Subject vertical positioning method, subject vertical positioning apparatus, and CT system

Abstract

The application relates to a subject vertical positioning method, a subject vertical positioning device and a CT system. The method comprises the following steps: acquiring the position of an examination bed after the subject is positioned; determining a measurement range corresponding to the organ of the subject on the examination bed, the measurement range comprising a starting point and an ending point in the horizontal direction; during the movement of the examination bed towards a scanning frame, starting the measurement of the distance from the subject by a sensor attached to the scanning frame when the starting point reaches a measurement position of the sensor, and stopping the measurement when the ending point reaches the measurement position, and acquiring the height of the examination bed while the sensor is measuring; calculating the organ center height based on the measurement result of the sensor, the height of the sensor and the height of the examination bed, the height representing the average height of the organ in the vertical direction; and adjusting the height of the examination bed based on the organ center height, so that the adjusted organ center height is equal to the isocenter height of the scanning frame, so as to realize the effects of minimizing the radiation dose of the subject and improving the CT imaging quality.

Description

TECHNICAL FIELD

[0001] The present application relates to positioning a subject, and in particular, to vertically positioning a subject before a medical examination of the subject using a medical imaging device. BACKGROUND

[0002] Before a medical examination of a subject using a medical imaging device (e.g., CT), the subject needs to be positioned so that the subject is in a proper position and posture on an examination bed of the medical imaging device for a proper medical examination.

[0003] CT scanning is divided into a topogram (TOPO) scan and a tomogram (TOMO) scan. Generally, a subject is first scanned with a low radiation dose to generate a topogram image, which is used to determine an accurate tomogram scan range for a tomogram scan; and then the subject is scanned with a high radiation dose to generate a tomogram image. In a CT scanning workflow, before the topogram scan, the subject is positioned on the examination bed to fix the position of the subject on the examination bed, while the center of the organ to be detected of the subject is close to the isocenter of a CT gantry in the vertical direction. Then, the examination bed is horizontally moved so that the subject reaches a topogram scan starting position (i.e., the horizontal starting point of the organ to be detected of the subject reaches the horizontal isocenter of the CT gantry). The topogram scan of the subject is then started.

[0004] Recent studies have shown that the misalignment of the center of the organ to be detected of the subject and the isocenter of the CT gantry in the vertical direction affects the radiation dose and image quality of the subject. However, one study found that almost 95% of the subjects who underwent chest CT examination were not properly vertically positioned, and the average deviation distance of the center of the organ to be detected of the subject from the isocenter of the CT gantry in the vertical direction was 33 mm. Therefore, it is necessary to make the center of the organ to be detected of the subject as close as possible to the isocenter of the CT gantry in the vertical direction to minimize the radiation dose of the subject and improve the CT imaging quality.

[0005] Currently, technicians use a laser-assisted system to visually estimate the proper position of the vertical positioning of the subject. That is, a plurality of beams of visible laser light (e.g., red laser light) is emitted from a laser source toward the isocenter of the CT gantry to mark the position of the isocenter of the CT gantry. Then, the technician manually adjusts the height of the examination bed so that the center of the organ to be detected of the subject coincides with the isocenter in the vertical direction. However, this requires the technician to be fully focused during the operation, because the accuracy of the vertical positioning of the subject depends on the accuracy of the operation of the technician. Also, it requires the technician to have certain professional knowledge to know the best bed height for patients of different sizes under different organ scanning schemes. Some technicians may need to adjust several times to obtain a better vertical position, which leads to low efficiency of the clinical workflow.

[0006] Therefore, a technical solution based on a 3D camera (combined with a time-of-flight, structured light, binocular camera, etc.) is proposed to solve this inaccurate and inefficient vertical positioning problem. In this solution, the depth map of the object is obtained by using a three-dimensional camera, so as to calculate the thickness of the subject. Together with other functions, the 3D camera can provide more abundant functions, but due to the high cost, it is still necessary to have an alternative cost-effective solution for low-end scanners. On the other hand, the current 3D camera needs to be installed on the ceiling of the scanning room to ensure that the entire body of the subject can be photographed when the subject lies on the examination bed. However, due to the difference of the scanning room, additional installation and adjustment procedures may be required on site. SUMMARY

[0007] The main purpose of the present application is to provide a subject vertical positioning method, a subject vertical positioning device and a CT system to solve the problem that it is difficult to simply and cost-effectively position a subject to be imaged for medical imaging examination with high precision in the prior art.

[0008] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a subject vertical positioning method for a CT machine attached with a sensor for measuring the distance to the subject is provided, the method comprising: obtaining the initial position of the examination bed of the CT machine when the horizontal positioning of the subject is completed; obtaining the measurement range of the sensor on the examination bed corresponding to the organ to be detected of the subject, the measurement range comprising a starting point and an ending point in the horizontal direction; during the movement of the examination bed towards the gantry of the CT machine, starting the measurement of the sensor when the starting point reaches the measurement position of the sensor, stopping the measurement of the sensor when the ending point reaches the measurement position, and obtaining the real-time height of the examination bed corresponding to the measurement range while the sensor is measuring; calculating the organ center height based on the measurement result of the distance to the subject by the sensor, the height of the sensor and the real-time height of the examination bed corresponding to the measurement range, the organ center height representing the average height of the organ to be detected corresponding to the measurement range in the vertical direction; and adjusting the height of the examination bed based on the calculated organ center height, so that the adjusted organ center height is equal to the height of the isocenter of the gantry.

[0009] In this way, the vertical height of the subject can be adjusted by the sensor, so that the organ center height of the adjusted subject is equal to the height of the isocenter of the gantry. Thus, the radiation dose of the subject is minimized and the CT imaging quality is improved.

[0010] Further, according to an embodiment of the present application, the calculating the organ center height comprises: calculating an organ average thickness of the subject corresponding to the measurement range based on the measurement result of the sensor, the height of the sensor, and the real-time height of the examination table corresponding to the measurement range, and calculating the organ center height based on the organ average thickness and the current height of the examination table.

[0011] In this way, by calculating the organ average thickness corresponding to the measurement range, the average height of the current organ center point can be obtained. For example, the organ center height is equal to the sum of half of the organ average thickness and the current height of the examination table.

[0012] Further, according to an embodiment of the present application, the obtaining the measurement range on the examination table corresponding to the organ to be detected of the subject comprises: obtaining an overhead image of the subject from a camera; determining an image range corresponding to the organ to be detected from the overhead image, the image range being defined by a pixel start coordinate and a pixel end coordinate along a horizontal direction; mapping the pixel start coordinate to an initial position of the start point on the examination table and mapping the pixel end coordinate to an initial position of the end point on the examination table based on imaging parameters of the camera and an initial position of the examination table; and determining the measurement range from the start point and the end point.

[0013] In this way, the accurate measurement range can be obtained by using the camera, so that the vertical positioning adjustment of the subject can be completed before the plain scan, so that the plain scan and the tomographic scan are performed at the optimized vertical position, thereby minimizing the radiation dose of the subject and maximizing the CT imaging quality.

[0014] Further, according to an embodiment of the present application, the calculating the organ center height based on the measurement result of the sensor, the height of the sensor, and the real-time height of the examination table corresponding to the measurement range comprises: obtaining a distance profile curve from the measurement result of the sensor, the distance profile curve indicating a distance from the sensor to the subject corresponding to each point in the measurement range, and calculating the organ center height corresponding to the measurement range based on the distance profile curve, the height of the sensor, and the real-time height of the examination table corresponding to the measurement range.

[0015] In this way, the distance profile curve corresponding to the measurement range can be obtained by using the sensor, and then the organ average thickness corresponding to the measurement range is calculated from the distance profile curve, the height of the sensor, and the real-time height of the examination table corresponding to the measurement range, so that the organ center height can be obtained.

[0016] Further, according to an embodiment of the present application, the acquiring the measurement range on the examination bed corresponding to the organ to be detected of the subject comprises: acquiring a plain film scanning range of a plain film scanning of the CT machine, the plain film scanning range being determined by the CT machine for the organ to be detected, and the plain film scanning range comprising a scanning start point and a scanning end point on the examination bed in a horizontal direction; and determining the measurement range based on the acquired plain film scanning range.

