Compact scanning treatment head for charged particle treatment device

Abstract

The invention relates to a compact scanning treatment head for a charged particle treatment device, which comprises a scanning magnet system and a beam monitoring system, and is characterized in that the scanning magnet system comprises a framework and a coil winding, the coil winding comprises a horizontal deflection coil and a vertical deflection coil, the horizontal deflection coil is wound around the inner side face of the framework to enable the particle beam to deflect in the horizontal direction, and the vertical deflection coil is wound around the outer side face of the framework to enable the particle beam to deflect in the vertical direction. The beam monitoring system is located at the downstream of the scanning magnet system and comprises a multi-wire proportional chamber for monitoring the position of the beam and a first dose ionization chamber and a second dose ionization chamber for monitoring the dose of the beam. According to the compact scanning treatment head for the charged particle treatment device, the horizontal deflection coil and the vertical deflection coil are wound on the same framework and are integrated, the size is reduced, and compact layout is achieved.

Description

Technical Field

[0001] The present invention relates to particle therapy, and more particularly to a compact scanning therapy head for a charged particle therapy device. Background Art

[0002] Particle radiotherapy is an advanced radiotherapy technology that uses charged particle beams such as protons and heavy ions to precisely irradiate tumors. Compared with traditional photon radiotherapy, particle radiotherapy can release radiation doses more concentratedly to the tumor target area, thereby maximizing the killing of tumor cells while effectively reducing radiation damage to surrounding normal tissues, thereby improving the accuracy and safety of tumor treatment.

[0003] Traditional particle radiotherapy mainly uses proton and carbon ion radiotherapy. In recent years, due to the advantages of helium ions such as better biological properties, better range control, and lower treatment cost than carbon ions, particle radiotherapy based on helium ions has received widespread attention and become a research hotspot.

[0004] Currently, particle radiotherapy treatment heads based on scanning technology are considered to be one of the most advanced treatment methods. Unlike passive scattering technology, scanning technology uses a precisely controlled scanning magnet system to actively scan and irradiate the tumor target area in the patient's body.

[0005] In a treatment head based on scanning technology, the scanning magnet and the beam monitoring system are two core key components.

[0006] The scanning magnet precisely controls the size and direction of the magnetic field to conduct a two-dimensional scan of the incident particle beam in the patient's body along a predetermined path, covering the entire tumor target area. The performance indicators of the scanning magnet, such as the maximum magnetic field strength, magnetic field uniformity, and response time, directly determine the accuracy and speed of the scan.

[0007] The beam monitoring system is responsible for real-time monitoring of the position, dose distribution and other parameters of the particle beam. It usually includes a position detector and a dose detector, which can provide accurate feedback data for adjusting the scanning magnet to ensure that each beam of scanning particles accurately hits the expected position of the tumor target, thereby avoiding unnecessary radiation damage to normal tissues.

[0008] However, the existing particle radiotherapy system based on scanning technology still has some shortcomings, especially when considering building a helium ion therapy device. These shortcomings will bring great difficulties to the engineering design, mainly including the following aspects.

[0009] Traditional scanning magnets adopt a separate design, with a source-axis distance (SAD) of about 9 meters. The overall volume is large, which is not conducive to the design and construction of compact treatment rooms, and also increases the size of the rotating treatment room frame. For helium ion beams, due to the difference in physical properties between helium ion beams and proton beams, a higher magnetic field strength is required than for proton beams, which puts higher requirements on magnet design.

[0010] Traditional beam monitoring systems mostly use ionization chamber detectors, but ionization chambers cannot amplify the initial charge signal and usually require tens of microseconds to integrate and sample the charge. The sampling rate cannot meet the urgent need for real-time monitoring of rapid particle scanning. Summary of the invention

[0011] In order to solve the problems of large size and the like in the above-mentioned prior art, the present invention provides a compact scanning treatment head for a charged particle treatment device.

[0012] According to the compact scanning therapy head for a charged particle therapy device of the present invention, it includes a scanning magnet system and a beam monitoring system, wherein the scanning magnet system includes a frame and a coil winding, wherein the coil winding includes a horizontal deflection coil and a vertical deflection coil, the horizontal deflection coil is wound on the inner side of the frame to deflect the particle beam in the horizontal direction, and the vertical deflection coil is wound on the outer side of the frame to deflect the particle beam in the vertical direction, and the beam monitoring system is located downstream of the scanning magnet system and includes a multi-wire proportional chamber to monitor the beam position and a first and a second dose ionization chamber to monitor the beam dose.

