JPH10223400A - Particle accelerator for medical use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously conduct angiocardiography diagnosis and proton radiation treatment by installing a small-size medical particle accelerator capable of radiation of radiation light and proton line, particularly in medical field, and to provide an operation method appropriate for a medical particle accelerator. SOLUTION: This accelerator is constituted of a proton linear accelerator 1, an electron linear accelerator 2, a synchrotron 3 and an electron storage ring 4. The synchrotron 3 is provided with a proton acceleration cavity 34 and an electron acceleration cavity 32 in orbit. The acceleration and ejection of protons injected from the proton linear accelerator 1 are carried out to enable proton irradiation on a patient. The acceleration of electrons injected from the electron linear accelerator 2 is carried out to accumulate electrons injected from the synchrotron 3 and to generate radiation light for angiocardiography diagnosis. In addition, the proton linear accelerator 1, the electron linear accelerator 2 and the synchrotron 3 are disposed inside of the electron storage ring 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical particle accelerator for medical treatment using synchrotron radiation and protons, and more particularly, to medical treatment using synchrotron radiation from free electrons such as angiographic diagnosis and high-speed protons such as proton beam irradiation therapy. The present invention relates to a medical use particle accelerator that can be used for any of medical uses.

[0002]

2. Description of the Related Art Synchrotron radiation has attracted attention in the fields of medicine, chemistry, biology, physics, and semiconductors such as lithography, and has been tested in facilities using radiation. Above all, application in the medical field is expected most, and particularly angiography used for diagnosis of cardiac coronary arteries is in the stage of empirical research at the Japan High Energy Physics Laboratory (KEK) and the like. Angiography involves injecting iodine into the blood as a contrast agent,
The difference between the images acquired by irradiating two types of X-rays having wavelengths before and after this using the difference in the mass absorption coefficient sandwiching the K absorption edge of iodine near V is obtained to obtain the coronary heart shape. This is a method of obtaining an artery image.

About 33 keV used for angiography
In order to obtain emission light having a peak at a point, the energy E (GeV) of the electron beam or positron beam accumulated in the electron storage ring and the magnetic field strength B (T) of the insertion light source installed in the ring are expressed by E ² × B ≒. 34 (1) is most efficient, and the ring for angiography has the left side of equation (1) above and below 1
It is preferable to design within 0%. On the other hand, research on medical treatment using protons is also underway, and it is known that a proton beam of several tens of MeV to 300 MeV is sufficient for effective treatment. For this purpose, a circular proton accelerator is used. I have. Both the angiography electron storage ring experimental facility and the proton ring have a large area where the equipment is installed, but there was no technical idea to make them work simultaneously, so conventionally they were separately installed. .

[0004] For example, Aahu, Denmark
s) A storage ring called ASTRID owned by the university is provided with the function of a synchrotron for ion acceleration for accelerating protons and the like. However, since the energy of the storage ring is 600 MeV, even if the insertion light source is configured using a superconducting conductive magnet of 20 T, which is possible with the current technology, Expression (1) cannot be satisfied. Therefore, 33
The radiation output efficiency near keV is very poor and is not suitable for use in angiography.

In addition, the European Nuclear Research Center (CERN) in Switzerland has designed an LEP in which both an electron storage ring and a proton ring are arranged in a complex manner to perform a particle collision experiment in consideration of area efficiency on equipment. Owns a ring called the Large Electron Positron Corridor. A device is provided for generating and accelerating high energy electrons, positrons or protons into the LEP in order to make them incident. The synchrotron at the last stage of the accelerator that supplies particles to the LEP is called SPS (Super Proton Synchrotron).

