2 illustrates a front view of a gantry mechanism 20 suitable for use with the disclosed method. For clarity, the cover of the gantry mechanism 20 is removed to show some of the major components inside the gantry mechanism 20. As shown in fig. 2, the stage mechanism 20 includes a fixed frame 40 and a rotating portion capable of rotating about a Z axis with respect to the fixed frame 40, the rotating portion including a rotating base 30 and a plurality of components mounted thereon. The rotational engagement between the fixed frame 40 and the rotating base 30 may be achieved, for example, by bearings (not shown). The bearing includes a moving coil and a stationary coil, both of which are centered about the Z axis. The rotating base 30 is mounted on the moving coil of the bearing, and the stationary coil of the bearing is connected to the fixed frame 40, so that the relative movement between the stationary coil and the moving coil of the bearing realizes the relative movement between the rotating base 30 and the fixed frame 40.

The components mounted for rotation on the rotating base 30 include an X-ray tube 36 for generating X-rays and a detector assembly 35 for receiving the X-rays for detection. Conventionally, power is fed to these power requiring components on the rotating base 30 through slip rings and slip ring brushes. As shown in fig. 1, an X-ray tube 36 is disposed on the rotating base 30 opposite the detector assembly 35. The X-ray tube 36 projects an X-ray beam, and the detector assembly 35 is capable of sensing the beam of light projected therethrough and generating a corresponding electrical signal based on the intensity of the received beam of light. For ease of description, the location of the X-ray tube 36 on the rotating base 30 shown in fig. 2, i.e., the twelve o' clock position, is defined as the 0 degree position, and degrees are measured in a counter-clockwise rotation about the Z-axis.

A motor 50 for providing a driving force to the rotating base 30 is fixedly installed on the fixed frame 40. The driving force output from the motor 50 is transmitted to the rotary base 30 through a transmission mechanism such as a belt, a chain, a gear, etc., so that the rotary base 30 rotates on the fixed frame 40 at a controllable rotational speed centering on the Z-axis. In the preferred embodiment, the motor 50 is mounted at the lower right of the fixed frame 40, as shown in fig. 2. The motor 50 is further provided with an associated motor controller 51 for controlling the operation of the motor 50. The motor controller 51 may be disposed adjacent to the motor 50 or may be integrated with the motor 50. With the aid of the built-in control logic of the motor controller 51, the motor controller 51 can control the motor 50 to drive the rotating base 30 to accelerate, decelerate, and rotate at a constant rotational speed.

During use of the CT imaging system, the rotating portion of the gantry mechanism 20 is rotated by the rotating base 30. It has been found that by acquiring and obtaining current or power signals from the motor 50, state data relating to a particular state of the CT imaging system, and in particular the gantry mechanism, can be obtained. Thus, the specific state of the gantry mechanism in the CT imaging system can be detected. In some embodiments, the particular state may be an unbalanced state of the gantry mechanism. In other embodiments, the particular state may be a state indicating one or more faults of the gantry mechanism.

Specifically, the signals that can be extracted from the current or power signals of the motor 50 include signals that occur one or more times per revolution of the rotating base 30. Such as a signal that appears once per revolution of the rotating base 30, a signal that appears twice per revolution of the rotating base 30, a signal that appears three times per revolution of the rotating base 30, etc. The signal from the motor 50 that occurs a particular number of times per revolution of the rotating base 30 may correspond to a particular physical quantity associated with the gantry mechanism 20 of the CT imaging system. These signals can be used to detect a particular state of the gantry mechanism according to a particular correspondence and adjust accordingly.

In some embodiments, the motor 50 provides a fluctuating signal that appears once per revolution of the rotating base 30 to reflect an imbalance in the rotating portion of the gantry mechanism 20. In other embodiments, the presence of a signal from the motor 50 twice per revolution of the rotatable base 30 may reflect a failure of the gantry mechanism 20, and therefore, the signal from the motor 50 may be used to detect a failure of the gantry mechanism and select an alarm based on the detection.

It is particularly advantageous that the signal extracted from the current or power signal of the motor 50, which appears once per revolution of the rotating base 30, reflects the imbalance of the rotating portion of the gantry mechanism 20. Accordingly, this signal provided by the motor 50 may be used in a method and system for detecting an imbalance condition of the gantry mechanism 20, and the condition detection method and apparatus may further include means for correcting the detected imbalance condition of the gantry mechanism 20.

Hereinafter, a method and a system for detecting and correcting an unbalanced state relating to the stage mechanism 20 will be exemplarily described.

When the CT gantry mechanism 20 is in operation, the weight, configuration, and location of the components disposed on the rotating base 30 often cause imbalance in the rotating portion, which can result in vibration of the entire gantry mechanism 20 at a frequency that occurs once per revolution of the rotating base 30. When this increase in vibration exceeds a certain threshold, unacceptable vibration artifacts can result, thereby affecting imaging quality. The balance correction of the rotating portion of the stage mechanism 20 generally includes static balance correction and dynamic balance correction. Specifically, the rotating portion of the gantry mechanism 20 may exhibit static imbalance, i.e., imbalance caused by the overall center of gravity of the rotating portion not coinciding with the axis of rotation. The static balance correction is mainly achieved by increasing or decreasing the number of counter weights in the first and

second weight mechanisms

31, 32 so that the center of gravity of the rotating portion coincides with the rotation axis thereof. On the other hand, the rotating portion of the gantry mechanism 20 may also be subject to dynamic imbalance, i.e., imbalance resulting from moment in the Z-direction due to uneven weight distribution in the rotating portion. The dynamic balance correction is mainly achieved by the movement and adjustment of the counter weight in the first and second

counter weight mechanisms

31, 32 in the Z-axis direction to cancel out the unbalanced moment. To overcome the above-described imbalance, a balance correction system is incorporated into the CT gantry mechanism 20, as shown in FIG. 2. The balance correction system comprises a counterweight mechanism located on the rotating base 30 of the gantry mechanism 20, in particular a first counterweight mechanism 31 in a first position and a second counterweight mechanism 32 in a second position, the first and second positions being two different circumferential positions around the axis of rotation of the rotating base 30. Preferably the rotation angles of the two weight means 31, 32 differ by 80-120 degrees, ideally the rotation angles of the two weight means 31, 32 differ by about 90 degrees. In the preferred embodiment shown in fig. 2, with the X-ray tube 36 position at the 0 degree position, the first counterweight mechanism 31 is in a first position rotated counterclockwise about the Z axis by about 66 degrees relative to the 0 degree position, and the second counterweight mechanism 32 is rotated about the Z axis by about 180 degrees relative to the 0 degree position. It will be appreciated that the location of the two counterbalance mechanisms may vary for different models of CT imaging systems due to differences and conditional limitations of the components on the rotating base 30 of the various CT imaging systems.