[0013] In a preferred embodiment, the skeleton is a ceramic skeleton.

[0014] In a preferred embodiment, the skeleton is a hollow structure.

[0015] In a preferred embodiment, the skeleton is a trumpet-shaped expansion structure.

[0016] In a preferred embodiment, the coil winding is made of finely stranded enameled wire with a diameter between 0.1 mm and 0.5 mm.

[0017] In a preferred embodiment, the scanning magnet system further comprises a cooling copper tube which is wound on the bobbin outside the vertical deflection coil.

[0018] In a preferred embodiment, the cooling copper tubes are arranged in series and around the periphery of the skeleton.

[0019] In a preferred embodiment, the scanning magnet system further comprises a circulating cooling device connected to the cooling copper pipe to cool the thermal effect generated by the coil winding.

[0020] In a preferred embodiment, the multi-wire proportional chamber consists of a horizontal cathode plane, a vertical cathode plane and an anode wire plane, wherein the horizontal cathode plane and the vertical cathode plane are respectively located on both sides of the anode wire plane and are responsible for detecting the horizontal and vertical positions of the beam.

[0021] In a preferred embodiment, the anode wire plane is a wire array structure composed of hundreds of thin metal wires arranged in parallel, the diameter of the metal wires is tens of microns, and the distance between adjacent metal wires is several microns.

[0022] According to the compact scanning treatment head for charged particle therapy device of the present invention, the horizontal deflection coil and the vertical deflection coil are integrated on the same frame, which reduces the volume size and realizes a compact layout. The scanning magnet system realizes the deflection scanning of charged particle beams such as protons and helium ions in the patient's body, controls the irradiation position of the beam in the tumor target area, and realizes high-speed and accurate scanning and high-precision real-time monitoring of the beam through the beam monitoring system, which significantly improves the overall performance of the particle radiotherapy system. In particular, the compact scanning treatment head for charged particle therapy device of the present invention can better meet the injection requirements of proton and helium ion therapy accelerators. The present invention belongs to a particle radiotherapy treatment head based on scanning technology. Compared with the existing passive scattering technology, it can better adapt to complex tumor targets with irregular shapes and accurately cover the entire irradiation area, thereby further improving the accuracy and uniformity of treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall structure of a compact scanning treatment head for a charged particle therapy device according to a preferred embodiment of the present invention.

[0024] Figure 2 yes Figure 1 Schematic diagram of the scanning magnet system.

[0025] Figure 3 yes Figure 2 Perspective view of the scanning magnet system.

[0026] Figure 4 yes Figure 1 Schematic diagram of the beam monitoring system. DETAILED DESCRIPTION

[0027] The preferred embodiments of the present invention are given below in conjunction with the accompanying drawings and described in detail.

[0028] like Figure 1As shown, a compact scanning treatment head for a charged particle therapy device according to a preferred embodiment of the present invention includes a scanning magnet system 1 and a beam monitoring system 2. The particle beam is transported to the scanning magnet system 1 through an acceleration pipeline. The scanning magnet system 1 realizes two-dimensional or three-dimensional deflection scanning of a charged particle (such as a proton or helium ion) beam in the patient's body by precisely controlling the size and direction of the magnetic field, and precisely controls the irradiation position of the beam in the tumor target area. The beam monitoring system 2 is located downstream of the scanning magnet system 1 and at the end of the treatment head, and is used to monitor key parameters such as the position and irradiation dose of the particle beam in real time. In addition, the compact scanning treatment head also includes a ridge filter following the scanning magnet system 1, which is used to widen the beam in the depth direction to ensure that the depth distribution of the beam in the patient's body is more uniform, thereby better covering the tumor target area.

[0029] In the present invention, the scanning magnet system 1 comprises an integrated compact fast scanning magnet. Figure 2 As shown, the scanning magnet system 1 includes a frame 3 and a coil winding 4 , wherein the coil winding 4 is wound on the frame 3 to ensure that the coil winding 4 fits tightly to the frame 3 .

[0030] In the present invention, the skeleton 3 is a ceramic skeleton. Compared with the existing silicon steel sheet skeleton, the ceramic skeleton has high processing accuracy, small thermal expansion coefficient, and good insulation performance. It is very suitable for the winding and bearing of the coil winding 4. Accordingly, the precise winding of the coil winding 4 can be ensured, the leakage and unevenness of the magnetic field can be reduced, and the uniformity of the magnetic field can be maintained at high temperature.