FIG. 5 is a schematic configuration diagram showing the equipment configuration from the particle generator to the SPS. The electrons emitted from the 600 MeV linac are sequentially sent to a 600 MeV electron positron accumulator (EPA). Also, 200MeV
An electron beam emitted from a linac is incident on a substance in an electron polarity converter, converted into a positron beam, and converted to 600 MeV.
It is accelerated by the linac accelerating tube and sent to the EPA sequentially.
In the EPA, a predetermined amount of electron beam is formed by accumulating the electrons or positrons that have been sent. The electron beam is then accelerated by a proton synchrotron (PS) that can accelerate to 3.5 GeV with electron energy and injected into the SPS. In SPS, electrons or positrons are further increased by 20 GeV
And then enters the LEP (not shown). Electrons and positrons orbit the slightly shifted orbit in the LEP ring at high speed in the opposite direction, and by making the orbits of the same position at the appropriate timing, collision of electrons and positrons can occur. .

[0007] The CERN is also provided with a proton linac that generates protons so that the generated protons can be accelerated to 50 MeV and injected into a protron synchrotron booster (PSB). 80Me in PSB
The protons accelerated to V are injected into the PS, and 10G
It is accelerated to about eV. The proton beam accelerated by the PS is used for a physical experiment such as antiproton generation, and is incident on a larger SPS to be accelerated to 400 GeV, and is taken out and used for a more advanced physical experiment. As described above, the collision type ring LEP of the CERN includes the proton linac, the electron linac, and the synchrotron, and the synchrotron is configured so that both electrons and protons can circulate.

However, since SPS is intended for advanced physics research such as particle collision experiments from a physical point of view, the energy provided by the accumulation ring, booster synchrotron, and proton ring is large. , The circumference of EPA, PS, and SPS is 1
In addition to the extremely large lengths of 20 m, 600 m, and 7 km, the accumulation ring and the booster synchrotron are disposed outside the proton ring, so that the area of the entire equipment is extremely large.

Thus, the synchrotron SPS of CERN
Are optimized for handling much larger energy than 3.2 GeV, which is required for an angiographic synchrotron radiation generator or medical proton generator, and are required in the medical field. There is no problem of area efficiency. As described above, no examples of medical equipment that can be installed in a small medical site with a storage ring dedicated to angiography or a synchrotron and a proton ring for medical use have not yet been seen. It is also difficult to put them into medical facilities.

[0010]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a small-sized apparatus capable of irradiating emitted light and a proton beam. It is an object of the present invention to provide a small-sized medical particle accelerator capable of performing a diagnosis using a laser and a treatment by proton irradiation, and an appropriate operation method of the medical particle accelerator.

[0011]

In order to solve the above-mentioned problems, an accelerator according to the present invention comprises a linear accelerator for protons (linac), a linear accelerator for electrons (linac), a synchrotron, and injection from the synchrotron. An electron storage ring for accumulating electrons to be obtained, wherein a linear accelerator for protons, a linear accelerator for electrons, and a synchrotron are disposed inside the electron storage ring. Furthermore, the synchrotron has a proton accelerator and an electron accelerator in its orbit, and receives proton injection from the proton linear accelerator, accelerates and ejects protons, and receives electron injection from the electron linear accelerator. To accelerate the electrons,
A medical particle accelerator characterized in that an electron storage ring accumulates electrons injected from a synchrotron and generates emitted light.

The proton linear accelerator and the electron linear accelerator may be arranged inside the synchrotron. Preferably, a superconducting wiggler is installed in the electron storage ring to generate radiation for angiographic diagnosis. Further, it is preferable that the synchrotron is formed to have a circumference within a range of 30 to 110 m and has a configuration in which the acceleration energy of electrons is 1.2 GeV or more and the acceleration energy of protons around 250 MeV can be generated. Further, it is preferable that the energy of protons accelerated by the linear accelerator for protons is 100 MeV or less, and the energy of electrons accelerated by the linear accelerator for electrons is in the range of 30 to 200 MeV.

[0013] In order to solve the above-mentioned problems, a method of operating a medical particle accelerator according to the present invention comprises: first operating a linear accelerator for electrons to inject electrons generated into a synchrotron; After accelerating, injecting the accelerated electrons into the electron storage ring and accumulating them, operating the proton linear accelerator to inject the generated protons into the synchrotron and accelerating the protons with the proton accelerator, It is characterized in that energy electrons and high energy protons are obtained simultaneously.

