Patent ID: 12232896

A list of reference numerals is as follows:

Reference signMeaning100Method for determining a target location of a single-slot collimating plate101-105Steps10Slot plate at an initial − shift location in a Z-axisdirection11Slot plate at an initial + shift location in a Z-axisdirection12-15X-ray16Second signal segment17First signal segment18Fourth signal segment19Third signal segment40Focal point50Detector array70First signal80Second signal90Calibrated combined measurement signal20Collimator assembly21Frame22Rotating carrier23Single-slot collimating plate24Rotational fulcrum25Spring26Recess27Handle28Locating pin29Fixing bolt40Micrometer caliper30Collimator assembly31Frame33First slot34Second slot35First spring36Second spring37Single-slot collimating plate41First micrometer caliper42Second micrometer caliper800Apparatus for determining a target location of a single-slot collimating plate801First acquiring module802Second acquiring module803First determining module804Calibration module805Second determining module806Alarm module900Control host of a CT system901Memory902Processor

DETAILED DESCRIPTION

To make technical solutions and advantages of the present disclosure clearer and more understandable, the present disclosure is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments herein are merely provided for describing the present disclosure and not intended to limit the protection scope of the present disclosure.

For concise and intuitive descriptions, solutions of this disclosure are stated below by using several representative embodiments. A large quantity of details in the embodiments is merely used for helping understand the solutions of this disclosure. However, obviously, embodiment of the technical solutions of the present disclosure may be not limited to these details. To avoid unnecessarily blurring the solutions of this disclosure, some embodiments are not described in detail, but only frames are provided. In the following, “comprise” refers to “comprise, but is not limited to”, and “according to . . . ” refers to “at least according to . . . , but not limited to only according to . . . ”.

The applicant finds that in the prior art, an X-ray source-side collimator generally uses a multi-slot structure. Therefore, in factory tuning up phase, air scanning needs to be performed multiple times (for example, at least seven times) to determine the locations of slots, and this tuning up process is time-consuming and complex. In addition, in the prior art, an additional mechanical motor or control component is further required to assist in tuning up the slot, which further increases complexity and increases production cost.

Considering the tuning up complexity of the multi-slot structure, in an embodiment of the present disclosure, a single-slot collimator including a single-slot collimating plate is used to replace the multi-slot collimator, thereby reducing complexity of tuning up process. In addition, in the embodiment of the present disclosure, a target location is determined based on center of gravity calculation of a signal, which may further ensure tuning-up accuracy. In addition, the embodiment of the present disclosure may further save costs caused by the mechanical motor, the control component, or the like.

FIG.1is a flowchart of an example method for determining a target location of a single-slot collimating plate according to an embodiment of the present disclosure. A single-slot collimator including the single-slot collimating plate is disposed on an X-ray source side. The method shown inFIG.1is preferably performed by a control host of a CT system. The target position of the single-slot collimating plate can be determined by means of two instances of air scanning.

As shown inFIG.1, the method includes the following steps.

Step101: Acquire a first measurement signal collected based on the first time of air scanning when a single-slot collimating plate moves from a start location to a first location by a predetermined distance along a first direction of a Z-axis.

Herein, the Z-axis is a row arrangement direction of a detector array.

When the single-slot collimating plate moves from the start location to the first location by the predetermined distance along the first direction of the Z-axis, the CT system performs the first time of air scanning. The detector array of the CT system detects a measurement signal (referred to as a first measurement signal) during the first time of air scanning. The first measurement signal is determined by X-ray intensity detected in the first time of air scanning in rows on the Z-axis. For example, the X-ray intensity may be used to describe the first measurement signal, or a logarithm of the X-ray intensity may be used to describe the first measurement signal. In addition, the detector array sends the first measurement signal to the control host by using a transmission link such as a cable.

Step102: Acquire a second measurement signal collected based on the second time of air scanning when the single-slot collimating plate moves from the start location to a second location by the predetermined distance along an opposite direction of the first direction.

Herein, the single-slot collimating plate returns from the first location to the start location. Further, when the single-slot collimating plate moves from the start location to the second location by the predetermined distance along the opposite direction of the first direction of the Z-axis, the CT system performs the second time of air scanning. The detector array detects a measurement signal (referred to as a second measurement signal) during the second time of air scanning. The second measurement signal is determined by X-ray intensity detected in the second time of air scanning in rows on the Z-axis. For example, the X-ray intensity may be used to describe the second measurement signal, or a logarithm of the X-ray intensity may be used to describe the second measurement signal. In addition, the detector array sends the second measurement signal to the control host by using a transmission link such as a cable.

