JPH1090499A - Radiation generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To grasp energy values easily and accurately and enable exact radiotherapy by measuring the energy of an electron beam launched into two metal members placed in the orbit of the beam. SOLUTION: An electric current value caught in a lower metal disc 15 is measured by an ampere meter 19 through a wire 18. An energy detecting unit 14 has upper aluminum plates 17a and 17b which are different in thickness from each other. By putting the aluminum plates with different thicknesses in the orbit 12 of an electron beam, the maximum range of the electron beam in aluminum can be found from the thickness of the aluminum plate when a current cannot be detected in the lower metal disc 15 and additionally the maximum energy of the electron beam can be derived from a specific equation. In this way, the energy of an electron beam and X rays can be measured so easily that measurement can be frequently conducted, which makes it possible to grasp the value of energy more accurately than ever. As a result, more exact radiotherapy can be conducted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation generating apparatus capable of directly measuring or monitoring the energy of an accelerated electron beam in a medical radiation therapy (generating) apparatus.

[0002]

2. Description of the Related Art The configuration of a conventional radiation generator will be described with reference to FIG. FIG. 10 is a diagram showing a configuration of a conventional radiation generator.

In FIG. 10, reference numeral 1 denotes an operation unit, 2 denotes a power box, 3 denotes an electron gun, 4 denotes a klystron, and 5 denotes an acceleration tube.

In the same figure, 6 is a beam duct,
7 is a target, 8 is a scatterer, 9 is an equalizer unit, 10 is a monitor chamber, 11 is a collimator,
Reference numeral 12 denotes the trajectory of the electron beam, and reference numeral 13 denotes a treatment center (isocenter).

Next, the radiation generating mechanism of the conventional radiation generator will be described. The electron beam generated from the electron gun 3 is given energy by the accelerating tube 5 in which the microwave amplified by the klystron 4 is stored, so that the electron beam becomes a high energy electron beam of about several MeV to about several tens MeV. The accelerated electron beam passes through the beam duct 6
After being deflected by 0 degrees, it is taken out to the atmosphere.

[0006] When X-rays are used for radiation therapy, an electron beam collides with a metal target such as Cu or Pt to generate braking X-rays. The dose of the generated X-ray is measured by a monitor chamber 10 which is a transmission type parallel plate ionization chamber.

[0007] The irradiation field on the treatment plane is the collimator 11.
Is limited by Further, an equalizer unit 9 is provided on the beam trajectory in order to flatten the X-ray dose distribution in the irradiation field. This equalizer unit 9
Has different shapes depending on the energy of the X-ray used for treatment (it depends on the energy of the electron beam to be accelerated), so that a plurality of equalizers are installed on the disk, and an appropriate equalizer is located on the beam orbit axis. So that it can rotate.

When an electron beam is used for radiotherapy, the electron beam extracted into the atmosphere is used as it is. However, in order to flatten the dose distribution in the irradiation field, the electron beam collides with the scatterer 8. The scatterer 8 is integrated with the target 7, and when the target 7 uses the electron beam mode, the scatterer 8 is driven such that the scatterer 8 is positioned on the beam orbit.

[0009]

In the conventional radiation generator as described above, the information on the X-ray or electron beam used for the treatment is only the irradiation dose monitored by the monitor chamber 10. The irradiation dose largely depends on the current value of the electron beam and the number of photons of the X-ray. The irradiation dose is related to the absorbed dose absorbed by the human body tissue on the isocenter 13, and can be said to be one of the most important quantities in performing radiation therapy.

[0010] However, the energy of electron beams and X-rays is also an important quantity. When an electron beam or an X-ray is incident on human body tissue, the dose distribution in the depth direction along the beam axis direction largely depends on these energies. Therefore, if the energy of the radiation applied to the patient is different from the energy assumed in the treatment plan, the absorbed dose of the tumor or normal tissue will be different.