According to the medical particle accelerator of the present invention, by using one set of accelerators, the circulating light in the electron storage ring is used to obtain the emitted light to diagnose the affected part, and separately to the synchrotron. Irradiated protons are injected into the synchrotron and accelerated by orbiting the synchrotron, and treatment can be performed. As described above, one synchrotron is used for both electrons and protons, so that one synchrotron can be saved. Also, to house other main elements inside the electronic storage ring that requires the largest area on the facility,
If there is a site that can accommodate the storage ring, facilities can be provided, and it becomes easier to install and use the particle accelerator at the medical site.

By arranging the linear accelerator for protons and the linear accelerator for electrons inside the synchrotron provided inside the electron storage ring, a simpler and easy-to-adjust structure can be obtained. it can. When one or one of these accelerators is arranged outside the synchrotron, there is an advantage that a larger accelerator having a large output can be installed. In addition, if a superconducting wiggler is installed on the electron storage ring to generate radiation of a predetermined wavelength, a clear image of the coronary artery of the heart can be obtained by angiography, which can assist a doctor in making an accurate diagnosis. it can.

Furthermore, if the circumference of the synchrotron is formed within the range of 30 to 110 m and the acceleration energy of the electrons is 1.2 GeV or more so that it can be used for angiography, no special additional device is required. Using the same synchrotron to increase the proton acceleration energy to 250 Me
It is relatively easy to make it possible to approach V. The proton energy accelerated by the proton linear accelerator is 100
If the energy is not more than MeV and the energy of the electrons accelerated by the electron linear accelerator is in the range of 30 to 200 MeV, the electron beam can be sufficiently efficiently accelerated in the synchrotron. According to the method for operating a medical particle accelerator of the present invention, an electron beam is first formed in an electron storage ring, and then protons are circulated in an unnecessary synchrotron. When used separately for medical treatment, it is of course possible to simultaneously use one or more patients.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a medical particle accelerator according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a layout diagram of a medical particle accelerator system showing one embodiment of the present invention, FIG. 2 is a flowchart showing an operation procedure of the medical particle accelerator of this embodiment, and FIGS. It is a system layout of a medical particle accelerator showing an example.

In FIG. 1, 1 is a linac for protons, 2
Is an electronic linac, 3 is a synchrotron, and 4 is an electron storage ring. The proton linac 1 and the electronic linac 2 are disposed inside a synchrotron 3, and the synchrotron 3 is disposed inside an electron storage ring 4. For this reason, all the main parts of the device are housed inside the storage ring 4 and do not require a larger installation area than the storage ring as a whole.

The proton linac 1 is composed of a proton generator 12 and a proton accelerator 14, and the proton beam generated by the generator is converted to about 100 MeV by the proton accelerator 14, for example, up to 15 MeV.
Synchrotron 3 with given energy such as MeV
Inject into The electronic linac 2 is an electron gun (gun) 22
And three high-frequency (RF) accelerators 24, 26, and 28, and the three-stage R beam
F accelerator in the range of 30-200 MeV, for example 15
A predetermined energy such as 0 to 170 MeV is applied to the synchrotron 3 at a predetermined speed.

The synchrotron 3 comprises four dipole electromagnets a having a deflection angle of 15 degrees and quadrupole electromagnets b disposed between the respective deflection electromagnets, and four units for giving a 90 degree deflection angle to charged particles. This is a circular accelerator that forms a circular orbit in combination, and accelerates an incident proton or electron or positron while maintaining the circular orbit. A six-pole electromagnet may be provided as necessary.

The synchrotron 3 is provided with a high-frequency electron acceleration cavity 32 for electron beam acceleration and a high-frequency proton acceleration cavity 34 for proton beam acceleration. The rotation frequency of a particle hardly changes with acceleration because the particle velocity is almost the speed of light at the incident energy of an electron. Since the frequency needs to be modulated, an acceleration cavity suitable for each is provided. In this way, electrons are accelerated to, for example, 2.2 GeV and protons are accelerated to 300 MeV in the synchrotron having a circumference of 68 m.

