JP4090863B2 - Medical radionuclide production equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for irradiating a target material with an ion beam accelerated by an accelerator and producing a medical radionuclide by a nuclear reaction.
[0002]
[Prior art]
As a diagnostic method in the field of nuclear medicine, a technique for visualizing organ functions by labeling a compound that accumulates a radionuclide in a specific organ and detecting γ rays emitted from the radionuclide is being developed. That is, a radionuclide (for example,¹¹C,¹³N,¹⁵O,¹⁸A radiopharmaceutical having a property of being metabolized in a diseased part (lesion) to be examined, mixed with a positron emitting nuclide such as F), and the radiopharmaceutical within the body of the subject after a predetermined time. It is specified by detecting the γ-rays emitted due to the radiopharmaceutical accumulated in the affected area, which part is accumulated (which part is consumed much). The positrons emitted from the radiopharmaceutical are combined with nearby electrons and annihilated, thereby releasing a pair of γ rays. Since these pair of γ-rays (hereinafter referred to as γ-ray pairs) are emitted in directions almost opposite to each other (strictly, 180 ° ± 0.6 °), based on the detection signal of the γ-rays, A straight line passing through the source position (affected area position) of the γ-ray can be specified. In the examination of the patient, the subject who contains a number of gamma ray pairs released from the body due to the radiopharmaceutical accumulated in the affected area in this way, and includes a location (affected site position) that consumes a lot of radiopharmaceutical based on the data A tomographic image of a tomograph (Positron Emission Tomography, PET).
[0003]
Many devices have already been proposed as medical radionuclide production apparatuses for performing such PET examinations. For example, after accelerating negative ions generated by a negative ion source of a cyclotron with a high-frequency electric field, the stripping foil placed on the outermost periphery strips off the negative ion electrons and converts them into positive ions, which are largely deflected outward. To the target material in the target container. In the target container, a nuclear reaction occurs in the target material by irradiation with an ion beam, and a desired radionuclide is generated.
[0004]
By the way, in the radionuclide production apparatus using the cyclotron as an accelerator, there are difficulties in terms of activation of the structure due to beam loss, the weight of the apparatus and the shield, the frequency of maintenance and inspection, and the ease thereof. In recent years, therefore, a linac (high-frequency linear accelerator), which has a smaller beam loss than a cyclotron, has attracted attention as an accelerator.
[0005]
For example, in the field of ion implantation equipment that implants ions into a semiconductor substrate or the like, a high-frequency quadrupole linac that introduces an ion beam and accelerates the ion beam, and ion implantation into the semiconductor substrate or the like using the accelerated ion beam A plurality of ion implantation chambers, a beam deflector that deflects an ion beam emitted from the high-frequency quadrupole linac in a plurality of directions and distributes the ion beams to a plurality of ion implantation chambers, and the high-frequency quadrupole linac. A high energy ion implantation apparatus having a pulse adjuster that changes a pulse width and a repetition period of a deflection voltage for controlling a beam deflector in accordance with a period of a high frequency high voltage to be driven has been proposed (for example, Patent Document 1). reference).
[0006]
[Patent Document 1]
JP-A-6-196119
[0007]
[Problems to be solved by the invention]
However, when the configuration of the above prior art is applied to the above-described medical radionuclide production apparatus, the following inconvenience occurs.
[0008]
That is, in the above prior art, the linac generates a high-frequency electric field, accelerates the ion beam by this high-frequency electric field, and collects the grouped beam groups sequentially and continuously while collecting at a clustering interval equal to the high-frequency period interval. However, the beam deflector must be distributed to each target container at a very high speed (with a short cycle) for each beam group (or for each of a plurality of beam groups) that successively come in succession at an extremely short group interval. Don't be. When such very short-cycle high-speed switching control is performed, it is technically very difficult to control deflection using a magnetic field, so control using an electric field is unavoidable, and it becomes very large and complicated. For this reason, not only the cost increases, but it is practically difficult to obtain a stable distribution performance.
[0009]
In particular, in a radionuclide production apparatus for medical use, if the distribution to each target container is not sufficiently successful, for example, a deflected beam hits the duct of the target container and the wall surface material of the duct is activated. And the radioactive material (for example, cobalt etc.) of the duct wall surface once generated and activated is knocked out by the ion beam incident again after that, and this may be mixed into the target material. In this case, since the purity of the radionuclide mixed in the medical drug is lowered, it is not preferable in view of the influence on the human body of the patient at the time of treatment.