FIG.2is a schematic cross-sectional diagram of air scanning of CT in a Z-axis direction according to an embodiment of the present disclosure.

The single-slot collimating plate moves from the start location (initial) to a current location (initial−shift) by the predetermined distance (shift) along the reverse direction of the Z-axis shown inFIG.2(that is, the opposite direction of the arrow marked with Z inFIG.2). Next, the CT system performs the first time of air scanning. Specifically, an X ray emitted from a focal point40undergoes a beam limiting action of a single-slot collimating plate10moving to the current location (initial−shift) to form a transmission range defined by an X ray12and an X ray13. When a detector array50has enough rows in the Z-axis direction, the detector array50may detect a measurement signal identified by a complete solid line curve70. However, since the detector array50typically has only a limited quantity of rows, the solid line curve70may not actually be fully detected. For example, as shown inFIG.2, the detector array50that includes the first row R1, the second row R2, . . . , and the nth row Rn detects, in the transmission range, a measurement signal identified by a solid line curve BE. A point B is an intersection point between a line connecting a tail end of the first row R1in the reverse direction of the Z-axis and the focal point40and the solid line curve70, and a point E is an intersection point between the X ray13and the detector array50. It can be seen that the solid line curve BE is a part of the solid line curve70. The solid line curve BE is a measurement signal (the first measurement signal) detected by the detector array50for the first time of air scanning, and is determined by intensity of X-rays detected in each row in the Z-axis direction in the first time of air scanning.

Then, the single-slot collimating plate returns from the current location (initial-shift) to the start location (initial) and moves from the start location (initial) to the current location (initial+shift) by the same predetermined distance (shift) in the forward direction of the Z-axis as shown inFIG.2(i.e., the arrow direction identified by Z inFIG.2). Next, the CT system performs the second time of air scanning. Specifically, an X ray emitted from a focal point40undergoes a beam limiting action of a single-slot collimating plate11moving to the current location (initial+shift) to form a transmission range defined by an X ray14and an X ray15. When the detector array50has enough rows, the detector array50may detect a measurement signal identified by a complete dotted line curve80. However, since the detector array50typically has only a limited quantity of rows, the dotted line curve80may not actually be fully detected. For example, as shown inFIG.2, the detector array50that includes the first row R1, the second row R2, . . . , and the nth row Rn detects, in the transmission range, a measurement signal identified by a dotted line curve DC. A point C is an intersection point between a line connecting a tail end of the nth row Rn in the forward direction of the Z-axis and the focal point40and the dotted line curve80, and a point D is an intersection point between the X ray14and the detector array50. It can be seen that the dotted line curve DC is a part of the dotted line curve80. The dotted line curve DC is a measurement signal (the second measurement signal) detected by the detector array50for the second time of air scanning, and is determined by intensity of X-rays detected in each row in the Z-axis direction in the second time of air scanning.

Step103: Determine a combined measurement signal and a combined air calibration signal based on the first measurement signal and the second measurement signal.

Herein, the control host determines the combined measurement signal and the combined air calibration signal based on the first measurement signal and the second measurement signal.

In an embodiment, step103of determining a combined measurement signal and a combined air calibration signal based on the first measurement signal and the second measurement signal includes: determining a demarcation point between the first measurement signal and the second measurement signal; combining a first signal segment that is in the second measurement signal and that extends from the demarcation point along the first direction of the Z-axis with a second signal segment that is in the first measurement signal and that extends from the demarcation point along the opposite direction into the combined measurement signal; and combining a third signal segment that is in the first measurement signal and that extends from the demarcation point along the first direction of the Z-axis with a fourth signal segment that is in the second measurement signal and that extends from the demarcation point along the opposite direction into the combined air calibration signal. The demarcation point may be an intersection point between the first measurement signal and the second measurement signal, or may be a peripheral point of an intersection point between the first measurement signal and the second measurement signal.

Following the example inFIG.2, the point A is an intersection point between the first measurement signal and the second measurement signal. The point A is used as a demarcation point between the first measurement signal and the second measurement signal.

A solid line AE included in the solid line curve BE is a second signal segment17, and a dotted line DA included in the dotted line curve DC is a first signal segment16. The first signal segment16and the second signal segment17are combined into a combined measurement signal.

FIG.3is a schematic diagram of combining to obtain a combined measurement signal according to an embodiment of the present disclosure. InFIG.3, the first signal segment16and the second signal segment17form a combined curve by using the point A, that is, a combined measurement signal.