The proton beam accelerated to a predetermined speed is radiated out of the synchrotron by a proton emitting deflection electromagnet provided in the synchrotron, and is used for medical treatment by irradiating an affected part of a patient. The electron beam accelerated to a predetermined speed is taken out of the synchrotron 3 by a bending electromagnet for transfer and injected into the storage ring 4.

The electron storage ring 4 is a 33-ke beam used for angiography from an electron beam circling at a relative speed.
A circular orbit is constituted by four sets of periodic magnet arrangements composed of a bending electromagnet a and a quadrupole electromagnet b, similarly to the synchrotron 3, for obtaining X-ray radiation near V. Each periodic magnet arrangement is sequentially symmetrical from the center of the center deflection magnet in the left-right direction, quadrupole electromagnet, deflection electromagnet, quadrupole electromagnet, quadrupole electromagnet, quadrupole electromagnet, quadrupole electromagnet, deflection electromagnet, quadrupole electromagnet, deflection It is provided with an electromagnet, a quadrupole electromagnet, a quadrupole electromagnet, and a quadrupole electromagnet. A set of periodic magnets deflects the electron beam because the deflection magnet deflects the electron beam by 15 degrees and the outermost deflection magnet has just half the length of the others and deflects the electrons by 7.5 degrees. 9 in total
Deflected 0 degrees.

Between the periodic magnet arrays of the storage ring 4,
An RF accelerating cavity 42 is provided that provides an accelerating voltage to compensate for the energy lost due to radiation loss. In addition, a superconducting wiggler 44 is provided in a linear portion between the periodic magnet arrays as an insertion light source for generating radiation light. Undulators 46 and 48 using permanent magnets
Are provided in the middle of four consecutively arranged four-pole electromagnets in the periodic magnet array. X-rays emitted from the superconducting wiggler 44 are used for angiographic diagnosis performed by irradiating the heart portion of the patient.

The magnetic field strength in the superconducting wiggler 44 is such that the limit of the superconducting magnetic field in the state of the art is 20 T
Considering that the significance of adoption of superconductivity arises when it is larger than normal conduction, it may be considered to be in the range of 3T to 20T. Therefore, considering the magnetic field strength of the superconducting wiggler and the above equation (1), the energy of the electron storage ring 4 is in the range of 1.2 GeV to 4 GeV,
If the energy is low, the circumference of the storage ring may be short.

The electron energy E of the synchrotron (Ge
It is known that there is a relationship of E = 0.3B × ρ (2) between V), the magnetic field strength B (T), and the radius of curvature ρ (m). The energy of the synchrotron 3 for injecting electrons into the electron storage ring 4 is 1.2 GeV to 4 GeV corresponding to the energy of the storage ring.
Is enough. Therefore, the normal conduction magnet has a good linearity of the relationship between the magnetic field strength and the applied current in the range of 1.5T.
When this formula is applied in consideration of the above, the radius of curvature ρ of the bending electromagnet a used for the synchrotron 3 is 2.
It turns out that 6 m-9 m are suitable. Considering that the synchrotron also requires elements other than the bending electromagnet such as the converging electromagnet and the deflection electromagnet at the incident part, the circumference of the ring is about 32 m to 110 m, and the average diameter is about 10 m to 35 m. .

On the other hand, for protons that are heavier than electrons, E = 0.3B × ρ / (1-1 / γ ² ) ^1/2 (3) in which the Lorentz factor γ is added to the above equation (2). Is established. According to equation (3), when the synchrotron 3 having a radius of curvature ρ of 2.6 m to 9 m designed for the electron acceleration is used as a proton synchrotron,
When the magnetic field strength is 1.5 T, the kinetic energy excluding the quiescent energy is 560 MeV to 3.2 GeV.
Therefore, by using the above-mentioned electron synchrotron as a proton synchrotron to adjust the magnetic field strength of the bending electromagnet a and modulate the RF frequency of the proton accelerating cavity 34 so as to be synchronized with the acceleration of the proton, for example, the treatment of cancer Me required for effective proton irradiation
Proton beams up to V can be easily generated.