As a countermeasure to this problem, conventionally, the dose distribution in the depth direction is measured using an aquarium or a tissue equivalent material, and the obtained data is compared with data previously measured by an appropriate facility. I was looking for energy. However, there is a problem that it is necessary to prepare a water tank, a tissue equivalent material, and a dosimeter in order to perform this measurement. Further, in order to use the relationship between the dose distribution in the depth direction and the energy measured previously, it is necessary to accurately reproduce the arrangement of the devices (mainly the positional relationship based on the isocenter 13). was there.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is intended to determine the energy of an electron beam or an X-ray, and is capable of easily measuring the electron beam energy after acceleration. The aim is to obtain a device.

[0013]

A radiation generating apparatus according to the present invention is provided on a trajectory of an electron beam accelerated by an acceleration tube and emitted by a beam duct, and is provided with two metal members insulated from the electron beam. And energy detecting means for measuring the energy of the electron beam from a current that can be detected by being incident on the electron beam.

Further, the radiation generating apparatus according to the present invention comprises:
As the energy detecting means, one of the two metal members is a metal disk, and the other is a plurality of metal plates having different thicknesses placed on the metal disk, and each metal plate is insulated from the metal disk. In this case, the plurality of metal plates on the electron beam trajectory can be exchanged by rotating a metal disk.

Further, the radiation generating apparatus according to the present invention comprises:
As the energy detecting means, the two metal members are two insulated metal plates, and the energy of a continuous electron beam is measured from a current detected from these metal plates.

Further, the radiation generating apparatus according to the present invention comprises:
The energy detecting means is incorporated in an equalizer disk for flattening an X-ray dose distribution.

Further, the radiation generating apparatus according to the present invention comprises:
The energy detecting means is also used as a scatterer provided to make the dose distribution of the electron beam uniform.

Further, the radiation generating apparatus according to the present invention comprises:
The energy detecting means is also used as a target for generating a braking X-ray by colliding an accelerated electron beam.

Further, the radiation generating apparatus according to the present invention comprises:
Further, a display for displaying the measured energy of the electron beam is provided.

Further, the radiation generating apparatus according to the present invention comprises:
Further, when the measured energy of the electron beam exceeds the allowable range, an interlock means for outputting an interlock signal to an operation device for controlling the operation of the electron gun for generating the electron beam is provided.

Further, in the radiation generating apparatus according to the present invention, the klystron means for determining the electron beam energy is further provided with automatic energy adjusting means for feeding back the detected current electron beam energy.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. The configuration of the radiation generator according to Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a configuration of the first embodiment of the present invention.
It should be noted that the operating devices 1 to the accelerating tube 5 and the collimator 11 are not shown. In each drawing, the same reference numerals indicate the same or corresponding parts.

In FIG. 1, 6 is a beam duct, 7 is a target, 8 is a scatterer, 9 is an equalizer unit, 1
0 indicates a monitor chamber, and 12 indicates the trajectory of the electron beam.

In FIG. 1, 14 is an energy detection unit, 15 is a metal disk, 16 is an insulator, 17a and 17b are metal plates, 18 is a wire, and 19 is an ammeter.

The energy detection unit 14 has a plurality of metal plates 17a, 17b,... Having different thicknesses on a metal disk 15 similar to the equalizer unit 9.
Each of the metal plates 17 a and 17 b is insulated from the metal disk 15 by an insulator 16. Like the equalizer unit 9, the metal disk 15 has a structure rotatable around an axis indicated by a dashed line, and can replace the metal plates 17a, 17b,... On the electron beam orbit 12. The metal disk 15 has such a thickness that the electron beam cannot pass therethrough, and has a wire 18 connected thereto so that the beam current can be measured by an ammeter 19 when the electron beam collides.

As a specific example, consider a case where aluminum (Al) is used as the metal plates 17a and 17b. Maximum energy Ema of electron beam with continuous energy
x (Emax> 0.8MeV) and the maximum range R in Al
Is given by Feather as Equation 1 below.

R (g / cm ² ) = 0.543 Emax (MeV) −0.160 Equation 1

Therefore, if the maximum range R (g / cm ² ) of the electron beam in Al can be measured, the maximum energy Emax (MeV) of the electron beam can be known.