A solid line BA included in the solid line curve BE is a third signal segment19, and a dotted line AC included in the dotted line curve DC is a fourth signal segment18. The third signal segment19and the fourth signal segment18are combined into a combined air calibration signal.

FIG.4is a schematic diagram of combining to obtain a combined air calibration signal according to an embodiment of the present disclosure. InFIG.4, the third signal segment19and the fourth signal segment18form a combined curve by using the point A, that is, a combined air calibration signal.

Step104: Calibrate the combined measurement signal by using the combined air calibration signal.

Herein, the control host calibrates the combined air calibration signal by using the combined measurement signal, to obtain the calibrated combined measurement signal.

Specifically, when both the first measurement signal and the second measurement signal are described by using logarithms of X-ray intensity detected in respective air scanning (that is, logarithm operation is performed on X-ray intensity detected in respective air scanning of both the first measurement signal and the second measurement signal), the combined air calibration signal may be subtracted from the combined measurement signal to obtain the calibrated combined air calibration signal. Alternatively, when both the first measurement signal and the second measurement signal are described by using X-ray intensity detected in respective air scanning (that is, logarithm operation is not performed on X-ray intensity detected in respective air scanning of both the first measurement signal and the second measurement signal), the combined measurement signal may be divided by the combined air calibration signal to obtain the calibrated combined air calibration signal.

FIG.5is a schematic diagram of a calibrated combined measurement signal according to an embodiment of the present disclosure. InFIG.5, a calibrated combined measurement signal90is displayed in a coordinate system in which a serial number of a row is a horizontal axis and signal intensity is a vertical axis.

Step105: Determine a target location of the single-slot collimating plate based on the calibrated combined measurement signal.

Herein, the control host may first determine a center of gravity of the calibrated combined measurement signal, and then determine the target location of the single-slot collimating plate based on the center of gravity. For a specific manner in which the control host determines the center of gravity of the calibrated combined measurement signal, references may be made to various center of gravity (COG) algorithms, which is not limited in the embodiment of the present disclosure.

Each detector in the detector array has a plurality of channels in a channel direction, where the channel direction is an arrangement direction of the channels in the detector array. The detector array is usually an arcuate detector array, so the channel direction is usually arcuate. For example, as shown in the lower right corner ofFIG.2, in a three-dimensional spatial rectangular coordinate system (X-Y-Z), the Z-axis direction is the arrangement direction of rows in the detector array, a channel direction Φ is located in an XY plane perpendicular to the Z-axis, and the channel direction Φ has an arcuate shape corresponding to an arcuate detector array.

The left channel group, the right channel group, and the middle channel group between the left channel group and the right channel group can be determined in advance along the channel direction.

For example, the left channel group, the right channel group, and the middle channel group may be determined based on the number sequence of the channels arranged in the channel direction. For example, assuming that the detector array has 768 channels in the channel direction, channel 1-channel 50 may be determined as the left channel group, channel 411-channel 460 are determined as the middle channel group, and channel 719-channel 768 are determined as the right channel group.

Examples of determining the channel group are illustrated in detail, a person skilled in the art may be aware that, the illustration described herein is exemplary, and is not intended to limit the protection scope of this embodiment manner of the present disclosure.

In an embodiment, a center of gravity of an average signal of each calibrated combined measurement signal detected by the middle channel group is determined, and a Z location offset of the single-slot collimating plate is determined based on the center of gravity. Specifically, a first average signal of a calibrated combined measurement signal of each channel in the middle channel group is determined; a center of gravity of the first average signal is determined; and a Z location offset of the single-slot collimating plate is determined based on the center of gravity of the first average signal. The center of gravity of the first average signal is in a coordinate system in which a serial number of a row is a horizontal axis and signal intensity of an X ray is a vertical axis.

For example, it is assumed that the middle channel group includes channel 411-channel 460. In this case, each channel in channel 411-channel 460 may separately acquire a calibrated combined measurement signal90shown inFIG.5(in the coordinate system in which the row number is the horizontal axis and the signal intensity is the vertical axis). That is, the middle channel group may acquire a total of 50 calibrated combined measurement signals90as shown inFIG.5(respectively obtained by using channel 411-channel 460). The average value of the 50 calibrated combined measurement signals90shown inFIG.5is the first average signal of the calibrated combined measurement signals of the channels in the middle channel group. Based on the center of gravity of the first average signal and a fixed parameter of the CT system (for example, a distance between the focal point and the single-slot collimating plate, a distance between the focal point and a rotation center (ISO), or an actual layer width of the detector array), the Z-location offset of the single-slot collimating plate can be determined.