Fig. 3 illustrates an exploded perspective view of the first counter weight mechanism 31. The first weighting mechanism 31 has a plurality of first weights 312, and these first weights 312 are optionally mounted to the first weighting base 311. These weights 312 each have a different weight and may include heavier weights and lighter weights, which may be made of, for example, steel and have different thicknesses and shapes to achieve a variety of different weight combinations, and may also be made of other specific gravity materials such as aluminum. The weight base 311 is provided with a plurality of holes in rows in the Z-axis direction so that the position of the weight block 312 is adjustable in the Z-axis direction. It will be appreciated that the selection of the number of weights and the weight of each weight on the weighted base 311 will affect the static balance of the rotating portion of the gantry mechanism 20, while the mounting location of the selected weight 312 on the base along the Z-axis will affect the dynamic balance of the rotating portion of the gantry mechanism 20.

Fig. 4 illustrates an exploded perspective view of the second counterbalance mechanism 32. The second weight mechanism 32 includes a plurality of second weights 322 and a plurality of spacers 323 mounted on the second weight base 321 by fastener rods. The second weight 322 is typically made of a heavier specific gravity material, such as steel, and the washer 323 is typically made of a lighter specific gravity material, such as aluminum. The second balancing weights 322 are each formed to have the same or different weight and shape, and the spacers 323 may also be formed to have the same or different thickness and shape, and the position of the second balancing weights 322 in the Z-axis direction may be adjusted as desired by selecting different numbers and/or thicknesses of the spacers 323. Thus, the static or dynamic balance of the rotating portion of the CT gantry 20 can be adjusted by various selections and combinations of the second counterweight 322 and the spacer 323 of the second counterweight mechanism 32.

The CT imaging system 10 is typically pre-calibrated before shipping, i.e., the first counterweight mechanism 31 and the second counterweight mechanism 32 are pre-set to maintain the amount of unbalance of the gantry mechanism 20 below a predetermined value. When the CT imaging system 10 is shipped to an installation destination for reassembly, the originally calibrated balance of the system 10 may be compromised for a variety of reasons, such as replacement of rotating components for maintenance. Therefore, it is necessary to perform the calibration, i.e., the balance correcting operation of the first and

second weight mechanisms

31, 32 again.

In accordance with a particular aspect of the present disclosure, a method and apparatus for detecting the condition of a gantry mechanism in a CT imaging system utilizes a motor 50 that drives a rotating base 30 of the gantry mechanism 20. Specifically, the method and system according to the present disclosure employ the motor 50 as a means of providing an imbalance signal. When the motor 50 provides driving force to drive the rotating base 30 to rotate at a constant speed, a resistance torque variation occurs in the gantry mechanism 20 due to imbalance of the rotating part, and the current or power of the motor 50 will react to the resistance torque variation in order to overcome the resistance torque by the driving force output from the motor 50. The inventors have found that a corresponding change in the current or power of the motor 50 can instantly reflect an imbalance in the X-Y plane of the gantry mechanism, and have in consequence proposed to use the motor 50 as a source of the imbalance signal by analyzing the current or power of the motor 50 to provide a measurement signal for the imbalance correction system.

Since in the gantry mechanism 20 an imbalance appears once per rotation of the rotating base, a fluctuating signal in the signal given by the current or power of the motor 50, which appears once per rotation of the rotating base 30, will reflect an imbalance in the rotating portion of the gantry mechanism 20. Accordingly, the gantry mechanism 20 can be provided with control means for acquiring and extracting from the current or power signal of the motor 50 a signal that appears once per revolution of the rotating base and using this signal for achieving a balance correction of the gantry mechanism 20.

Advantageously, the acquisition of the initial signal from the motor 50 may be by means of an existing motor controller 51. The control means of the gantry mechanism 20 can be software, hardware, firmware or a combination thereof for enabling the collection, processing and extraction of the signals of the motor 50. In some embodiments, the control device of the gantry mechanism 20 can be part of the motor controller 51. In other embodiments, the control device of the gantry mechanism 20 can be a separate device from the motor controller 51. In other alternative embodiments, the motor controller may be integrated as part of the control device of the gantry mechanism 20 as the motor control module 450, as shown in fig. 9.

Generally, the current or power signal of the motor 50 may be collected at a fixed sampling frequency or at fixed time intervals.

Fig. 5 exemplarily shows a time domain signal obtained by sampling the current or power of the motor 50 collected from the motor 50 at set time intervals by the control device. The control device is configured to convert the collected signals into frequency domain signals by fourier transform or least squares, as illustrated in fig. 6, and then extract from the frequency domain signals a signal that appears once per revolution of the rotating base 30. Since the extracted signal is caused by the unbalance of the rotating portion, it can be used for the balance correction. For example, if the exemplary rotating base 30 rotates two revolutions per second, then the signal appearing twice a second in the frequency domain signal is due to an imbalance in the gantry mechanism 20, and is extracted for use in a balance correction of the CT gantry mechanism 20.

