CN112741643A

CN112741643A - CT system capable of automatically positioning and scanning and positioning and scanning method thereof

Info

Publication number: CN112741643A
Application number: CN202011635690.XA
Authority: CN
Inventors: 刘猛
Original assignee: Suzhou Boying Medical Technology Co ltd
Current assignee: Suzhou Boying Medical Technology Co ltd
Priority date: 2020-12-31
Filing date: 2020-12-31
Publication date: 2021-05-04

Abstract

A CT system capable of automatic positioning and scanning and a positioning and scanning method thereof, comprising a CT imaging system and a positioning system, wherein the CT imaging system comprises an annular frame, a scanning bed with a vertical motion system and a horizontal motion system, and a control and imaging unit, and is characterized in that: the positioning system comprises an image acquisition device fixed relative to the annular frame and an image processing unit for acquiring and analyzing the acquired image of the image acquisition device, and the image processing unit is connected with the control and imaging unit of the CT imaging system and can exchange data; and an identification module is arranged in the image processing unit and used for analyzing the acquired image, identifying the patient on the scanning bed, acquiring key points of the human body and analyzing the posture of the human body. After the system is installed, calibration is firstly carried out by utilizing calibration positioning so as to realize accurate positioning. The invention realizes automatic positioning and positioning scanning, does not need medical personnel to enter a scanning room, and can effectively avoid cross infection between doctors and patients.

Description

CT system capable of automatically positioning and scanning and positioning and scanning method thereof

Technical Field

The invention relates to medical equipment, in particular to a CT system, and particularly relates to a CT system capable of realizing automatic positioning and scanning.

Background

A ct (computed tomography) system, i.e. an electronic computed tomography system, is a device for providing high-resolution sectional images of a human body, has the characteristics of fast scanning time, clear images and the like, and can be used for the examination of various diseases.

At present, in a large-scale hospital, the number of people needing CT diagnosis and examination is large, the queuing time is long, and the adverse effect is brought to clinical diagnosis. One reason for this is that the existing CT system requires a technician to enter the scanning room and manually position the patient, which takes a long time and is not accurate enough in positioning. How to realize quick positioning and reduce scanning clearance time has great significance for improving the utilization rate of CT.

On the other hand, some diseases are infectious, and for example, in the epidemic prevention process against the new coronavirus, diagnosis of the disease using CT is an important basis for the accurate diagnosis of the disease. Considering that the disease has strong infectivity, how to avoid cross infection caused by the contact of medical staff and patients due to arrangement in the CT diagnosis process is the first problem to be solved in epidemic prevention work. Similar problems exist in the process of diagnosing other diseases with strong infectivity.

Therefore, it is of great significance to realize automatic positioning and scanning of the CT system.

Disclosure of Invention

The invention aims to provide a CT system capable of automatically positioning and scanning, so as to automatically position and place a patient and automatically perform CT tomography, thereby ensuring the rapidness and the accuracy of positioning and scanning, simultaneously avoiding medical staff from entering a scanning room, isolating the medical staff from the patient and avoiding cross infection. It is another object of the present invention to provide a method for such an automatically positionable and scannable CT system. It is still another object of the present invention to provide a calibration method for such an automatically positionable and scannable CT system.

In order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows: an automatically positionable and scannable CT system comprising a CT imaging system and a positioning system, said CT imaging system comprising an annular gantry and a couch having a vertical motion system and a horizontal motion system, and a control and imaging unit, wherein: the positioning system comprises an image acquisition device fixed relative to the annular frame and an image processing unit for acquiring and analyzing the acquired image of the image acquisition device, and the image processing unit is connected with the control and imaging unit of the CT imaging system and can exchange data; the image processing unit is internally provided with an identification module which analyzes the collected image, identifies the patient on the scanning bed, acquires the key points of the human body and analyzes the posture of the human body.

The ring gantry comprises at least one X-ray tube and at least one X-ray detector located opposite the X-ray tube, the X-ray tube and the X-ray detector being rotatable within the ring gantry.

In the above technical solution, the CT imaging system is a prior art, and generally, a main body of the CT imaging system is disposed in a shielding chamber, and the control unit is composed of a controller disposed in the ring-shaped gantry and a computer disposed in an operation chamber adjacent to the shielding chamber, and the computer is provided with human-computer interaction software.

