WO2015169011A1

WO2015169011A1 - Extra high energy electron beam or photon beam radiotherapy robot system

Info

Publication number: WO2015169011A1
Application number: PCT/CN2014/085119
Authority: WO
Inventors: 袁建军; 中岛一久; 张伟军; 陈黎明
Original assignee: 上海交通大学
Priority date: 2014-05-07
Filing date: 2014-08-25
Publication date: 2015-11-12
Also published as: CN104001270B; CN104001270A

Abstract

Provided in the present invention is an extra high energy electron beam (100) or photon beam (101) radiotherapy robot system, comprising a laser driving system (2), a laser plasma accelerator (3), an electron beam focusing system (4), a photon beam aiming system (5), a robot body (6) and a laser beam stabilization system (7), wherein the laser driving system (2) generates intense laser pulses (12) and spreads same to the laser plasma accelerator (3) installed at the tail end of the robot body (6) to generate electron beams (100); the electron beam focusing system (4) guides the electron beams (100) to diseased parts of a patient (200); the photon beam aiming system (5) enables the electron beams (100) to generate high energy photon beams (101) to perform extra high energy electron beam (100) or photon beam (101) radiotherapy; the robot body (6) spreads the electron beams (100) or the photon beams (101) to the diseased parts of the patient (200) in multiple directions; and the laser beam stabilization system (7) monitors the positions of the laser beams and corrects errors. The extra high energy electron beam (100) or photon beam (101) radiotherapy robot system of the present invention is more compact, more efficient, cheaper and easier to operate, and has a higher performance than an external irradiation radiation therapy system in the prior art.

Description

Ultra high energy electron beam or photon beam radiation therapy robot system

The present invention relates to an external radiation therapy robot system in the field of new medical device technology, and in particular to a robot system using ultra high energy electron beam or photon beam radiation therapy. Background technique

Radiation therapy uses high-energy radiation such as X-rays, gamma rays, electrons, protons, heavy ions, and neutrons to destroy the cancer cell's DNA to kill it. Since radiotherapy kills cancer cells while also damaging normal cells, treatment must be carefully planned to minimize this side effect. Radiation for cancer treatment can come from devices outside the body, called external radiation therapy, or from radioactive substances implanted in the body close to cancer cells, known as internal or external radiotherapy. External beam radiation therapy usually uses a photon beam (X-ray or gamma-ray). The electron beam decreases rapidly after a finite distance, and thus does not affect deeper normal tissues. Electron beam therapy is commonly used for the treatment of cancer in shallow tumors such as the skin area or in the skin, limbs and other parts of the body. For deeper areas, surgical electron radiation therapy is used. Many types of external radiation therapy use a device called a medical linear accelerator driven by a radio frequency (RF) power amplifier, such as a magnetron or a klystron, to produce an electron beam with an energy of 6-20 MeV.

The technical advantages of external beam radiotherapy can provide an effective three-dimensional dose distribution shape and accurate spatial dose-delivery map through image verification. These techniques, including three-dimensional conformal radiotherapy (3D-CRT), intensity-modulated radiation therapy (IMRT), image-guided radiotherapy (IGRT), and hadron therapy, enhance radiation doses to tumor areas and reduce specific sensitive areas of surrounding normal tissue. Radiation effects. With sophisticated computing software and advanced treatment equipment (including precision robotic arms and compact medical accelerators), body stereotactic radiotherapy (SBRT) uses a smaller radiation field and higher in most cases than 3D-CRT. Dose, but more accurately target the target area and shorten the course of treatment.

As disclosed in Document 1 and Document 2, a radiotherapy apparatus using X-rays is disclosed, that is, a small linear accelerator is mounted on a multi-joint robot arm or a rotary table, and the position of the robot arm or the rotary table is controlled, thereby generating a small size. The X-rays of the grating are concentrated to the center point for illumination.

However, under the above-mentioned range of electron beam levels generated by current medical RF linear accelerators, the maximum penetration depth and lateral penumbra quality all restrict the application of this advanced mode in actual cancer treatment. Once the electronic energy level is higher than 50MeV, these problems can be overcome, the penetration depth is deeper, and the horizontal penumbra is sharper, even though the vertical penumbra Also increased. The Monte Carlo simulation study compared the effects of photon, proton and ultra-high-energy electron beams on intensity-modulated radiotherapy for prostate cancer. The best target dose is the proton beam, and the target coverage of the electron beam is comparable to that of the photon beam. Sometimes better than a photon beam. In addition, ultra-high energy electron beams are significantly better than photon beams in avoiding dose effects on sensitive structures and normal tissues. As for the dose effects of secondary particles produced by the interaction of bremsstrahlung and electron nuclear reactions, neutron doses such as ultra-high energy electron beams applied to the whole body are one to two orders of magnitude lower than proton beam therapy and photon intensity modulated radiation therapy.