On the other hand, in order to detect a specific state of the gantry mechanism in the CT imaging system, as shown in fig. 2, the gantry mechanism 20 may further be provided with one or more sensors 60 on its fixed frame 40. The sensor 60 serves as a detection component for acquiring state data of the gantry mechanism 20 and as a component of the CT balance system for providing a signal related to the imbalance state in the Z-axis direction, thereby providing supplemental state data in addition to the state data that can be provided by the motor 50. In a preferred embodiment, the sensor 60 may be disposed on the left leg of the fixed frame 40.

In the preferred embodiment, the sensor 60 is a strain gauge sensor. In other alternative embodiments, the sensor 60 may also be a velocity sensor, an acceleration sensor, a piezoelectric sensor, a displacement sensor, or other sensor capable of measuring Z-axis imbalance of the gantry mechanism 20. The sensor can be arranged at the corresponding detection signal sensitive position on the rack mechanism according to the characteristics of the sensor. For example, the acceleration sensor, the velocity sensor, and the displacement sensor may be provided in an upper portion or a middle portion of the fixed frame of the stage mechanism; the strain sensor and the piezoelectric sensor may be provided at a lower portion of the fixed frame of the stage mechanism. The sensor 60 may be arranged to detect deformation and/or vibration due to imbalance of the gantry mechanism 20 in the Z-axis direction.

Similarly, the signals that can be extracted from the signals output by the sensor 60 include signals that occur one or more times per revolution of the rotating base 30. Such as a signal that appears once per revolution of the rotating base 30, a signal that appears twice per revolution of the rotating base 30, a signal that appears three times per revolution of the rotating base 30, etc. The signals from the sensor 60 that occur a particular number of times per revolution of the rotating base 30 may correspond to particular physical quantities associated with the gantry mechanism 20 of the CT imaging system. These signals can be used to detect a specific corresponding state of the gantry mechanism according to a specific correspondence and be adjusted accordingly. The signal appearing once per revolution of the rotating base 30 in the signal output by the sensor 60 will reflect the imbalance of the rotating portion of the gantry mechanism 20, and the control device collects and extracts the signal appearing once per revolution of the rotating base and uses the signal to effect a balance correction of the gantry mechanism 20. The acquisition, processing and extraction of the signals may be accomplished by software, hardware, firmware or a combination thereof in the control means of the gantry mechanism 20.

In conjunction with the signals from the motor 50 and the sensor 60, a two-plane balancing method can be performed on the CT gantry mechanism 20. The two-plane balancing process may include a data acquisition step in which a current or power signal of the motor 50 and a signal output from the sensor 60 are acquired, and a state data acquisition step in which signals from the motor 50 and the sensor 60 are subsequently processed to obtain state data related to the two-plane balanced state of the CT gantry mechanism. The obtained state data can correspond to the arrangement of the weight mechanism on the spin base 30, and the weight mechanism can be adjusted based on the balance calculation result of the state data.

In the preferred embodiment, first, the two-plane balancing method performs the step of testing the reference test data or signal. The motor 50 is caused to rotate the rotating base 30, and advantageously the rotational speed of the rotating base 30 is brought to or near a constant value by means of the control logic of the motor controller 51. In the data acquisition step, the measurement values of the sensor 60, the current or power signal of the motor 50, the sampling time, and the rotational phase angle of the rotating base 30 are acquired by the control device.

The signals acquired from both the motor 50 and the sensor 60 generally need to be processed in order to extract the desired wave signal. When the signal is obtained by sampling at equal time intervals, the sampling can be performed by Fourier transform or least-square methodProcessing the sample signal; when the signal is obtained by sampling at unequal time intervals, the sampled signal may be processed by a least square method. The sampled signal of the current or power of the motor 50 can be processed by the control means, from which a signal occurring once per revolution is extracted and expressed as a vector signal X₀. At the same time, the sampled signal from the sensor 60 is processed to extract the fluctuating signal appearing once per revolution and to express it as a vector signal Z₀. Vector signal X₀Sum vector signal Z₀Both amplitude and phase angles.

Next, the test procedure of the test block a was performed. The weight and position of the test block a are preset. For example, the test mass a is mounted at an angle of about 180 degrees at which the second weight mechanism 32 is located. When the test block a is mounted, the stage mechanism 20 is activated, the rotating base 30 starts to rotate relative to the fixed frame 40, and when the rotating base 30 reaches or approaches a constant rotation speed, a current or power signal is collected from the motor 50. This signal can be processed by the control means, from which a fluctuation signal occurring once per revolution of the rotating part of the gantry means 20 is extracted and expressed as a vector signal X_a. At the same time, the signal of the sensor 60 is processed, from which a fluctuating signal occurring once per revolution is extracted and expressed as a vector signal Z_a. Vector signal X_aSum vector signal Z_aBoth amplitude and phase angles.

Subsequently, the test block a was removed and the test block B was mounted for another test. Similarly, the weight and position of the test block B were preset, but the position of the test block B in the directions of X, Y and the Z axis was different from that of the test block a. For example, the test block B is disposed at a position rotated clockwise by about 30 degrees with respect to the 0-degree position, and the test block B is shifted forward and backward in the Z-axis direction with respect to the test block a. When the test block B is mounted, the CT gantry 20 is again activated and the motor 50 rotates the rotatable base 30, and a current or power signal is collected from the motor 50 when the rotatable base 30 reaches a constant rotational speed. From the signals collected from the motor 50, which can be processed by the control device, one revolution per revolution is extractedThe signal appearing once is circled and expressed as a vector signal X_b. At the same time, the signals of the sensor 60 are processed, from which signals occurring once per revolution are extracted and expressed as vector signals Z_b. Vector signal X_bSum vector signal Z_bBoth amplitude and phase angles.

After all three test data have been acquired, the state data can be correlated with the configuration of the counterweight mechanism on the rotating base for balance correction. Specifically, from these vectors, the following matrix formula (sensitivity matrix [ c ]) can be determined.