In order to install the proton linac 1 and the electron linac 2 inside the synchrotron 3 having an average diameter of 10 to 35 m as in the case of the embodiment of FIG. 5m or more even considering space
It can be 30 m. As described above, the medical particle accelerator according to the present invention is a small medical particle accelerator in which the storage ring 4 dedicated to angiography and the synchrotron 3 serving both as a booster for the electron beam and for generating a medical proton beam coexist. Becomes

The medical particle accelerator of the present invention may be used for any of angiography diagnosis and proton beam irradiation. However, the electron beam necessary for the storage ring 4 is stored in the storage ring 4 and the proton beam is supplied to the synchrotron 3 at the same time. It can be stored so that two medical actions can be performed simultaneously or independently. FIG. 2 is a flowchart illustrating a procedure for simultaneously operating the storage ring 4 and the synchrotron 3.

When the operation is started (S101), first, the electron gun 22 and the RF accelerators 24, 26, and 28 are started to operate the electronic linac 2 to generate an electron beam.
The energy of MeV to 200 MeV is applied and injected into the synchrotron 3 (S102). At this time, the RF electron accelerating cavity 32 in the synchrotron 3 is operated to accumulate the electron beam and accelerate the electron beam to 1.2 to 4 GeV (S103). The electron beam that has reached the predetermined energy is injected into the storage ring 4 and stored (S104). After the required amount of electron beams has been stored in the storage ring 4, the operation of the storage ring 4 is continued, the linac 2 for electrons is stopped, and the electron accelerating cavity 34 of the synchrotron 3 is stopped (S105).

Next, the proton linac 1 is operated to generate a proton beam and accelerate the energy to 20 MeV (S106). This time, the RF proton accelerating cavity 34 in the synchrotron 3 is operated to gradually increase the frequency to reduce the energy of the proton beam circulating in the synchrotron by 2
It is increased to 50 MeV (S107). In this way, the electron beam circulates in the storage ring 4 and the proton beam circulates in the synchrotron.

An angiography diagnosis is performed by positioning a patient at a position irradiated with the radiation generated by the superconducting wiggler insertion light source 44 inserted into the storage ring 4. Since the energy of the electron beam reduced by the radiation is supplemented by the RF accelerating cavity 42, multiple irradiations over a long time are possible. When necessary, the proton beam in the synchrotron is extracted by a pulse magnet and irradiated to the affected part of the patient positioned at the irradiation position of the beam, thereby exhibiting a therapeutic effect. (S108). When the quantity or quality of the accumulated electron beam deteriorates, the operation is stopped (S10).
9) The electron beam is stored again.

FIGS. 3 and 4 are layout diagrams of a medical particle accelerator system showing another embodiment of the present invention. In the figure, elements having the same functions as those in FIG. 1 are denoted by the same reference numerals, and the description is omitted or simplified. FIG. 3 shows a case where the proton linac 1 is disposed inside the storage ring 4 and outside the synchrotron 3. Since the diameter of the storage ring 4 is larger than the diameter of the synchrotron 3, this arrangement allows a larger linac to be used as compared to the arrangement of FIG. Of course, an electronic linac 2 may be provided outside the synchrotron 3 instead of the proton linac 1.

FIG. 4 shows a storage ring 4 and a synchrotron 3 for both a proton linac 1 and an electron linac 2.
It shows the case where it is arranged between. Obviously, even with such an arrangement, a larger linac can be adopted. Since the polarities of electrons and protons are opposite to each other, the emission direction of the proton linac 1 and the emission direction of the electron linac 2 are introduced into the synchrotron 3 so as to face each other, and orbit in the opposite directions. However, when positrons are used instead of electrons, it is preferable that protons are also injected into the synchrotron from the same direction and arranged so as to orbit in the same direction.