[0010]
In general, this type of radionuclide production apparatus for medical use is often placed at a medical site, and there are no engineers or maintenance workers with specialized knowledge at the site. In such a situation, activation of the duct wall surface as described above is not preferable from the viewpoint of exposure to the human body.
[0011]
As described above, even if the prior art related to the ion implantation apparatus such as a semiconductor substrate equipped with a linac is applied to a medical radionuclide production apparatus, it is practically difficult to obtain a stable distribution performance. Application is difficult.
[0012]
An object of the present invention is to provide a medical radionuclide production apparatus capable of producing a radionuclide for medical use efficiently and stably with reduced beam loss.
[0013]
[Means for Solving the Problems]
  (1) In order to achieve the above object, the present invention comprises a positive ion source for generating a positive ion beam,An ion source power source that outputs pulsed power to the positive ion source and emits a pulsed positive ion beam from the positive ion source;Pulsedhigh frequencyOutput powerA high frequency power supply,thisHigh frequency power supplyMore suppliedPulsed high frequencyBased on electricityPulsedA high frequency electric field is generated and incident from the positive ion source by this high frequency electric field.PulsedThe positive ion beam is accelerated and gathered at a gathering interval corresponding to the periodic interval of the high frequency, and the gathered beam group is supplied as described above.Pulsed high frequencyA linac that is output as a beam lump for each cycle of the pulse of power, and a plurality of target containers that store the target material, introduce the beam lump output from the linac and irradiate the target material,A magnetic field is generated based on the power supply for the electromagnet that generates AC power and the power supplied by the power supply for the electromagnet.The beam masses sequentially output from the linac are deflected and sequentially distributed to the plurality of target containers for each beam mass.A deflection electromagnet, and a synchronous control device that controls power output of the ion source power source, the high frequency power source, and the electromagnet power source, and the synchronous control device outputs the high frequency power of the high frequency power source in a pulsed manner. A control signal is output to the high-frequency power source, and in synchronization with the control signal output to the high-frequency power source, a control signal for outputting the power of the ion source power source in a pulse shape is output to the ion source power source, and Outputs a control signal for controlling the electromagnet power supply so that the time-varying magnetic field period of the deflection electromagnet is an integer multiple of the power pulse period of the high-frequency power supply.
[0014]
  In the present invention, the linac isHigh frequency power supplyMore suppliedPulsed high frequencyBased on electricityPulsedA high frequency electric field is generated and incident from a positive ion source by this high frequency electric field.PulsedThe positive ion beam is linearly accelerated and collected at an extremely short gathering interval corresponding to a high frequency period interval, and a plurality of gathered beam groups are output. In this way, by linearly accelerating the ion beam using a linac as an accelerating means, it is possible to accelerate the beam while reducing the beam loss as compared with a cyclotron that accelerates while circling the ion beam.
[0015]
  In the present invention,High frequency power supplyIs pulsedhigh frequencySupply power to Linac. Linac is this pulse-shapedhigh frequencyGenerated based on powerPulsedBy high frequency electric fieldPulsedAccelerate the positive ion beam,Pulsed high frequencyA beam lump (multiple beam groups) for each pulse period of power is output in pulses. AndDeflection magnetIs supplied to the linac, for example, the period of time variation of its deflection magnetic fieldhigh frequencyBy setting an integral multiple of the power pulse period, the beam masses sequentially output from the linac are sequentially deflected for each beam mass and distributed to a plurality of target containers so as to be substantially uniform.At that time, the synchronous control device outputs a control signal for outputting the high-frequency power of the high-frequency power source in a pulse form to the high-frequency power source, and pulses the power of the ion source power source in synchronization with the control signal output to the high-frequency power source. Control signal for controlling the electromagnet power supply so that the time-varying magnetic field period of the deflecting electromagnet is an integral multiple of the pulse period of the power of the high frequency power supply. Output. in this wayWhile synchronously controlling the ion source power supply, high frequency power supply and electromagnet power supplyStable distribution unlike the conventional structure, in which pulsed beam masses are distributed according to the temporal change of the deflection magnetic field, and each beam group that is continuously flying from the linac one after another at very short intervals between the linacs using an electric field. Performance can be obtained. In addition, at this time, there is no increase in cost as in the case of electric field control, and for example, it is possible to prevent the beam from hitting the duct of the target container and activating the duct wall surface material.