The ultra-high energy electron beam used in the ultra-high energy electron beam treatment can be generated by a conventional radio frequency-based linear accelerator, including an electronic ejection device, a main acceleration structure called LINAC, an electron beam propagation system, and a final console. . Electrospray devices are typically comprised of a photocathode microwave electron gun or a thermionic high voltage direct current gun and several bunching chambers for generating an electron beam. The LINAC consists of a series of room temperature or superconducting RF cavities with an acceleration gradient of 10 MV/m. The electron beam propagation system includes an electron beam focusing and defocusing electric quadrupole magnet. The operator station is equipped with a vacuum electron beam propagation system and a series of electron beam bending and focusing electromagnets. In order to achieve external beam radiotherapy based on RF linacs, the overall size of the RF linac is estimated to be about 50 meters long. Together with the return table that can guide the electron beam in multiple directions, the total weight can reach hundreds of tons. As a result, the cost of construction and operation of such facilities is unbelievable, which has made it difficult to popularize ultra-high-energy electron beam radiotherapy systems based on conventional accelerators to small-scale hospitals. Although a high-energy electron beam radiation therapy system using a more compact LINAC accelerator and a gantry turret is disclosed in the literature 3, since the principle is still based on a linear accelerator, the structure is still not more compact and compact.

Document 1: Adler Jr Jr, Chang SD, Murphy MJ, Doty J, Geis P and Hancock SL, "The Cyberknife: a frameless robotic system for radiosurgery", Stereotactic Functional Neurosurgery, pp.124-128, 69 (1-4 Pt 2), 1997;

Literature 2: David H. Whittum, "Microwave Electron Linacs for Oncology", Reviews of Accelerator Science and Technology, pp. 63-92, Vol.2, Iss. l, 2009;

Document 3: US patent application No. 13/765,017, filed on Feb. 12, 2013, entitled PLURIDIRECTIONAL VERY HIGH ELECTRON ENERGY RADIATION THERAPY SYSTEMS AND PROCESSES, Pub. No. US 20130231516 Al _;

In view of the deficiencies in the prior art, it is an object of the present invention to provide a robotic system for performing external radiation therapy using an ultra-high energy electron beam or a photon beam.

The ultra high energy electron beam or photon beam radiation therapy robot system of the present invention comprises the following parts: a laser driving system, forming a strong laser pulse; a laser plasma accelerator, the intense laser pulse is directed and focused thereto to generate an electron beam; an electron beam focusing system for directing an electron beam from the laser plasma accelerator to a patient's patient to perform ultra-high energy electrons Beam radiotherapy

a photon beam aiming system, the electron beam from the laser plasma accelerator generates a high energy photon beam for treatment; the robot body is provided with a vacuum optical system, and the strong laser pulse is guided and focused to the laser in the vacuum optical system Plasma accelerator

A laser beam stabilization system monitors the position of the laser beam and corrects their errors in a vacuum optical system. Preferably, the laser driving system comprises:

The front end is capable of generating low energy laser pulses;

An amplifier chain that amplifies the energy of the low energy laser pulse to form a high energy laser pulse;

a pulse compression chamber that converts the high energy laser pulse into a strong laser pulse;

The vacuum pump system maintains the pulse compression chamber, the interior of the robot body, and the vacuum pressure of the accelerator chamber. Preferably, the laser plasma accelerator comprises:

a first gas chamber filled with a mixed gas, which is used to generate plasma and electrons by gas;

a second chamber filled with pure hydrogen or helium to accelerate the electrons;

Gas flow control system;

The intense laser pulse output by the laser drive system is focused by a spherical mirror or an off-axis parabolic mirror into the laser plasma accelerator. The strong laser pulse ionizes the mixed gas in the first chamber to generate plasma and electrons, and the strong laser pulse is in the second gas. The chamber continues to generate and accelerate the electrons, and the gas flow control system controls and delivers the gases into the first and second chambers at different pressures, respectively.

This laser plasma accelerator can efficiently generate ultra-high-energy and high-quality electron beams using a high-acceleration electric field. The laser plasma accelerator can generate electron beam energy between l-250 MeV and better between 50-250 MeV.

Preferably, the laser plasma accelerator is capable of adjusting the second chamber length to control electron beam energy. More preferably, the bellows structure can be driven by the power element to adjust the second chamber length.

Preferably, the laser plasma accelerator is connected to an external transfer chamber, and the electron beam focusing system is mounted in an external transfer chamber of the laser plasma accelerator.

Preferably, the electron beam focusing system has means for providing a thin layer pencil beam output. More preferably, the Ministry The piece can be a four-pole permanent magnet array structure.

Preferably, the electron beam focusing system is expandable without damaging the vacuum of the laser plasma accelerator.

Preferably, the photon beam sighting system comprises a conventional bremsstrahlung conversion target and a collimator, and the electron beam output by the laser plasma accelerator produces a therapeutic high energy photon beam in the photon beam sighting system. The electron beam focusing system and the photon beam aiming system are detachable and easy to assemble and replace.