[0017] In this way, the measurement range can be determined directly by using the plain film scanning range determined by the CT machine, and thus the use of an additional camera is avoided, thereby simplifying the determination of the measurement range and the configuration of the CT system that can perform the vertical positioning of the subject.

[0018] Further, according to an embodiment of the present application, the determining the measurement range based on the acquired plain film scanning range comprises: determining the start point and the end point of the measurement range based on the scanning start point of the plain film scanning range.

[0019] In this way, the start point and the end point of the measurement range are determined by using the scanning start point of the plain film scanning range, and thus the measurement range of the sensor can be obtained.

[0020] Further, according to an embodiment of the present application, a distance between the start point and the end point is equal to a distance between the sensor and an isocenter of the scanning gantry in the horizontal direction.

[0021] In this way, the measurement of the sensor ends exactly when the subject moves to the plain film scanning start position. That is, the measurement of the sensor can be performed during the movement of the examination bed to the plain film scanning start position for performing the plain film scanning, and thus the additional movement of the examination bed is avoided, and the measurement process of the sensor is simplified.

[0022] Further, according to an embodiment of the present application, the calculating the organ center height corresponding to the measurement range based on the measurement result of the sensor, the height of the sensor, and the real-time height of the examination bed corresponding to the measurement range comprises: obtaining a distance profile curve based on the measurement result of the sensor, the distance profile curve indicating a distance between the sensor and the subject corresponding to each point in the measurement range; determining a calculation range corresponding to the organ to be detected based on the distance profile curve, the calculation range being located in the measurement range; determining an updated profile curve based on the calculation range, the updated profile curve indicating a distance between the sensor and the subject corresponding to each point in the calculation range; and calculating the organ center height corresponding to the measurement range based on the updated profile curve, the height of the sensor, and the real-time height of the examination bed corresponding to the calculation range in the measurement range.

[0023] In this way, the organ center height corresponding to the organ to be detected can be determined from the measurement range with low precision, so as to calculate the organ center height with high precision. In this way, even if the camera is not used, the high-precision adjustment of the vertical position of the subject can be realized.

[0024] Further, according to an embodiment of the present application, determining the measurement range based on the acquired flat scan range comprises: determining the start point of the measurement range based on the start point of the flat scan range, and determining the end point of the measurement range based on the end point of the flat scan range, wherein the measurement range contains the flat scan range.

[0025] In this way, the measurement of the sensor can be performed at the same time as the flat scan. Thus, the additional movement of the examination bed is avoided. Moreover, the measurement of the sensor is completed when the flat scan is completed, so as to avoid spending additional time on the sensor measurement in the CT workflow, so that the measurement of the sensor is realized without affecting the CT workflow, and thus the subject vertical positioning method is more easily realized on the CT machine.

[0026] Further, according to an embodiment of the present application, calculating the organ center height based on the measurement result of the sensor, the height of the sensor, and the real-time height of the examination bed comprises: obtaining a distance profile curve based on the measurement result of the sensor, the distance profile curve indicating the distance from the sensor to the subject corresponding to each point in the measurement range; acquiring a calculation range from the CT machine, the calculation range being a tomographic scan range in the horizontal direction determined by the CT machine, the tomographic scan range being determined by the CT machine from the flat image generated by the flat scan and located within the flat scan range; determining an updated profile curve from the distance profile curve based on the calculation range, the updated profile curve indicating the distance from the sensor to the subject corresponding to each point in the calculation range; and calculating the organ center height corresponding to the measurement range based on the updated profile curve, the height of the sensor, and the real-time height of the examination bed corresponding to the calculation range in the measurement range.

[0027] In this way, by using the tomographic scan range determined by the CT machine as the calculation range for high-precision calculation, not only can the high-precision calculation of the organ center height and the high-precision adjustment of the vertical height of the subject be realized, but also additional processing of the measurement range is avoided, so as to simplify the adjustment process of the vertical height of the subject.

[0028] According to another aspect of the present application, there is also provided a subject vertical positioning device for a CT machine, the device comprising: an acquisition module configured to acquire an initial position of a couch of the CT machine from the CT machine when a subject horizontal positioning is completed, and acquire a measurement range on the couch corresponding to a to-be-detected organ of the subject, the measurement range comprising a start point and an end point along a horizontal direction; a sensor attached to a gantry of the CT machine, and a signal emission direction of the sensor intersects with an isocenter axis of the gantry, the sensor being configured to start measuring a distance to the subject when the start point reaches a measurement position of the sensor and stop measuring when the end point reaches the measurement position during movement of the couch towards the gantry; wherein the acquisition module is further configured to acquire a real-time height of the couch corresponding to the measurement range while the sensor is measuring; a calculation module configured to calculate an organ center height based on a measurement result of the sensor, a height of the sensor, and the real-time height of the couch corresponding to the measurement range, the organ center height representing an average height of the to-be-detected organ corresponding to the measurement range in a vertical direction; and an adjustment module configured to adjust the height of the couch based on the calculated organ center height, so that an adjusted organ center height is equal to a height of the isocenter of the gantry.

[0029] In this way, the vertical height of the subject can be adjusted by the sensor, so that the adjusted organ center height is equal to the height of the isocenter of the gantry. Thus, the radiation dose of the subject is minimized and the CT imaging quality is improved.

[0030] Further, according to an embodiment of the present application, calculating the organ center height comprises: calculating an organ average thickness of the subject corresponding to the measurement range based on the measurement result of the sensor, the height of the sensor, and the real-time height of the couch corresponding to the measurement range, and calculating the organ center height based on the organ average thickness and a current height of the couch.

[0031] In this way, by calculating the organ average thickness corresponding to the measurement range, the average height of the current organ center point can be obtained. For example, the organ center height is equal to a sum of half of the organ average thickness and the current height of the couch.

[0032] Further, according to an embodiment of the present application, the subject vertical positioning device further comprises a camera configured to capture a top view image of the subject when the subject horizontal positioning is completed; the obtaining module is further configured to: obtain the top view image, and determine an image range corresponding to the organ to be detected from the top view image, the image range being defined by a pixel start coordinate and a pixel end coordinate along a horizontal direction; map the pixel start coordinate to an initial position of the start point on the examination bed and map the pixel end coordinate to an initial position of the end point on the examination bed based on imaging parameters of the camera and the initial position of the examination bed; and determine the measurement range from the start point and the end point.

[0033] In this way, the measurement range can be obtained accurately by using the camera, so that the vertical positioning adjustment of the subject can be completed before the plain scan, and thus the plain scan and the tomography scan can be performed in an optimized vertical position, thereby minimizing the radiation dose of the subject and maximizing the CT imaging quality.

[0034] Further, according to an embodiment of the present application, the calculating module is further configured to: determine a distance profile curve corresponding to the measurement range based on the measurement result of the sensor, the distance profile curve indicating a distance from the sensor to the subject corresponding to each point in the measurement range, and calculate the organ center height corresponding to the measurement range based on the distance profile curve, a height of the sensor, and a real-time height of the examination bed corresponding to the measurement range.

[0035] In this way, the distance profile curve corresponding to the measurement range can be obtained by using the sensor, and then the organ center height corresponding to the measurement range can be calculated from the distance profile curve, the height of the sensor, and the real-time height of the examination bed corresponding to the measurement range.

[0036] Further, according to an embodiment of the present application, the obtaining module is further configured to: obtain a plain scan range of a plain scan from the CT machine, the plain scan range being determined by the CT machine for the organ to be detected, and the plain scan range comprising a scan start point and a scan end point on the examination bed along a horizontal direction, and determine the measurement range based on the obtained plain scan range.

[0037] In this way, the measurement range can be determined directly by using the plain scan range determined by the CT machine, and thus the determination of the measurement range is simplified, and the structure of the CT system capable of performing the vertical positioning of the subject is simplified.

[0038] Further, according to an embodiment of the present application, determining the measurement range based on the acquired flat scan range comprises: determining the start point and the end point of the measurement range based on the scan start point of the flat scan range.

[0039] In this way, the start point and the end point of the measurement range are determined based on the scan start point of the flat scan range, so that the measurement range of the sensor can be obtained.