In the above-described embodiment, specific numerical values are applied to the specifications, including the shapes and combinations of the components of the synchrotron and the storage ring. It is used for ease of understanding and is merely a design choice. It goes without saying that those skilled in the art can select and combine other appropriate shapes and values based on the technical idea of the invention. No. Also, it is needless to say that not all the devices need to be on the same plane, and for example, some of them may be installed underground. The electron, positron or proton beams from both linacs can be used for various experiments as they are.

[0036]

As described above in detail, the medical particle accelerator of the present invention is a small medical particle accelerator capable of simultaneously performing angiographic diagnosis and proton irradiation treatment, and is conventionally used for the same purpose. Compared to a particle accelerator, not only can a synchrotron be constructed economically with one less unit, but it can be installed on a much smaller site.

[Brief description of the drawings]

FIG. 1 is a layout view of a medical particle accelerator system showing one embodiment of the present invention.

FIG. 2 is a flowchart showing an operation procedure of the medical particle accelerator of the present invention.

FIG. 3 is a plan view of a medical particle accelerator system showing another embodiment of the present invention.

FIG. 4 is a plan view of a medical particle accelerator system showing still another embodiment of the present invention.

FIG. 5 is a system configuration diagram of an accelerator showing an example of a conventional electron-proton combined use synchrotron.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Proton linac 12 Proton generator 14 Proton accelerator 2 Electron linac 22 Electron gun 22 24,26,28 High frequency (RF) accelerator 3 Synchrotron 32 High frequency electron acceleration cavity 34 High frequency proton acceleration cavity 4 Electron storage ring 42 High frequency electron acceleration Cavity 44 Superconducting wiggler 46, 48 Undulator a Bending electromagnet b Quadrupole electromagnet

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Korcuganov Vladimir, No. 11, Academica Lavrencheva Street, Novosibirsk, Russian Federation Inside Institute Yadelnoy Fijiki IM G.E.

Claims (6)

[Claims] 1. An accelerator comprising a linear accelerator for protons, a linear accelerator for electrons, a synchrotron, and an electron storage ring for accumulating electrons injected from the synchrotron, wherein the linear accelerator for protons is provided. An accelerator, the linear accelerator for electrons, and the synchrotron are disposed inside the electron storage ring, and the synchrotron includes a proton accelerator and an electron accelerator, and receives protons from the linear accelerator for protons. Accelerating and emitting protons, receiving electrons from the linear accelerator for electrons to accelerate electrons, and storing the electrons injected from the synchrotron and generating emitted light by the electron storage ring. A medical particle accelerator. 2. The medical particle accelerator according to claim 1, wherein the linear accelerator for protons and the linear accelerator for electrons are disposed inside the synchrotron. 3. The medical particle accelerator according to claim 1, wherein a superconducting wiggler for generating radiation for angiography diagnosis is installed in the electron storage ring. 4. The synchrotron has a circumference of 30 to 110 m and an electron acceleration energy of 1.2.
4. The method according to claim 1, wherein an acceleration energy of protons of not less than GeV and around 250 MeV can be generated.
The medical particle accelerator according to any one of the above. 5. The energy of protons accelerated by the linear accelerator for protons is 100 MeV or less, and the energy of electrons accelerated by the linear accelerator for electrons is in the range of 30 to 200 MeV. The medical particle accelerator according to any one of claims 1 to 4, wherein: 6. The medical particle accelerator according to claim 1, wherein electrons are injected into a synchrotron by a linear electron accelerator for electrons to accelerate the electrons, and the accelerated electrons are stored in an electron storage ring. A method of operating a medical particle accelerator, wherein high-speed electrons and high-speed protons are simultaneously obtained by injecting protons into a synchrotron with a linear accelerator for protons and accelerating the protons with a proton accelerator. .