[0017]
  (2)the above(1), PreferablyThe synchronization control device includes:SaidDeflection magnetThe ratio between the period of the temporal change of the deflection magnetic field generated and the period of the pulse of the power supplied to the linac is made equal to the number of the target containers.
[0018]
  As a result, the beam mass that is sequentially output from the linacDeflection magnetCan be deflected and distributed in the direction of each target container (deflection angle) one by one in accordance with the temporal change of the deflection magnetic field generated by. Therefore, in each target container, the time during which the beam lump is not irradiated can be shortened as much as possible.
[0019]
  (3) Above (1)Or (2)In any one of the above, preferablyDeflection magnetThe time change of the magnetic field is substantially sinusoidal.
[0020]
  in this wayDeflection magnetBy using a configuration that generates a magnetic field that changes with time in a substantially sinusoidal form, for example, it can be made relatively simple compared to a configuration that generates a magnetic field that changes with time in a substantially rectangular waveform.
[0021]
  (4) Above (1)-(3), Preferably, a beam position detecting means provided in the incident portion of the target containerAnd beforeBased on the detection result of the beam position detectorControl the power value of the electromagnet power supplyThe aboveDeflection magnetControl the strength of the generated magnetic fieldFurther provided with an irradiation position control device.
[0022]
  in this wayThe irradiation position control deviceBased on the detection result of the beam position detection means of the target containerControl the power value of the electromagnet power supplyThe aboveDeflection magnetSince the intensity of the generated magnetic field is controlled, the deflection angle of the beam mass distributed by the deflection magnetic field can be stabilized. Therefore, for example, it is possible to reliably prevent the beam from hitting the duct of the target container and activating the duct wall surface material.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0024]
A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a block diagram showing a schematic configuration of a medical radionuclide production apparatus according to the present embodiment.
[0025]
In FIG. 1, a medical radionuclide production apparatus 1 includes a positive ion source 2 that generates a positive ion beam, an ion source power source 3 that supplies electric power to the positive ion source 2, and a high frequency that outputs high frequency power. A high-frequency electric field is generated based on the power supply 4 and the high-frequency power supplied from the high-frequency power supply 4, and the positive ion beam incident from the positive ion source 2 is linearly accelerated to a predetermined energy (for example, about 10 MeV) by the high-frequency electric field. The linac 5 and the target material 6 (see FIG. 6 to be described later) are accommodated, and a positive ion beam output from the linac 5 is introduced to irradiate the target material 6 and a medical radionuclide (for example, by a nuclear reaction)¹¹C,¹³N,¹⁵O,¹⁸For example, two target containers 7A and 7B that generate positron emitting nuclides such as F), an electromagnet power source 8 that generates AC power of a predetermined frequency, for example, and a magnetic field is formed based on the electric power supplied from the electromagnet power source 8 Then, the positive ion beam output from the linac 5 is deflected by the deflection angle θ by the time change of the magnetic field.₁Or θ₂And a synchronous control device 10 for controlling the power output of the ion source power source 3, the high frequency power source 4, and the electromagnet power source 8 respectively. And beam position detectors 11A and 11B provided on the target containers 7A and 7B, respectively, for detecting the position of the introduced positive ion beam, and an irradiation position control device 12 for controlling the power value of the electromagnet power supply 8. Yes.
[0026]
The positive ion source 2 is, for example, a duoplasmatron that generates a positive ion beam from plasma generated by arc discharge, or a micro ion source that generates a positive ion beam by microwave discharge. Microwave power necessary for voltage or microwave discharge is supplied from the ion source power supply 3.
[0027]
The linac 5 includes a high-frequency quadrupole linac (RFQ) 5A that accelerates a positive ion beam incident from the positive ion source 2 to about 3 MeV, for example, and a drift tube linac (DTL) that further accelerates the positive ion beam to about 10 MeV, for example. ) 5B.
[0028]
Although not shown in detail, the high-frequency quadrupole linac 5A includes four electrodes having a wavy shape along the axial direction (left-right direction in FIG. 2). A high-frequency electric field is generated between these electrodes, thereby accelerating the positive ion beam passing through the central portion of the four electrode positions.