P_af＝m_a*R_a＜θ_a P_bf＝m_b*R_b＜θ_b (4)

P_a＝P_1f*R_a＜α_a P_b＝P_2f*R_b＜α_b (5)

In the above formula, X₀For the vector signal from the motor 50 in the reference test step, Z₀For the vector signal, X, from the sensor 60 in the reference test step_aVector signal from the motor 50 in the test step for test block A, Z_aIs a vector signal, X, from the sensor 60 during the test step of the test block A_bVector signal from the motor 50 in the test step for test block B, Z_aIs the vector signal from sensor 60 in the test step of test block B.

Based on the three stepsMeasured vector signal X₀、Z₀、X_a、Z_a、X_b、Z_bBy means of the above-mentioned sensitivity matrix [ c ]]Can be solved to obtain P_aAnd P_b。P_aAnd P_bTwo initial unbalance amounts of the rotating portion of the CT-gantry mechanism 20 in the initial state are respectively shown.

The sensitivity matrix c may be stored and reused later. The sensitivity matrix is a function of the gantry mechanism and does not change over time. For example, when reused to solve for a new configuration of a set of counterweight mechanisms, the test blocks a and B need not be reconnected, thereby saving time required for balancing operations.

When P is present_aAnd P_bAfter determination, P can be corrected by a solving procedure and algorithm including the following formula_aAnd P_bThe resulting imbalance is corrected. Since the CT gantry mechanism 20 includes the first counterweight mechanism 31 and the second counterweight mechanism 32 at two different angular positions, a specific new configuration for each counterweight mechanism is then calculated to enable the balance correction to be achieved by the forces and moments generated by the combination of the two counterweight mechanisms.

F_x-add＝I_m(P_a)+I_m(P_b)

F_y-add＝R_e(P_a)+R_e(P_b) (6)

D_x-add＝R_e(P_a)*(Z_po-Z_pa)+R_e(P_b)*(Z_po-Z_pb)

D_y-add＝I_m(P_a)*(Z_po-Z_pa)+I_m(P_b)*(Z_po-Z_pb)

In the above formulae (6) and (7), F_x-add、F_y-add、D_x-add、D_y-addRespectively represent by P_aAnd P_bInduced forces and moments, F_x-initial、F_y-initial、D_x-initial、D_y-initialRepresenting the forces and moments resulting from the initial configuration of the first 31 and second 32 counterweight mechanisms, respectively, and F_x-new、F_y-new、D_x-new、D_y-newRepresenting the forces and moments caused by the new configuration of the first and

second counterweight mechanisms

31 and 32, respectively. I is_mRepresenting the vector P in the back brackets_aOr P_bImaginary part of, R_eRepresenting the vector P in the back brackets_aOr P_bReal part of, Z_paA coordinate value, Z, representing the Z direction of the center of gravity of the test block A in the coordinate system_pbA coordinate value, Z, representing the Z direction of the center of gravity of the test block B in the coordinate system_poThe coordinate value in the Z direction in the coordinate system of the plane in which the center of mass of the rotating part is located will not change if mass is added to this plane. Wherein F_x-add、F_y-add、D_x-add、D_y-addCan be obtained from equation (6).

F_x-new、F_y-new、D_x-new、D_y-newAfter the value of (d) is determined by the formula (7), then, the new configurations of the first counterweight mechanism 31 and the second counterweight mechanism 32 are further solved by the following formula.

In the above formula F_x-1-new、F_y-1-new、D_x-1-new、D_y-1-newRespectively, the total unevenness caused by the new configuration to be set by the first counter-weight means 31Constant value, F_x-2-new、F_y-2-new、D_x-2-new、D_y-2-newRespectively, the total unbalance magnitude caused by the new configuration to be set by the second counterweight mechanism 32. Δ F_xAnd Δ F_yRefers to the amount of static imbalance in the X and Y directions, respectively, and Δ D_xAnd Δ D_yRespectively the dynamic unbalance in the X and Y directions, Δ S_tRepresents the total static imbalance tolerance allowed by the CT system, and Δ D_tIndicating the total dynamic imbalance tolerance allowed for the CT system.

The appropriate weight block and the corresponding Z-axis position of each of the first counterweight mechanism 31 and the second counterweight mechanism 32 can be obtained through solution by a calculation algorithm. Subsequently, the first and

second weight mechanisms

31 and 32 mounted on the CT system in place are reset according to the calculation result.

The calculation algorithm may be executed by software in the control device of the gantry mechanism 20, and the new configuration of the

counterweight mechanisms

31 and 32 may be output to a user by means of a display or a printer, etc., so that the user can conveniently complete the adjustment of the

counterweight mechanisms

31 and 32 at the installation site.

Fig. 7A and 7B show a flow chart 100 of a two-plane balancing method according to a preferred embodiment of the present disclosure. The logic of the associated flowchart 100 may be implemented by the control means of the CT gantry mechanism 20 according to the present disclosure, as well as by other hardware, software, firmware, or combinations thereof. The two-plane balancing method according to flowchart 100 includes the steps of:

in step 110, the motor 50 rotates the spin base 30 at a constant rotational speed.

In step 112, the motor signal, the sampling time, the angular position of the rotating base 30, etc. are measured.

In this step 112, the acquisition of the relevant data can preferably be done by means of the motor controller 51 and/or the control means of the gantry mechanism.

In step 114, the rotational speed and rotational speed accuracy of the spin base 30 are calculated. In this step 114, the calculation of the rotation speed and the rotation speed accuracy of the spin base 30 may be performed by the control device of the stage mechanism.

In step 116, it is determined whether or not the rotational speed accuracy is equal to or less than a set value. If the determination result is negative, the flow proceeds to step 118, and if the determination result is positive, the flow proceeds to step 119.

In step 118, the motor controller 51 controls the spin base 30 to rotate to improve the rotational speed accuracy. After step 118 is completed, the process returns to step 114 and the rotational speed and rotational speed accuracy of the spin base 30 are again calculated.