The control unit comprises a motion control unit used for controlling the vertical motion and the horizontal motion of the scanning bed. The long symmetrical axis of the scanning bed is taken as the Z-axis direction, the direction perpendicular to the Z-axis in the horizontal plane is the X-axis direction, the plane of the bed surface of the scanning bed is an XOZ plane, and the vertical direction is the Y-axis direction. The vertical movement means that the scanning bed moves along the positive direction or the negative direction of the Y axis under the control of the motion control unit. Horizontal motion means that the scanning bed moves in a positive or negative z-axis direction under the control of the motion control unit. Wherein, the bed entering is that the scanning bed moves towards the negative direction of the Z axis, and the bed returning is that the scanning bed moves towards the positive direction of the Z axis.

The ring frame has a circular aperture with a passage therein forming an aperture. In the working process of the CT system, the scanning bed carries the patient to move towards the negative direction of the Z axis under the control of the motion control unit to enter the aperture, and the scanning is received in the aperture; the geometric center of the aperture is called the ISO center. The plane passing through the ISO center and perpendicular to the Z axis is called the ISO plane.

The positioning refers to the operation of an operation technician in a manner of adjusting the relative position between the scanning bed and the annular frame according to the scanning part required by the patient so as to enable the required scanning part to be in the scannable range of the CT imaging system; the positioning refers to the process of determining the position and range of the CT scanning in the positioning process.

In the technical scheme, one examination of a patient comprises CT (computed tomography) scout image scanning and tomography, and in one examination, the scout image scanning or the tomography can be carried out only or simultaneously; the positioning image scanning means that a patient lies on a scanning bed, lies on the prone position or lies on the side, the scanning bed moves through a bed plate to enable the patient to pass through an aperture channel of the annular frame, and meanwhile, the annular frame shoots an image of a required area of the patient at any angle; the tomography refers to that a patient lies on a bed, lies on the stomach or lies on the side, the bed moves through a bed plate to enable the patient to pass through an aperture channel of the annular frame, and meanwhile, the annular frame rotates to carry out intermittent or continuous tomography images on the patient.

In the technical scheme, one or more image acquisition devices are arranged and used for acquiring information of a patient on a scanning bed, wherein at least one image acquisition device is arranged right above or laterally above the scanning bed and vertically downwards and/or downwards shoots an image of the patient on the scanning bed at a certain inclination angle; other image acquisition devices are located on the left and right sides of the scanning bed, and take images of the patient on the scanning bed in the horizontal direction.

The field of view of the image acquisition device located directly above or laterally above the couch along the X-axis covers at least the width of the couch.

The visual field ranges of the image acquisition devices positioned at the left side and the right side of the scanning bed along the Y axis at least cover the allowable scanning height range.

Preferably, the scan height range is greater than 300 mm.

The image acquisition system can acquire the image of the patient at one time, and can acquire and splice the image of the patient for multiple times through the movement of the scanning bed.

The image processing unit can be one or more of an embedded processor, a GPU, a computer and a cloud computing platform. The image processing unit can detect key points of a human body on a human body image and calculate the relative positions of the key points of the human body and the annular rack through the image, and the image processing unit can also detect the parts of the human body on a CT positioning image and analyze the position range of tomography. And human body image information can be detected, human body gestures can be analyzed through the relative positions of the human body key points, and the CT system plays voice prompts for a patient through results of the human body gestures so as to adjust the position of the patient to be suitable for CT scanning. The body key points include at least one or more of a head, crown, neck, shoulder, elbow, hand, eye, hip, knee, ankle. The human body key point detection means that an image processing unit calculates and analyzes the image pixel position where the human body key point is located on the human body image.

The invention also provides an automatic positioning and scanning method for the CT system, which comprises the following steps of (1) after a patient lies down on a scanning bed, an operating technician loads a scanning protocol in the CT system;

(2) the CT imaging system controls the motion of the scanning bed, and meanwhile, the image processing unit acquires the image information of the human body through the image acquisition device;

(3) the image processing unit detects key points of a human body in the acquisition process;

(4) the CT imaging system determines the initial position and the scanning length of the patient needing to be subjected to CT scout image scanning and the posture of the patient according to the height information of the scanning bed, the detection result of the key points of the human body and the position information of the scanning protocol;

(5) starting to scan a scout image of the patient;

(6) the image processing unit analyzes the tomographic scanning position range according to the positioning image;

(7) starting tomography, and finishing the automatic positioning and scanning process.