Next, the operation of the radiation generator according to the first embodiment will be described.

When performing energy measurement, the target 7 / scatterer 8 deviates from the trajectory 12 of the electron beam, and the electron beam extracted from the beam duct 6 into the atmosphere can enter the energy detection unit 14. When the electron beam enters the Al plate (for example, 17a) of the energy detection unit 14, the electron beam stops in the Al plate or transmits while losing energy. Only the transmitted electron beam can strike the lower metal disk 15. The lower metal disk 15 has a thickness sufficient to stop all the electron beams transmitted through the upper Al plate 17a.

The current value of the electron beam captured by the lower metal disk 15 is measured by an ammeter 19 through a wire 18. The energy detection unit 14 has a plurality of upper Al plates having different thicknesses. By placing the Al plates having various thicknesses on the orbit 12 of the electron beam, current can be detected from the lower metal disk 15. The maximum range of the electron beam in Al can be known from the thickness of the Al plate at the time of disappearance, and the maximum energy of the electron beam can be known from Equation 1 above.

The energy detecting unit 14 has a portion where a hole is formed without placing a metal plate. When performing radiation therapy, the portion of the hole is positioned on the trajectory 12 of the electron beam. Thus, the first embodiment
Since the radiation generator has the energy detection unit 14, the energy measurement can be easily performed without requiring any special preparation.

That is, the radiation generating apparatus according to the first embodiment detects the electron beam energy by making the accelerated electron beam incident on two insulated metal plates (for example, 15 and 17a). It is provided with. Therefore, since the energy of the electron beam or the X-ray can be easily measured, the measurement can be performed frequently, and the value of the energy can be grasped more accurately than before. As a result, more accurate radiation treatment can be performed.

The radiation generator according to the first embodiment converts the electron beam accelerated by the electron beam accelerator into a C beam.
In a radiation generating (therapeutic) apparatus for irradiating a malignant tumor or the like with an X-ray or an accelerated electron beam generated by colliding with a target 7 such as u or Pt, and curing the malignant tumor, Different metal plates 17a, 1
7b,... Each of which is insulated from the metal disk 15.
Energy calculator (not shown) that can replace the metal plate on the electron beam axis by rotating 5
In this method, the energy of the electron beam is measured from the thickness of the upper metal plate and the current detected by the lower metal disk. That is, the energy calculation device controls the driving of the metal disk 15 and calculates the energy from the detected current.

Embodiment 2 Embodiment 2 A radiation generator according to Embodiment 2 of the present invention will be described with reference to FIGS. FIG. 2 is a diagram showing a configuration of the second embodiment of the present invention. FIG. 3 is a diagram showing how the electron beam in Al is attenuated in the radiation generator according to the second embodiment. It should be noted that the operating devices 1 to the accelerating tube 5 and the collimator 11 are not shown.

In FIG. 2, 6 is a beam duct, 7 is a target, 8 is a scatterer, 9 is an equalizer unit, 1
0 indicates a monitor chamber, and 12 indicates the trajectory of the electron beam.

In the same figure, 14A is an energy detector, 15A is a metal plate, 16 is an insulator, 17A is a metal plate, 18a and 18b are wires, and 19a and 19b are ammeters.

In FIG. 3, the vertical axis indicates the relative intensity of the electron beam, and the horizontal axis indicates the thickness of aluminum (Al).

Reference numeral 14A shown in FIG. 2 is an energy detector 14A composed of two metal plates 15A and 17A insulated by an insulator 16. Wires 18a, 18b are connected to the two metal plates 15A, 17A, and when an electron beam collides therewith, beam current can be measured by ammeters 19a, 19b.

When performing energy measurement, the target 7 / scatterer 8 deviates from the trajectory 12 of the electron beam, and the electron beam taken out of the beam duct 6 into the atmosphere can be incident on the energy detector 14A.

In the first embodiment, the thickness of the plurality of metal plates 17a, 17b,... Mounted on the metal disk 15 of the energy detection unit 14 cannot be changed continuously. The value of the energy applied is intermittent. However, the following method is also conceivable for energy measurement utilizing the absorption of an electron beam in a substance.