[0029]
Although not shown in detail, the drift tube type linac 5B is arranged in a straight line along the beam acceleration axis direction (left and right direction in FIG. 2) and includes a number of drift tubes incorporating magnets acting as beam acceleration electrodes. I have. A high-frequency electric field is generated between these adjacent drift tubes to accelerate the positive ion beam passing through the center portion of the drift tube.
[0030]
FIG. 2 is a block diagram showing a schematic structure of the electromagnet power supply 8.
[0031]
In FIG. 2, an electromagnet power supply 8 includes a rectifier 14 that converts AC power from an AC power supply 13 into DC power, a charging capacitor 15 that stores DC power of the rectifier 14, and charging of the charging capacitor 15. The voltage is detected, and the detected value becomes a predetermined set value (a preset set value or a set value corrected according to a correction amount signal (details will be described later) input from the irradiation position control device 12). The charging voltage regulator 16 that controls the output of the rectifier 14 and the ON / OFF switching according to a control signal (details will be described later) input from the synchronous control device 10, thereby changing the DC power of the charging capacitor 15 into a rectangular wave shape. A resonance capacity that forms a parallel resonance circuit by being connected to a pulse modulator 17 for converting to pulse power and an exciting coil 9a of the deflection electromagnet 9. 18 is composed of a.
[0032]
The exciting coil 9a of the deflecting electromagnet 9 is excited by the electromagnet power supply 8, and the resonance current of the exciting coil 9a becomes a sinusoidal alternating current due to the characteristics of the resonance circuit. As a result, the deflection electromagnet 9 generates a magnetic field (see FIG. 4E described later) that changes with time in a substantially sine wave shape.
[0033]
Here, as a major feature of the present embodiment, the synchronous control device 10 outputs a control signal (pulse signal) for outputting the high-frequency power of the high-frequency power source 4 in a pulse shape to the high-frequency power source 4, and the high-frequency power source For example, a control signal (pulse signal) for controlling the pulse modulator 17 of the electromagnet power supply 8 so that the magnetic field period of the deflection electromagnet 9 that changes with time in a substantially sinusoidal manner is doubled with respect to the pulse period of 4 electric power. Is output to the pulse modulator 17.
[0034]
The synchronization control device 10 outputs a control signal (pulse signal) for outputting the power of the ion source power source 3 in a pulsed manner to the ion source power source 3 in synchronization with the control signal output to the high frequency power source 4. It is supposed to be. Hereinafter, the details will be described.
[0035]
FIG. 3 is a diagram illustrating changes over time in control signals output to the ion source power source 3, the high frequency power source 4, and the electromagnet power source 8 in the synchronous control device 10. FIG. 4A is a characteristic diagram showing the change with time of the positive ion beam output from the positive ion source 2, and FIG. 4B is a characteristic diagram showing the change with time of the high-frequency power output from the high-frequency power source 4. FIG. 4C is a characteristic diagram showing the change with time of the high-frequency electric field generated by the linac 5, and FIG. 4D is a characteristic diagram showing the change with time of the positive ion beam output from the linac 5. 4 (e) is a characteristic diagram showing the change over time of the magnetic field generated by the deflecting electromagnet 9, and FIG. 4 (f) is a characteristic diagram showing the change over time of the positive ion beam incident on the target containers 7A and 7B. 5A is a diagram for explaining the details of the A portion in FIG. 4C, and FIG. 5B is a diagram for explaining the details of the B portion in FIGS. 4D and 4F. is there.
[0036]
In FIG. 3, FIG. 4 (a) to FIG. 4 (f), FIG. 5 (a), and FIG. 5 (b), the horizontal axis represents time in common. The vertical axis represents current, the vertical axis in FIG. 4B represents power, the vertical axis in FIG. 4C represents electric field output, and FIG. ) Represents the current, the vertical axis of FIG. 4 (e) represents the magnetic field strength, the vertical axis of FIG. 4 (f) represents the current, and FIG. The vertical axis of (a) represents voltage, and the vertical axis of FIG. 5 (b) represents current.
[0037]
First, the synchronous control device 10 outputs a control signal having a pulse width of 100 μs to the high-frequency power supply 4 (specifically, an output duration of a control signal instructing power output), for example, every pulse period of 10 ms. The high-frequency power supply 4 outputs high-frequency power having a pulse width (specifically, output duration time of high-frequency power) of about 100 μs to the linac 5 every pulse period of about 10 ms in accordance with this control signal.
