WO2022140992A1 - 叶片位置检测装置、多叶准直器及放射治疗设备 - Google Patents

叶片位置检测装置、多叶准直器及放射治疗设备 Download PDF

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Publication number
WO2022140992A1
WO2022140992A1 PCT/CN2020/140396 CN2020140396W WO2022140992A1 WO 2022140992 A1 WO2022140992 A1 WO 2022140992A1 CN 2020140396 W CN2020140396 W CN 2020140396W WO 2022140992 A1 WO2022140992 A1 WO 2022140992A1
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Prior art keywords
magnet
blade
magnetic
position detection
leaf collimator
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PCT/CN2020/140396
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English (en)
French (fr)
Inventor
李君峰
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北京大医通汇创新科技有限公司
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Priority to PCT/CN2020/140396 priority Critical patent/WO2022140992A1/zh
Publication of WO2022140992A1 publication Critical patent/WO2022140992A1/zh

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy

Definitions

  • the present application relates to the field of mechanical equipment, and in particular, to a blade position detection device, a multi-leaf collimator and radiotherapy equipment.
  • Multi-leaf collimator also known as multi-leaf grating MLC
  • the irradiation area and shape of the rays are adjusted by the multi-leaf collimator to ensure the therapeutic effect of the radiotherapy equipment. Due to the important role of the multi-leaf collimator in radiotherapy equipment, the accuracy of the positioning of the leaves of the multi-leaf collimator directly affects the treatment effect.
  • the multi-leaf collimator drives the leaves to move to a proper position through a drive mechanism, and usually the positioning of the leaves is determined by an encoder or a resistive film on the drive mechanism to determine the actual position of the leaves.
  • the encoder on the drive mechanism often cannot accurately reflect the actual position of the blade; and due to the technological limitations of the resistive film, the use of the resistive film for blade positioning leads to low positioning accuracy, low stability, and easy damage.
  • one of the technical problems solved by the embodiments of the present application is to provide a blade position detection device of a multi-leaf collimator, a multi-leaf collimator and a radiotherapy device, so as to overcome at least the existing problems in the prior art. part of the problem.
  • a blade position detection device for a multi-leaf collimator which includes: a magnet; a magneto-sensitive sensor arranged opposite to the magnet; the magnet or the magneto-sensitive sensor is connected to the blade, so that the When the blade moves, the magnet and the magnetic sensitive sensor rotate relatively; the magnetic sensitive sensor converts the detected change of the magnetic field of the magnet into the position information output of the blade.
  • the magnet or the magneto-sensitive sensor is connected to the blade through friction driving, or the magnet or the magneto-sensitive sensor is connected to the blade through a transmission mechanism, so that when the blade moves, the magnet and the magneto-sensitive sensor rotate relative to each other.
  • the magnet is a magnet with a single pole or a magnet with multiple poles.
  • the magnet is a magnet with a single magnetic pole
  • the magnet and the magneto-sensitive sensor are arranged eccentrically.
  • a multi-leaf collimator which includes: a plurality of sets of oppositely arranged leaves; a box body carrying the plurality of sets of leaves; The device is arranged in one-to-one correspondence with the plurality of blades, and both the magnet and the magnetic sensor are arranged on the box body.
  • the multi-leaf collimator further includes an integrated support frame, the support frame is arranged on the box body, and both the magnet and the magnetic sensor are arranged on the support frame.
  • the support frame is rotatably connected to the box body through the main shaft, and the multi-leaf collimator further includes a tensioning mechanism, which is connected between the box body and the support frame and applies tension to the support frame toward the blades. tight.
  • the box body includes a fixed base
  • the tensioning mechanism includes: a first connecting piece, the first connecting piece is fixedly connected to the support frame and can drive the support frame to move relative to the fixed base; a second connecting piece, a second connecting piece
  • the connecting piece is fixedly arranged on the fixed base; the elastic piece is connected between the first connecting piece and the second connecting piece, and applies a tension force toward the blade to the support frame through the first connecting piece.
  • a part of the blade position detection devices are arranged at the upper end of the blade in the height direction, and the remaining blade position detection devices are arranged at the lower end of the blade in the height direction.
  • the position detection devices of two adjacent blades are alternately arranged in the blade height direction.
  • the multi-leaf collimator further includes a magnetic shield, and the magnetic shield is disposed outside the magnet to prevent magnetic field interference between the magnets corresponding to adjacent leaves.
  • a radiotherapy apparatus comprising a radiation source and the above-described multi-leaf collimator.
  • the magnet or the magnetic sensor of the blade position detection device provided in the embodiment of the present application is connected to the blade, so that when the blade moves, the magnetic sensor and the magnet rotate relative to each other, so that the magnetic field of the magnet detected by the magnetic sensor changes, The magnetic field change is then converted into an electrical signal output indicating the position information of the blade.
  • the magnetic sensor has high detection accuracy and good detection stability, and has Helps to ensure the stability and reliability of the position detection of the blade.
  • FIG. 1 shows a schematic three-dimensional structure diagram of a multi-leaf collimator configured with a leaf position detection device according to an embodiment of the present application
  • FIG. 2 shows a three-dimensional schematic diagram of the cooperation between the blade position detection device and the blade in the embodiment of the present application
  • Fig. 3 shows a partial enlarged view of the blade position detection device in Fig. 2;
  • FIG. 4 shows a partial enlarged top view of the blade position detection device when the blade position detection device cooperates with the blade in the embodiment of the present application
  • FIG. 5 shows a schematic plan view of the structure of the first magnetic sensor and the magnet of the blade position detection device according to the embodiment of the present application
  • FIG. 6 shows a schematic three-dimensional structure diagram of a second type of magnetic sensitive sensor and a magnet of the blade position detection device according to the embodiment of the present application.