In general, how the number of electrons attenuates when an electron beam passes through a substance depends on the energy of the incident beam. FIG. 3 shows how the number of electrons in the electron beam is attenuated by the Al plate. Electron beam is energy detector 1
4A, the current i1 is detected from the upper metal plate 17A and the current i2 is detected from the lower metal plate 15A. This indicates that the number of electrons from the electron beam decreases by the amount of the current flowing through the metal plate. The slope of the electron number decay curve in the substance can be known from i1 and i2.

Therefore, the relationship between various electron energies and the decay curve in the metal is measured in advance, and the slope calculated by an energy calculator (not shown) is compared with those data to obtain the electron beam. You can know the energy. The energy detector 14A can be removed from the electron beam trajectory 12 by a driving mechanism.
As described above, in the second embodiment, the first embodiment is used.
With a device smaller than the device shown in (1), continuous energy measurement is possible.

In the radiation generator according to the second embodiment of the present invention, the energy calculator calculates energy from current values detected from the two insulated metal plates 15A and 17A, so that the radiation generator is continuous ( It can measure electron beam energy (not intermittent values).

Embodiment 3 A radiation generator according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 4A is a diagram showing a configuration of the third embodiment of the present invention, and FIG. 4B is a diagram showing a plane view of the equalizer unit with an energy detection unit of FIG. It should be noted that the operating devices 1 to the acceleration tube 5, the monitor chamber 10, and the collimator 11 are not shown.

In FIG. 4, reference numeral 6 denotes a beam duct, 7 denotes a target, 8 denotes a scatterer, 9A denotes an equalizer unit with an energy detector, and 12 denotes an electron beam orbit.

In the same figure, 14B is an energy detector, and 9a, 9b and 9c are ordinary equalizers.

In the second embodiment, the energy detecting section 14A is provided independently.
Sets the energy detector 14B to the equalizer unit 9A
It is attached above. In the third embodiment, a special driving mechanism is not required unlike the second embodiment, and the energy detection unit 14B can be provided at a low cost and compactly.

In the radiation generating apparatus according to Embodiment 3 of the present invention, the energy detecting section 14B is incorporated in a metal disk of an equalizer for flattening the dose distribution of X-rays, thereby saving space in the energy measuring section. It is intended. That is, a metal plate is provided on the metal disk with an insulator interposed therebetween, and an ammeter is connected to each.

Embodiment 4 Embodiment 4 A radiation generator according to Embodiment 4 of the present invention will be described with reference to FIG. FIG. 5 is a diagram showing a configuration of the fourth embodiment of the present invention. It should be noted that the operating devices 1 to the acceleration tube 5, the equalizer unit 9, the monitor chamber 10, and the collimator 11 are not shown.

In FIG. 5, reference numeral 6 denotes a beam duct, 7 denotes a target, 14C denotes a scatterer / energy detecting unit, and 12 denotes a trajectory of an electron beam.

In the second embodiment, the electron beam passes through the metal plate of the energy detector 14A,
The electron beam is scattered. Since the scattering position of the electron beam must be a position determined with respect to the isocenter, the electron beam scattered here cannot be used for treatment. In the fourth embodiment, a scatterer for flattening the dose distribution of the electron beam at the isocenter has an energy detecting function. As shown in FIG. 5, the scatterer / energy detecting unit 14 </ b> C is insulated from the target 7 by the insulator 16. Thus, the energy of the electron beam can be measured while performing the electron beam therapy.

In the radiation generator according to the fourth embodiment of the present invention, the scatterer provided to make the dose distribution of the electron beam uniform is made of two insulated metal plates. The third object is achieved, and the measurement of the electron beam energy is possible even during the treatment.

Embodiment 5 FIG. Embodiment 5 A radiation generator according to Embodiment 5 of the present invention will be described with reference to FIG. FIG. 6 is a diagram showing a configuration of the fifth embodiment of the present invention. It should be noted that the operating devices 1 to the acceleration tube 5, the equalizer unit 9, the monitor chamber 10, and the collimator 11 are not shown.