In step 119, the rotary base 30 is controlled to rotate and motor signals, sensor signals, sampling time, angular position of the rotary base 30, and the like are collected as reference test data of the test. In this step 119, the acquisition of reference test data is carried out under conditions of substantially constant rotation speed of the rotating base 30, the rotation speed of the rotating base 30 preferably being close to or equal to the maximum rated rotation speed of the rotating base 30, and on the basis of these acquired signals, the signals occurring once per revolution of the rotating base 30 are extracted by the control means by processing the current or power of the motor and the signals of the sensors, and the vector signal X can be obtained₀And Z₀。

In step 120, the amount of unbalance of the stage mechanism 20 is calculated.

In step 121, it is determined whether the unbalance amount is less than or equal to a set value. If the result of the determination is negative, it indicates that the amount of unbalance of the stage mechanism 20 exceeds the predetermined range, and the process goes to step 122; if the judgment result is yes, it indicates that the amount of unbalance of the stage mechanism 20 is within the predetermined range, and the process is ended.

In step 122, test block a is added. In this step 122, the weight and position of the test block a are preset. The test mass a may be mounted at an angle of about 180 degrees where the second weight mechanism 32 is located.

In step 124, the rotary base 30 is controlled to rotate and motor signals, sensor signals, sampling time, angular position of the rotary base 30, etc. are collected as test a data. In this step 124, the acquisition of test A data is carried out under conditions of substantially constant rotation speed of the rotating base 30, the rotation speed of the rotating base 30 preferably being close to or equal to the maximum rated rotation speed of the rotating base 30, and based on these acquiredThe control device processes the current or power of the motor and the signal of the sensor to extract the signal appearing once per rotation of the rotary base 30, and a vector signal X can be obtained_aAnd Z_a。

In step 126, test block a is removed.

In step 128, test block B is added. In this step 128, the weight and position of the test block B are preset. For example, the test block B is disposed at a position rotated clockwise by about 30 degrees with respect to the 0-degree position.

In step 130, the rotary base 30 is controlled to rotate and motor signals, sensor signals, sampling time, angular position of the rotary base 30, etc. are collected as test B data. Based on the collected data, the control device processes the current or power of the motor and the signal of the sensor, extracts the signal appearing once per rotation of the rotary base 30, and can obtain the vector signal X_bAnd Z_b。

In step 132, test block B is removed.

In step 134, a sensitivity matrix [ c ] is calculated]. In step 134, calculation can be performed by using the above formulas (1), (2), (3), (4), and (5), and based on the vector signal X obtained in

steps

119, 124, and 130₀、Z₀、X_a、Z_a、X_b、Z_bBy these formulas, P can be solved_aAnd P_b。

In step 136, the initial configuration of the two counterweight mechanisms on the gantry mechanism is entered.

In step 138, the new configuration of the two counterbalance mechanisms on the gantry mechanism 20 is calculated using the resolver. In this step 138, the new configuration of the counterweight mechanism can be deduced by equations (6), (7), (8), (9), and (10).

In step 140, the two counterweight mechanisms on the gantry mechanism are reconfigured in the new configuration to correct the gantry mechanism imbalance.

In step 142, based on the two counterweight mechanisms rearranged on the gantry mechanism, the rotating base 30 is controlled to rotate and motor signals, sensor signals, sampling time, and the angular position of the rotating base 30, etc. are acquired. In this step 142, the spin base 30 is preferably also rotated at a substantially constant rotational speed that is close to or equal to the highest rated rotational speed.

In step 144, the current or power of the motor and the signal of the sensor are processed by the control device to extract the fluctuation signal occurring once per rotation of the rotating base 30, and the unbalance amount of the gantry mechanism is calculated again.

In step 146, it is determined whether the unbalance amount is less than or equal to the set value. If the determination is negative, indicating that the imbalance correction has not been expected, the process loops to step 138 where the previously stored sensitivity matrix [ c ] is used]Can be called directly; if the determination result is yes, it indicates that the imbalance correction is expected, and the process ends. In this step 146, it is determined whether the unbalance amount is smaller than the set value Δ S based on the formulas (9) and (10)_tAnd Δ D_t。

In accordance with another aspect of the present disclosure, the current or power signal of the motor 50 may be used to make a static balance correction for the CT system. This is particularly advantageous for low speed CT imaging systems. For low rotational speed CT imaging systems, dynamic imbalance effects are small and no correction can be made, but only a balance correction of static balance is made. In this case, the balance correction can be performed only by the signal delivered from the motor 50 without providing or using a dedicated sensor 60 for measuring the Z-axis directional unbalance. Similar to the two-plane balance correction, the process of the static balance correction may also include a data acquisition step in which only the current or power signal of the motor is acquired, and a state data acquisition step in which the current or power signal from the motor 50 is subsequently processed to obtain state data relating to the static balance state of the CT gantry mechanism. The obtained state data can correspond to the arrangement of the weight mechanism on the spin base 30, and the weight mechanism is adjusted based on the balance calculation result of the state data. The static balancing method of performing the balance correction of the stage mechanism 20 using the signal of the motor 50 is as follows.

First, the motor 50 rotates the rotary base 30, and advantageously, the rotation speed of the rotary base 30 is made to reach a constant value as much as possible by the motor controller 51 of the motor 50, and signals such as the current or power of the motor 50, the sampling time, and the angular position of the rotary base 30 are collected by the control device of the gantry mechanism 20.

If the signal acquisition is performed at equal intervals, the signal occurring once per revolution of the rotating base 30 can be processed and extracted using fourier transform or least squares, and if not, least squares. The control means process the signal of the current or power of the motor 50, extract the ripple signal appearing once per revolution of the rotating bed 30, and express it as a vector signal V comprising amplitude and phase angle₁。

Then, the obtained vector signal V is used₁The output torque M of the motor 50 is calculated by the following formula₁：

M₁＝K_t*V₁ (11)

Wherein, K_tIs a conversion factor of the current and the output torque of the motor 50, which is known.