It can be learned that, in this embodiment of the present disclosure, the Z location offset of the single-slot collimating plate can be conveniently determined by using the center of gravity of the first average signal formed by the middle channel group.

In an embodiment, a center of gravity of an average signal of the combined measurement signal detected by the left channel group is determined, a center of gravity of an average signal of the combined measurement signal detected by the right channel group is determined, and parallelism of the single-slot collimating plate is determined based on the two centers of gravity. The parallelism of the single-slot collimating plate reflects parallelism between emergent light of a collimator and a mechanical axis of the collimator.

In an embodiment, a second average signal of a calibrated combined measurement signal of each channel in the left channel group is determined; a center of gravity of the second average signal is determined; a third average signal of a calibrated combined measurement signal of each channel in the right channel group is determined; a center of gravity of the third average signal is determined; and parallelism of the single-slot collimating plate is determined based on the center of gravity of the second average signal and the center of gravity of the third average signal. Both the center of gravity of the second average signal and the center of gravity of the third average signal are in the coordinate system in which the serial number of the row is the horizontal axis and the signal intensity of the X ray is the vertical axis.

For example, it is assumed that the left channel group includes channel 1-channel 50, and the right channel group includes channel 719-channel 768. In this case, each channel in channel 1-channel 50 and channel 411-channel 460 may separately acquire a calibrated combined measurement signal90shown inFIG.5(in the coordinate system in which the row number is the horizontal axis and the signal intensity is the vertical axis). Specifically, the left channel group may acquire a total of 50 calibrated combined measurement signals90as shown inFIG.5(respectively obtained by using channel 1-channel 50). The right channel group may acquire a total of 50 calibrated combined measurement signals90as shown inFIG.5(respectively obtained by using channel 719-channel 768). The average value of the 50 combined measurement signals90acquired by the left channel group is a second average signal of the calibrated combined measurement signals of each channel in the left channel group. The average value of the 50 combined measurement signals90acquired by the right channel group is a third average signal of the calibrated combined measurement signals of each channel in the right channel group. Based on the center of gravity of the second average signal, the center of gravity of the third average signal, and the fixed parameter of the CT system (for example, the total quantity of channels, the maximum channel number in the left channel group, and the maximum channel number in the right channel group), parallelism of the single-slot collimating plate may be determined.

It can be learned that, in this embodiment of the present disclosure, the parallelism of the single-slot collimating plate can be conveniently determined by using the center of gravity of the second average signal formed by the left channel group and the center of gravity of the third average signal formed by the right channel group.

In an embodiment, curvature of the single-slot collimating plate is determined based on the center of gravity of the second average signal, the center of gravity of the third average signal, and the center of gravity of the first average signal. When the curvature is greater than a predetermined curvature threshold, alarm information indicating to replace the single-slot collimating plate is sent. The center of gravity of the first average signal, the center of gravity of the second average signal, and the center of gravity of the third average signal are all located in the coordinate system in which the serial number of the row is the horizontal axis and the signal intensity of the X ray is the vertical axis.

For example, it is assumed that the middle channel group includes channel 411-channel 460, the left channel group includes channel 1-channel 50, and the right channel group includes channel 719-channel 768. In this case, each channel in the middle channel group, the left channel group, and the right channel group may separately acquire a calibrated combined measurement signal90shown inFIG.5(in the coordinate system in which the row number is the horizontal axis and the signal intensity is the vertical axis).

The middle channel group may acquire a total of 50 calibrated combined measurement signals90as shown inFIG.5(respectively obtained by using channel 411-channel 460). The average value of the 50 calibrated combined measurement signals90acquired by the middle channel group as shown inFIG.5is the first average signal of the calibrated combined measurement signals of the channels in the middle channel group. The left channel group may acquire a total of 50 calibrated combined measurement signals90as shown inFIG.5(respectively obtained by using channel 1—channel 50). The average value of the 50 combined measurement signals90acquired by the left channel group is a second average signal of the calibrated combined measurement signals of each channel in the left channel group. The right channel group may acquire a total of 50 calibrated combined measurement signals90as shown inFIG.5(respectively obtained by using channel 719-channel 768). The average value of the 50 combined measurement signals90acquired by the right channel group is a third average signal of the calibrated combined measurement signals of each channel in the right channel group.