In FIG. 6, 6 is a beam duct, 14D
Denotes a target / energy detection unit, 8 denotes a scatterer, and 12 denotes a trajectory of an electron beam.

In the fourth embodiment, the energy cannot be measured when performing X-ray therapy. In the fifth embodiment, a Cu or Pt target for generating a braking X-ray by colliding an electron beam is provided with an energy detecting function. As shown in FIG. 6, the target / energy detecting unit 14D is made of three metal plates sandwiching an insulator. The upper two metal plates are for detecting the energy and the lowermost metal plate is for preventing the transmission of the electron beam. Thus, the energy of the electron beam can be measured while performing X-ray therapy.

The radiation generating apparatus according to the fifth embodiment of the present invention has an X-ray mode in which a target for generating a braking X-ray by colliding an accelerated electron beam is insulated. Also enables measurement of electron beam energy during treatment.

Embodiment 6 FIG. A radiation generator according to Embodiment 6 of the present invention will be described with reference to FIG. FIG. 7 is a diagram showing a configuration of the sixth embodiment of the present invention. It should be noted that the operating device 1 to the klystron 4 and the targets 7 to the collimator 11 are not shown.

In FIG. 7, 5 is an accelerating tube, 6 is a beam duct, 14X is an energy detecting unit, 20 is an arithmetic unit including a CPU and the like, 21 is a display including a CRT, a solid-state display (liquid crystal or the like), 12 Indicates the trajectory of the electron beam.

In Embodiments 2 to 5, the current captured by the two metal plates is measured by an ammeter. In Embodiment 6, energy is calculated from the two measured current values. Further, it has a function of displaying the calculated energy. In FIG. 7, the energy detection unit 1
4X is one of the energy detectors of the second to fifth embodiments, and the arithmetic unit 20 calculates the slope of the attenuation curve when the electron beam passes through the metal from the current flowing through the two metal plates. , And the calculated energy is compared with the existing data, and the display 21 displays the calculated energy.

The radiation generator according to the sixth embodiment of the present invention is different from the above-described second to fifth embodiments in that the radiation generator is provided with a circuit for comparing two detected current values and monitoring electron beam energy. It is.

Embodiment 7 A radiation generator according to Embodiment 7 of the present invention will be described with reference to FIG. FIG. 8 is a diagram showing a configuration of the seventh embodiment of the present invention. The illustration of the targets 7 to the collimator 11 is omitted.

In FIG. 8, 1 is an operating device, 2 is a power box,
3 is an electron gun, 4 is a klystron, 5 is an accelerating tube, 6 is a beam duct, 14Y is an energy detector, and 22 is a CPU.
The energy interlock device 12 includes the trajectory of the electron beam.

In the sixth embodiment, only the calculated energy is displayed. However, in the seventh embodiment, the energy detection unit 14Y is configured to display the energy during the treatment as in the fourth and fifth embodiments. Can be detected,
When the calculated energy exceeds a specified value, the apparatus has a function of stopping radiation generation by an interlock.

In FIG. 8, an energy detecting section 14Y is a detecting section capable of measuring energy during treatment as shown in the fourth or fifth embodiment. The energy interlock device 22 obtains a slope of a decay curve when the electron beam passes through the metal from a current value flowing through the two metal plates,
The energy is calculated by comparing it with the existing data. If the calculated energy exceeds a specified value, an interlock signal is output to the operating device 1. When the interlock signal is output, the operating device 1 immediately stops generating radiation.

The radiation generating apparatus according to the seventh embodiment of the present invention is similar to the radiation generating apparatus according to the fourth and fifth embodiments, except that
The system is provided with a system that calculates energy by comparing two current values and outputs an interlock signal when the calculated energy exceeds an allowable range.

Embodiment 8 FIG. Embodiment 8 A radiation generator according to Embodiment 8 of the present invention will be described with reference to FIG. FIG. 9 is a diagram showing a configuration of the eighth embodiment of the present invention. The illustration of the targets 7 to the collimator 11 is omitted.