[0038]
Thereby, the linac 5 generates a high-frequency electric field having a pulse width (specifically, the output duration of the high-frequency electric field) of about 100 μs every pulse period of about 10 ms. As a result, the linac 5 accelerates the positive ion beam incident from the ion source 2 by a high-frequency electric field of, for example, several tens of MHz, and collects them at a collection interval equal to the high-frequency periodic interval, for example, every several hundred ns (FIG. 5). (Refer to (a) and FIG. 5 (b)), and the collected beam group is a beam lump (multiple beam groups) of about 100 μs in pulse width (specifically, output duration time of a plurality of beam groups), and a pulse period of about 10 ms. It is designed to output every time.
[0039]
Next, the synchronization control device 10 applies a control signal having a pulse width of, for example, 10 ms to the pulse modulator 17 of the electromagnet power supply 8, for example, for a pulse period of 20 ms (that is, for a pulse period of 10 ms of the control signal to the high frequency power supply 4). Output every 2 times). The pulse modulator 17 of the electromagnet power supply 8 is switched ON / OFF according to this control signal, and the excitation coil 9a of the deflection electromagnet 9 is excited. Thereby, the deflection electromagnet 9 generates a magnetic field that changes with time in a substantially sinusoidal manner with a period of about 20 ms.
[0040]
At this time, the magnetic field generated by the deflecting electromagnet 9 has a period of time change (20 ms) that is twice that of the pulse period (10 ms) of power supplied from the high frequency power source 4 to the linac 5. Further, as shown in the figure, the magnetic field strength when the beam mass is sequentially output from the linac 5 (in other words, the phase of the beam output of the linac 5) is S.₁Or S₂It has become. As a result, for example, the deflection electromagnet 9 converts the first beam block into the magnetic field strength S.₁Deflection angle θ₁(Refer to the above-mentioned FIG. 1) and the beam is emitted to the target container 7A.₂Deflection angle θ₂(Refer to the above-mentioned FIG. 1). The beam is deflected and emitted to the target container 7B. By repeating this, the beam mass sequentially output from the linac 5 is distributed substantially evenly to the target containers 7A and 7B. .
[0041]
Furthermore, the synchronous control device 10 outputs a control signal having a pulse width of 200 μs, for example, to the ion source power supply 3 every pulse period of 10 ms (ie, equal to the pulse period of 10 ms of the control signal of the high frequency power supply 4 described above). In response to this control signal, the ion source power supply 3 outputs power having a pulse width of about 200 μs to the positive ion source 2 for each pulse period, whereby the positive ion source 2 has a pulse width (specifically, beam output continuation). Time) A positive ion beam of about 200 μs is emitted to the linac 5 every pulse period of about 10 ms.
[0042]
At this time, the pulse cycle (10 ms) of the positive ion beam output from the positive ion source 2 is equal to the pulse cycle (10 ms) of the power supplied from the high frequency power source 4 to the linac 5. Further, as shown in the figure, when a high-frequency electric field is output by the linac 5, a positive ion beam is output from the positive ion source 2. The duration of the beam output of the positive ion source 2 (pulse width 200 μs) is about twice the duration of the high-frequency electric field of the linac 5 (pulse width 100 μs). This is because the poor response of rising and falling at the time of OFF and the instability of the beam are taken into consideration.
[0043]
FIG. 6 is a cross-sectional view showing the detailed structure of the target container 7A (or 7B).
[0044]
In FIG. 6, a target container 7A (or 7B) has a hollow duct structure made of, for example, a metal, a vacuum passage 19 for receiving a beam mass deflected by a deflection magnetic field of the deflection electromagnet 9, and the target material. 6 (eg radionuclide¹¹When generating C, [^{1 4}N] Nitrogen gas, radionuclide¹³To generate N, [^{1 6}O] Water, radionuclide¹⁵When generating O, [^{1 5}N] Nitrogen gas, radionuclide¹⁸To generate F, [¹⁸O] a target chamber 20 for storing concentrated water or the like) is separated by a vacuum partition wall 21. As a result, the beam mass from the vacuum passage 19 passes through the vacuum diaphragm 21, irradiates the target material 6 in the target chamber 20, and generates a medical radionuclide by a nuclear reaction.