At this time, the static unbalance torque S caused by the rotating part of the stage mechanism 20₁Equal to the output torque M of the motor 50₁Namely:

S₁＝K_t*V₁ (12)

it will be appreciated that when an equal and opposite torque Q is added₁The resulting increase in the reactive static imbalance force F on the rotating portion of the gantry mechanism 20 is then commensurate_x-addAnd F_y-add. If a new static unbalance force F is generated by a new configuration of the first counterweight mechanism 31 and the second counterweight mechanism 32_x-new1And F_y-new1And F is_x-new1And F_y-new1Initial static unbalance force F generated from initial configuration of the first and second

counter-weight mechanisms

31 and 32_x-initialAnd F_y-initialSatisfying the following equation, the gantry mechanism can achieve static balance.

Accordingly, the required number of weight blocks and the corresponding Z-direction mounting positions on the first and

second weight mechanisms

31, 32 can be determined using a solving program and algorithm by means of the following equations (14) and (15).

In the above formula,. DELTA.F_xAnd Δ F_yDenotes the static unbalance in the X and Y directions, respectively, and Δ S_tIndicating the total static imbalance tolerance allowed for the CT system. After the configurations of the first counter-weight mechanism 31 and the second counter-weight mechanism 32 of the gantry mechanism are reset based on the obtained calculation results, correction of the static balance of the gantry mechanism can be carried out.

Fig. 8A and 8B show a flow chart 200 of a static balancing method according to a preferred embodiment of the present disclosure. The logic of the associated flow chart 200 may be implemented by the control means of the CT gantry mechanism 20 according to the present disclosure, as well as by other hardware, software, firmware, or combinations thereof. The static balancing method according to flowchart 200 includes the steps of:

in step 210, the spin base 30 is rotated at a constant rotation speed. In this step 210, the rotation of the spin base 30 may be controlled by the motor controller 51, preferably such that the spin base 30 rotates at a constant rotational speed that is close to or equal to the highest rated rotational speed of the spin base 30.

In step 212, the motor signal, the sampling time, the angular position of the rotating base 30, etc. are measured. In this step 212, the acquisition of relevant data may preferably be done by means of the motor controller 51 and the control means of the gantry mechanism.

In step 214, the rotational speed and rotational speed accuracy of the spin base 30 are calculated. In step 214, the calculation of the rotation speed and the accuracy of the rotation speed of the spin base 30 may be performed by the control device of the stage mechanism.

In step 216, it is determined whether the rotational speed accuracy meets a preset value. If the determination is negative, the process goes to step 218; if the determination is yes, the process goes to step 220.

In step 218, the motor controller 51 controls the spin base 30 to rotate to improve the rotational speed accuracy. Subsequently, the process returns to step 214, and the rotation speed accuracy of the spin base 30 are calculated again.

In step 220, the magnitude, and phase angle, of the gantry mechanism, representing the imbalance, are calculated. In this step 220, the signal of the current or power of the motor is processed by the control means with the aid of the current and power signals of the motor, the signal occurring once per revolution of the rotating base 30 is extracted and expressed as a vector signal V comprising an amplitude and a phase angle₁。

In step 222, it is determined whether the magnitude of the imbalance satisfies a predetermined value. If the result of the determination is negative, it indicates that the amount of unbalance of the stage mechanism 20 exceeds the predetermined range, and the process goes to step 224; if the judgment result is yes, it indicates that the amount of unbalance of the stage mechanism 20 is within the predetermined range, and the process is ended.

In step 224, the initial configuration of the two counterweight mechanisms on the gantry mechanism is entered.

In step 226, the new configuration of the two counterweight mechanisms on the gantry mechanism is calculated using the resolver. In step 226, a new configuration of the two counterweight mechanisms can be calculated by equations (11), (12), (13), (14), and (15).

In step 228, the two counterweight mechanisms on the gantry mechanism are adjusted to a new configuration to correct the gantry mechanism static imbalance. Then, the process loops to step 210, and the determination is made again whether the rotation speed and the rotation speed accuracy of the rotating base and the static unbalance amount meet the preset requirements until the static unbalance amount is within the tolerance range, and the static balance correction process is terminated.

In performing the dynamic and static balance correction, the rotation speed of the spin base 30 may be set as high as possible. When there is an imbalance in the rotating portion of the gantry mechanism 20, as the rotational speed of the spin base 30 increases, the forces and moments created by the imbalance increase accordingly. Theoretically, the moment generated by the imbalance is proportional to the square of the speed, and therefore, as the rotational speed of the rotating base 30 increases, the magnitude of the signal generated by the motor 50 and the sensor 60 in response to the imbalance increases accordingly. Therefore, the constant rotation speed of the spin base 30 can be set to be close to or equal to the rated maximum rotation speed of the spin base 30 when the dynamic and static balance correction is performed.

For a high rotational speed CT imaging system, multiple balance correction operations may be performed. In a preferred embodiment, the spin base 30 can be rotated at a lower rotation speed during the first balance calibration; during the subsequent balancing correction, the rotating base 30 is rotated at a higher or near nominal maximum rotational speed. This has the advantage that the accuracy of the balance correction can be improved as much as possible while ensuring the safety of the system. Here, the number of balance corrections and the balance correction rotational speed are illustrative and not restrictive.

The rotation of the rotating base 30 at a uniform speed is advantageous for the measurement accuracy. That is, the smaller the fluctuation in the rotation speed of the rotary base 30, the more accurately the vector signal can be obtained to reflect the imbalance of the rotating portion of the stage mechanism 20.

It should be appreciated that in other alternative embodiments, the rotating base 30 is not required to rotate at or near a constant rotational speed if the signal acquisition of the current or power of the motor 50 is performed with reference to a defined sampling angle of rotation of the rotating base 30, i.e., the acquisition of the motor and sensor signals may also be performed during an acceleration or deceleration rotation of the rotating base 30.