  • an embodiment of the present application provides a blade position detection device for a multi-leaf collimator, which includes a magnet 20 and a magnetic sensor 30 , the magnetic sensor 30 is disposed opposite the magnet 20 , and the magnet 20 or the magnetic The sensitive sensor 30 is connected with the blade 80 , so that when the blade moves, the magnet 20 and the magnetic sensitive sensor 30 rotate relative to each other;
  • the magnet 20 or the magnetic sensor 30 of the blade position detection device of the multi-leaf collimator is connected to the blade 80, so that when the blade 80 moves, the magnetic sensor 30 and the magnet 20 rotate relative to each other, so that the magnetic sensor 30 detects
  • the resulting magnetic field of the magnet 20 changes, which in turn converts the magnetic field change into an electrical signal output indicating the position information of the blade 80 .
  • the magnetic sensitive sensor 30 has high detection accuracy and detection stability Well, it helps to ensure the stability and reliability of the position detection of the blade 80 .
  • the magnet 20 and the vane 80 are connected to the vane 80 through a friction driving manner, so that when the vane 80 moves, the magnet and the magnetic sensor rotate relatively. In this way, when the blade 80 moves (the moving direction is shown in FIG. 1 ), the magnet 20 is driven to rotate by the friction force.
  • the magnet 20 includes a magnetic pole and a rotating rod, the magnetic pole is connected to the first end of the rotating rod, and the second end of the rotating rod is used for abutting with the blade 80 to realize frictional transmission; in this way, when the blade 80 moves along its length direction , Driven by the friction force between the rotating rod and the side of the blade, the rotating rod drives the magnetic pole to rotate relative to the magnetic sensor, and the magnetic sensor converts the detected change of the magnetic field of the magnet into the position information output of the blade to realize the position of the blade. detection.
  • the second end of the rotating rod may be provided with a friction-increasing structure, so as to increase the frictional force between the rotating rod and the blade 80 .
  • the friction enhancing structure is used to make the friction coefficient of the second end higher than the other parts of the rotating rod.
  • the friction-increasing structure may be knurling, friction-increasing textures, or friction-increasing films, coatings, and the like.
  • the friction driving in this embodiment can also be realized without setting a rotating rod, and the outer peripheral surface of the magnet 20 with the magnetic pole can be directly abutted with the side surface of the blade 80, so as to realize the driving of the magnet 20 by the blade 80, The magnet 20 is rotated relative to the magneto-sensitive sensor.
  • the magnet 20 is connected with the blade 80 through a transmission mechanism, so that when the blade 80 moves, the magnet 20 and the magnetic sensor 30 rotate relative to each other.
  • the transmission mechanism may include a gear and a rack, the rack can be processed on the blade 80 or a rack belt can be added to the blade, and the gear is sleeved on the rotating rod.
  • the rotating rod is driven to rotate, and the rotating rod drives the magnetic pole to rotate relative to the magnetic sensor, and the magnetic sensor converts the detected magnetic field change of the magnet 20 into the position information output of the blade 80 , to realize the detection of the blade position.
  • the transmission mechanism may be in other forms, which are not limited in this embodiment.
  • a transmission mechanism is used to realize the driving of the magnet 20 , and it may not be realized by arranging a rotating rod.
  • a cogging slot may be directly formed on the outer peripheral surface of the magnet 20 with magnetic poles or the outer peripheral surface of the magnet 20 may be driven.
  • Gears are installed to realize the driving of the magnet 20 by the blade 80, so that the magnet 20 rotates relative to the magnetic sensor. It should be noted that the length of the tooth slot, the rack belt, etc. on the blade 80 should be greater than the maximum stroke of the blade 80, so as to ensure full-range detection.
  • the magneto-sensitive sensor 30 is connected to the blade 80 through a frictional drive, or the magneto-sensitive sensor 30 is connected to the blade 80 through a transmission mechanism, so that when the blade 80 moves, the magnet 20 and the magneto-sensitive sensor 30 relative rotation.
  • the manner in which the magnetic sensor 30 is connected with the blade 80 may be similar to the manner in which the magnet 20 is connected with the blade 80 , so it will not be repeated here.
  • the magnet 20 of the embodiment of the present application is a magnet with a single magnetic pole or a magnet with multiple magnetic poles.
  • a single magnetic pole can be understood as the magnet 20 having a pair of N-S magnetic pole pairs
  • a multi-magnetic pole can be understood as the magnet 20 includes two or more pairs of N-S magnetic pole pairs.
  • the magnet 20 is a single-pole magnet.
  • the magnet 20 and the magnetic sensor 30 are eccentrically arranged.
  • the eccentric arrangement can be understood as the deviation of the detection center of the magnetic sensor 30 from the magnetic field center 22 of the magnet 20 .
  • the magnetic field change detected by the magnetic sensitive sensor 30 is clearer, so that the magnetic sensitive sensor 30 is more sensitive to the magnetic field change, and has stronger versatility.
  • the magnet 20 and the magnetic sensor 30 may not be eccentrically disposed, which is not limited in this embodiment.
  • the magnet 20 is a multi-pole magnet.
  • the outer circumferential surface of the magnet 20 is magnetized, and an even number of magnetic poles with equal lengths are continuously formed on the outer circumferential surface.
  • the vane 80 drives the magnet 20 to rotate, it generates a periodically distributed spatial leakage magnetic field.
  • the magneto-sensitive sensor 30 is opposite to the outer peripheral surface of the magnet 20 to detect the variation of the spatial leakage magnetic field.
  • the magneto-sensitive sensor 30 includes a magnetic head and a processing circuit.
  • the processing circuit is connected to the magnetic head.