Preferably, the robot body has various forms, and may be a multi-joint robot or a parallel robot or a robot turret. The robot body can propagate an electron beam or a photon beam from a plurality of directions to a patient's patient site, and can provide a raster scan of the pencil-shaped harness in combination with the treatment bed and the laser beam stabilization system.

Preferably, the end of the robot body is provided with an accelerator cavity, and the laser plasma accelerator is installed in the accelerator cavity at the end of the robot body.

More preferably, the robot body comprises a base, a rotary table, a rotary drive mechanism, a first rotating shaft, a second rotating shaft, a boom and a third rotating shaft, wherein: the rotary driving mechanism is mounted on the rotary table, thereby realizing the relative rotation of the rotary table The base is the rotation of the first rotating shaft; the second rotating shaft connects the rotating table and the arm frame to achieve relative rotation, and the third rotating shaft connects the arm frame and the accelerator cavity to realize the rotation.

Preferably, the laser beam stabilization system is arranged along the inner arm frame and the axis of the robot body to monitor the position of the laser beam and correct the error, so that the propagation direction of the strong laser pulse always coincides with the rotation axis of each joint of the robot.

Preferably, the laser plasma accelerator, the vacuum optical system, and the laser beam stabilization system are all installed in a vacuum environment, and the inside of the robot body is a hollow vacuum structure, and the vacuum pump system maintains a certain vacuum pressure.

Preferably, the duration of the electron beam or photon beam irradiation is controllable from single pulse irradiation to continuous illumination, if it is faster than the breathing interval of the human body, if it is smaller than the heartbeat interval, if it is smaller than the single pulse pulse of the laser driving pulse. The width is best.

Compared with the prior art, the present invention has the following beneficial effects:

The laser drive system of the present invention produces an energy amplified high energy laser pulse and further forms a strong laser pulse. The intense laser pulse is directed inside the robot body having a hollow vacuum structure and focused into a laser plasma accelerator mounted in an accelerator cavity at the end of the robot body to produce an electron beam. The electron beam focusing system directs the electron beam to the patient's patient or produces a high-energy photon beam in the photon beam aiming system for ultra-high energy electron beam or photon beam radiation therapy. The robot body enables the propagation of electron beams or photon beams from multiple directions to the patient's patient. The laser beam stabilization system monitors the position of the laser beam and corrects the error. Compared with the prior art, the present invention has the following beneficial effects:

1. Ultra-high-energy electron beam is generated by laser plasma accelerator instead of linear accelerator. The volume and quality advantages of laser plasma accelerator make the whole device miniaturized, and the price and installation site layout advantages are obvious;

2. Multi-angle illumination and scanning are realized by the robot body, and vacuum propagation of the strong pulse laser is realized by the robot body;

3. Can be easily replaced by treatment with electron beam or photon beam;

The ultra high energy electron beam or photon beam radiotherapy robot system of the present invention is more compact, efficient, inexpensive, simpler to operate, and has higher performance than prior art external beam radiation therapy systems. DRAWINGS

Other features, objects, and advantages of the present invention will become more apparent from the Detailed Description of Description

1a and 1b are schematic diagrams showing the system structure of an embodiment of the present invention;

Figure 2 is a schematic view of a first air chamber and a second air chamber of the laser plasma accelerator of the system shown in Figures la, lb;

Figure 3 is a schematic diagram of an electron acceleration mechanism based on a laser wake field;

4a, 4b are schematic diagrams of a laser plasma accelerator of the ultra high energy electron beam or photon beam radiation therapy robot system shown in Figs. la and 1b, including the first gas chamber and the second gas chamber of Fig. 2;

Figure 5 is a schematic view of a miniature quadrupole permanent magnet (PMQ);

6 is a schematic diagram of an electron beam focusing system according to an embodiment of the present invention, which is composed of three quadrupole permanent magnets (PMQ) shown in FIG. 5;

7a, 7b are schematic views of a vacuum optical system embedded in the robot body of the ultra high energy electron beam or photon beam radiation therapy robot system shown in Figs.

FIG. 8 is a schematic diagram of a laser beam stabilization system according to an embodiment of the present invention; FIG.

FIG. 9 is a schematic diagram of an embodiment of a parallel robot according to another embodiment of the present invention.