In the above steps, the detection and analysis of the tomography range of the human body key points may be a deep learning detection method based on a neural network, or may not use a deep learning detection method.

In addition to the above method, the present invention provides a calibration method, which is implemented by any CT system capable of automatic positioning and scanning, and comprises the following steps:

(1) selecting the height of a scanning bed of at least one CT system which allows tomography;

(2) placing a calibration object on the scanning bed at a position within the shooting range of the image acquisition device, wherein the calibration object is provided with two calibration edges parallel to the ISO plane of the annular frame;

(3) the image acquisition device shoots a calibration image containing the calibration object and records the position of the scanning bed during shooting;

(5) setting at least 2 calibration points on each calibration edge image;

(6) CT scanning is carried out to obtain a CT sectional image of the calibration object and the position of a scanning bed when the calibration edge is positioned on an ISO plane is calculated;

(7) calculating to obtain a calculation formula of any pixel position, the moving distance of the scanning bed, the height of the scanning bed and the scanning initial position of the CT scout image in the shooting range of the image acquisition device;

(8) and applying the calculation formula to the CT system capable of automatically positioning and scanning.

Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages:

1. according to the invention, through image recognition, detection of key points of a human body and calibration in a matching manner, automatic positioning and positioning scanning are realized, medical personnel do not need to enter a scanning room, and cross infection between doctors and patients can be effectively avoided;

2. the system judges the posture of the human body by detecting key points of the human body and guides the patient to adjust the posture by matching with voice playing, thereby ensuring the normal operation of CT scanning under the condition that medical care personnel do not enter a shielding room.

Drawings

FIG. 1 is a schematic coordinate system of a CT system illustrating the X-axis, Y-axis, Z-axis and CT patient orientation;

FIG. 2 is a block diagram of the connection between the positioning system and the CT imaging system in an exemplary embodiment;

FIG. 3 is a schematic side view of the relative positions of the image acquisition device and the CT system in the embodiment;

FIG. 4 is a schematic diagram of the relative positions of the image acquisition device and the CT system in the embodiment;

FIG. 5 is a schematic diagram of an embodiment in which an image processing unit acquires human body images through multi-stitching;

FIG. 6 is a flowchart of the operation of the automatic positioning and scanning method in an embodiment;

FIG. 7 is a diagram illustrating an exemplary embodiment of an image processing unit analyzing a start position of scout scan;

FIG. 8 is a schematic diagram of a calibration method used in the embodiment.

Detailed Description

The invention is further described with reference to the following figures and examples:

the first embodiment is as follows:

a CT system capable of automatic positioning and scanning comprises a CT imaging system and a positioning system;

the CT imaging system includes:

an annular frame with an aperture;

a scanning bed for carrying a patient and capable of horizontal and vertical movement;

the control console at least comprises human-computer interaction software and a computer;

wherein the horizontal and vertical movements of the scanning bed are controlled by a motion control unit.

The CT imaging system comprises a voice playing unit capable of receiving a voice playing command or playing a preset voice prompt; in the scanning process, the CT imaging system plays voice through the voice playing unit so as to guide or prompt the patient to get on the bed, lie down, breathe, lift hands and the like.

The man-machine interaction software at least can perform loading scanning protocol operation, scanning preparation operation, exposure operation, command receiving or prompt operation;

the coordinate system of the CT imaging system is shown in fig. 1.

In this embodiment, the vertical movement means that the scanning bed moves in a positive direction or a negative direction along the y-axis under the control of the motion control unit.

The horizontal movement means that the scanning bed moves along the positive direction or the negative direction of the z axis under the control of the motion control unit.

The bed entering is that the scanning bed moves towards the negative direction of the z-axis.

The bed returning is that the scanning bed moves to the positive direction of the z axis.

The aperture refers to a circular hole on the stand, and in the working process of the CT system, the scanning bed carries the patient to move towards the negative direction of the z axis under the control of the motion control unit to enter the aperture, and the scanning is received in the aperture; the geometric center of the aperture is called the ISO center.