  • an applied potential is applied to the magnetic head, and on the other hand, the electrical signal output by the magnetic head is subjected to signal processing.
  • the magnetic head includes a magneto-resistive element (such as a magneto-sensitive resistor or a magneto-sensitive diode, etc.).
  • the magnetic sensor 30 converts the changing magnetic field signal into the change of the resistance value through the magnetoresistance effect. Under the action of the applied potential, the changed resistance value is converted into the change of the voltage. After processing, the analog voltage signal is converted into a displacement signal, so as to realize the displacement detection of the blade 80 .
  • the above-mentioned magnetic sensitive sensor 30 and magnet 20 can accurately detect the position of the blade 80 and realize the secondary feedback of the position of the blade 80 during the operation of the multi-leaf collimator.
  • a multi-leaf collimator which includes a plurality of sets of oppositely disposed leaves 80 , a box 70 carrying the plurality of sets of leaves 80 , and a plurality of the foregoing leaf position detection devices.
  • the plurality of blade position detection devices are arranged in a one-to-one correspondence with the plurality of blades 80 , and the magnets 20 and the magnetic sensors 30 are both arranged on the box body 70 .
  • the multi-leaf collimator can detect the displacement of the vane 80 without contact between the magnet 20 and the magnetic sensor 30 through the vane position detection device, so as to accurately perform secondary feedback of the vane 80 position.
  • the leaf position detection devices can be arranged alternately. For example, they are alternately arranged in the height direction of the blades 80 or the moving direction of the blades 80 .
  • a part of the blade position detection devices are provided at the upper end of the blade 80 in the height direction, and the remaining blade position detection devices are provided at the lower end of the blade 80 in the height direction.
  • the blade position detection devices of two adjacent blades are alternately arranged in the blade height direction. That is, if the blade position detection device corresponding to blade A is located at the upper end of blade A in the height direction, the blade position detection device corresponding to blade B adjacent to blade A is located at the lower end of blade B in the height direction.
  • the multi-leaf collimator is usually used in radiotherapy equipment, and the radiation source of the radiotherapy equipment generally has radiation, such radiation will cause radiation damage to the magnetic sensor 30, in order to prolong the service life of the magnetic sensor 30 , the magnetic sensor can be installed at the lower end of the blade 80 in the height direction (that is, the end away from the radiation source), so that the radiation can be attenuated by the blade.
  • the radiation damage will also be small, thus ensuring the normal use of the magnetic sensor and prolonging its service life.
  • the plurality of blade position detection devices may be divided into at least two groups, and the at least two groups of blade position detection devices are arranged at intervals along the moving direction of the blade 80, and the blade positions of two adjacent blades are The detection devices are alternately arranged in the moving direction of the blades, so that mutual influence can be avoided, and a small gap can be accommodated, and the smooth movement of the blades is facilitated.
  • the multi-leaf collimator further includes an integrated support frame 10, the support frame 10 is arranged on the box 70, the magnet 20 and the magnetic sensor 30 are both arranged on the support frame 10 .
  • the support frame 10 may be directly disposed on the box body 70, or may be indirectly disposed on the box body 70 through other connecting structures.
  • the magnetic sensitive sensor 30 and the magnet 20 may be installed on different fixtures, as long as it is ensured that there is no relative movement between the magnetic sensitive sensor 30 and the magnet 20 .
  • the support frame 10 includes an upper wall and a lower wall, the magnetic sensor 30 is arranged on the upper wall, and the magnet 20 is arranged on the lower wall.
  • a bearing can be provided on the lower wall.
  • the magnet 20 can include a magnetic pole and a rotating rod. One end of the rotating rod is connected to the magnetic pole, and the other end passes through the bearing. One end of the rotating rod passing through the bearing is in contact with the blade 80 .
  • the support frame 10 is rotatably connected to the box body 70 through the main shaft 50, and the multi-leaf collimator also includes a tensioning mechanism, which is connected to the box body 70 and the support. between the brackets 10 , and apply a tension force toward the blades 80 to the support bracket 10 .
  • the tensioning mechanism By setting the tensioning mechanism, it is ensured that when a gap occurs between the blade 80 and the magnet 20 (or the magnetic sensor 30 ), the tensioning mechanism can automatically drive the support frame 10 to move toward the blade 80 , thereby making the magnet 20 (or the magnetic sensor 30 ). 30) Close contact or reliable engagement with the blade 80, and will not change the relative position between the magnet 20 and the magnetic sensor 30, thereby ensuring the close contact or reliable engagement between the magnet 20 and the blade 80, thereby ensuring The magnet 20 can be driven to rotate in real time as the blade 80 moves.
  • the box body 70 includes a fixed base 40
  • the tensioning mechanism includes a first connecting member 61 , a second connecting member 62 and an elastic member 63 , and the first connecting member 61 It is fixedly connected to the support frame 10, and can drive the support frame 10 to move relative to the fixed base 40; the second connecting piece 62 is fixedly arranged on the fixed base 40; the elastic piece 63 is connected to the first connecting piece 61 and the second connecting piece 62 , and the tension force toward the blade 80 is applied to the support frame 10 through the first connecting piece 61 .
  • the elastic member 63 is, for example, a spring, which is always kept in an extended state
  • the first connecting member 61 and the second connecting member 62 can be any suitable structures such as connecting pins or connecting rods, which are mainly used to connect with the spring and make it remain in an extended state.
  • the fixing base 40 is provided with a waist-shaped hole, and the first connecting piece 61 passes through the waist-shaped hole and is fixedly connected with the support frame 10 , so that the spring can apply a direction to the support frame 10 .
  • the force of the blades 80 keeps the magnets 20 on the support frame 10 in close contact or reliable engagement with the blades 80 all the time.