[0040] Further, according to an embodiment of the present application, the distance between the start point and the end point is equal to the distance between the sensor and the isocenter of the scan gantry in the horizontal direction.

[0041] In this way, when the subject moves to the flat scan start position, the measurement of the sensor just ends. That is, the measurement of the sensor can be performed during the movement of the examination bed to the flat scan start position for performing the flat scan, so that additional movement of the examination bed is avoided, and the measurement process of the sensor is simplified.

[0042] Further, according to an embodiment of the present application, the calculation module is further configured to: determine a distance profile curve from the measurement result of the sensor, the distance profile curve indicating the distance from the sensor to the subject corresponding to each point in the measurement range, determine a calculation range corresponding to the organ to be detected based on the distance profile curve, the calculation range being located in the measurement range, determine an updated profile curve based on the calculation range, the updated profile curve indicating the distance from the sensor to the subject corresponding to each point in the calculation range, and calculate the organ center height corresponding to the measurement range based on the updated profile curve, the height of the sensor, and the real-time height of the examination bed corresponding to the calculation range in the measurement range.

[0043] In this way, the calculation range corresponding to the organ to be detected with high precision can be determined from the measurement range with low precision, so that the organ center height is calculated with high precision. In this way, even without using a camera, high-precision adjustment of the vertical position of the subject can be achieved.

[0044] Further, according to an embodiment of the present application, the acquisition module is further configured to: determine the start point of the measurement range based on the scan start point of the flat scan range, and determine the end point of the measurement range based on the scan end point of the flat scan range, wherein the measurement range contains the flat scan range.

[0045] In this way, the measurement of the sensor can be performed at the same time as the flat scan. Thus, the additional movement of the examination bed is avoided, and the measurement process of the sensor is simplified.

[0046] Further, according to an embodiment of the present application, the acquisition module is further configured to acquire a calculation range from the CT machine, the calculation range being a tomographic scanning range in the horizontal direction determined by the CT machine, the tomographic scanning range being determined by the CT machine from the flat image generated by the flat scan and located within the flat scanning range, the calculation module is further configured to determine a distance profile curve from the measurement result of the sensor, the distance profile curve indicating the distance from the sensor to the subject corresponding to each point within the measurement range; determine an updated profile curve from the distance profile curve based on the calculation range, the updated profile curve indicating the distance from the sensor to the subject corresponding to each point within the calculation range; and calculate the organ center height corresponding to the measurement range based on the updated profile curve, the height of the sensor, and the real-time height of the examination bed corresponding to the calculation range within the measurement range.

[0047] In this way, by using the tomographic scanning range determined by the CT machine as the calculation range for high-precision calculation, not only can the organ center height be calculated with high precision, and the vertical height of the subject be adjusted with high precision, but also the additional processing of the measurement range is avoided, thereby simplifying the adjustment process of the vertical height of the subject.

[0048] Further, according to an embodiment of the present application, the sensor includes a single sensor unit, or an array including a plurality of sensor units.

[0049] In this way, a single sensor unit or an array including a plurality of sensor units can be selected for distance measurement according to the need for adjustment accuracy. For example, a single time-of-flight sensor can be used for point-by-point measurement, or an array of multiple time-of-flight sensors can be used for line-by-line or segment-by-segment measurement.

[0050] According to another aspect of the present application, a CT system is also provided, which includes the above-described subject vertical positioning device, and a CT machine including an examination bed capable of vertical movement under the control of the subject vertical positioning device, and a scan gantry configured to perform a flat scan or a tomographic scan on a subject within the scan gantry, wherein the sensor of the subject vertical positioning device is attached to the scan gantry, and the signal emission direction of the sensor intersects the isocenter axis of the scan gantry.

[0051] In this way, the CT system can be realized, which can adjust the vertical height of the subject with high precision, thereby minimizing the radiation dose of the subject and improving the CT imaging quality. In addition, the CT system according to the present application can automatically position the subject vertically without manual operation of the operator, thereby greatly improving the efficiency of the clinical workflow. Especially in the case of multi-site scanning, the corresponding subject height is automatically adjusted for each site, so that the radiation dose of the subject is reduced while the working time of the CT system is avoided. Moreover, the CT system integrates the sensor with the scanning gantry, which is easier to install and maintain compared with the traditional 3D camera-based solution. In addition, by combining the sensor-based vertical automatic positioning and the RGB camera-based horizontal automatic positioning, a full-automatic positioning system can be provided for entry-level CT products in a low-cost manner.

[0052] In the embodiments of the present application, the technical scheme is provided by setting the sensor, measuring the vertical distance from the subject during the movement of the examination bed by using the sensor, thereby measuring the average height of the center of the organ to be detected in the vertical direction by using a plurality of vertical distances corresponding to the organ to be detected, and then adjusting the height of the examination bed so that the adjusted organ center height is equal to the height of the isocenter of the scanning gantry, to at least solve the problem in the prior art that it is difficult to position the subject vertically with high precision without affecting the CT working efficiency, thereby achieving the effect of minimizing the radiation dose of the subject and improving the CT imaging quality without affecting the CT working efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0053] The drawings accompanying the specification of the present application form a part thereof, serve to provide further understanding of the present application, and together with the specification explain the present application. The use of the same reference numerals in different drawings indicates similar or identical components.

[0054] Figure 1 is a flowchart of a subject vertical positioning method according to an embodiment of the present application;

[0055] Figure 2 is a structural schematic diagram of a subject vertical positioning device according to an embodiment of the present application;

[0056] Figure 3 is a structural schematic diagram of a CT system including a subject vertical positioning device according to an embodiment of the present application;

[0057] Figure 4 is a schematic diagram of the installation of a sensor in a subject vertical positioning device according to an embodiment of the present application on a CT scanning gantry;

[0058] Figure 5Fig. 1 is a schematic diagram showing various installation positions of a sensor in a subject vertical positioning device according to an embodiment of the present application on a CT gantry;

[0059] Figure 6 Fig. 2 is a schematic diagram showing the principle of distance measurement of a subject by a time-of-flight sensor according to an embodiment of the present application;

[0060] Figure 7 Fig. 3 is a schematic diagram showing distance measurement of a subject by a time-of-flight sensor according to a first exemplary embodiment of the present application;

[0061] Figure 8 Fig. 4 is a schematic diagram showing distance measurement of a subject by a time-of-flight sensor according to a second exemplary embodiment of the present application;

[0062] Figure 9 Fig. 5 is a schematic diagram showing distance measurement of a subject by a time-of-flight sensor according to a third exemplary embodiment of the present application;

[0063] Figure 10 Fig. 6 is a schematic diagram showing height adjustment after distance measurement of a subject by a time-of-flight sensor according to an embodiment of the present application.

[0064] In the above drawings, the following reference signs are used:

[0065] 200: subject vertical positioning device

[0066] 201: acquisition module

[0067] 205: sensor

[0068] 207: calculation module

[0069] 209: adjustment module

[0070] 211: camera

[0071] 300: CT system

[0072] 310: CT machine

[0073] 301: examination bed

[0074] 303: gantry

[0075] 600: subject

[0076] C: isocenter of the gantry

[0077] Za: isocenter axis of the gantry

[0078] I1: top view image of the subject taken by the camera

[0079] I2: a flat image generated by a flat scan of the CT machine

[0080] S0: an image range determined on the overhead image captured by the camera

[0081] a1: a starting pixel coordinate of the image range

[0082] b1: a terminal pixel coordinate of the image range

[0083] S1: a measurement range of the time-of-flight sensor

[0084] P1: a starting point of the measurement range

[0085] P2: a terminal point of the measurement range

[0086] S2: a calculation range

[0087] P3: a starting point of the calculation range

[0088] P4: a terminal point of the calculation range DETAILED DESCRIPTION

[0089] For the purpose of explanation, the embodiments and features in the embodiments in the present application can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0090] It should be noted that, unless otherwise specified, all the technical and scientific terms used in the present application have the same meaning as that generally understood by the ordinary skilled in the art to which the present application belongs.

[0091] In the present application, unless otherwise specified, the orientation words such as “up, down, top, bottom” are generally directed to the directions shown in the drawings, or are directed to the vertical, perpendicular or gravity directions of the components themselves; likewise, for the purpose of understanding and description, “inner, outer” refers to the inner and outer relative to the contour of the components themselves, but the above orientation words are not used to limit the present application.