In the above picture:

1 is the front end, 10 is the low energy laser pulse, 11 is the high energy laser pulse, 12 is the strong laser pulse, 13 and 14 are the mirrors, and 15 is the off-axis parabolic mirror;

2 is the laser drive system, 21 is the amplifier chain, 22 is the pulse compression chamber, and 23 is the pulse compression optics. 24, vacuum pump system, 25, 26 for the diffraction grating, 27 for the vertical transmitter, 28 for the fixed mirror, 29 for the outer casing;

3 is a laser plasma accelerator, 30 is a gas flow control system, 31 is a first gas chamber, 32 is a second gas chamber, 33 is a mixed gas, 34 is a pure gas, 35 is a joint, 36 is a power component, 37 is a corrugation Tube structure, 38 is a multi-degree of freedom adjustment table, 39 is a laser absorber;

4 is the electron beam focusing system, 40 is the outer casing, 41 is the adapter, 42 is the magnet array, 43 and 44 are the four-pole permanent magnets (wedge permanent magnets), 45 is the central cavity, 46 is the outer cavity, 47 is Bracket, 48 is a vacuum linear movement system, and 49 is a linear guide;

5 is a photon beam aiming system, 51 is a bremsstrahlung conversion target, and 52 is a collimator;

6 is the robot body, 60 is the base, 61 is the rotary table, 62 is the rotary drive, 63 is the first rotating shaft, 64 is the second rotating shaft, 65 is the boom, 66 is the third rotating shaft, 67 is the light guiding arm, 68 For the rotary axis, 69 is a parallel drive unit;

7 is a laser beam stabilization system, 70 is a laser source, 71 is a calibration beam, 72 is a CCD camera, 73 is a mirror bracket, and 74 is a precision motor;

8 is an accelerator cavity, 80 is a vacuum window, 81 is a linear guide, and 82 is a base mechanism;

100 is an electron beam, 101 is a photon beam, 200 is a patient, 201 is a treatment bed, 303 is a fine dotted line, 304 is a thick dotted line, 305 is a thick solid line, 306 is a thin dotted line, 307 is an electronic vacuole, 308 is strong The longitudinal electric field, 309 is the electron trajectory, and 310 is the trajectory. detailed description

The invention will now be described in detail in connection with specific embodiments. The following examples are intended to further understand the present invention by those skilled in the art, but are not intended to limit the invention in any way. It should be noted that a number of variations and modifications may be made by those skilled in the art without departing from the inventive concept. These are all within the scope of protection of the present invention.

As shown in FIG. 1A, the embodiment provides an ultra-high energy electron beam or photon beam radiation therapy robot system, including: a laser driving system 2, a laser plasma accelerator 3, an electron beam focusing system 4, a photon beam aiming system 5, and a robot. The body 6 and the laser beam stabilization system 7, the laser drive system 2 produces an energy amplified high energy laser pulse and further forms a strong laser pulse. The intense laser pulse is guided inside the robot body 6 having a hollow vacuum structure and focused into a laser plasma accelerator 3 installed in an accelerator chamber at the end of the robot body, thereby generating an electron beam. The electron beam focusing system 4 directs the electron beam to the patient's patient, photon beam imaging The quasi-system 5 produces a high-energy photon beam by means of an electron beam for ultra-high energy electron beam or photon beam radiation therapy. The robot body 6 enables the propagation of electron beams or photon beams from a plurality of directions to a patient's patient. The laser beam stabilization system 7 monitors the position of the laser beam and corrects the error. The various parts involved are described in detail below. Laser drive system 2

As shown in FIG. 1, the laser drive system 2 includes a front end 1, an amplifier chain 21, a pulse compression chamber 22, and a vacuum pump system 24. The front end 1 is used to generate and output a low energy laser pulse 10. The low energy laser pulse 10 enters and passes through the amplifier chain 21 to be amplified and forms a high energy laser pulse 11. A pulse compression optics 23 is mounted in the pulse compression chamber 22, and the amplified high energy laser pulse 11 is compressed in the pulse compression optics 23 in the time domain. The pulse compression chamber 22 is evacuated by a vacuum pump system 24 to maintain a pressure of 10 - ^{3 -} 10 - ⁴ Pa. The strong laser pulse 12 formed by the compression of the pulse compression chamber 22 is propagated to the laser plasma accelerator 3 mounted at the end of the robot body 6. The outer casing 29 serves to protect the entire laser drive system 2.

The pulse compression optics 23 includes a pair of diffraction gratings 25, 26, a vertical reflector 27 and a fixed mirror 28 that combine the various spectral components of the pulse in the time domain. The output intense laser pulse 12 generated by the pulse compression optics 23 then has ultra-high energy and ultra-short pulse width, so its energy and pulse width can be further optimized to accelerate the electron beam 100. Laser plasma accelerator 3

As shown in Figures la, 2 and 4a, the laser plasma accelerator comprises: a first gas chamber filled with a mixed gas; a second gas chamber filled with pure hydrogen or helium; and a gas flow control system.

The intense laser pulse 12 compressed in the pulse compression chamber 22 is focused by a spherical mirror or an off-axis parabolic mirror 15 at the entrance of the laser plasma accelerator 3. The first gas chamber 31, referred to as the injection stage, is filled with a mixed gas 33, such as a helium-nitrogen mixed gas composed of 98% helium gas and 2% nitrogen gas. The second gas chamber 32, called the acceleration stage, is filled with a clean gas 34 such as hydrogen or helium. These gases are propagated through the joint 35 to the laser plasma accelerator 3 at different pressures under the control of the gas flow control system 30, respectively. The length of the second plenum 32 can be adjusted by the power element 36 driving the bellows structure 37.