[0045]
The target chamber 20 is provided with a transfer pipe 22 for transferring the target material 6 containing the generated medical radionuclide, a supply pipe 23 for supplying the target material 6, and a target material 6 provided on the outer wall side (right side in FIG. 6). And a cooling water pipe 24 for cooling the water.
[0046]
Further, in the vacuum passage 19, the beam position detector 11A (or 11B) for detecting the incident position of the beam mass (the vertical position in FIG. 6) and the irradiation range of the beam mass expand beyond the desired range. A collimator 25 is provided. The beam position detector 11A (or 11B) includes two metal plates 11a and 11b, and induced voltages V generated on the metal plates 11a and 11b by beam masses passing between the metal plates 11a and 11b, respectively.₁, V₂Is output to the irradiation position control device 12.
[0047]
The irradiation position control device 12 receives an induced voltage V input from the beam position detector 11A (or 11B).₁, V₂Based on the above, the deviation of the beam incident position (specifically, the deviation between the center position in the vertical direction in FIG. 6 between the metal plates 11a and 11b) ΔX is calculated from the following equation (1).
ΔX = K (V₁-V₂) / (V₁+ V₂) …… (1)
K: Proportional constant (constant determined by the structure of the beam position detector)
The irradiation position control device 12 generates a correction amount signal by performing a predetermined calculation process in accordance with the calculated beam incident position shift ΔX, and sends the correction amount signal to the charging voltage adjuster 16 of the electromagnet power supply 8. Output. The charging voltage adjuster 16 corrects the setting value of the charging voltage in accordance with the correction amount signal, and controls the output of the rectifier 14 so that the charging voltage of the charging capacitor 15 becomes the correction setting value. Thereby, the intensity of the deflection magnetic field of the deflection electromagnet 9 is adjusted, and the deflection angle (incident position) of the beam lump by the deflection magnetic field of the deflection electromagnet 9 is feedback-controlled.
[0048]
That is, for example, it is detected that the beam incident position is shifted from the center position to the lower side in FIG. 6 in the target container 7A, and that the beam incident position is shifted from the center position to the upper side in FIG. (In other words, the deflection angle θ shown in FIG.₁, Θ₂Is too small), the charging voltage regulator 16 of the magnet power supply 8 increases the charging voltage of the charging capacitor 15 according to the correction amount signal from the irradiation position control device 12. Thereby, the magnetic field strength S of the deflection electromagnet 9 is obtained.₁, S₂(See FIG. 4 (e) above) is increased, and the deflection angle θ of the beam mass₁, Θ₂Is supposed to increase. Further, for example, it is detected that the beam incident position is shifted from the center position to the upper side in FIG. 6 in the target container 7A, and it is detected from the target container 7B that the beam incident position is shifted from the center position to the lower side in FIG. (In other words, the deflection angle θ shown in FIG.₁, Θ₂Is too large), the charging voltage adjuster 16 of the magnet power supply 8 decreases the charging voltage of the charging capacitor 15 according to the correction amount signal from the irradiation position control device 12. Thereby, the magnetic field strength S of the deflection electromagnet 9 is obtained.₁, S₂(Refer to FIG. 4 (e) described above)₁, Θ₂Is supposed to be smaller.
[0049]
In the above, the high frequency power source 4 constitutes a power supply means for outputting the pulsed power described in each claim, and the electromagnet power source 8 and the deflection electromagnet 9 generate a time-varying magnetic field described in each claim. The magnetic field generating means is configured. The vacuum passage 19 constitutes an incident part of the target container, and the beam position detectors 11A and 11B constitute beam position detecting means provided in the incident part of the target container.
[0050]
The operation and action / effect of this embodiment will be described.
[0051]
For example, a radionuclide for medical use for PET examination (for example,¹¹C,¹³N,¹⁵O,¹⁸When generating a positron emitting nuclide such as F), first, a pulsed control signal is input to the ion source power source 3 from the synchronous control device 10, and the ion source power source 3 outputs pulsed power to the positive ion source 3. To do. As a result, a positive ion beam having a pulse shape (for example, a pulse width of 100 μs and a pulse period of 10 ms) is emitted from the positive ion source 2 to the linac 5.