The curvature of the single-slot collimating plate may be determined based on the center of gravity of the first average signal, the center of gravity of the second average signal, the center of gravity of the third average signal, and the fixed parameter of the CT system (for example, a distance between the focal point and the single-slot collimating plate, a distance between the focal point and the ISO, an actual layer width of the detector array, the total quantity of channels, the maximum channel number in the left channel group, and the maximum channel number in a right channel group).

It can be learned that, in this embodiment of the present disclosure, the curvature of the single-slot collimating plate can be conveniently determined based on the center of gravity of the second average signal, the center of gravity of the third average signal, and the center of gravity of the first average signal, and an alarm is given when the curvature exceeds the threshold.

The following describes an embodiment of the present disclosure with reference to a specific algorithm.

In the channel direction, the left channel group L, the right channel group R, and the middle channel group M located between the left channel group L and the right channel group R are determined. For example, L=719:768; M=411:460; R=1:50. That is, the left channel group L includes channel 719-channel 778, the right channel group R includes channel 1-channel 50, and the middle channel group M includes channel 411-channel 460.

First, the single-slot collimating plate moves by a predetermined distance shift in a direction (for example, the reverse direction of the Z-axis) of the Z-axis from the start location z-initial on the Z-axis, arrives at the location initial-shift, and performs the first time of air scanning. Measurement data acquired by the detector array is S−(m,q,n), where m is a channel number, q is a row number, and n is a reading.

Then, the single-slot collimating plate returns from the upright location to the start location Z-initial, moves by the same predetermined distance shift in another direction of the Z-axis (for example, the forward direction of Z-axis), arrives at the location initial+shift, and performs the second time of air scanning. Measurement data acquired by the detector array is S+(m,q,n). Before the second time of air scanning, the measurement data S−(m,q,n) acquired during the first time of air scanning may be pre-checked, so as to ensure that the start location z-initial is acceptable.

Then, S+(m,q,n) and S_(m,q,n) are combined to respectively obtain a combined measurement signal datacombine(m,q,n) and a combined air calibration signal aircalcombine(m,q,n). where:

a⁢i⁢r⁢c⁢a⁢lc⁢o⁢m⁢b⁢i⁢n⁢e(m,q,n)={S-(m,q,n)1≤q≤q′S+(m,q,n)q′+1≤q≤N(1)datac⁢o⁢m⁢b⁢i⁢n⁢e(m,q,n)={S+(m,q,n)1≤q≤q′S-(m,q,n)q′+1≤q≤N(2)q′ is a demarcation point between the measurement data acquired during the first time of air scanning and the measurement data acquired by the second time of air scanning, and q′ meets the following relationship:

1Nr×NM⁢∑n=1Nr∑m∈MS-(m,q′,n)≤1Nr×NM⁢∑n=1Nr∑m∈MS+(m,q′,n)(3)1Nr×NM⁢∑n=1Nr∑m∈MS-(m,q′+1,n)≥1Nr×NM⁢∑n=1Nr∑m∈MS+(m,q′+1,n)(4)where Nris the quantity of readings, and NMis the quantity of channels included in the middle group M.

Then, the combined measurement signal datacombine(m, q, n) is calibrated by using the combined air calibration signal aircalcombine(m, q, n) and is averaged on the reading n to obtain the calibrated combined measurement signal Scomb′(m, q). When S+(m, q, n) and S−(m, qn) are respectively represented by logarithms of X-ray intensity detected in respective air scanning, Scomb′(m, q) is the average value of datacombine(m, q, n)−air calcombine(m, q, n) on the reading n. When S+(m, q, n) and S−(m, q, n) are respectively represented by X-ray intensity detected in respective air scanning, datacombine(m, q, n)−aircalcombine(m, q, n) is the average value on the reading n.

Then, Scomb′(m, q) is averaged according to the channel quantities in respective channel groups, to separately calculate respective average signals SL,M,Rqa of the left channel group L, the right channel group R, and the middle channel group M, where:

SqL,M,R=1NL,M,R⁢∑m∈L,M,RSc⁢o⁢m⁢b′(m,q)(5)

NL,M,Rindicates the quantities of channels in the left channel group L, the right channel qCOGL,M,Rgroup R, and the middle channel group M.

Then, a COG algorithm is used to separately calculate respective centers of gravity q COG of the left channel group L, the right channel group R, and the middle channel group M, where:

qCOGL,M,R=∑(q-Qc)⁢SL,M,R∑SqL,M,R(6)

QCis the number of central row.