As shown in Figure 4a, the laser plasma accelerator 3 is mounted above a multi-degree of freedom adjustment stage 38, such as a commercial Hexapod six-axis precision platform. The alignment of the laser plasma accelerator 3 with the intense laser pulse 12 is accomplished by a multi-degree of freedom adjustment stage 38. The residual intense laser pulse 12 passing through the laser plasma accelerator 3 is finally absorbed by the laser absorber 39 mounted at the bottom of the multi-degree of freedom adjustment stage 38. As shown in Figures 2 and 4a, in the first plenum 31, the intense laser pulse 12 excites a large amplitude plasma wake field, wherein the accelerating electric field captures the plasma inner electrons and induces electrons by ionization. The intense laser pulse 12 produces a plasma wake field of the order of 100 GV/m in the second plenum 32. The electron beam 100 pre-accelerated in the first gas chamber 31 is further accelerated to the lGeV level in the second gas chamber 32.

Figure 3 illustrates the physical process of the wake field excitation and the capture and acceleration of electrons in the wake field. This produces a wake field when the strong laser pulse 12 propagates in the neutral mixed gas 33 of the first gas chamber 31. In Fig. 3, the plasma electron density change curve is shown in the upper diagram 301, and the excited longitudinal tail field is shown in the lower portion 302.

As shown by 300 in the middle of Fig. 3, the outer electrons of 氦 and up to N ⁵⁺ are completely ionized at the front of the intense laser pulse 12 having a light intensity of 1.5 x 10 ¹⁶ W/cm ² and plasma electrons are formed around the strong laser pulse 12 . The boundary of the intense laser pulse 12 is indicated by a thin dotted line 303 in the figure. Since the two inner shell (K-shell) electrons of N ⁶⁺ and N ⁷⁺ need to be laser ionized with a light intensity higher than 1 X 10 ¹⁹ ATM ² , the inner shell electrons only peak at the strong laser pulse 12 Ionization near the light intensity. A strong laser with a normalized laser field (a ₀ 0. ⁸⁵⁵ x l0- ⁹ / ^1/2 [f ATM ² [ ^] = ² , where /[f ATM ² ] is the light intensity, the laser wavelength) The intensity map of pulse 12 is indicated by thick dotted line 304. In the upper portion of the figure 301, the thick solid line 305 indicates the degree of progress of nitrogen ionization along the propagation axis (the number of electrons of the ionized helium atom). The boundaries of the plasma region including the inner shell electrons ionized from N ⁶⁺ and N ⁷⁺ are indicated by thin dashed lines 306.

The plasma electrons in the boundary of the fine dotted line 303 are pushed away by the radiation pressure (mass dynamic) of the strong laser pulse 12 having a relative intensity of ^>>1, and a narrow electron sheath is formed behind the laser pulse to surround the spherical-like ions. The zone, also often referred to as electron bubble 307. This charge separation produces a strong longitudinal electric field 308 on the order of 100 GV/m with a plasma electron density of 10 ¹⁸ cm- ³ , which is three orders of magnitude higher than the amplitude of the accelerating electric field of a conventional RF accelerator. In the electron bubble 307, the electrons are simultaneously subjected to a strong focusing force. Therefore, once the electron beams 100 are captured into the electron cells 307, they are rapidly accelerated to a high energy level of 1 GeV within a length of 1 cm.

The inner shell electrons ionized from N ⁶⁺ and N ⁷⁺ are close to the center of the electron bubble, where the wake potential has a maximum value and the laser pulse has the lowest kinetic power. The pre-ionized free electron trajectory is mostly a narrow sheath movement along the outside of the electron bubble. Conversely, the electrons ionized from the inner shell layer move closer to the electron bubble axis to the electron bubble tail, where the tail wave potential energy is the smallest, if the electron is obtained With sufficient kinetic energy, they will eventually be captured into the wake field as shown by electron trace 309. However, the electrons shown by trace 310 are off-axis and ionized earlier, and slip away from the potential well will not be captured. This mechanism, known as ionization-induced implantation, can occur at intensity as low as the light field ionization threshold of the inner shell electrons of the mixed gas, and greatly increases the trapped charge. Since the capture occurs near the bubble axis, the amplitude of the oscillation is reduced after capture compared to the free injection from the electron sheath. Theoretical analysis of reference ionization induced implantation, in order to capture electrons ionized at the peak of the laser electric field, the minimum laser intensity must be 1- ≤ 0.64, where ^ = (1 ^1/2 is The Lorentz factor is the phase velocity of the plasma wake. In order for the electron to be captured at the front end of the laser envelope, the intensity must be a ₀ ≥ \ .23, at this time ^ = 33. Electron beam focusing system 4 and photon beam aiming system 5

As shown in Figures la and 4a, the electron beam focusing system 4 has means for providing a thin layer of pencil beam output using a four pole permanent magnet array. The electron beam 100 output from the laser plasma accelerator 3 is collimated by the four-pole permanent magnet array of the electron beam focusing system 4 and then propagated to the patient of the patient 200 to form a thin-layer pencil beam. The electron beam focusing system 4 is mounted in an adapter 41 outside the plasma accelerator 3, and the electron beam focusing system 4 can be expanded and contracted without damaging the vacuum of the plasma accelerator 3.