The scanning refers to a process that after a patient is carried into an aperture of a frame by a scanning bed, an X-ray tube emits X-ray beams, and a detector receives the X-rays which pass through the patient and forms an image.

The loading of the scanning protocol operation refers to that an operator selects and adds a scanning protocol of a part of a patient needing scanning to a scanning program on the human-computer interaction software. The scanning protocol is a group of parameter combinations which correspond to human body parts and at least cover current parameters, voltage parameters, scanning time parameters and scanning length parameters.

The exposure operation is an operation of causing an X-ray tube to emit X-rays.

The scanning preparation operation refers to the operation of preparing before scanning by the system after the scanning protocol is loaded; after preparation for a scanning operation, the scanning bed starts to move, to be set in position, etc.

The receiving command or prompt refers to a command or prompt fed back by the system, which is transmitted to the man-machine interaction software and displayed. The human-computer interaction software is run on the computer system.

Referring to fig. 2, the positioning system includes an image processing unit connected to the CT imaging system for performing data interaction with the CT imaging system, and an image capturing device connected to the image processing unit for receiving control information of the image processing unit and capturing images in vertical, downward, and horizontal directions.

The image processing unit in this embodiment may be an embedded processor, a GPU, a computer, or a device connected to a remote cloud processing platform.

Referring to fig. 3 and 4, which are portions of the ring gantry 100 and the scanning bed 200 of the CT imaging system, a ring-shaped through hole is formed in the middle of the ring gantry 100, and is generally an arc-shaped structure in the Z direction, and

image capturing devices

401 and 402 are installed at a fixed position relative to the ring gantry 100; the scanning bed 200 of the CT imaging system comprises a bed plate 211 which can move horizontally along the Z direction and a vertical lifting mechanism 201 which can vertically lift along the Y direction; after the patient 300 lies on the bed board 211, the

image acquisition devices

401 and 402 are controlled by the image processing unit to take images while the CT control and imaging unit controls the scanning bed to move, the CT control and imaging unit sends the moving distance of the scanning bed to the image processing unit, and the image processing unit processes the images through the taken images and the moving distance of the scanning bed to obtain an image containing at least one human body part.

Preferably, the

image capturing devices

401 and 402 are installed inside the annular through hole of the annular frame 100.

Fig. 6 is a schematic scanning flow chart of a CT system capable of automatic positioning and scanning according to an embodiment of the present invention, and as shown in the drawing, the operation flow chart of the present invention includes:

s101: the operator prompts by voice to guide the patient to lie down on the scanning bed without disorder; then an operator loads a scanning protocol in the man-machine interaction software and carries out the operation of preparing scanning, and meanwhile, the control and imaging unit sends the scanning part information of the scanning protocol to the image processing unit;

s201: the control and imaging unit starts to control the bed entering, and the image acquisition device starts to shoot a patient positioning image;

s301: the image processing unit carries out splicing processing on the human body images and starts to carry out human body key point detection at the same time;

s302: the image processing unit judges the posture of the human body and matches the scanning part in the scanning protocol;

s303: when the image processing unit judges that the human body posture is not matched with the scanning part, the voice for guiding the patient to adjust the posture is played, and meanwhile, the control and imaging unit is informed to prepare to shoot the patient positioning image again;

s304: after the control and imaging unit obtains the posture correction completion information, the control and imaging unit starts to execute step S201 again;

s401: when the image processing unit judges that the human body posture is matched with the scanning part, the image processing unit carries out position detection and calculation of the initial positioning scanning through the detected positions of the key points of the human body;

s501: the image processing unit returns the initial position of the scout image scanning to the control and imaging unit, and then the control and imaging unit starts to control the bed to move and perform scout image scanning;

s601: after the control and imaging unit finishes scout image scanning, the obtained scout image is sent to the image processing unit, the image processing unit carries out tomography region detection according to the position requirement, and the detection result is returned to the control and imaging unit;

s701: the control and imaging unit performs tomographic scanning according to the tomographic area range returned by the image processing unit.