The optimal Z location offset Zoptimalmay then be calculated, where:

ZoptimalL,M,R=z-initial-qCOGL,M,R×w×dFcdF(7)Zoptimal=ZoptimalM(8)w is the actual layer width of the detector array, dFc is the distance between the focal point and the single-slot collimating plate, dF is the distance between the focal point and the rotation center (ISO), and z-initial is the start location on the Z axis.

In addition, parallelism ΔZequalParallelmay also be calculated, where:
ΔZequalParallel=(ZoptimalL−ZoptimalR)×RChannelGroup(9)
RChannelGroup=M′/(muL−muR)  (10)

M′ is the total quantity of channels, muLis the maximum channel number in the left channel group L, and muRis the maximum channel number in the right channel group R.

In addition, ΔZequalParallelshould meet the following conditions:
|ΔZequalParallel|≤ΔZParallel(11)

ΔZParallelis the parallelism threshold value of the single-slot collimating plate.

Finally, the curvature

❘"\[LeftBracketingBar]"(ZoptimalL+ZoptimalR-2×ZoptimalM2❘"\[RightBracketingBar]"
may be calculated.

In addition, the calculated curvature should meet the following conditions:

❘"\[LeftBracketingBar]"(ZoptimalL+ZoptimalR-2×ZoptimalM2❘"\[RightBracketingBar]"≤Δ⁢ZCurv(12)

ΔZCurvis a threshold value of the curvature.

It can be learned that, compared with the prior art in which multiple air measurement are required to tune up the location of the slot, in this embodiment of the present disclosure, tuning up of the slot can be completed by using signal combination through only two times of air measurement, which is more efficient, simpler, and convenient. In addition, because a quantity of times of air scanning is significantly reduced, costs such as a mechanical motor or a control component can be further reduced in the embodiment of the present disclosure.

Based on the foregoing description, an embodiment of the present disclosure further proposes a collimator assembly adapted to a tuned-up location.FIG.6is a first schematic diagram of tuning up a target location of a single-slot collimating plate in a collimator assembly according to an embodiment of the present disclosure. The location of the collimating plate can be conveniently tuned up without using a mechanical motor or a control component.

InFIG.6, a collimator assembly20includes:a frame21, adapted to be disposed on a rotating carrier22;a single-slot collimating plate23, disposed in the frame21;a rotational fulcrum24, fixed at a first end of the frame21; anda spring25, disposed between an opposite end of the first end of the frame21and the rotating carrier22;where the single-slot collimating plate23includes a recess26, and the frame21has a rotation degree of freedom around the rotational fulcrum24; the single-slot collimating plate23is adapted to be moved to a target location based on a rotation process of the frame21around the rotational fulcrum24or a process of filling the recess26with a gasket, where the target location is determined by using the method for determining a target location of a single-slot collimating plate as described above.

The rotating carrier22may be implemented as a flange-shaped structural component, and provides fixed support for a rotating component such as a ball tube, a collimator assembly, and a detector. The single-slot collimating plate23is preferably made of an X-ray shielding material of high-density metal such as a tungsten alloy.

After a control host determines a Z location offset and a target value of parallelism of the single-slot collimating plate23based on the method for determining a target location of a single-slot collimating plate shown inFIG.1, the rotation amount of the frame21around the rotational fulcrum24may be tuned up by using a micrometer caliper40coupled to a first end of the frame21, so that the parallelism of the single-slot collimating plate23meets the target value. After the parallelism of the single-slot collimating plate23reaches the target value, a gasket of an appropriate specification is filled in the recess26, so that a Z location of the single-slot collimating plate23meets the Z location offset. After the location of the single-slot collimating plate23is tuned up, four fastening bolts29on the frame21may be used, so that the frame21is fixed to the rotating carrier22. Preferably, a locating pin28is disposed at a location on the frame21that is opposite to the recess opening to fix the gasket in the recess26.

Preferably, in the frame21, two parallel handles27are disposed at two ends of the single-slot collimating plate23along the Z-axis direction. A user may conveniently move the frame21by using the two handles27.

Based on the foregoing description, an embodiment of the present disclosure further proposes another collimator assembly adapted to a tuned-up location.FIG.7is a second schematic diagram of tuning up a target location of a single-slot collimating plate in a collimator assembly according to an embodiment of the present disclosure. The location of the slot may be tuned up without using a mechanical motor or a control component.