In the system and method for detecting or performing balance correction of the state of the gantry mechanism according to the present disclosure, the motor 50 that is originally provided in the gantry mechanism is used as a sensor for measuring the rotational resistance torque of the gantry mechanism, and it is not necessary to provide a special measuring sensor. The signal of the motor 50 can be used for detecting and correcting dynamic balance and static balance, and the system cost is saved. In addition, by reducing the fluctuation in the rotation speed of the motor 50, the accuracy of the signal expression unbalance degree of the motor 50 can be improved, thereby realizing high-accuracy balance correction on the premise of low cost.

For a low-speed system, only a motor is needed to realize balance correction, and the whole CT imaging system is further simplified.

According to another preferred embodiment, as illustrated in fig. 9, the present disclosure also provides a status detection apparatus of a medical imaging system. The apparatus includes a data acquisition module 410 and a status data acquisition module 420, wherein the data acquisition module 410 acquires a current or power signal of the motor to obtain a first signal, and the status data acquisition module 420 acquires status data based on the first signal and related to a particular status of the medical imaging system. More specifically, the data acquisition module 410 is configured to sample a current or power signal of the motor 50 as the motor 50 drives the rotating base 30 to rotate relative to the fixed frame 40, obtaining a first signal. The detection and status data acquisition module 420 is configured to extract from the first signal a signal corresponding to a particular status of the gantry mechanism, for example due to an imbalance of the gantry mechanism, which signal occurs once per revolution of the rotating base 30; or a signal due to a failure of the gantry mechanism, which is a signal that appears twice or three times per revolution of the rotating base 30. The state data acquisition module 420 may be further configured to calculate, based on the extracted signals, a magnitude and phase angle associated with a particular state of the gantry mechanism 20, such as a magnitude and phase angle associated with an unbalanced state of the gantry mechanism 20. In the application of balance correction, the amplitude and associated phase angle correspond to the configuration of the counterweight mechanism on the rotating base, and balance correction can be achieved by balance calculation based on the amplitude and phase angle.

In performing the two-plane balancing method to correct the dynamic balance of the gantry mechanism 20, the data acquisition module 410 may be further configured to sample the output signal of the sensor 60 disposed on the gantry mechanism 20 to obtain a second signal. And the status data acquisition module 420 acquires status data based on the second signal and related to a particular status of the medical imaging system. And the state data acquisition module 420 is configured to extract from the second signal a signal corresponding to a particular state of the gantry mechanism, for example a signal due to an imbalance of the gantry mechanism, which signal occurs once per revolution of the rotating base 30; or a signal due to a failure of the gantry mechanism, which is a signal that appears twice or three times per revolution of the rotating base 30. Meanwhile, the state data acquisition module 420 is configured to acquire state data related to a dynamic balance state based on a first signal and a second signal, wherein the second signal is also a fluctuating signal that occurs once per rotation of the spin base. The computational adjustment based on the state data may provide a balance correction to the dynamic balance of the gantry mechanism 20.

In some embodiments, the status data acquisition module 420 may include a signal extraction module and a calculation module. The signal extraction module 420 is configured to extract a signal from the first signal, for example, due to an imbalance of the gantry mechanism. The calculation module may be configured to calculate, based on the extracted signals, a magnitude and a phase angle associated with a particular state of the gantry mechanism, such as a magnitude and a phase angle of an imbalance of a rotating portion of the gantry mechanism 20. The signal extraction module may include a processing module configured to perform fourier transform or least squares processing on the acquired signals to obtain a signal that occurs once per revolution of the rotating base 30. If the signals are obtained by sampling at equal time intervals, the processing module carries out Fourier transform processing on the acquired signals. If the signals are not obtained by sampling at equal time intervals, the processing module carries out least square processing on the acquired signals.

Further, in some embodiments, the condition detection device 400 may further include or integrate a motor control module 450, the motor control module 450 being configured to control a motor to rotate the rotating base 30 of the gantry mechanism at an acceleration, a deceleration, or a constant rotational speed, wherein the constant rotational speed is close to or equal to a rated maximum rotational speed of the rotating base 30.

The techniques described herein may be implemented in hardware, software, firmware, or any combination thereof unless specifically described as being implemented in a particular manner. Any features described as modules or components may also be implemented together in an integrated logic device or separately as discrete but interoperable logic devices. If implemented in software, the techniques may be realized at least in part by a non-transitory computer-readable storage medium comprising instructions that, when executed, perform one or more of the methods described above. The non-transitory processor-readable data storage medium may form part of a computer program product that may include packaging materials. The program code may be implemented in a high level procedural or object oriented programming language to communicate with a processing system. Program code can also be implemented in assembly or machine language, if desired. Indeed, the mechanisms described herein are not limited in scope to any particular programming language. In any case, the language may be a compiled or interpreted language.

One or more aspects of at least some embodiments may be implemented by representative instructions stored on a machine-readable medium which represent various logic in a processor, which when read by a machine causes the machine to fabricate logic to perform the techniques described herein. Such machine-readable storage media may include, but are not limited to, non-transitory tangible arrangements of articles manufactured or formed by machines or devices that include storage media such as: a hard disk; any other type of disk including floppy disks, optical disks, compact disk read-only memories (CD-ROMs), compact disk rewritables (CD-RWs), and magneto-optical disks; semiconductor devices such as Read Only Memory (ROM), Random Access Memory (RAM) such as Dynamic Random Access Memory (DRAM) and Static Random Access Memory (SRAM), Erasable Programmable Read Only Memory (EPROM), flash memory, Electrically Erasable Programmable Read Only Memory (EEPROM); phase Change Memory (PCM); magnetic or optical cards; or any other type of media suitable for storing electronic instructions.

The disclosure, while disclosing preferred embodiments, is not intended to limit the disclosure, and alterations and modifications may be effected therein by those skilled in the art without departing from the spirit and scope of the disclosure. Therefore, any modification, equivalent change and modification of the above embodiments according to the technical spirit of the present disclosure may fall within the protection scope defined by the claims of the present disclosure, without departing from the technical solution of the present disclosure.

Claims

1. A method of condition detection in a medical imaging system comprising a stationary frame and a rotating part comprising a rotating base driven by a motor, the method comprising:

a data acquisition step of acquiring a current or power signal of the motor to obtain a first signal; and

a state data acquisition step of acquiring state data which is based on the first signal and is related to a specific state of the medical imaging system.