[0092] Figure 1 is a flowchart of a subject vertical positioning method according to an embodiment of the present application. As shown in Figure 1 , the CT machine is attached with a sensor for measuring the distance to the subject, and the subject vertical positioning method comprises:

[0093] S101, acquiring an initial position of a couch of the CT machine when horizontal positioning of the subject is completed;

[0094] S103, acquiring a measurement range of the sensor on the couch corresponding to the organ to be detected of the subject, the measurement range comprising a starting point and a terminal point in the horizontal direction;

[0095] S105, starting the measurement of the sensor when the starting point reaches the measurement position of the sensor, stopping the measurement of the sensor when the ending point reaches the measurement position, and acquiring the real-time height of the examination table corresponding to the measurement range while the sensor is measuring during the movement of the examination table towards the gantry of the CT machine;

[0096] S107, calculating the organ center height based on the measurement result of the sensor to the distance of the subject, the height of the sensor, and the real-time height of the examination table corresponding to the measurement range, the organ center height representing the average height of the center of the organ to be detected corresponding to the measurement range in the vertical direction; and

[0097] S109, adjusting the height of the examination table based on the calculated organ center height so that the adjusted organ center height is equal to the height of the isocenter of the gantry.

[0098] In this way, the vertical height of the subject can be adjusted by the distance measurement of the sensor so that the adjusted organ center height is equal to the height of the isocenter of the gantry. Thus, the radiation dose of the subject is minimized and the CT imaging quality is improved.

[0099] Figure 2 is a structural schematic diagram of a subject vertical positioning device according to an embodiment of the present application. As shown in Figure 2 the subject vertical positioning device 200 includes: an acquisition module 201 configured to acquire the initial position of the examination table of the CT machine from the CT machine when the horizontal positioning of the subject is completed, and acquire a measurement range on the examination table corresponding to the organ to be detected of the subject, the measurement range including a starting point and an ending point along the horizontal direction; a sensor 205 attached to the gantry of the CT machine, and the signal emission direction of the sensor intersects with the isocenter axis of the gantry, the sensor 205 is configured to: start measuring the distance to the subject when the starting point reaches the measurement position of the sensor, and stop measuring when the ending point reaches the measurement position of the sensor during the movement of the examination table towards the gantry; wherein the acquisition module 201 is further configured to acquire the real-time height of the examination table corresponding to the measurement range while the sensor is measuring; a calculation module 207 configured to calculate the organ center height based on the measurement result of the sensor, the height of the sensor, and the real-time height of the examination table corresponding to the measurement range, the organ center height representing the average height of the center of the organ to be detected corresponding to the measurement range in the vertical direction; and an adjustment module 209 configured to adjust the height of the examination table based on the calculated organ center height so that the adjusted organ center height is equal to the height of the isocenter of the gantry.

[0100] Figure 2 The subject vertical positioning device 200 shown is used to perform Figure 1The vertical positioning method shown can minimize the radiation dose of the subject and improve the CT imaging quality without affecting the CT work efficiency.

[0101] Further, according to an embodiment of the present application, the subject vertical positioning device 200 can further comprise a camera 211 (as shown in Figure 7 The camera 211 is configured to take an overhead image of the subject after the subject is positioned on the examination bed, and the acquisition module 201 is further configured to: determine an image range corresponding to the organ to be detected from the overhead image, the image range being defined by a pixel start coordinate and a pixel end coordinate along a horizontal direction; map the pixel start coordinate to an initial position of a start point on the examination bed and map the pixel end coordinate to an initial position of an end point on the examination bed based on imaging parameters of the camera and the initial position of the examination bed; and determine the measurement range from the start point and the end point.

[0102] Figure 3 is a structural schematic diagram of a CT system comprising a subject vertical positioning device according to an embodiment of the present application. As shown in Figure 3 The CT system 300 comprises: Figure 2 The subject vertical positioning device 200 shown, and a CT machine 310, the CT machine 310 comprising: an examination bed 301 capable of vertical movement under the control of the subject vertical positioning device 200; and a scan gantry 303 configured to perform a flat scan or a tomographic scan on a subject 600 in the scan gantry 303; wherein the sensor 205 of the subject vertical positioning device 200 is attached to the scan gantry 303, and the signal emission direction of the sensor 205 intersects with the isocenter axis Za of the scan gantry 303.

[0103] The following will refer to Figures 4 to 10 The subject vertical positioning method, the subject vertical positioning device, and the CT system comprising the device according to an embodiment of the present application will be specifically described. In Figures 4 to 10 The sensor 205 is a time-of-flight sensor, for example, a time-of-flight laser radar sensor. However, those skilled in the art will understand that other ranging sensors can also be used.

[0104] Figure 4 is a schematic diagram of the installation of a time-of-flight sensor in a subject vertical positioning device according to an embodiment of the present application on a CT scan gantry. Figure 4Fig. 2 (a) shows a side view of a CT machine 310 and a time-of-flight sensor 205, in which an examination table 301 is arranged in the z direction, and the time-of-flight sensor 205 is fixed on a gantry 303 of the CT machine 310 above the examination table 301 to measure the distance from the sensor to a subject on the examination table 301 of the CT machine. Note that hereinafter, the horizontal movement direction of the examination table 301 is fixed as the z direction, the vertical (height) direction of the examination table 301 is fixed as the y direction, and the left-right direction of the examination table 301 is fixed as the x direction.

[0105] Figure 4 Fig. 2 (b) shows a top view of the CT machine 310 and the time-of-flight sensor 205, in which the signal transmission direction of the time-of-flight sensor 205 intersects with an isocenter axis Za of the gantry 303 (the isocenter axis Za is positioned in the z direction and passes through the isocenter C of the gantry, and the x coordinate of Za coincides with the x center coordinate of the examination table 301) to measure the distance to the subject at the x direction center position on the examination table 301.

[0106] Figure 5 Fig. 3 is a diagram showing various mounting positions of a time-of-flight sensor in a subject vertical positioning device according to an embodiment of the present application. In Figure 5 In each of Figs. 3 (a) to (d), the upper part shows a side view with respect to the yz direction of the gantry 303, and the lower part shows a side view with respect to the xz direction of the gantry 303.

[0107] Figure 5 Fig. 3 (a) shows a case where the time-of-flight sensor 205 is mounted at the upper center of the gantry 303. The time-of-flight sensor 205 coincides with the x coordinate of the isocenter C of the gantry 303 in the x direction, is located at a higher position of the gantry 303 in the y direction, and is located at the outer surface of the gantry 303 closest to the examination table 301 in the z direction. At this time, the time-of-flight sensor 205 vertically downward emits a measurement signal (e.g., infrared laser light) to measure the distance to the subject's body surface.

[0108] Figure 5 Fig. 3 (b) shows a case where the time-of-flight sensor 205 is mounted outside the gantry 303. A bracket is extended in the z direction on the gantry 303, and the time-of-flight sensor 205 is mounted at the end of the bracket. That is, compared with Figure 5 Fig. 3 (c) shows a case where the time-of-flight sensor 205 is mounted at the lower center of the gantry 303. The time-of-flight sensor 205 coincides with the x coordinate of the isocenter C of the gantry 303 in the x direction, is located at a lower position of the gantry 303 in the y direction, and is located at the outer surface of the gantry 303 closest to the examination table 301 in the z direction. At this time, the time-of-flight sensor 205 vertically downward emits a measurement signal to measure the distance to the subject's body surface. Figure 5 Fig. 3 (b), the time-of-flight sensor 205 is closer to the examination table 301 in the z direction. At this time, the time-of-flight sensor 205 vertically downward emits a measurement signal to measure the distance to the subject's body surface.

[0109] Figure 5(c) shows the time-of-flight sensor 205 mounted off-center on the upper part of the scanning rig 303. The positions of the time-of-flight sensor 205 in the y and z directions are... Figure 5 The same as in (a), but the position in the x-direction is different. Figure 5 The x-position in (a) shifts to the right. At this time, the time-of-flight sensor 205 emits a measurement signal to the lower left, the direction of which intersects the isocentric axis Za, to measure the distance to the subject's body surface.