Figure 5 shows a four-pole permanent magnet array structure consisting of 12 symmetrically arranged Halbach type quadrupole permanent magnets (PMQ) 43, 44, comprising a central cavity 45 and an outer cavity 46, and a bracket 47 for supporting And positioning.

The quadrupole magnetic field is composed of four radial wedge-shaped permanent magnets 43 having a high remanence material, such as Nd ₂ FeuB or S _m CO, etc., whose magnetization directions are indicated by arrows. The external magnetic field closure is formed by an additional eight wedge shaped permanent magnets 44. Since the four main wedge blocks are strongly attracted to the center of the quadrupole, the mechanical position accuracy and magnetic field accuracy must be obtained by inserting the central cavity 45 and the outer cavity 46 of the magnet array 42 with a non-magnetic material precision hollow cylinder.

As shown in FIG. 6, the electron beam focusing system 4 includes two or three sets of magnet arrays 42. As shown in Fig. 5, the magnetic field gradient of the two-dimensional Halbach type quadrupole permanent magnet (PMQ) is =2 (r, - ¹ -^- ¹ ), where is the tip field strength, r, the inner hole radius, r. The outer radius of the PMQ. For NdFeB rare earth magnets with a mass of N50 (N 3⁄4 ₁₄ 5), if β _Γ = 1.45 _Γ and r corp. 2.5 mm, the magnetic field gradient is = 1160 [77 ] (l-2.5/r. [ ] ).

As shown in Fig. 6, two or three sets of magnet arrays 42 mounted in the outer casing 40 of the electron beam focusing system 4 constitute a binary (FD) or triplet (FDF) structure. The vacuum linear motion system 48 and the linear guides 49 are both parallel to the longitudinal axis of the electron beam 100 and are fixed inside the outer casing 40, and all of the magnet arrays 42 pass through and are linearly movable along the linear guides 49. The number of linear movement systems 48 is the same as the number of magnet arrays 42, and each linear movement system 48 controls only one and a different position of the magnet array 42 along the longitudinal axis of the electron beam 100, which is separately adjusted and optimized by the computer. The linear guides 49 ensure the structural alignment and rigidity of the magnet array 42.

As shown in FIGS. 1b and 4b, the photon beam sighting system 5 includes a bremsstrahlung conversion target 51 and a collimator 52 installed therein, and the electron beam 101 generated by the laser plasma accelerator 3 is incident on the bremsstrahlung conversion target. 51 and collimator 52 produce photon beam 101. The photon beam sighting system 5 and the electron beam focusing system 4 can be disassembled and replaced in a simple manner. Robot body 6 and accelerator cavity 8

The intense laser pulse 12 from the pulse compression chamber 22 is propagated through the robot body 6 to the accelerator chamber 8 mounted at the end of the robot body 6, and is then focused to the entrance of the laser plasma accelerator 3, ultimately producing an electron beam 100 or a photon beam 101. The robot body 6 is capable of manipulating and adjusting the position and posture of the electron beam 100 or the photon beam 101 to effect radiotherapy of the patient 200. At the same time, under the motion cooperation of the treatment bed 201, the robot body 6 can also manipulate the electron beam 100 to achieve fine scanning treatment.

The laser beam stabilization system 7 is arranged along the inner arm frame and the axis of the robot body 6, so that the propagation direction of the strong laser pulse 12 always coincides with the rotation axis of each joint of the robot. The interior of the robot body 6 is a hollow vacuum structure that is evacuated by a vacuum pump system 24 to maintain a pressure of 10 - ^{3 -} 10 - ⁴ Pa.

The robot body 6 has various forms. Figure la is a schematic view of the robot body 6 using a multi-joint robotic arm. Fig. 9 is a schematic view of the robot body 6 realized by a parallel robot.

As shown in FIG. la, the robot body 6 includes a base 60, a turntable 61, a swing drive 62, a first rotating shaft 63, a second rotating shaft 64, a boom 65, and a third rotating shaft 66. The slewing drive 62 is mounted on the turntable 61 to effect rotation of the turntable 61 relative to the base 60, i.e., the first rotating shaft 63. The second rotating shaft 64 is connected to the rotary table 61 to perform relative rotation with the boom 65, and the third rotating shaft 66 is coupled to the boom 65 and the accelerator chamber 8 for rotation. Both the second shaft 64 and the third shaft 66 take an external drive system similar to 62. Depending on the implementation, the number of shafts can be increased or decreased, and the present invention is not limited thereto.