[0052]
Then, a pulsed control signal synchronized with the control signal from the synchronous control device 10 to the ion source power source 3 is input to the high frequency power source 4, and the high frequency power source 4 is pulsed to the linac 5 (for example, a pulse width of 100 μs and a pulse period of 10 ms). ) Of high frequency power. As a result, the linac 5 generates a high-frequency electric field of, for example, several tens of MHz in a pulse form based on the high-frequency power supplied from the high-frequency power supply 4, and the positive ion beam incident from the positive ion source 2 is linearly generated by this high-frequency electric field. The collected beam group is output in a pulse form as a beam lump for each pulse period of the supplied power, while being gathered at a gathering interval equal to the periodic interval of high frequency, for example, about several hundred ns.
[0053]
As described above, in the present embodiment, the ion beam is linearly accelerated using the linac as an accelerating means, so that it is possible to accelerate the ion beam while reducing the beam loss as compared with the cyclotron that accelerates while circling the ion beam. .
[0054]
Next, a pulse-like control signal from the synchronous control device 10 is input to the electromagnet power supply 8, and the electromagnet power supply 8 generates AC power, and the excitation coil 9a of the deflection electromagnet 9 is excited by this power. As a result, a deflecting magnetic field that changes in time in a sinusoidal manner is generated by the deflecting electromagnet 9, and the period of the temporal change of the deflecting magnetic field is set to, for example, twice (20 ms) the pulse period of the power supplied to the linac 5. The beam masses sequentially output from the linac 5 are sequentially deflected for each beam mass. That is, the first beam mass is changed to the magnetic field strength S.₁Deflection angle θ₁To the target container 7A and the next beam mass is changed to the magnetic field strength S.₂Deflection angle θ₂To the target container 7B, and this is repeated.
[0055]
As a result, the beam mass sequentially output from the linac 5 is distributed to the two target containers 7A and 7B so as to be substantially equal, and the target material 6 in the target containers 7A and 7B is irradiated to the medical radioactive material by the nuclear reaction. Generate nuclides. In addition, different types of medical radionuclides may be generated in the target containers 7A and 7B.
[0056]
As described above, in the present embodiment, the pulsed beam mass is distributed according to the temporal change of the deflection magnetic field, so that an electric field is used for each beam group successively coming from the linac 5 one after another at an extremely short gathering interval. Unlike the conventional distribution structure, stable distribution performance can be obtained. In addition, at this time, there is no increase in cost as in the case of electric field control, and it is also possible to prevent the duct wall material (for example, cobalt or the like) from being activated by the beam hitting the duct of the target containers 7A and 7B. it can.
[0057]
In the present embodiment, the dielectric voltage V detected by the beam position detection device 11A of the target container 7A (or the beam position detection device 11B of the target container 7B).₁, V₂Based on the calculated beam incident position deviation ΔX, the irradiation position control device 12 outputs a correction amount signal to the electromagnet power supply 8, and the magnetic field strength S of the deflection electromagnet 9.₁, S₂The deflection angle θ of the beam mass that is distributed by the deflection magnetic field.₁, Θ₂Can be stabilized. Accordingly, for example, it is possible to reliably prevent the beam from hitting the duct of the target containers 7A and 7B and activating the duct wall surface material.
[0058]
In the present embodiment, the period of the temporal change of the deflection magnetic field generated by the deflection electromagnet 9 is twice the pulse period of the power supplied to the linac 5 and is equal to the number of target containers 7A and 7B. As a result, the beam masses sequentially output from the linac 5 can be deflected and distributed to the target containers 7A and 7B one by one in accordance with the temporal change of the deflection magnetic field. As a result, in each of the target containers 7A and 7B, the time during which the beam lump is not irradiated (see FIG. 4F) can be shortened as much as possible.
[0059]
Further, in the present embodiment, the configuration of the electromagnet power supply 8 that generates a magnetic field that changes in time in a substantially sinusoidal shape in the deflection electromagnet 9 is compared with, for example, a configuration that generates a magnetic field that changes in time in a substantially rectangular wave shape. Can be simplified.
[0060]
In this embodiment, a positive ion beam is emitted from the positive ion source 2 to the linac 5 in a pulsed manner in synchronization with the pulse period of the power supplied to the linac 5. As a result, unnecessary beams in the linac 5 can be reduced.
[0061]
A second embodiment will be described with reference to FIGS.