[0031] In the present invention, the skeleton 3 is a hollow structure, which ensures that the incident channel of the beam is unobstructed, reduces beam loss, and improves the efficiency and accuracy of scanning.

[0032] In the present invention, the frame 3 is a trumpet-shaped expansion structure to ensure that the scanning magnet system 1 generates a sufficiently large scanning field of view. In a preferred embodiment, the scanning field of view is 22 cm×22 cm.

[0033] In the present invention, the coil winding 4 is wound with a finely twisted enameled wire having a diameter between 0.1 mm and 0.5 mm. The finely twisted enameled wire can reduce resistance and improve the ability of current to pass, thereby generating a stronger magnetic field. In a preferred embodiment, the maximum magnetic field strength can reach 2.5 T. Winding with finely twisted enameled wire can reduce skin effect and proximity effect, and improve the uniformity and response speed of the magnetic field. In a preferred embodiment, the magnetic field uniformity is as high as 10 ppm, which is sufficient to meet the high requirements for scanning with heavy particle beams (e.g., helium ion beams).

[0034] like Figure 3As shown, the coil winding 4 includes a horizontal (X-direction) deflection coil 4a and a vertical (Y-direction) deflection coil 4b, wherein the horizontal deflection coil 4a is wound on the inner side of the frame 3, and generates a horizontal magnetic field through current, so that the particle beam is deflected in the horizontal direction; the vertical deflection coil 4b is wound on the outer side of the frame 3, and generates a vertical magnetic field through current, so that the particle beam is deflected in the vertical direction.

[0035] In the present invention, the horizontal deflection coil 4a and the vertical deflection coil 4b are wound on the same frame 3 and integrated into one body. Compared with the prior art using two independent orthogonal separate magnets one in front and one behind, the present invention can effectively reduce the volume and size and achieve a compact layout. The present invention uses an integrated hollow horn-shaped fast scanning magnet design to replace the traditional separate magnet, which greatly shortens the distance (SAD) between the radiation source and the patient's body surface from about 9 meters to about 2.5 meters, which is conducive to the construction of compact and rotating treatment rooms.

[0036] like Figure 2 and Figure 3 As shown, the scanning magnet system 1 further comprises a cooling copper tube 5, which is wound on the frame 3 outside the vertical deflection coil 4b. In a preferred embodiment, the cooling copper tube 5 is arranged on the periphery of the frame 3 in a series winding manner.

[0037] In addition, the scanning magnet system 1 also includes a circulating cooling device 6, which is connected to the cooling copper tube 5 and is used to cool the thermal effect generated by the coil winding 4. When irradiated with a high-dose beam, the coil winding 4 will generate a large amount of heat. The cooling copper tube 5 and the circulating cooling device 6 can effectively cool the coil winding 4 to ensure that the coil winding 4 operates stably under high current, thereby maintaining a high-intensity magnetic field. When the current changes rapidly, the coil winding 4 will generate more heat. The cooling copper tube 5 and the circulating cooling device 6 can ensure that the coil winding 4 is not damaged due to overheating under rapidly changing current, thereby achieving rapid scanning.

[0038] In the present invention, the scanning magnet system 1 can generate a high-intensity and high-uniformity magnetic field. Under the control of the scanning magnet system 1, the beam can achieve a 100mm / ms rapid scan of a medical helium ion beam within a 22cm×22cm field of view, that is, the scanning magnet system 1 can move the beam 100 mm in a very short time (1 millisecond) to cover an area of ​​22cm×22cm. The rapid scanning speed of up to 100mm / ms is significantly improved compared to the existing 50mm / ms, and the large field of view scanning irradiation field of 22cm×22cm meets the application needs.