In the step S301, whether the image processing unit needs to perform image stitching depends on the view range of the image capturing device in the Z-axis direction, and an advantage of the present invention is that there is no limitation on the view range of the image capturing device in the Z-axis direction; fig. 5 is an image including a head, a chest, a abdomen, and an arm of a human body obtained by 4 times of image stitching processing of 501, 502, 503, and 504 by an image processing unit, for such an image of a human body, the 4 times of image stitching are only for explaining the image-taking principle, and actually, different selection is performed according to the field of view of the used image-taking device in the Z direction, and any number of times of image stitching may be performed to form a similar image.

Preferably, in the steps S301 and S302, the human body key point detection and the human body posture determination may be performed by a neural network-based artificial intelligence algorithm, and the detection and the determination are performed by a large number of human body key point positions and human body posture labels and learning in advance; the human body key points at least comprise a head, a vertex, a neck, a shoulder, an elbow, a hand, an eye, a hip, a knee and an ankle; the human body posture at least comprises arm lifting, arm natural dropping, eye closing and breath holding.

Optionally, in step S302, the human body posture may be determined by establishing a mathematical model according to the relative positions of the key points of the human body.

Preferably, in step S303, the playing of the voice guiding the patient to adjust the posture is performed by automatically playing the related reminding voice when the CT system automatically detects an unexpected posture of the patient, where the unexpected posture at least includes hand placement, head angle, eyes opening and closing, and breathing movement.

Alternatively, in step S303, the voice for guiding the patient to adjust the posture is played by the operation technician viewing the image through a display device connected to the image processing unit and capable of displaying the patient positioning image and then prompting the user through manual calling.

Preferably, in the above step S304, the control and imaging unit determines whether to perform the step S201 again by analyzing the voice information fed back by the patient.

Alternatively, in step S304 described above, the control and imaging unit triggers the re-execution of step S201 by means of a delay time.

Alternatively, in the above step S304, the operation technician judges whether the patient has completed posture adjustment by observing the display device connected to the image processing unit and capable of displaying the patient positioning image, and then notifies the control and imaging unit whether to execute step S201 through the human-computer interaction software.

Fig. 7 is a detailed illustration case of the specific process of the step S401, after the bed plate 311 of the scanning bed moves a certain distance, the image capturing device completes the capturing of the image 410 of the patient 300 and detects the key point position 411 of the expected scout image scanning start of the patient 300, and knows that the image capturing device moves a distance t in the scanning bed through the information recorded during the capturing, and obtains an image of the key point position 411 when capturing a single visual field image 412, and the image processing unit obtains a pixel point of the key point position 411 on the image 412 as (i, j) through calculation.

Zs is calculated from the formula of the scanning start position of the pixel point on the image 412 calibrated in advance, and the position Zs is used as the scanning start position of the scout image in the above step S501.

The above-mentioned calculation process of step S401 is only illustrated in fig. 7, and the calculation of the height position of the actual scanning bed and the calculation of the scanning start position of the scout image other than those illustrated in the figures can be realized by similar methods.

Fig. 8 is a schematic diagram of a distance calibration method for distance between a view boundary of an image acquisition apparatus on a Z-axis and an ISO plane according to the present embodiment, and with reference to fig. 8, a specific calibration method and steps are described as follows:

b101: operating the lifting of the scanning bed, and setting a height allowing tomography;

b102: a thinner rectangular calibration object is placed on the scanning bed;

b103: adjusting the position, the direction and the inclination angle of the calibration object placed on the scanning bed to enable two opposite sides of the calibration object to be parallel to the ISO plane of the CT system, wherein the two opposite sides are called calibration sides;

b104: moving the scanning bed to enable the calibration object to be completely shot by the image acquisition device to obtain a complete image 412, wherein the image 412 may generate an inclination angle with the X-axis of the CT system, but the calibration edges 610 and 620 of the image 600 of the calibration object are parallel to the X-axis of the CT system, and recording the moving position t0 of the scanning bed;

b105: taking two

index points

611, 612, 621 and 622 on the

images

610 and 620 of the calibration edge respectively, wherein a total of four index points are found, and the pixel coordinates of the four index points are respectively (i1, j1), (i2, j2), (i3, j3), (j4, j 4);

b106: scanning a tomography image of the calibration object by using a thinner layer thickness scanning protocol, wherein the tomography range is required to cover the complete form of the calibration object, and the starting position and the ending position of the scanning are required to be outside the form of the calibration object, namely the tomography at least covers the calibration object;

b107: observing a calibration object tomography image obtained by scanning in the B105, and calculating positions t1 and t2 of a scanning bed when the calibration edge is positioned at the ISO center according to the scanning bed position information and the scanning protocol information of the tomography image;

b108: when the height of the scanning bed is calculated by using a geometric method, the calibration formula Zs of the scout image scanning starting position of the pixel point 413 with any pixel position (i, j) on the image 412 with the position t when the scanning bed moves to the position t is as follows