Figure 9 shows another robot body 6 implemented in parallel robot mode. The light guide arm 67 is formed by repeated series connection of the plurality of booms 65 and the rotary shaft 68, and is connected to the pulse compression chamber 22 and the accelerator chamber 8 at both ends of the light guide arm 67 to form an internal hollow vacuum structure that communicates with each other, by a vacuum pump system. 24 Pump to vacuum to maintain a pressure of 10 - ³ -10 - ⁴ Pa. A plurality of parallel drive units 69 are mounted external to the accelerator chamber 8 and can be realized by a power element such as a commercially available electric push rod. The position and attitude adjustment of the accelerator chamber 8, that is, the electron beam 100 or the photon number 101, relative to the patient 200 is achieved by controlling the relative length of the parallel drive unit 69. The number of the boom 65, the rotary shaft 68, and the parallel drive unit 69 may vary depending on the particular implementation, and the present invention is not limited thereto.

As shown in FIGS. 1a and 4a, the accelerator chamber 8 is mounted at the end of the robot body 6. Inside the accelerator chamber 8, there are mainly linear guides 81, a base structure 82, a vacuum window 80, a mirror 14, an off-axis parabolic mirror 15, a laser plasma accelerator 3, a multi-degree-of-freedom adjustment stage 38, and a laser absorber 39. The base structure 82 is fixed inside the accelerator chamber 8, and the linear guide 81 is mounted on the base structure 82, thereby preventing the linear guide 81 from being deformed when the accelerator chamber 8 is drawn to a vacuum. The mirror 14, the off-axis parabolic mirror 15, the laser plasma accelerator 3, the multi-degree-of-freedom adjustment stage 38 and the laser absorber 39 are mounted coaxially on the linear guide 81 so that the lateral and longitudinal alignment are easy Adjust and ensure accuracy. Wherein the mirror 14 is located opposite the entrance of the intense pulsed laser 12, the off-axis parabolic mirror 15 is located at the top of the accelerator chamber 8, the laser plasma accelerator 3 is mounted above the multi-degree of freedom adjustment stage 38, and the laser absorber 39 is mounted in multiple freedoms. At the bottom of the adjustment stage 38, the laser plasma accelerator 3 and the multi-degree of freedom adjustment stage 38 and the laser absorber 39 are co-located at the bottom of the accelerator chamber 8, and the intense pulsed laser 12 enters the accelerator chamber 8 and is reflected by the radiation mirror 14 to the off-axis paraboloid. The mirror 15 is focused at the entrance of the laser plasma accelerator 3. A vacuum window 80 is mounted at the bottom outlet of the accelerator chamber 8 to separate the vacuum optical system and the laser plasma accelerator 3 from the outside air and the patient 200. Because the significant diffusion of the angle will affect beam performance and clinical accuracy, the vacuum window 80 uses a thin foil of low atomic number elements such as helium. Laser beam stabilization system 7

The alignment of the vacuum optical system due to the movement and elastic deformation of the robot body 6 can be corrected by the laser beam stabilization system 7, as shown in Figs. la and 8. The intense laser pulse 12 is transmitted from the fixed mirror 28 to the vacuum optical system composed of the mirrors 13, 14 and the off-axis parabolic mirror 15 in the pulse compression chamber 22, and reaches the entrance of the laser plasma accelerator 3. The mirror 13 is used to adjust the propagation direction of the intense pulsed laser 12, and is arranged at an angle of 45 degrees with the propagation axis of the intense pulsed laser 12. A laser source 70, such as a holmium laser, provides a calibration beam 71. The position of the collimated beam 71 transmitted by each of the mirrors is detected using a CCD camera 72. Generally, once the motion or elastic deformation of the robot body 6 causes the calibration beam 71 to be displaced at a certain mirror, the mirror will pass through two or three precision motors 74, such as piezoelectric, integrated on the mirror holder 73. The motor is adjusted to its position and attitude to ensure that the intense pulsed laser 12 can accurately focus on the entrance of the laser plasma accelerator 3, as shown in Figures 7a and 7b. This process of detecting the position of the laser beam on each mirror and then correcting the position and attitude of the corresponding mirror will be repeated until the laser beam position is stabilized.

In a specific embodiment of the ultra-high energy electron beam or photon beam radiotherapy robot system driven by the laser plasma accelerator of the present invention, different electron beam energies are provided according to specific requirements, for example: 50 MeV, 100 MeV, 150 MeV, 200 MeV and 250 MeV. The requirements for electron beam power are determined by the radiotherapy program. For example, the treatment of lOcc lung tumors requires a dose of 100 mega volts electrons in 10 seconds in 1 second. From this it is possible to derive various specific parameter requirements including the wavelength or energy of the intense laser pulse 12 and the laser plasma accelerator 3. The content of the present invention is not limited to a specific technical parameter configuration.