In FIG. 9, 1 is an operating device, 2 is a power box,
3 is an electron gun, 4 is a klystron, 5 is an accelerating tube, 6 is a beam duct, 14Y is an energy detector, and 23 is a CPU.
Automatic energy adjustment device including 24, high voltage circuit, 1
Reference numeral 2 denotes the trajectory of the electron beam.

In the eighth embodiment, the energy can be detected during the treatment as in the fourth and fifth embodiments, and the energy is detected by the output of the klystron 4 which determines the electron beam energy. It has the function of stabilizing the electron beam energy by feeding back the current electron beam energy.

In FIG. 9, the energy detector 14Y
Is an apparatus capable of measuring energy during treatment as described in Embodiment 4 or Embodiment 5. Further, the automatic energy adjusting device 23 obtains the slope of the attenuation curve when the electron beam passes through the metal from the current values flowing through the two metal plates, calculates the energy by comparing with the existing data, and calculates the energy. The difference between the obtained energy and the required energy is fed back to the high voltage circuit 24 described later. Further, the high voltage circuit 24 generates a high voltage pulse which determines the output of the klystron 4 according to the value set from the operation device 1. As a result, according to the eighth embodiment,
It is possible to perform radiation therapy using an electron beam of the same energy at all times.

The radiation generator according to the eighth embodiment of the present invention differs from the fourth and fifth embodiments in that the two current values detected by the automatic energy adjusting device 23 are compared, and the comparison signal is fed back to the high voltage circuit 24. By doing so, a system for stabilizing the energy of the electron beam during treatment is provided.

According to the embodiments of the present invention, radiation of energy different from the intended one is treated by easy direct measurement and monitoring of the energy of the electron beam, interlocking against energy fluctuation, or stabilization of the energy. Can be prevented. That is,
Since the energy of the radiation used for the treatment can be accurately grasped, the dose distribution in the patient can be accurately grasped, and the radiation treatment can be performed with high accuracy.

[0073]

As described above, the radiation generating apparatus according to the present invention is provided on the trajectory of the electron beam accelerated by the accelerating tube and emitted by the beam duct, and the two metal sheets insulated from the electron beam. An energy detecting means for measuring the energy of the electron beam from a current which can be detected by being incident on a member is provided.
The energy of the line can be easily measured, and the measurement can be performed more frequently, and the value of the energy can be grasped more accurately than before. As a result, more accurate radiation treatment can be performed. Play.

Further, the radiation generating apparatus according to the present invention
As described above, as the energy detecting means,
One of the two metal members is a metal disk, and the other is a plurality of metal plates having different thicknesses placed on the metal disk, and each metal plate is insulated from the metal disk. Has a structure in which the plurality of metal plates on the electron beam trajectory can be replaced by rotating, so that there is an effect that energy measurement can be easily performed without requiring special preparation.

Further, the radiation generating apparatus according to the present invention
As described above, as the energy detecting means,
Since the two metal members are two insulated metal plates, and the energy of the continuous electron beam is measured from the current detected from these metal plates, continuous energy measurement can be performed by a small-scale device. It has the effect that it becomes possible.

Further, the radiation generator according to the present invention comprises:
As described above, since the energy detecting means is incorporated in the disc of the equalizer for flattening the dose distribution of X-rays, it is not necessary to provide a special driving mechanism and the like, and the energy detecting means is provided in a compact and inexpensive manner. This has the effect that it can be performed.

Further, the radiation generator according to the present invention comprises:
As described above, since the energy detecting means is also used as a scatterer provided for equalizing the dose distribution of the electron beam, the energy of the electron beam can be measured while performing the electron beam treatment. This has the effect.

Further, the radiation generating apparatus according to the present invention
As described above, since the energy detecting means is also used as a target for generating a braking X-ray by colliding an accelerated electron beam, the energy of the electron beam is measured while performing X-ray treatment. This has the effect that it can be performed.

Further, the radiation generating apparatus according to the present invention
As described above, since the display device for displaying the measured energy of the electron beam is further provided, it is possible to prevent radiation having energy different from the expected one from being used for the treatment.