  • the vane 80 and the vane positioning detection device can always be kept in close contact or reliable engagement, so as to avoid losing steps during detection.
  • the multi-leaf collimator further includes a magnetic shield, and the magnetic shield is disposed outside the magnets 20 to prevent magnetic field interference between the magnets 20 corresponding to adjacent leaves 80 .
  • the magnetic shield can be a cover made of any material that can isolate the magnetic field, as long as it can shield the magnetic field and prevent the magnetic fields from interacting with each other.
  • the integrated support frame 10 is connected to the fixed base 40 (eg, a fixing plate) through the main shaft 50 , and at the same time, the support frame 10 is connected with a tensioning mechanism, and the second connecting member 62 of the tensioning mechanism is fixed
  • the first connecting piece 61 of the tensioning mechanism passes through the fixed base 40 and is connected with the support frame 10
  • the elastic piece 63 is connected between the first connecting piece 61 and the second connecting piece 62, and is located in the In the extended state, the elastic member 63 applies a tension force toward the blade 80 to the support frame 10 .
  • the first connecting piece 61 moves in the waist-shaped hole and drives the support frame 10 around The main shaft 50 is rotated, so that the magnet 20 is in close contact with or securely engaged with the blade 80 .
  • the linear displacement of the blade is converted into the rotation of the magnet 20 through the friction transmission or meshing transmission between the blade 80 and the magnet 20, thereby causing the change of the magnetic field strength (the direction of the magnetic field line and the magnetic flux change). , the strength of the magnetic field lines is different).
  • the resistance value of the magnetic sensor 30 changes, and with the rotation of the magnet 20, a periodically distributed alternating space leakage magnetic field will be generated, and then a periodically changing alternating magnetic field intensity will be generated, so the resistance value is also periodic
  • the waveform of the periodically changing resistance value may be different, and in one case, the waveform may be a sine wave.
  • the magneto-sensitive sensor 30 converts the changing magnetic field signal into the change of the resistance value through the magnetoresistance effect. Under the action of the applied potential, the changed resistance value is converted into the change of the voltage, and then processed by the subsequent signal processing circuit. The voltage signal is converted into a displacement signal to realize the detection of the displacement of the blade 80 .