[0110] Figure 5 (d) shows the case where the time-of-flight sensor 205 is mounted on the inner surface of the scanning frame 303. In this case, the time-of-flight sensor 205 is mounted on the inner surface of the annular scanning frame 303. That is, with... Figure 5 Compared to case (a), the time-of-flight sensor 205 is lower in the y-direction. In this case, the time-of-flight sensor 205 emits a measurement signal vertically downwards to measure the distance to the subject's body surface.

[0111] Figure 6 This is a schematic diagram illustrating the principle of using a time-of-flight sensor to measure distance to a subject according to an embodiment of this application. Figure 6 The position of the time-of-flight sensor 205 in the middle corresponds to Figure 5 The position shown in (a). Figure 6 As shown in (a), the subject 600 completes a horizontal positioning on the examination bed 301, at which point the examination bed is at its initial height H0. As the subject moves horizontally to the right with the examination bed, the time-of-flight sensor 205 emits infrared light to measure the distance to the subject 600 on the examination bed 301, thereby obtaining a distance profile curve of the subject 600.

[0112] Specifically, such as Figure 6 As shown in (a), the subject 600 moves to the right along with the examination bed 301. In response to the subject reaching the measurement position of the time-of-flight sensor 205 at time t1 (directly below the sensor 205 in the figure), the time-of-flight sensor 205 begins to measure the distance s to the subject 600. Figure 6 (b) shows the position of the subject 600 at time t2, after time t1. At this time, the subject 600 enters the scanning gantry 303 along with part of the examination bed 301. Then, the time-of-flight sensor 205 continues scanning until it stops in response to a scan end signal.

[0113] Figure 6(c) shows the distance profile curve of the subject obtained by the time-of-flight sensor 205 from the start of scanning at time t1, through time t2, until the end of the scanning. The horizontal axis of the distance profile curve is the scanning time t, and the vertical axis s is the distance from the time-of-flight sensor 205 to the subject 600 measured by the time-of-flight sensor 205.

[0114] Next, using Figure 6 The measurement principle shown will be referenced. Figures 7 to 10 The method of adjusting the altitude of a subject using a time-of-flight sensor 205, which is controlled and executed by a subject vertical positioning device 200 in different embodiments, is described in detail.

[0115] It should be noted that, Figures 7 to 9 The distance profile curve obtained and Figure 6 The difference in the distance profile curves shown is that: Figures 7 to 9 The horizontal coordinate of the distance profile curve obtained is the horizontal coordinate (i.e., the z-coordinate) of the examination bed 301, rather than the scanning time. In one embodiment, the z-coordinate of the examination bed 301 is represented by the horizontal distance between a fixed point on the examination bed 301 (e.g., the upper right corner of the examination bed 301) and the isocenter C of the scanning gantry 303.

[0116] Figure 7 This is a schematic diagram illustrating distance measurement of a subject using a time-of-flight sensor according to a first exemplary embodiment of this application. Figure 7 A method for adjusting the height of a subject using a time-of-flight sensor 205 in conjunction with a camera 211 is shown, and this method is performed before a planar scan.

[0117] like Figure 7 As shown in (a), the camera 211 is mounted in a fixed position above the examination bed 301 (e.g., attached to the scanning frame 303 at a certain distance) so that its imaging range covers the entire examination bed 301.

[0118] First, the subject 600 is positioned horizontally on the examination bed 301. Upon completion of the horizontal positioning, the examination bed 301 is at a preset initial height H0, and its horizontal position (z-direction position) is known. For example, by setting the isocenter C (or other fixed point) of the scanning gantry 303 as the origin in the z-direction, the initial horizontal position z of each point on the examination bed 301 can be determined. Additionally, the time-of-flight sensor 205 is in a fixed position, and its height Ht and horizontal position Zt are known. The height Hc and horizontal position Zc of the isocenter C are also known.

[0119] Then, camera 211 is used to capture a top-view image I1 of the subject 600 on the examination bed 301.

[0120] Next, an image range S0 in which the time-of-flight sensor 205 measures in the z direction is determined on the captured image I1 based on the organ to be examined (e.g., the chest) of the subject (as shown in (b) of FIG. 10). This image range S0 is defined by a start pixel coordinate al and an end pixel coordinate a2 in the z direction on the image I1. Note that this image range S0 can also be manually determined by an operator if necessary. Figure 7

[0121] Then, the start pixel coordinate al and the end pixel coordinate a2 corresponding to the selected image range S0 are mapped to the positions of coordinate points on the examination table 301 based on the imaging parameters of the camera 211, the distance from the camera 211 to the examination table 301, and the like. The mapped positions of the coordinate points are determined as a measurement start point PI and a measurement end point P2 on the examination table 301. The measurement start point PI and the measurement end point P2 define a measurement range SI on the examination table 301.

[0122] Then, the examination table 301 is moved toward the gantry 303.

[0123] During the movement of the examination table 301, the distance to the subject 600 is measured by the time-of-flight sensor 205 in response to the measurement start point PI reaching the measurement position of the time-of-flight sensor 205 (this response can be triggered based on time or distance, e.g., the real-time z coordinate of the examination table 301 is acquired from the CT machine, and the measurement of the sensor 205 is triggered in response to the z coordinate changing to a value at which the start point PI is just positioned directly below the time-of-flight sensor 205). The measurement of the time-of-flight sensor 205 is stopped in response to the measurement end point P2 reaching the measurement position of the time-of-flight sensor 205. The real-time height HI of the examination table 301 corresponding to the measurement range SI is acquired while the time-of-flight sensor 205 is measuring.

[0124] Note that in the present application, the height of the examination table 301 can change during the movement of the examination table 301 toward the gantry 303. Therefore, the real-time height HI of the examination table 301 corresponding to each point in the measurement range SI needs to be acquired while the time-of-flight sensor 205 is measuring. The real-time height HI of the examination table 301 can be acquired from the CT machine. When the height of the examination table 301 remains constant during the movement of the examination table 301, only the initial height HO of the examination table 301 needs to be acquired.

[0125] After the measurement of the time-of-flight sensor 205 is completed, a distance profile curve of the subject 600 in the measurement range SI is obtained based on the measurement results of the time-of-flight sensor 205. This profile curve indicates the distance s from the time-of-flight sensor 205 to the subject 600 corresponding to each point in the measurement start point PI to the measurement end point P2.

[0126] ​Based on the distance profile curve, the height Ht of the time-of-flight sensor 205, and the real-time height Hl of the examination bed 303 corresponding to the measurement range SI, the organ center height H of the subject 600 within the measurement range SI can be calculated. The organ center height H represents the average height of the center of the organ corresponding to the measurement range SI in the vertical direction (y direction). For example, the organ center height H is equal to the sum of half of the average thickness of the organ and the current height H2 of the examination bed 303. That is, the calculated organ center height H is the organ center height at the current time.

[0127] For example, by subtracting the distance s corresponding to each point on the distance profile curve from the height Ht of the time-of-flight sensor 205, and subtracting the real-time height Hl of the examination bed 303 corresponding to each point, the subject organ thickness Ht-s-Hl corresponding to each point from the measurement start point PI to the measurement end point P2 can be obtained. By averaging all the subject organ thicknesses corresponding to all the points, the average subject organ thickness Ha within the measurement range SI can be obtained. Therefore, at the current time, the organ center height H = Ha / 2 + H2.

[0128] After the organ center height H of the subject 600 within the measurement range SI is calculated, the calculated organ center height H can be compared with the isocenter height Hc of the gantry 303. Since the organ center height H represents the average height of the center point of the organ to be detected, it is ideal that the organ center height H is equal to the isocenter height Hc. At this time, the center of the organ to be detected coincides with the isocenter of the gantry 303 in the y direction, which can minimize the radiation dose of the subject receiving the CT examination and improve the image quality of the imaging.

[0129] When the calculated organ center height H is not equal to the isocenter height Hc, the height of the examination bed 301 is adjusted so that the adjusted organ center height H' is equal to the isocenter height Hc. For example, when the organ center height H < the isocenter height Hc, the height of the examination bed 301 is raised by Hc-H; when the organ center height H > the isocenter height Hc, the height of the examination bed 301 is lowered by H-Hc.