The specific embodiments of the present invention have been described above. It is to be understood that the invention is not limited to the specific embodiments described above, and various modifications and changes may be made by those skilled in the art without departing from the scope of the invention.

Claims

claims

1. An ultra-high-energy electron beam or photon beam radiotherapy robot system, characterized by including the following parts: a laser drive system to form strong laser pulses;

Laser plasma accelerator, the intense laser pulse generated by the laser drive system is guided and focused to the laser plasma accelerator, thereby generating an electron beam;

The electron beam focusing system is used to guide the electron beam from the laser plasma accelerator to the patient's site to perform ultra-high-energy electron beam radiotherapy;

Photon beam aiming system for converting electron beams from laser plasma accelerators into high-energy photon beams for treatment;

The robot body is equipped with a vacuum optical system, and the strong laser pulse is guided and focused into the above-mentioned laser plasma accelerator in the vacuum optical system;

Laser beam stabilization system monitors laser beam positions and corrects their errors in vacuum optical systems.

2. An ultra-high-energy electron beam or photon beam radiotherapy robot system according to claim 1, characterized in that the laser plasma accelerator includes:

The first gas chamber filled with mixed gas is used to ionize the gas to generate plasma and electrons;

A second gas chamber filled with pure hydrogen or helium to accelerate electrons;

Gas flow control system;

The strong laser pulse output from the laser drive system is focused by a spherical mirror or an off-axis parabolic mirror and then enters the laser plasma accelerator. The strong laser pulse ionizes the mixed gas in the first gas chamber to generate plasma and electrons. The strong laser pulse ionizes the mixed gas in the first gas chamber to generate plasma and electrons. The chamber continues to generate and accelerate electrons, and the gas flow control system controls and delivers gas into the first gas chamber and the second gas chamber respectively at different pressures.

3. An ultra-high-energy electron beam or photon beam radiotherapy robot system according to claim 2, characterized in that the length of the second air chamber of the laser plasma accelerator is adjusted and controlled by a power element driving a bellows structure. Electron beam energy.

4. An ultra-high-energy electron beam or photon beam radiotherapy robot system according to any one of claims 1 to 3, characterized in that the posture alignment of the laser plasma accelerator is achieved through a multi-degree-of-freedom adjustment table. Finish.

5. An ultra-high-energy electron beam or photon beam radiotherapy robot system according to claim 1, characterized in that the electron beam focusing system has a four-pole permanent magnet array structure that provides thin-layer pencil beam output.

6. An ultra-high-energy electron beam or photon beam radiotherapy robot system according to claim 1 or 5, It is characterized in that the electron beam focusing system can be expanded and retracted without destroying the vacuum of the plasma accelerator.

7. An ultra-high-energy electron beam or photon beam radiotherapy robot system according to claim 6, characterized in that the electron beam focusing system and the photon beam aiming system are detachable and easy to disassemble and replace. .

8. An ultra-high-energy electron beam or photon beam radiotherapy robot system according to claim 1, characterized in that an accelerator cavity is provided at the end of the robot body, and a laser plasma accelerator is installed in the accelerator cavity, driven by the laser The strong laser pulse of the system is propagated into the accelerator cavity through the robot body, and then focused to the entrance of the laser plasma accelerator, ultimately producing an electron beam or photon beam.

9. An ultra-high-energy electron beam or photon beam radiotherapy robot system according to claim 1 or 8, characterized in that the robot body is a multi-joint mechanical arm or a parallel robot or a robot turntable, and the robot body can Propagates an electron or photon beam to the patient's site from multiple directions and can be combined with a treatment table and laser beam stabilization system to provide raster scanning of a pencil beam.

10. An ultra-high-energy electron beam or photon beam radiotherapy robot system according to any one of claims 1 to 3, characterized in that the laser beam stabilizing system is arranged along the internal arm frame and axis of the robot body to Monitor the position of the laser beam and correct the error so that the propagation direction of the strong laser pulse always coincides with the rotation axis of each joint of the robot.

11. An ultra-high-energy electron beam or photon beam radiotherapy robot system according to any one of claims 1 to 3, characterized in that the laser plasma accelerator, vacuum optical system, and laser beam stabilization system are all installed In a vacuum environment, and the inside of the robot body is a hollow vacuum structure, a certain vacuum pressure is maintained by the vacuum pump system.

12. An ultra-high-energy electron beam or photon beam radiation therapy robot system according to any one of claims 1 to 3, characterized in that the duration of electron beam or photon beam radiation irradiation is controllable from single pulse irradiation to continuous irradiation. , this duration is faster than the breathing interval of the human body, or shorter than the heartbeat interval, or shorter than the single pulse width of the laser driving pulse.