[0039] In the present invention, the beam monitoring system 2 is a beam monitoring system based on a multi-wire proportional chamber. Figure 4As shown, the beam monitoring system 2 includes a multi-wire proportional chamber located in a protective cover 11 to monitor the beam position. In the present invention, the multi-wire proportional chamber is composed of an X-direction cathode plane 6, a Y-direction cathode plane 7 and an anode wire plane 8, which is used to monitor the beam position in real time with high precision. The X-direction cathode plane 6 and the Y-direction cathode plane 7 are respectively located on both sides of the anode wire plane 8, and are responsible for detecting the position of the beam in the X direction and the Y direction. The anode wire plane 8 is a wire array structure composed of hundreds of parallel thin metal wires, the diameter of these metal wires is less than 100 microns (for example, tens of microns), and the spacing is several microns. When the beam passes through the wire array, a gas avalanche effect is triggered near the metal wire close to the beam trajectory, generating more ionized charges. This charge amplification effect performs primary amplification on the beam signal, providing basic conditions for high-precision measurement of the beam position. The anode wire plane 8 adopts a charge amplification mode, which can amplify the initial ionization charge by 2-100 times and output the amplified charge signal. This high magnification capability enables the multi-wire proportional chamber to achieve high-resolution real-time monitoring of the beam position, meeting the urgent need for monitoring in high-speed scanning. The amplified charge signal is converted into a voltage analog signal and output through the data acquisition system. This process ensures that each beam of scanning particles can accurately hit the expected position of the tumor target, thereby improving the accuracy and effectiveness of treatment.

[0040] like Figure 4 As shown, the beam monitoring system 2 also includes a first dose ionization chamber 9 and a second dose ionization chamber 10 located in the protective cover 11 to monitor the beam dose. In the present invention, the first dose ionization chamber 9 and the second dose ionization chamber 10 are redundant designs to improve the system safety margin. When the first dose ionization chamber 9 fails, the second dose ionization chamber 10 can continue to work to ensure safety in emergency situations. In this way, the first dose ionization chamber 9 and the second dose ionization chamber 10 are respectively used to measure the total amount of ionized charge generated when the beam passes through, so as to determine the dose of the beam. Specifically, by measuring the total amount of initial ionized charge generated by the beam on the filling gas path and comparing it with the calibration curve, the dose value of the beam is obtained. This design not only improves the accuracy of the measurement, but also enhances the reliability and safety of the system through redundant configuration.

[0041] The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The above embodiment of the present invention can also be modified in various ways. That is, all simple, equivalent changes and modifications made according to the claims and the description of the present invention fall within the scope of protection of the claims of the present invention. The contents not described in detail in the present invention are all conventional technical contents.

Claims

1. A compact scanning treatment head for a charged particle therapy device, characterized in that: The compact scanning therapy head includes a scanning magnet system and a beam monitoring system, wherein the scanning magnet system includes a frame and a coil winding, wherein the coil winding includes a horizontal deflection coil and a vertical deflection coil, the horizontal deflection coil is wound on the inner side of the frame to deflect the particle beam in the horizontal direction, and the vertical deflection coil is wound on the outer side of the frame to deflect the particle beam in the vertical direction, and the beam monitoring system is located downstream of the scanning magnet system and includes a multi-wire proportional chamber to monitor the beam position and a first and a second dose ionization chamber to monitor the beam dose.

2. The compact scanning treatment head according to claim 1, characterized in that: The skeleton is a ceramic skeleton.

3. The compact scanning treatment head according to claim 1, characterized in that: The skeleton is a hollow structure.

4. The compact scanning treatment head according to claim 1, characterized in that: The skeleton is a trumpet-shaped expansion structure.

5. The compact scanning treatment head according to claim 1, characterized in that: The coil winding is made of finely stranded enameled wire with a diameter between 0.1mm-0.5mm.

6. The compact scanning treatment head according to claim 1, characterized in that: The scanning magnet system also includes a cooling copper tube which is wound on the bobbin outside the vertical deflection coil.

7. The compact scanning treatment head according to claim 6, characterized in that: The cooling copper tubes are arranged in series and around the periphery of the frame.

8. The compact scanning treatment head according to claim 6, characterized in that: The scanning magnet system also includes a circulating cooling device connected to the cooling copper pipe to cool the thermal effect generated by the coil winding.

9. The compact scanning treatment head according to claim 1, characterized in that: The multi-wire proportional chamber consists of a horizontal cathode plane, a vertical cathode plane and an anode wire plane, wherein the horizontal cathode plane and the vertical cathode plane are located on both sides of the anode wire plane respectively and are responsible for detecting the position of the beam in the horizontal and vertical directions.

10. The compact scanning treatment head according to claim 9, characterized in that: The anode wire plane is a wire array structure composed of hundreds of thin metal wires arranged in parallel. The diameter of the metal wire is tens of microns, and the distance between adjacent metal wires is several microns.

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