As shown inFIG.7, a collimator assembly30includes:a frame31, adapted to be arranged on a rotating carrier, the frame31being arranged with a first slot33and a second slot34arranged in parallel along a Z-axis direction;a single-slot collimating plate37, disposed in the frame31;a first spring35, where a first end of the first spring35is fixed to the frame31, and a second end of the first spring35is in contact with a sidewall of the single-slot collimating plate37; anda second spring36, where a first end of the second spring36is fixed to the frame31, and a second end of the second spring36is in contact with the sidewall;where a first end of the single-slot collimating plate37has a moving degree of freedom along the first slot33, and an opposite end of the first end of the single-slot collimating plate37has a moving degree of freedom along the second slot34; and the single-slot collimating plate37is adapted to move to a target location base on combined movement of the first end of the single-slot collimating plate37along the first slot33and the opposite end of the first end of the single-slot collimating plate37along the second slot34, movement of the first end of the single-slot collimating plate37along the first slot33, or movement of the opposite end of the first end of the single-slot collimating plate37along the second slot34, where the target location is determined by using the above method for determining a target location of a single-slot collimating plate.

The frame31may be disposed on the rotating carrier. The rotating carrier may be implemented as a flange-shaped structural component, and provides fixed support for a rotating component such as a ball tube, a collimator assembly, and a detector.

Example 1: When the control host determines the Z location offset and the target value of the parallelism of the single-slot collimating plate37based on the method for determining a target location of a single-slot collimating plate shown inFIG.1, and the user finds that current parallelism of the single-slot collimating plate37is equal to the target value, the user synchronously tunes up a first micrometer caliper41coupled to a first end of the single-slot collimating plate37and a second micrometer caliper42coupled to a second end of the single-slot collimating plate37, so that the single-slot collimating plate37keeps moving in the Z direction with the parallelism, and the Z location to which the single-slot collimating plate37moves meets the Z location offset.

Example 2: When the control host determines the Z location offset and the target value of the parallelism of the single-slot collimating plate37based on the method for determining a target location of a single-slot collimating plate shown inFIG.1, and the user finds that current parallelism of the single-slot collimating plate37is not equal to the target value, the user may simultaneously tune up a first micrometer caliper41coupled to a first end of the single-slot collimating plate37and a second micrometer caliper42coupled to a second end of the single-slot collimating plate37, so that the single-slot collimating plate37reaches the parallelism and moves in the Z direction, and the Z location to which the single-slot collimating plate37moves meets the Z location offset.

Example 3: When the control host determines the Z location offset and the target value of the parallelism of the single-slot collimating plate37based on the method for determining a target location of a single-slot collimating plate shown inFIG.1, and the user finds that current parallelism of the single-slot collimating plate37is not equal to the target value, the user may separately tune up a first micrometer caliper41coupled to a first end of the single-slot collimating plate37or separately tune up a second micrometer caliper42coupled to a second end of the single-slot collimating plate37, so that the single-slot collimating plate37reaches the parallelism and moves in the Z direction, and the Z location to which the single-slot collimating plate37moves meets the Z location offset.

Typical structures of the single-slot collimating plate are illustrated in detail, a person skilled in the art may be aware that, the illustration described herein is merely exemplary, and is not intended to limit the protection scope of this embodiment manner of the present disclosure.

Based on the foregoing description, an embodiment of the present disclosure further provides an apparatus for determining a target location of a single-slot collimating plate.

FIG.8is a structural diagram of an apparatus for determining a target location of a single-slot collimating plate according to an embodiment of the present disclosure.

As shown inFIG.8, an apparatus800includes:a first acquiring module801, configured to acquire a first measurement signal collected based on the first time of air scanning when a single-slot collimating plate moves from a start location to a first location by a predetermined distance along a first direction of a Z-axis;a second acquiring module802, configured to acquire a second measurement signal collected based on the second time of air scanning when the single-slot collimating plate moves from the start location to a second location by the predetermined distance along an opposite direction of the first direction;a first determining module803, configured to determine a combined measurement signal and a combined air calibration signal based on the first measurement signal and the second measurement signal;a calibration module804, configured to calibrate the combined measurement signal by using the combined air calibration signal; anda second determining module805, configured to determine a target location of the single-slot collimating plate based on the calibrated combined measurement signal.

In an embodiment, the first determining module803is configured to: determine a demarcation point between the first measurement signal and the second measurement signal; combine a first signal segment that is in the second measurement signal and that extends from the demarcation point along the first direction of the Z-axis with a second signal segment that is in the first measurement signal and that extends from the demarcation point along the opposite direction into the combined measurement signal; and combine a third signal segment that is in the first measurement signal and that extends from the demarcation point along the first direction of the Z-axis with a fourth signal segment that is in the second measurement signal and that extends from the demarcation point along the opposite direction into the combined air calibration signal.