  • a radiation therapy apparatus comprising a radiation source and the aforementioned multi-leaf collimator.
  • each leaf 80 of the multi-leaf collimator can realize secondary positioning feedback through the leaf position detection device, so as to accurately determine the actual position of the leaf 80 and then determine the multi-leaf collimator Whether the shape of the adjusted target area is consistent with the requirements can not only improve the positioning accuracy of the blade 80, but also ensure the shape of the target area, thereby preventing unnecessary damage to healthy cells during the treatment process.
  • Each blade is connected to a set of magnets and a magnetic sensor by means of magnetic sensitivity.
  • the magnet is driven to rotate, so that the direction and intensity of the magnetic field lines change, and then the magnetic field changes are detected by the magnetic sensor and a corresponding voltage is generated.
  • the volume of the magnet and the magneto-sensitive sensor can be set smaller, so that they are accommodated in the gap between adjacent blades, which makes installation more convenient.

Abstract

一种叶片位置检测装置、多叶准直器及放射治疗设备。叶片位置检测装置包括磁体（20）；与磁体（20）相对设置的磁敏传感器（30）；磁体（20）或磁敏传感器（30）与叶片（80）连接，使得在叶片（80）运动时，磁体（20）和磁敏传感器（30）相对转动；磁敏传感器（30）将检测到的磁体（20）的磁场变化转换为叶片（80）的位置信息输出。叶片位置检测装置可靠性更高。

Description

叶片位置检测装置、多叶准直器及放射治疗设备 技术领域
本申请涉及机械设备领域，尤其涉及一种叶片位置检测装置、多叶准直器及放射治疗设备。
背景技术
多叶准直器(又称多叶光栅MLC)是放射治疗设备中的重要组成部分。在放射治疗设备中通过多叶准直器调整射线的照射区域和形状，以保证放射治疗设备的治疗效果。由于多叶准直器在放射治疗设备中的重要作用，使得多叶准直器的叶片定位的准确度直接影响了治疗效果。
相关技术中，多叶准直器通过驱动机构驱动叶片运动到合适的位置，通常叶片定位是靠驱动机构上的编码器或者电阻膜等确定叶片的实际位置。驱动机构上的编码器往往不能准确反映叶片的实际位置；而受制于电阻膜的工艺限制，导致采用电阻膜进行叶片定位的方式定位精度低、稳定性不高，而且极易损坏。
发明内容
有鉴于此，本申请实施例所解决的技术问题之一在于提供一种多叶准直器的叶片位置检测装置、多叶准直器及放射治疗设备，用以克服现有技术中存在的至少部分问题。
根据本申请实施例的第一方面，提供了一种多叶准直器的叶片位置检测装置，其包括：磁体；与磁体相对设置的磁敏传感器；磁体或磁敏传感器与叶片连接，使得在叶片运动时，磁体和磁敏传感器相对转动；磁敏传感器将检测到的磁体的磁场变化转换为叶片的位置信息输出。
可选地，磁体或磁敏传感器通过摩擦驱动方式与叶片连接，或者，磁体或磁敏传感器通过传动机构与叶片连接，使得在叶片运动时，磁体和磁敏传感器相对转动。
可选地，磁体为具有单一磁极的磁体或具有多磁极的磁体。
可选地，当磁体为具有单一磁极的磁体时，磁体与磁敏传感器偏心设置。
根据本申请的另一方面，提供一种多叶准直器，其包括：多组相对设置的叶片；承载多组叶片的箱体；多个如上述的叶片位置检测装置，多个叶片位置检测装置与多个叶片一一对应设置，磁体和磁敏传感器均设置在箱体上。
可选地，多叶准直器还包括一体的支撑架，支撑架设置于箱体，磁体和磁敏传感器均设置在支撑架上。
可选地，支撑架通过主轴可转动地连接在箱体上，多叶准直器还包括张紧机 构，张紧机构连接在箱体和支撑架之间，并向支撑架施加朝向叶片的张紧力。
可选地，箱体包括固定基座，张紧机构包括：第一连接件，第一连接件固定连接在支撑架上，且能够带动支撑架相对固定基座运动；第二连接件，第二连接件固定设置在固定基座上；弹性件，弹性件连接在第一连接件和第二连接件之间，并通过第一连接件向支撑架施加朝向叶片的张紧力。
可选地，一部分叶片位置检测装置设置在叶片的高度方向上的上端，剩余的叶片位置检测装置设置在叶片的高度方向上的下端。
可选地，相邻两个叶片的位置检测装置在叶片高度方向上交替设置。
可选地，多叶准直器还包括磁屏蔽罩，磁屏蔽罩设置在磁体外，以防止相邻叶片对应的磁体之间的磁场干扰。
根据本申请的另一方面，提供一种放射治疗设备，放射治疗设备包括放射源和上述的多叶准直器。
本申请实施例提供的叶片位置检测装置的磁体或者磁敏传感器与叶片连接，使得叶片在移动时，磁敏传感器和磁体之间发生相对转动，使磁敏传感器检测到的磁体的磁场发生变化，进而将磁场变化转换为指示叶片的位置信息的电信号输出。通过这种方式一方面实现了磁体和磁敏传感器之间的无接触检测，避免了位置检测装置的磨损，提升了使用寿命；另一方面磁敏传感器的检测精度高、检测稳定性好，有助于保证对叶片的位置检测的稳定性和可靠性。
附图说明