Further, the radiation generating apparatus according to the present invention
As described above, the apparatus further includes an interlock unit that outputs an interlock signal to an operation device that controls an electron gun that generates an electron beam when the measured energy of the electron beam exceeds an allowable range. So
This has the effect of preventing the use of radiation having a different energy from the intended one for treatment.

Further, as described above, the radiation generator according to the present invention further includes an automatic energy adjusting means for feeding back the detected current electron beam energy to the klystron means for determining the electron beam energy. Therefore, there is an effect that radiation treatment can always be performed using an electron beam having the same energy.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a radiation generating apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a diagram showing a configuration of a radiation generating apparatus according to Embodiment 2 of the present invention.

FIG. 3 is a diagram showing how an electron beam in Al is attenuated in a radiation generator according to Embodiment 2 of the present invention.

FIG. 4 is a diagram showing a configuration of a radiation generating apparatus according to Embodiment 3 of the present invention.

FIG. 5 is a diagram showing a configuration of a radiation generating apparatus according to Embodiment 4 of the present invention.

FIG. 6 is a diagram showing a configuration of a radiation generating apparatus according to Embodiment 5 of the present invention.

FIG. 7 is a diagram showing a configuration of a radiation generating apparatus according to Embodiment 6 of the present invention.

FIG. 8 is a diagram showing a configuration of a radiation generating apparatus according to Embodiment 7 of the present invention.

FIG. 9 is a diagram showing a configuration of a radiation generating apparatus according to Embodiment 8 of the present invention.

FIG. 10 is a diagram showing a configuration of a conventional radiation generator.

[Explanation of symbols]

1 actuator, 2 power box, 3 electron gun, 4 klystron, 5 accelerating tube, 6 beam duct, 7 target,
8 scatterer, 9 equalizer unit, 10 monitor chamber, 11 collimator, 14 energy detection unit, 14A, 14B, 14X, 14Y energy detector, 14C scatterer and energy detector, 1
4D target / energy detector, 15 metal disk, 16 insulator, 17a, 17b metal plate, 18 wire, 19 ammeter, 20 arithmetic unit, 21 display,
22 Energy interlock device, 23 Automatic energy adjustment device, 24 High voltage circuit.

Claims (9)

[Claims] 1. An electron beam, which is provided on the trajectory of an electron beam accelerated by an acceleration tube and emitted by a beam duct, and which can be detected from a current which can be detected by making the electron beam incident on two insulated metal members. A radiation generator comprising an energy detecting means for measuring energy. 2. The energy detection means, wherein one of the two metal members is a metal disk, and the other is a plurality of metal plates having different thicknesses mounted on the metal disk. The radiation generating apparatus according to claim 1, wherein the metal plate is insulated from the metal disk, and has a structure in which the plurality of metal plates on the electron beam track can be replaced by rotating the metal disk. . 3. The energy detecting means includes two metal plates in which the two metal members are insulated, and measures energy of a continuous electron beam from a current detected from these metal plates. The radiation generator according to claim 1, characterized in that: 4. The radiation generating apparatus according to claim 1, wherein said energy detecting means is incorporated in a disk of an equalizer for flattening an X-ray dose distribution. 5. The radiation generating apparatus according to claim 1, wherein said energy detecting means also serves as a scatterer provided for uniformizing the dose distribution of the electron beam. 6. The radiation generating apparatus according to claim 1, wherein said energy detecting means also serves as a target for generating a braking X-ray by colliding an accelerated electron beam. 7. The radiation generating apparatus according to claim 1, further comprising a display for displaying the measured energy of the electron beam. 8. An interlock means for outputting an interlock signal to an operation device for controlling an electron gun for generating an electron beam when the measured energy of the electron beam exceeds an allowable range. 7. The radiation generator according to claim 5, wherein 9. The radiation generating apparatus according to claim 5, wherein said klystron means for determining the electron beam energy further comprises automatic energy adjusting means for feeding back the detected current electron beam energy. apparatus.