[0130] After the height of the examination bed 301 is adjusted, the height of the center point of the organ to be detected coincides with the height of the isocenter of the gantry 303. Then, the height of the examination bed 301 is kept unchanged, and the subject 600 is sequentially subjected to the flat scan and the tomographic scan.

[0131] Figure 8 is a schematic diagram of distance measurement of a subject using a time-of-flight sensor according to the second exemplary embodiment of the present application. Figure 8 A method of height adjustment of a subject using only a time-of-flight sensor 205 is shown, and the method is performed before the flat scan.

[0132] Figure 8 The method shown in Figure 7 The method shown in Figure 8 The camera is not used to determine the precise time-of-flight scanning range before measurement by the time-of-flight sensor 205.

[0133] First, the subject 600 is horizontally positioned on the examination bed 301. When the horizontal positioning is completed, the examination bed 301 is at a preset initial height H0, and its horizontal position (z-direction position) is known. The time-of-flight sensor 205 is at a fixed position, and its height Ht and horizontal position Zt are known. The position (Zc, Hc) of the isocenter C of the gantry 303 is known.

[0134] The measurement range S1 of the time-of-flight sensor 205 is determined according to the organ to be detected. The measurement range S1 can be determined in advance according to the organ to be scanned. The measurement range S1 can be defined by a measurement starting point P1 and a measurement ending point P2 along the horizontal direction on the subject 600 (or on the scanning bed corresponding thereto). For simplicity, the horizontal distance between the measurement starting point P1 and the measurement ending point P2 (i.e., the scanning range) is also denoted by S1.

[0135] In an exemplary embodiment, the measurement starting point P1 is determined by the scout scan starting point. That is, a scout scan range corresponding to the organ to be detected is obtained from the CT machine, which has been pre-stored by the CT machine. The scout scan range includes a scout scan starting point and a scout scan ending point along the horizontal direction on the examination bed 301. The scout scan starting point is determined as the measurement starting point P1 of the time-of-flight sensor 205, as shown in (a) of FIG. 6. Figure 8

[0136] In an exemplary embodiment, the measurement ending point P2 is determined by the scout scan starting point. That is, the horizontal position of the measurement ending point P2 = the horizontal position of the scout scan starting point - (Zc-Zt). In this way, when the subject moves to the scout scan starting position (i.e., the scout scan starting point reaches the isocenter C of the gantry 303), the measurement ending point P2 just reaches the measurement position of the time-of-flight sensor 205, as shown in (b) of FIG. 6. In this way, when the subject 600 moves to the scout scan starting position, the measurement of the time-of-flight sensor 205 just ends, and the scout scan can be directly started next without additional movement of the examination bed 301. Figure 8

[0137] However, it should be noted that the above measurement starting point P1 and measurement ending point P2 are only examples, and any measurement range S1 corresponding to the organ to be detected can be determined.

[0138] ​​After the measurement range S1 is determined, the examination bed 301 is moved toward the gantry 303.

[0139] As shown in (a) of FIG. 10, in response to the measurement start point P1 reaching the measurement position of the time-of-flight sensor 205, the time-of-flight sensor 205 starts measuring the distance to the subject 600. The response can be triggered based on time or distance. Alternatively, the measurement start point P1 is made to be just below the time-of-flight sensor 205 when the subject 600 is horizontally positioned. In this case, the time-of-flight sensor 205 starts measuring at the same time when the gantry 303 starts moving. Figure 8 As shown in (b) of FIG. 10, in response to the measurement end point P2 reaching the measurement position of the time-of-flight sensor 205, the time-of-flight sensor 205 stops measuring. During the measurement of the time-of-flight sensor 205, the real-time height H1 of the examination bed 303 corresponding to the measurement range S1 is acquired.

[0140] Figure 8 As shown in (c) of FIG. 10, based on the measurement result of the time-of-flight sensor 205, a distance profile curve of the subject 600 within the measurement range S1 is obtained. The profile curve indicates the distance s of the time-of-flight sensor 205 to the subject 600 corresponding to each point between the measurement start point P1 and the measurement end point P2.

[0141] As shown in (d) of FIG. 10, a calculation range S2 is selected from the distance profile curve. The calculation range S2 is defined by a calculation start point P3 and a calculation end point P4, which are located between the measurement start point P1 and the measurement end point P2. The distance between the calculation start point P3 and the calculation end point P4 is also denoted by S2. Generally, 0.5S1 < S2≤ S1. Figure 7 Based on the selected calculation range S2, an updated distance profile curve is obtained, which indicates the distance s of the time-of-flight sensor 205 to the subject 600 corresponding to each point between the calculation start point P3 and the calculation end point P4.

[0142] Then, similar to the steps of the method shown in (a) of FIG. 11, based on the updated distance profile curve, the height Ht of the time-of-flight sensor 205, and the real-time height H1 of the examination bed 303 corresponding to the calculation range S2 within the measurement range S1, the organ center height H of the subject 600 within the calculation range S2 is calculated.

[0143] As shown in (b) of FIG. 11, in response to the calculation start point P3 reaching the measurement position of the time-of-flight sensor 205, the time-of-flight sensor 205 starts measuring the distance to the subject 600. The response can be triggered based on time or distance. Alternatively, the calculation start point P3 is made to be just below the time-of-flight sensor 205 when the subject 600 is horizontally positioned. In this case, the time-of-flight sensor 205 starts measuring at the same time when the gantry 303 starts moving.

[0144] Figure 9 As shown in (c) of FIG. 11, in response to the calculation end point P4 reaching the measurement position of the time-of-flight sensor 205, the time-of-flight sensor 205 stops measuring. During the measurement of the time-of-flight sensor 205, the real-time height H2 of the examination bed 303 corresponding to the calculation range S2 is acquired.

[0145] ​​Next, the calculated organ center height H is compared with the isocenter height Hc of the gantry 303. When the calculated organ center height H is not equal to the isocenter height Hc, the height of the examination table 301 is adjusted so that the adjusted organ center height H' is equal to the isocenter height Hc.

[0146] After the height of the examination table 301 is adjusted, the subject 600 is sequentially subjected to a flat scan and a tomographic scan.

[0147] Figure 9 Fig. 6 is a schematic diagram of distance measurement of a subject using a time-of-flight sensor according to a third exemplary embodiment of the present application. Figure 8 A method of height adjustment of a subject using only a time-of-flight sensor 205 is shown, and in this method, the measurement period of the time-of-flight sensor 205 partially overlaps with the period of a flat scan.

[0148] First, the subject 600 is horizontally positioned on the examination table 301. When the horizontal positioning is completed, the examination table 301 is at a preset initial height H0, and its horizontal position (z-direction position) is known. The time-of-flight sensor 205 is at a fixed position, and its height Ht and horizontal position Zt are known. The position (Zc, Hc) of the isocenter C of the gantry 303 is known.

[0149] Then, a flat scan range of a flat scan of the CT machine corresponding to the organ to be detected is obtained, and a measurement range SI of the time-of-flight sensor 205 is determined based on the flat scan range. The flat scan range has been pre-stored in the CT machine. The flat scan range includes a flat scan start point and a flat scan end point on the examination table 301 in the horizontal direction. In this embodiment, the measurement range SI contains the flat scan range.

[0150] In an exemplary embodiment, the measurement start point PI of the measurement range SI is determined by the flat scan start point. For example, the flat scan start point is determined as the measurement start point PI. At this time, the measurement of the time-of-flight sensor 205 is earlier than the start of the flat scan.

[0151] In an exemplary embodiment, the measurement end point P2 of the measurement range SI is determined by the flat scan end point. For example, the horizontal position of the measurement end point P2 = the horizontal position of the flat scan end point - (Zc - Zt). In this way, when the subject 600 moves to the flat scan end position (i.e., the flat scan end point reaches the isocenter C of the gantry 303), the measurement end point P2 just reaches the measurement position of the time-of-flight sensor 205. In this way, when the flat scan ends, the measurement of the time-of-flight sensor 205 also ends.