2. The method of claim 1, wherein the first signal comprises a current or power ripple signal that occurs once per revolution of the rotating base.

3. The method of claim 2, wherein the status data includes an amplitude and a phase angle of the first signal, the status data corresponding to a configuration of a counterweight mechanism on the rotating base.

4. The method of claim 2, wherein the data acquisition step further comprises: collecting a second signal output from a sensor provided on the fixed frame, an

The status data acquiring step further comprises acquiring supplemental status data based on the second signal and relating to a particular status of the medical imaging system, wherein a fluctuating signal occurring once per revolution of the rotating base corresponds to a configuration of counterweight mechanisms on the rotating base.

5. The method of claim 4, wherein the status data obtaining step comprises: extracting a fluctuation signal appearing once per rotation of the rotary base from the first signal or the second signal; and

calculating a magnitude associated with the particular state of the medical imaging system based on the extracted fluctuation signal.

6. The method of any of claims 1-5, further comprising: controlling the motor to rotate the rotating base at a constant rotating speed, wherein the constant rotating speed is close to or equal to the rated maximum rotating speed of the rotating base, and the data acquisition step is carried out under the condition that the rotating base rotates at the constant rotating speed.

7. A status detecting apparatus of a medical imaging system including a fixed frame and a rotating portion including a rotating base driven by a motor, the status detecting apparatus comprising:

a data acquisition module configured to acquire a current or power signal of the motor to obtain a first signal; and

a status data acquisition module configured to acquire status data based on the first signal and relating to a particular status of the medical imaging system.

8. The condition sensing device as recited in claim 7 wherein the first signal comprises a current or power ripple signal occurring once per revolution of the rotating base.

9. The condition sensing device as recited in claim 8 wherein the condition data includes an amplitude and a phase angle of the first signal, the condition data corresponding to a configuration of a counterweight mechanism on the rotating base.

10. The status detection apparatus according to claim 8,

the data acquisition module is further configured to acquire a second signal output by a sensor disposed on the fixed frame, and

the status data acquisition module is further configured to acquire supplemental status data based on the second signal and related to a particular status of the medical imaging system, wherein a fluctuating signal occurring once per revolution of the rotating base corresponds to a configuration of a counterweight mechanism on the rotating base.

11. The status detection device of claim 10, wherein the status data acquisition module is further configured to:

extracting a fluctuation signal appearing once per rotation of the rotary base from the first signal or the second signal; and

12. A condition detecting device according to any one of claims 7-11, further comprising:

a motor control module configured to control the motor to rotate the rotating base at a constant rotational speed, wherein the constant rotational speed is close to or equal to a rated maximum rotational speed of the rotating base.

13. The condition detecting device according to claim 7, wherein the first signal includes a current or power fluctuation signal appearing a plurality of times per one rotation of the rotating base, and the second signal includes a fluctuation signal appearing a plurality of times per one rotation of the rotating base.

14. A CT imaging system, the CT imaging system comprising:

a fixed frame and a rotating part including a rotating base driven by a motor;

at least one counterbalance mechanism comprising at least one counterbalance weight that is adjustable;

a state detection device comprising a data acquisition module configured for acquiring a current or power signal of the motor to obtain a first signal and a state data acquisition module configured for acquiring state data based on the first signal and related to a specific state of the CT imaging system, the state data being indicative of an adjustment of the at least one counterweight.

15. The CT imaging system of claim 14, further comprising a sensor disposed on the fixed frame,

wherein the sensor is disposed at an upper portion or a middle portion of the fixed frame when the sensor is selected from the group consisting of an acceleration sensor, a velocity sensor, and a displacement sensor, and disposed at a lower portion of the fixed frame when the sensor is selected from the group consisting of a strain sensor and a piezoelectric sensor.

16. The CT imaging system of claim 15, wherein the data acquisition module is further configured to acquire the signal of the sensor to obtain a second signal, the state data acquisition module being further configured to acquire supplemental state data based on the second signal and related to a particular state of the CT imaging system, wherein a fluctuating signal occurring once per revolution of the rotating base corresponds to a configuration of a counterweight mechanism on the rotating base.

17. The CT imaging system of claim 14, further comprising a first test block and a second test block, the first test block and the second test block having a predetermined weight and a predetermined mounting position, respectively, the first signal comprising a ripple signal occurring once per revolution of the rotating base with the first test block and the second test block mounted, respectively, without the first test block and the second test block mounted.

18. The CT imaging system of claim 14, wherein the first signal comprises a current or power fluctuation signal occurring a plurality of times per rotation of the rotating base.

19. The CT imaging system of claim 14, wherein the rotating portion further comprises an X-ray tube mounted on the rotating base, the X-ray tube disposed at a 0 degree position about a central axis of the rotating portion, and

the at least one weight mechanism includes a first weight mechanism and a second weight mechanism, the first weight mechanism and the second weight mechanism rotate about the central axis by an angle of 80-120 degrees, wherein the second weight mechanism is disposed at a position rotated by about 180 degrees relative to the 0 degree position.

20. The CT imaging system of claim 16,

the at least one counterweight mechanism comprises a first counterweight mechanism and a second counterweight mechanism; and is

The status data acquisition module is further configured to:

processing the first signal or the second signal using one of fourier transform and least square method when the first signal or the second signal is obtained by sampling at equal time intervals;

processing the first signal or the second signal using a least squares method when the first signal or the second signal is obtained by sampling at unequal time intervals;

extracting from the processed first and second signals a current or power fluctuation signal occurring once per revolution of the rotating base;

calculating an amplitude and a phase angle associated with the particular state of the CT imaging system based on the extracted fluctuation signal; and

and when the calculated amplitude does not meet a preset value, calculating new configurations of the first counterweight mechanism and the second counterweight mechanism arranged at different positions on the rotating part according to the amplitude and the phase angle.