为了更清楚地说明本申请实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请实施例中记载的一些实施例，对于本领域普通技术人员来讲，还可以根据这些附图获得其他的附图。
图1示出了本申请实施例的配置叶片位置检测装置的多叶准直器的立体结构示意图；
图2示出了本申请实施例中叶片位置检测装置与叶片配合的立体结构示意图；
图3示出了图2中叶片位置检测装置处的局部放大图；
图4示出了本申请实施例中叶片位置检测装置与叶片配合时叶片位置检测装置处的局部放大俯视图；
图5示出了本申请实施例的叶片位置检测装置的第一种磁敏传感器与磁体配合的俯视结构示意图；
图6示出了本申请实施例的叶片位置检测装置的第二种磁敏传感器与磁体配合的立体结构示意图。
附图标记说明：10、支撑架；20、磁体；22、磁场中心；30、磁敏传感器；40、固定基座；50、主轴；61、第一连接件；62、第二连接件；63、弹性件；70、箱体；80、叶片。
具体实施方式
为了使本领域的人员更好地理解本申请实施例中的技术方案，下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅是本申请实施例一部分实施例，而不是全部的实施例。基于本申请实施例中的实施例，本领域普通技术人员所获得的所有其他实施例，都应当属于本申请实施例保护的范围。
参照图1-图5，本申请实施例提供了一种多叶准直器的叶片位置检测装置，其包括磁体20和磁敏传感器30，磁敏传感器30与磁体20相对设置，磁体20或磁敏传感器30与叶片80连接，使得在叶片运动时，磁体20和磁敏传感器30相对转动；磁敏传感器30将检测到的磁体20的磁场变化转换为叶片80的位置信息输出。
该多叶准直器的叶片位置检测装置的磁体20或者磁敏传感器30与叶片80连接，使得叶片80在移动时，磁敏传感器30和磁体20之间发生相对转动，使磁敏传感器30检测到的磁体20的磁场发生变化，进而将磁场变化转换为指示叶片80的位置信息的电信号输出。通过这种方式一方面实现了磁体20和磁敏传感器30之间的无接触检测，避免了位置检测装置的磨损，提升了使用寿命；另一方面磁敏传感器30的检测精度高、检测稳定性好，有助于保证对叶片80的位置检测的稳定性和可靠性。
在第一种情况中，以磁体20与叶片80连接为例进行说明如下：
在一示例中，磁体20与叶片80之间通过摩擦驱动方式与叶片80连接，使得在叶片80运动时，磁体和磁敏传感器相对转动。这样在叶片80移动(移动方向如图1所示)时，通过摩擦力驱动磁体20转动。
例如，磁体20包括磁极和转杆，磁极连接在转杆的第一端，转杆的第二端用于与叶片80抵接，并实现摩擦传动；这样，在叶片80沿其长度方向运动时，在转杆和叶片侧面之间的摩擦力的驱动下，转杆带动磁极相对于磁敏传感器发生转动，磁敏传感器将检测到的磁体的磁场变化转换为叶片的位置信息输出，实现叶片位置的检测。
为了保证传动精度和可靠性，转杆的第二端可设置增摩擦结构，以提升转杆与叶片80之间的摩擦力。增摩擦结构用于使第二端的摩擦系数相较于转杆的其他部分更高。增摩擦结构可以是滚花、增摩擦纹路或者增摩擦的贴膜、涂层等。
当然，可以理解的是，本实施例的摩擦驱动也可以不通过设置转杆来实现，可以直接使具有磁极的磁体20的外周面与叶片80侧面抵接，实现叶片80对磁体20的驱动，使磁体20相对于磁敏传感器发生转动。
或者，在另一示例中，磁体20通过传动机构与叶片80连接，使得在叶片80运动时，磁体20和磁敏传感器30相对转动。
仍以前述的磁体20包括磁极和转杆为例，传动机构可以包括齿轮和齿条，齿条可以加工在叶片80上或者在叶片上加装齿条带，齿轮套设在转杆上。叶片80移动时，通过齿条与齿轮的啮合，驱动转杆转动，转杆带动磁极相对于磁敏传感器发生转动，磁敏传感器将检测到的磁体20的磁场变化转换为叶片80的位置信息输出，实现叶片位置的检测。当然，传动机构可以是其他形式，本实施例对此不作限 制。
同样地，本实施例采用传动机构实现对磁体20的驱动，也可以不通过设置转杆来实现，可以直接在具有磁极的磁体20的外周面上开设齿槽或在磁体20的外周面上加装齿轮，实现叶片80对磁体20的驱动，使磁体20相对于磁敏传感器发生转动。需要说明的是，叶片80上的齿槽、齿条带等的长度应大于叶片80的最大行程，从而保证全范围的检测。
类似地，在第二种情况中，磁敏传感器30通过摩擦驱动方式与叶片80连接，或者，磁敏传感器30通过传动机构与叶片80连接，使得在叶片80运动时，磁体20和磁敏传感器30相对转动。此种情况中，磁敏传感器30与叶片80连接的方式可以和磁体20与叶片80连接的方式类似，故不再赘述。
本申请实施例的磁体20为具有单一磁极的磁体或具有多磁极的磁体。其中，单一磁极可以理解为磁体20具有一对N-S磁极对，多磁极可以理解为磁体20包括两对或两对以上的N-S磁极对。
如图2和图3所示，在一示例中，磁体20为单一磁极的磁体。
可选地，针对单一磁极的磁体20，为了确保位置检测的灵敏度，当磁体20为具有单一磁极的磁体时，磁体20与磁敏传感器30偏心设置。
如图5所示，偏心设置可以理解为磁敏传感器30的检测中心与磁体20的磁场中心22偏离。这样使得磁体20在转动时磁敏传感器30检测到的磁场变化更加清晰，从而使磁敏传感器30对磁场变化更加敏感，而且通用性更强。
当然，在其他示例中，磁体20和磁敏传感器30可以不偏心设置，本实施例对此不作限制。
如图6所示，在另一示例中，磁体20为多磁极的磁体。磁体20外圆周面被磁化，且其外圆周面上连续形成具有偶数个长度相等的磁极。叶片80驱动磁体20转动时，其产生周期分布的空间漏磁场。磁敏传感器30与磁体20的外周面相对，以检测空间漏磁场变化。
可选地，磁敏传感器30包括磁头和处理电路，处理电路与磁头连接，一方面对磁头施加外加电势，另一方面对磁头输出的电信号进行信号处理。磁头包括磁阻元件(如磁敏电阻或磁敏二极管等)。
在磁体20转动时，磁敏传感器30通过磁电阻效应将变化着的磁场信号转化为电阻阻值的变化，在外加电势的作用下，变化的电阻值转化成电压的变化，经过信号处理电路的处理，模拟的电压信号转化成位移信号，实现对叶片80的位移检测。
通过上述的磁敏传感器30和磁体20能够实现对叶片80位置的准确检测，实现在多叶准直器运行过程中叶片80位置的二次反馈。
根据本申请的另一方面，提供一种多叶准直器，其包括多组相对设置的叶片80、承载多组叶片80的箱体70和多个前述的叶片位置检测装置。多个叶片位置检测装置与多个叶片80一一对应设置，磁体20和磁敏传感器30均设置在箱体70上。