In an embodiment, the second determining module805is configured to: determine a center of gravity of the calibrated combined measurement signal, and determine the target location of the single-slot collimating plate based on the center of gravity.

In an embodiment, the second determining module805is configured to: determine a left channel group, a right channel group, and a middle channel group between the left channel group and the right channel group based on a channel number sequence; determine a first average signal of a calibrated combined measurement signal of each channel in the middle channel group; determine a center of gravity of the first average signal; and determine a Z-location offset of the single-slot collimating plate based on the center of gravity of the first average signal.

In an embodiment, the second determining module805is further configured to: determine a second average signal of a calibrated combined measurement signal of each channel in the left channel group; determine a center of gravity of the second average signal; determine a third average signal of a calibrated combined measurement signal of each channel in the right channel group; determine a center of gravity of the third average signal; and determine parallelism of the single-slot collimating plate based on the center of gravity of the second average signal and the center of gravity of the third average signal.

In an embodiment, the second determining module805is further configured to determine curvature of the single-slot collimating plate based on the center of gravity of the second average signal, the center of gravity of the third average signal, and the center of gravity of the first average signal.

In an embodiment, the apparatus800further includes an alarm module806, configured to: when the curvature is greater than a predetermined curvature threshold, send alarm information indicating to replace the single-slot collimating plate.

Based on the foregoing description, an embodiment of the present disclosure further provides a control host of a CT system.

FIG.9is a structural diagram of a control host of a CT system according to an embodiment of the present disclosure.

As shown inFIG.9, a control host900includes a memory901and a processor902, where the memory901stores an application program capable of being executed by the processor902, so that the processor902executes the method for determining a target location of a single-slot collimating plate.

The memory901may be specifically implemented as a plurality of storage media such as an electrically erasable programmable read-only memory (EEPROM), a flash memory, and a programmable program read-only memory (PROM). The processor902may be implemented as one or more central processing units or one or more field programmable gate arrays, where the field programmable gate array is integrated into one or more central processing units. Specifically, the central processing unit or the central processing unit core may be implemented as a CPU, an MCU, a DSP, or the like.

Not all steps and modules in the procedures and the structural diagrams are necessary, and some steps or modules may be omitted according to an actual need. An execution sequence of the steps is not fixed and may be tuned up according to needs. Division of the modules is merely functional division for ease of description. During actual embodiment, one module may be implemented separately by a plurality of modules, and functions of the plurality of modules may alternatively be implemented by the same module. The modules may be located in the same device or in different devices.

Hardware modules in the foregoing embodiments may be implemented in a mechanical manner or an electronic manner. For example, a hardware module may include a specially designed permanent circuit or logic device (such as a dedicated processor like an FPGA or an ASIC) for performing a specific operation. The hardware module may also include a programmable logic device or circuit (such as a general purpose processor or another programmable processor) that is temporarily configured by software to perform a specific operation. Whether the hardware module is specifically implemented in the mechanical manner, by using a dedicated permanent circuit, or by using a temporarily configured circuit (configured using software) may be determined according to costs and time considerations.

The present disclosure further provides a machine readable storage medium for storing instructions for causing a machine to execute the method described herein. Specifically, a system or an apparatus equipped with a storage medium may be provided. Software program code for implementing a function in any one of the foregoing embodiments is stored in the storage medium, and a computer (or a CPU or an MPU) of the system or apparatus reads and executes program code stored in the storage medium. In addition, an operating system operated on a computer or the like may be enabled to complete some or all actual operations by using a program code-based instruction. The program code read from the storage medium may be written into a memory disposed in an extension board inserted into the computer or into a memory disposed in an extension unit connected to the computer. Subsequently, a program code-based instruction enables a CPU installed on the extension board or the extension unit to perform some and all actual operations, so as to implement a function of any one of the foregoing embodiments.

The storage medium embodiment for providing program code includes a floppy disk, a hard disk, a magneto-optical disk, an optical disc (such as a CD-ROM, a CD-R, a CD-RW, a DVD-ROM, a DVD-RAM, a DVD-RW, and a DVD+RW), a magnetic tape, a non-volatile memory card, and a ROM. Alternatively, program code may be downloaded from a server computer via a communication network.

The foregoing descriptions are merely preferred embodiments of the present disclosure, are not intended to limit the protection scope of the present disclosure. A person skilled in the art may make various modifications and changes to this disclosure. Any modification, equivalent replacement, or improvement made without departing from the spirit and principle of this application shall fall within the protection scope of this disclosure.