[0152] After the measurement range SI is determined, the examination table 301 is moved toward the gantry 303. Similarly toFigure 9 In the step of FIG. 10, the time-of-flight sensor 205 measures the distance to the subject 600 for the measurement range S1 and obtains a distance profile curve corresponding to the measurement range S1 (as shown in the lower part of FIG. 10). The profile curve indicates the distance s of the time-of-flight sensor 205 to the subject 600 corresponding to each point in the measurement range S1 from the measurement start point P1 to the measurement end point P2. Meanwhile, the detectors in the gantry 303 perform a flat scan on the subject 600 to generate a flat image I2 corresponding to the flat scan range. During the measurement of the time-of-flight sensor 205, the real-time height H1 of the examination bed 303 corresponding to the measurement range S1 is also obtained from the CT machine 310. Figure 7

[0153] Then, a calculation range S2 is obtained, or the flat image I2 and the calculation range S2 (the calculation range S2 is within the flat scan range) are obtained. The calculation range S2 is defined by a calculation start point P3 and a calculation end point P4 in the horizontal direction.

[0154] In an exemplary embodiment, the calculation range S2 is obtained from the CT machine 310. That is, the calculation range is a tomographic scan range in the horizontal direction determined by the CT machine 310, which is determined by the CT machine 310 from the flat image I2 generated by the flat scan and is within the flat scan range. Since the measurement range S1 contains the flat scan range, the calculation start point P3 and the calculation end point P4 of the calculation range S2 must be located between the measurement start point P1 and the measurement end point P2. For simplicity, the distance between the calculation start point P3 and the calculation end point P4 is also denoted by S2. Generally, 0.5S1 < S2 < S1.

[0155] Based on the obtained calculation range S2, an updated profile curve is determined from the measured profile curve, which indicates the distance of the sensor 205 to the subject 600 corresponding to each point within the calculation range S2 (i.e., each point from the calculation start point P3 to the calculation end point P4).

[0156] Then, similar to the steps of the method shown in FIG. 11, based on the updated profile curve, the height Ht of the time-of-flight sensor 205, and the real-time height H1 of the examination bed 303 corresponding to the calculation range S2 within the measurement range S1, the organ center height H of the subject 600 within the calculation range S2 is calculated. Figure 10

[0157] The calculated organ center height H is compared with the isocenter height Hc of the gantry 303. When the calculated organ center height H is not equal to the isocenter height Hc, the height of the examination bed 301 is adjusted so that the adjusted organ center height H' is equal to the isocenter height Hc.

[0158] ​​After adjusting the height of the examination bed 301, the subject is subjected to tomography.

[0159] Figure 10 Fig. 1 is a schematic diagram of height adjustment of a subject using a time-of-flight sensor according to an embodiment of the present application.

[0160] As shown in (a) of Fig. 2, before the time-of-flight sensor 205 measures the subject 600, the examination bed 301 is at an initial height H0. The initial height H0 is a preset value. Figure 10 As shown in (b) of Fig. 2, after the height of the subject 600 is measured and adjusted using the time-of-flight sensor 205 according to the method described with reference to Fig. 1, the examination bed 301 is adjusted to an optimized height H'. At this time, the height H coincides with the isocenter C of the gantry 303 in the y direction, i.e., H' = Hc.

[0161] Figures 7 to 9 As shown in (b) of Fig. 2, after the height of the subject 600 is measured and adjusted using the time-of-flight sensor 205 according to the method described with reference to Fig. 1, the examination bed 301 is adjusted to an optimized height H'. At this time, the height H coincides with the isocenter C of the gantry 303 in the y direction, i.e., H' = Hc. Figures 7 to 10 It should be noted that the time-of-flight sensor 205 used in the above description with reference to Fig. 1 is a single time-of-flight sensor, which emits a single beam of infrared light or the like as a measurement signal toward the subject 600. Those skilled in the art can understand that the time-of-flight sensor 205 can also be composed of multiple time-of-flight sensors. The multiple time-of-flight sensors can constitute a row of time-of-flight sensors or an array of time-of-flight sensors.

[0162] Figures 7 to 10 It should be noted that, by using the subject vertical positioning method described with reference to Fig. 1, the offset distance between the vertical center of the organ to be detected of the subject and the isocenter C of the CT gantry 303 can be reduced to at least 20 mm or less. In the case of using a high-precision camera or a high-precision time-of-flight sensor, the offset between the vertical center of the organ and the isocenter C of the gantry 303 can be further reduced.

[0163] It should be noted that the embodiments described above are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should fall within the scope of protection of the present application. ​ It should be noted that the terms used herein are only intended to describe specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise, and it should also be understood that the terms "comprise" and / or "include" as used in the specification indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0164] It should be noted that the terms used herein are only intended to describe specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise, and it should also be understood that the terms "comprise" and / or "include" as used in the specification indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0165] It should be noted that the terms used herein are only intended to describe specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise, and it should also be understood that the terms "comprise" and / or "include" as used in the specification indicate the presence of features, steps, operations, devices, components and / or combinations thereof.​​

[0166] It should be noted that the terms "first", "second", and the like, used in the description and in the claims of the present application as well as above-mentioned figures are used to distinguish similar objects and are not necessarily used to describe a specific sequential or chronological order. It is to be understood that the use of these terms here is not meant to limit the scope of the application to the precise embodiments described but rather is used to delineate the different embodiments of the application from one another.

[0167] The preferred embodiments of the application described herein are not meant to be limiting and thus the application should be interpreted by the claims appended hereto that follow and by their equivalents.

Claims

1. A method for vertical positioning of a subject for a CT machine, characterized by, The CT machine is attached with a sensor for measuring the distance to the subject, and the method comprises: acquiring an initial position of a couch of the CT machine when a horizontal positioning of the subject is completed; acquiring a measurement range of the sensor on the couch corresponding to a to-be-detected organ of the subject, the measurement range comprising a starting point and an ending point along a horizontal direction, wherein acquiring the measurement range of the sensor on the couch corresponding to the to-be-detected organ of the subject comprises: acquiring an overhead image of the subject from a camera; determining an image range corresponding to the to-be-detected organ from the overhead image, the image range being defined by a starting pixel coordinate and an ending pixel coordinate along a horizontal direction; mapping the starting pixel coordinate to an initial position of the starting point on the couch and mapping the ending pixel coordinate to an initial position of the ending point on the couch based on imaging parameters of the camera and the initial position of the couch; and determining the measurement range from the starting point and the ending point; starting the sensor to measure when the starting point reaches a measurement position of the sensor, stopping the sensor from measuring when the ending point reaches the measurement position, and acquiring a real-time height of the couch corresponding to the measurement range while the sensor is measuring during movement of the couch towards a gantry of the CT machine; calculating an organ center height based on a measurement result of the sensor to the subject, a height of the sensor, and the real-time height of the couch corresponding to the measurement range, the organ center height representing an average height of a center of the to-be-detected organ corresponding to the measurement range in a vertical direction; and adjusting the height of the couch based on the calculated organ center height so that an adjusted organ center height is equal to a height of an isocenter of the gantry.

2. The method for vertical positioning of a subject for a CT machine of claim 1, wherein, Calculating the organ center height comprises: calculating an organ average thickness of the subject corresponding to the measurement range based on the measurement result of the sensor, the height of the sensor, and the real-time height of the couch corresponding to the measurement range, and calculating the organ center height based on the organ average thickness and a current height of the couch.

3. The method for vertical positioning of a subject for a CT machine of claim 1, wherein, Calculating the organ center height based on the measurement result of the sensor, the height of the sensor, and the real-time height of the couch corresponding to the measurement range comprises: obtaining a distance profile curve from the measurement result of the sensor, the distance profile curve indicating a distance from the sensor to the subject corresponding to each point in the measurement range, and calculating the organ center height corresponding to the measurement range based on the distance profile curve, the height of the sensor, and the real-time height of the couch corresponding to the measurement range.

4. The method for vertical positioning of a subject for a CT machine of claim 1, wherein, Acquiring the measurement range of the sensor on the couch corresponding to the to-be-detected organ of the subject comprises: acquiring a flat scan range of a flat scan of the CT machine, the flat scan range being determined by the CT machine for the to-be-detected organ, and the flat scan range comprising a scan starting point and a scan ending point on the couch along a horizontal direction; determining the measurement range based on the acquired flat scan range comprises:

5. The method for vertical positioning of a subject for a CT machine of claim 4, wherein, determining the start point and the end point of the measurement range based on the scan start point of the flat scan range. determining the start point and the end point of the measurement range based on the scan start point of the flat scan range.