Zs = t + (t1-t0) + (t1-t2)*(A*i+B*j+C1)/|C1-C2|

Wherein a = j3-j4, B = i4-i3 or a = j1-j2, B = i2-i 1;

C1=i1*j2-i2*j1，C2=i3*j4-i4*j3

and selecting other allowable tomography heights different from B101, and repeating B102-B108 to obtain calibration formulas Zs at more bed heights.

Therefore, the embodiment realizes automatic positioning of the patient and automatic scanning on the premise of not requiring medical staff to enter the shielding room, and ensures the accuracy and the rapidness of the scanning. By using the automatic positioning and scanning CT system, cross infection between doctors and patients can be prevented.

Claims

1. An automatically positionable and scannable CT system comprising a CT imaging system and a positioning system, said CT imaging system comprising an annular gantry and a couch having a vertical motion system and a horizontal motion system, and a control and imaging unit, wherein: the positioning system comprises an image acquisition device fixed relative to the annular frame and an image processing unit for acquiring and analyzing the acquired image of the image acquisition device, and the image processing unit is connected with the control and imaging unit of the CT imaging system and can exchange data; the image processing unit is internally provided with an identification module which analyzes the collected image, identifies the patient on the scanning bed, acquires the key points of the human body and analyzes the posture of the human body.

2. The automatically positionable and scannable CT system of claim 1, wherein: the image acquisition device acquires the image of the patient through one-time acquisition, or the image acquisition device acquires the image of the patient through multiple times of acquisition and splicing of the movement of the scanning bed.

3. The automatically positionable and scannable CT system of claim 1, wherein: the image processing unit is one or more of an embedded processor, a GPU, a computer and a cloud computing platform.

4. The automatically positionable and scannable CT system of claim 1, wherein: and a scanning judgment module is arranged in the image processing unit, and the relative positions of the key points of the human body and the annular rack are calculated through images according to the key points of the human body obtained by the identification module, so that the detection of the parts of the human body is carried out, and the position range of the tomography is analyzed.

5. The automatically positionable and scannable CT system of claim 1, wherein: the CT system comprises a positioning reminding module, and voice prompts are played for the patient to adjust to the position suitable for CT scanning according to the human body posture obtained by the image processing unit.

6. The automatically positionable and scannable CT system of claim 1, wherein: the body key points include one or more of a head, a crown of a head, a neck, a shoulder, an elbow, a hand, an eye, a hip, a knee, and an ankle.

7. An automatic positioning and scanning method for a CT system, characterized by: the implementation of the automatically positionable and scannable CT system of any of claims 1 to 6, comprising the steps of:

(1) after the patient lies down on the scanning bed, the operation technician loads the scanning protocol in the CT system;

(4) the CT imaging system determines the initial position and the scanning length of the patient needing to be subjected to CT positioning image scanning and the human body posture of the patient according to the height information of the scanning bed, the detection result of the human body key points and the position information of the scanning protocol;

(5) starting to scan a scout image of the patient;

8. The automated positioning and scanning method for a CT system of claim 7, wherein: the human body key point detection and analysis tomography range is realized by a neural network-based deep learning detection method.

9. The automated positioning and scanning method for a CT system of claim 7, wherein: and (4) judging whether the requirement of the scanning protocol is met or not according to the human body posture of the patient, and if not, playing a voice prompt for the patient to adjust the position of the patient to be suitable for CT scanning to be placed.

10. A calibration method for automatic positioning and scanning of a CT system is characterized in that: the implementation of the automatically positionable and scannable CT system of any of claims 1 to 6, comprising the steps of:

(5) setting at least 2 calibration points on each calibration edge image;