该多叶准直器通过叶片位置检测装置可以实现在磁体20和磁敏传感器30无接触的情况下检测叶片80的位移，从而准确地对叶片80进行位置的二次反馈。
由于多叶准直器包括多个叶片对，且相邻叶片80之间的间隙非常小，为了满足空间需求，叶片位置检测装置可以交替设置。例如，沿叶片80的高度方向或者叶片80的移动方向交替设置。
例如，在一示例中，一部分叶片位置检测装置设置在叶片80的高度方向上的上端，剩余的叶片位置检测装置设置在叶片80的高度方向上的下端。这样使得可以充分利用高度上的空间，而避免叶片80之间的间隙较小，导致叶片位置检测装置不易安装的问题。
可选地，相邻两个叶片的叶片位置检测装置在叶片高度方向上交替设置。也就是说，若叶片A对应的叶片位置检测装置位于叶片A高度方向上的上端，则与叶片A相邻的叶片B对应的叶片位置检测装置位于叶片B的高度方向上的下端。
优选地，由于多叶准直器通常应用于放射治疗设备，而放射治疗设备的放射源一般都有辐射，此类辐射会对磁敏传感器30产生辐射损伤，为了延长磁敏传感器30的使用寿命，可以将磁敏传感器整体安装在叶片80高度方向的下端(即远离放射源的一端)，这样可以利用叶片对辐射射线进行衰减，由于衰减后透射射线量非常小，对磁敏传感器30产生的辐射损伤也会较小，从而保证磁敏传感器的正常使用，延长其使用寿命。
又例如，在另一示例中，多个叶片位置检测装置可以分为至少两组，且这至少两组叶片位置检测装置沿叶片80的移动方向上间隔设置，而且相邻两个叶片的叶片位置检测装置在叶片的移动方向上交替设置，这样既可以避免相互影响，又可以适应较小的间隙，且便于叶片的顺利运动。
可选地，为了保证对叶片位置检测的准确性，且方便磁体20和磁敏传感器30的安装，多叶准直器还包括一体的支撑架10，支撑架10设置于箱体70，磁体20和磁敏传感器30均设置在支撑架10上。
支撑架10可以直接设置在箱体70上，也可以通过其他连接结构间接地设置在箱体70上。通过将磁体20和磁敏传感器30均安装在一个一体式的支撑架10上，保证了磁体20只能相对磁敏传感器30转动，而不会产生相对移动，由此确保磁敏传感器30检测到的磁场变化均是由于叶片80的移动导致的，进而保证磁场强度的周期性变化稳定，避免由于磁体20相对磁敏传感器30移动而造成误检，确保定位准确性。
当然，在其他可行方式中，磁敏传感器30可以与磁体20安装到不同的固定物上，只要保证磁敏传感器30与磁体20之间没有相对移动即可。
可选地，支撑架10包括上壁和下壁，磁敏传感器30设置在上壁上，磁体20设置在下壁上。为了使磁体20转动顺畅可以在下壁上设置轴承，磁体20可以包括磁极、转杆，转杆一端连接磁极，另一端穿过轴承，穿过轴承的转杆一端与叶片80抵接。
通过在每个叶片80上设置磁体20和磁敏传感器30的方式，使得可以准确地检测每个叶片80的位移，而为了确保磁体20(或磁敏传感器30)始终与叶片80接触，从而保证不会出现丢步现象，在一可行方式中，支撑架10通过主轴50可转动地连接在箱体70上，多叶准直器还包括张紧机构，张紧机构连接在箱体70和支 撑架10之间，并向支撑架10施加朝向叶片80的张紧力。
通过设置张紧机构，保证了在叶片80和磁体20(或磁敏传感器30)之间出现空隙时，张紧机构能够自动驱动支撑架10朝向叶片80移动，进而使磁体20(或磁敏传感器30)与叶片80紧密抵接或可靠啮合，而且不会使磁体20和磁敏传感器30之间的相对位置发生变化，由此保证了磁体20与叶片80的紧密接触或可靠啮合，进而可以保证在叶片80移动时能够实时地驱动磁体20转动。
可选地，在本实施例中，如图4所示，箱体70包括固定基座40，张紧机构包括第一连接件61、第二连接件62和弹性件63，第一连接件61固定连接在支撑架10上，且能够带动支撑架10相对固定基座40运动；第二连接件62固定设置在固定基座40上；弹性件63连接在第一连接件61和第二连接件62之间，并通过第一连接件61向支撑架10施加朝向叶片80的张紧力。
弹性件63例如为弹簧，其始终保持在伸长状态，第一连接件61和第二连接件62可以为连接销或者连接杆等任何适当的结构，其主要用于与弹簧连接，并使其保持在伸长状态。
为了与第一连接件61配合，固定基座40上设置有腰型孔，第一连接件61穿过该腰型孔，并与支撑架10固定连接，这样弹簧就可以向支撑架10施加朝向叶片80的作用力，使支撑架10上的磁体20的始终保持与叶片80紧密抵接或可靠啮合。
通过这种方式可以使得叶片80和叶片定位检测装置之间始终保持紧密抵接或可靠啮合，从而避免检测时丢步。
而为了进一步提升检测准确性，避免磁体20相互之间的磁场干扰导致检测不准确，可以使相邻磁体20之间保持一定距离。
或者，多叶准直器还包括磁屏蔽罩，磁屏蔽罩设置在磁体20外，以防止相邻叶片80对应的磁体20之间的磁场干扰。磁屏蔽罩可以是任何能够隔绝磁场的材料制作的罩体，只要能够屏蔽磁场，防止磁场相互影响即可。
下面结合附图对叶片位置检测装置的工作过程进行说明如下：
如图3所示，一体式的支撑架10通过主轴50与固定基座40(例如为固定板)连接，同时，支撑架10上连接有张紧机构，张紧机构的第二连接件62固定在固定基座40上，张紧机构的第一连接件61穿过固定基座40并与支撑架10连接，弹性件63连接在第一连接件61和第二连接件62之间，且处于伸长状态，这样弹性件63向支撑架10施加朝向叶片80的张紧力。
在磁体20与叶片80之间存在间隙导致磁体20未与叶片80紧密接触或可靠啮合时，在张紧力的作用下，第一连接件61在腰型孔内运动，并带动支撑架10绕着主轴50转动，从而使磁体20与叶片80紧密接触或可靠啮合。
当叶片80被驱动而移动时，通过叶片80与磁体20之间的摩擦传动或啮合传动，将叶片的直线位移转换为磁体20的转动，从而引起磁场强度变化(磁感线方向和磁通量发生变化，磁感线强度就不同)。
由于磁场变化，导致磁敏传感器30的电阻值改变，随着磁体20的转动会产生周期分布的交变的空间漏磁场，进而会产生周期性变化的交变磁场强度，因此电 阻值也是周期性地变化的，根据偏心距离的不同，周期性变化的电阻值的波形可能不同，一种情况中波形可以是正弦波。
磁敏传感器30通过磁电阻效应将变化着的磁场信号转化为电阻阻值的变化，在外加电势的作用下，变化的电阻值转化成电压的变化，进而经过后续信号处理电路的处理，模拟的电压信号转化成位移信号，实现对叶片80位移的检测。
根据本申请的另一方面，提供一种放射治疗设备，其包括放射源和前述的多叶准直器。