6. The method for vertical positioning of a subject for a CT machine of claim 5, wherein, the distance between the start point and the end point is equal to the distance between the sensor and the isocenter of the gantry in the horizontal direction.

7. The method for vertical positioning of a subject for a CT machine of claim 4, wherein, calculating the organ center height based on the measurement result of the sensor, the height of the sensor, and the real-time height of the examination bed corresponding to the measurement range comprises: obtaining a distance profile curve based on the measurement result of the sensor, the distance profile curve indicating the distance from the sensor to the subject corresponding to each point in the measurement range, determining a calculation range corresponding to the organ to be detected based on the distance profile curve, the calculation range being located in the measurement range, determining an updated profile curve based on the calculation range, the updated profile curve indicating the distance from the sensor to the subject corresponding to each point in the calculation range, and calculating the organ center height corresponding to the measurement range based on the updated profile curve, the height of the sensor, and the real-time height of the examination bed corresponding to the calculation range in the measurement range.

8. The method for vertical positioning of a subject for a CT machine of claim 4, wherein, determining the measurement range based on the acquired flat scan range comprises: determining the start point of the measurement range based on the scan start point of the flat scan range, and determining the end point of the measurement range based on the scan end point of the flat scan range, wherein the measurement range contains the flat scan range.

9. The method for vertical positioning of a subject for a CT machine of claim 8, wherein, calculating the organ center height based on the measurement result of the sensor, the height of the sensor, and the real-time height of the examination bed corresponding to the measurement range comprises: obtaining a distance profile curve based on the measurement result of the sensor, the distance profile curve indicating the distance from the sensor to the subject corresponding to each point in the measurement range, obtaining a calculation range from the CT machine, the calculation range being a tomographic scan range in the horizontal direction determined by the CT machine from the flat scan image generated by the CT machine, and being located in the flat scan range, determining an updated profile curve from the distance profile curve based on the calculation range, the updated profile curve indicating the distance from the sensor to the subject corresponding to each point in the calculation range, and calculating the organ center height corresponding to the measurement range based on the updated profile curve, the height of the sensor, and the real-time height of the examination bed corresponding to the calculation range in the measurement range.

10. A subject vertical positioning device for a CT machine, characterized by, comprises: an acquisition module (201) configured to: acquire an initial position of an examination bed of the CT machine from the CT machine when the horizontal positioning of the subject is completed; acquire a measurement range on the examination table corresponding to an organ to be detected of the subject, the measurement range comprising a start point and an end point along a horizontal direction; a camera (211) configured to capture a top view image of the subject when the horizontal positioning of the subject is completed; the acquisition module (201) is further configured to: acquire the top view image and determine an image range corresponding to the organ to be detected from the top view image, the image range being defined by a start pixel coordinate and an end pixel coordinate along a horizontal direction; map the start pixel coordinate to an initial position of the start point on the examination table and map the end pixel coordinate to an initial position of the end point on the examination table based on imaging parameters of the camera and an initial position of the examination table; and determine the measurement range from the start point and the end point; a sensor (205) attached to a gantry of the CT machine and a signal emission direction of the sensor intersects with an isocenter axis of the gantry, the sensor (205) is configured to: start measuring a distance to the subject when the start point reaches a measurement position of the sensor and stop measuring when the end point reaches the measurement position during movement of the examination table towards the gantry; wherein the acquisition module (201) is further configured to acquire a real-time height of the examination table corresponding to the measurement range while the sensor is measuring; a calculation module (207) configured to calculate an organ center height based on the measurement result of the sensor, a height of the sensor, and the real-time height of the examination table corresponding to the measurement range, the organ center height representing an average height of a center of the organ to be detected corresponding to the measurement range in a vertical direction; and an adjustment module (209) configured to adjust the height of the examination table based on the calculated organ center height so that the adjusted organ center height is equal to a height of the isocenter of the gantry. The calculation of the organ center height comprises calculating an organ average thickness of the subject corresponding to the measurement range based on the measurement result of the sensor, the height of the sensor, and the real-time height of the examination table corresponding to the measurement range, and calculating the organ center height based on the organ average thickness and a current height of the examination table.

11. The subject vertical positioning apparatus for a CT machine of claim 10, wherein, The calculation module (207) is further configured to:

12. The subject vertical positioning apparatus for a CT machine of claim 10, wherein, determine a distance profile curve based on the measurement result of the sensor, the distance profile curve indicating a distance from the sensor to the subject corresponding to each point within the measurement range, and calculate the organ center height corresponding to the measurement range based on the distance profile curve, the height of the sensor, and the real-time height of the examination table corresponding to the measurement range. The acquisition module (201) is further configured to:

13. The subject vertical positioning apparatus for a CT machine of claim 10, wherein, acquire a plain film scanning range of a plain film scan from the CT machine, the plain film scanning range being determined by the CT machine for the organ to be detected, and the plain film scanning range comprising a scan start point and a scan end point on the examination table along a horizontal direction, and ​ determining the measurement range based on the acquired flat scan range comprises:

14. The subject vertical positioning apparatus for a CT machine of claim 13, wherein, determining the start point and the end point of the measurement range based on the scan start point of the flat scan range. the distance between the start point and the end point is equal to the distance between the sensor and the isocenter of the gantry in the horizontal direction.

15. The subject vertical positioning apparatus for a CT machine of claim 14, wherein, the computing module (207) is further configured to:

16. The subject vertical positioning apparatus for a CT machine of claim 13, wherein, determine a distance profile curve from the measurement results of the sensor, the distance profile curve indicating the distance from the sensor to the subject corresponding to each point in the measurement range, determine a calculation range corresponding to the organ to be detected based on the distance profile curve, the calculation range being located in the measurement range, determine an updated profile curve based on the calculation range, the updated profile curve indicating the distance from the sensor to the subject corresponding to each point in the calculation range, and calculate the organ center height corresponding to the measurement range based on the updated profile curve, the height of the sensor, and the real-time height of the examination bed corresponding to the calculation range in the measurement range. the acquisition module (201) is further configured to:

17. The subject vertical positioning apparatus for a CT machine of claim 13, wherein, determine the start point of the measurement range based on the scan start point of the flat scan range, and determine the end point of the measurement range based on the scan end point of the flat scan range, wherein the measurement range contains the flat scan range. the acquisition module (201) is further configured to:

18. The subject vertical positioning apparatus for a CT machine of claim 17, wherein, acquire a calculation range from the CT machine, the calculation range being a tomographic scan range in the horizontal direction determined by the CT machine from the flat image generated by the flat scan and located in the flat scan range, the computing module (207) is further configured to: determine a distance profile curve from the measurement results of the sensor, the distance profile curve indicating the distance from the sensor to the subject corresponding to each point in the measurement range, determine an updated profile curve from the distance profile curve based on the calculation range, the updated profile curve indicating the distance from the sensor to the subject corresponding to each point in the calculation range, and calculate the organ center height corresponding to the measurement range based on the updated profile curve, the height of the sensor, and the real-time height of the examination bed corresponding to the calculation range in the measurement range. the sensor (205) comprises a single sensor unit or an array comprising a plurality of sensor units.

19. The subject vertical positioning apparatus for a CT machine of claim 10, wherein, comprises:

20. A CT system, characterized by, the subject vertical positioning device (200) according to any one of claims 10 to 19, and a CT machine (310) comprising: an examination bed (301) capable of vertical movement under the control of the subject vertical positioning device (200), and a gantry (303) configured to perform flat scan or tomographic scan on a subject (600) in the gantry (303), ​ The sensor (205) of the subject vertical positioning device (200) is attached to the gantry (303) and the signal emission direction of the sensor (205) intersects the isocenter axis (Za) of the gantry (303). The sensor (205) of the subject vertical positioning device (200) is attached to the gantry (303) and the signal emission direction of the sensor (205) intersects the isocenter axis (Za) of the gantry (303). The sensor (205) of the subject vertical positioning device (200) is attached to the gantry (303) and the signal emission direction of the sensor (205) intersects the

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