采用上述多叶准直器的放射治疗设备，由于多叶准直器各叶片80都可以通过叶片位置检测装置实现二次定位反馈，从而准确地确定叶片80的实际位置进而确定多叶准直器调整出的靶区形状是否与需求一致，这样不仅能够提高叶片80的定位精度，而且可以保证靶区形状，从而防止在治疗过程中对健康细胞造成不必要的伤害。
本申请的叶片位置检测装置具有如下有益效果：
通过磁敏方式，每个叶片连接一组磁体和磁敏传感器，当叶片发生位移时，驱动磁体转动，使得磁感线方向和强度发生变化，进而通过磁敏传感器检测磁场变化并产生相应的电压信号输出，以根据电压信号的变化计算出叶片运动的位置。这种方式精度高、成本低、耐受性强，且适合多种复杂工况，可以提高叶片二次反馈的精度，降低成本，提高稳定性。
此外，由于相邻叶片间的间隙非常小，而磁体和磁敏传感器的体积可以设置的较小，从而被容纳在相邻叶片的间隙中，使得安装更加方便。
最后应说明的是：以上实施例仅用以说明本申请实施例的技术方案，而非对其限制；尽管参照前述实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的精神和范围。

Claims (12)

  1. 一种多叶准直器的叶片位置检测装置，其特征在于，包括：
    磁体(20)；
    与所述磁体(20)相对设置的磁敏传感器(30)；
    所述磁体(20)或所述磁敏传感器(30)与所述叶片(80)连接，使得在所述叶片运动时，所述磁体(20)和所述磁敏传感器(30)相对转动；
    所述磁敏传感器(30)将检测到的所述磁体(20)的磁场变化转换为叶片(80)的位置信息输出。
  2. 根据权利要求1所述的叶片位置检测装置，其特征在于，所述磁体(20)或所述磁敏传感器(30)通过摩擦驱动方式与所述叶片(80)连接，或者，所述磁体(20)或所述磁敏传感器(30)通过传动机构与所述叶片(80)连接，使得在所述叶片(80)运动时，所述磁体和所述磁敏传感器相对转动。
  3. 根据权利要求1所述的叶片位置检测装置，其特征在于，所述磁体(20)为具有单一磁极的磁体或具有多磁极的磁体。
  4. 根据权利要求3所述的叶片位置检测装置，其特征在于，当所述磁体(20)为具有单一磁极的磁体时，所述磁体(20)与所述磁敏传感器(30)偏心设置。
  5. 一种多叶准直器，其特征在于，包括：
    多组相对设置的叶片(80)；
    承载多组叶片(80)的箱体(70)；
    多个如权利要求1-4任一项所述的叶片位置检测装置，所述多个叶片位置检测装置与所述多个叶片(80)一一对应设置，所述磁体(20)和所述磁敏传感器(30)均设置在所述箱体(70)上。
  6. 根据权利要求5所述的多叶准直器，其特征在于，所述多叶准直器还包括一体的支撑架(10)，所述支撑架(10)设置于所述箱体(70)，所述磁体(20)和所述磁敏传感器(30)均设置在所述支撑架(10)上。
  7. 根据权利要求6所述的多叶准直器，其特征在于，所述支撑架(10)通过主轴(50)可转动地连接在所述箱体(70)上，所述多叶准直器还包括张紧机构，所述张紧机构连接在所述箱体(70)和所述支撑架(10)之间，并向所述支撑架(10)施加朝向所述叶片(80)的张紧力。
  8. 根据权利要求7所述的多叶准直器，其特征在于，所述箱体(70)包括固定基座(40)，所述张紧机构包括：
    第一连接件(61)，所述第一连接件(61)固定连接在所述支撑架(10)上，且能够带动所述支撑架(10)相对所述固定基座(40)运动；
    第二连接件(62)，所述第二连接件(62)固定设置在所述固定基座(40)上；
    弹性件(63)，所述弹性件(63)连接在所述第一连接件(61)和所述第二连接件(62)之间，并通过所述第一连接件(61)向所述支撑架(10)施加朝向所述叶片(80)的张紧力。
  9. 根据权利要求5所述的多叶准直器，其特征在于，一部分所述叶片位置检测装置设置在所述叶片(80)的高度方向上的上端，剩余的所述叶片位置检测装置设置在所述叶片(80)的高度方向上的下端。
  10. 根据权利要求9所述的多叶准直器，其特征在于，相邻两个叶片的所述位 置检测装置在所述叶片高度方向上交替设置。
  11. 根据权利要求5所述的多叶准直器，其特征在于，所述多叶准直器还包括磁屏蔽罩，所述磁屏蔽罩设置在所述磁体(20)外，以防止相邻所述叶片(80)对应的磁体(20)之间的磁场干扰。
  12. 一种放射治疗设备，其特征在于，所述放射治疗设备包括放射源和权利要求5-11中任一项所述的多叶准直器。
PCT/CN2020/140396 2020-12-28 2020-12-28 叶片位置检测装置、多叶准直器及放射治疗设备 WO2022140992A1 (zh)

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JP2009072443A (ja) * 2007-09-21 2009-04-09 Toshiba Corp マルチリーフコリメータおよび放射線治療装置
CN104667427A (zh) * 2013-11-29 2015-06-03 上海联影医疗科技有限公司 多叶光栅的叶片位置监测装置、多叶光栅、放疗设备
CN206355455U (zh) * 2016-10-27 2017-07-28 深圳市艾华联盟科技有限公司 一种多叶准直器叶片位置反馈装置
CN109125953A (zh) * 2018-07-18 2019-01-04 上海联影医疗科技有限公司 反馈装置及多叶光栅系统
CN209166336U (zh) * 2018-12-28 2019-07-26 成都宏明电子股份有限公司 一种用于线位移测量的磁敏传感器
CN110538387A (zh) * 2019-09-09 2019-12-06 上海联影医疗科技有限公司 一种多叶准直器及放疗设备

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009072443A (ja) * 2007-09-21 2009-04-09 Toshiba Corp マルチリーフコリメータおよび放射線治療装置
CN104667427A (zh) * 2013-11-29 2015-06-03 上海联影医疗科技有限公司 多叶光栅的叶片位置监测装置、多叶光栅、放疗设备
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