This embodiment is an embodiment in which three target containers are provided.
[0062]
FIG. 7 is a block diagram showing a schematic configuration of the medical radionuclide manufacturing apparatus according to the present embodiment. FIG. 8 shows the synchronous control apparatus 10 to the ion source power source 3, the high frequency power source 4, and the electromagnet power source 8. FIG. 9A is a characteristic diagram showing the change over time of the positive ion beam output from the positive ion source 2, and FIG. 9B is a characteristic diagram showing the change over time of the output control signal. FIG. 9C is a characteristic diagram showing a change with time of the high-frequency electric power to be output, FIG. 9C is a characteristic diagram showing a change with time of the high-frequency electric field generated by the linac 5, and FIG. FIG. 9E is a characteristic diagram showing a change with time of the ion beam, FIG. 9E is a characteristic diagram showing a change with time of the magnetic field generated by the deflecting electromagnet 9, and FIG. 9F is incident on the target containers 7A, 7B, and 7C. With time of positive ion beam It is a characteristic diagram showing a. In these FIG. 7, FIG. 8, and FIG. 9 (a)-(f), the same code | symbol is attached | subjected to the part equivalent to the said embodiment, and description is abbreviate | omitted suitably.
[0063]
In the present embodiment, the medical radionuclide production apparatus 26 accommodates the target material 6, introduces the beam mass output from the linac 5 without being deflected, and irradiates the target material 6 to perform medical treatment by nuclear reaction. A third target container 7C for generating a radionuclide is provided.
[0064]
The synchronous control device 10 outputs control signals similar to those of the first embodiment to the ion source power source 3 and the high frequency power source 4, respectively. As a result, as in the first embodiment, the linac 5 generates a high-frequency electric field of, for example, several tens of MHz in a pulse shape based on the high-frequency power supplied from the high-frequency power supply 4 and is incident from the positive ion source 2 by this high-frequency electric field. The positive ion beam is linearly accelerated and gathered at a gathering interval equal to a high-frequency periodic interval, for example, about several hundred ns, and the gathered beam group is pulsed as a beam lump with a pulse period of about 10 ms of supplied power. To output.
[0065]
In addition, the synchronization control device 10 outputs a control signal having a pulse width of, for example, 15 ms to the electromagnet power source 8, for example, every pulse cycle of 30 ms. As a result, a deflection magnetic field that changes in time in a sinusoidal manner is generated by the deflecting electromagnet 9, and the period of time change of the deflection magnetic field is, for example, three times (30 ms) the pulse period of the power supplied to the linac 5. The beam mass sequentially output from the linac 5 is sequentially deflected for each beam mass.
[0066]
That is, for example, the first beam mass is changed to the magnetic field strength S.₁Deflection angle θ₁To the target container 7A and the next beam mass is changed to the magnetic field strength S.₂Deflection angle θ₂To the target container 7B, and the next beam mass is emitted to the target container 7C without being deflected (in other words, the magnetic field intensity is zero), and this is repeated.
[0067]
Also in the present embodiment configured as described above, acceleration can be performed while reducing beam loss using the linac 5 as in the first embodiment. In addition, stable distribution performance can be obtained by distributing the pulse-shaped beam mass according to the temporal change of the deflection magnetic field.
[0068]
In the first embodiment, the configuration in which the two target containers 7A and 7B are provided and in the second embodiment the three target containers 7A, 7B, and 7C are described. It is good also as a structure which provided many target containers, such as one, five.
[0069]
In the first and second embodiments described above, the magnetic field generating means has been described with respect to the configuration in which the deflecting electromagnet 9 generates a sinusoidal time-varying magnetic field by the AC power generated by the electromagnet power supply 8. Not exclusively. That is, for example, the power supply for the electromagnet may generate power that changes with time in a rectangular waveform, and the deflection electromagnet 9 may generate a magnetic field that changes with time in a rectangular waveform. Also in this case, the same effects as those of the first and second embodiments can be obtained.
[0070]
【The invention's effect】
According to the present invention, a radionuclide for medical use can be produced efficiently and stably with reduced beam loss.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of a first embodiment of a medical radionuclide production apparatus of the present invention.
FIG. 2 is a block diagram showing a schematic structure of an electromagnet power source constituting the first embodiment of the medical radionuclide production apparatus of the present invention.
FIG. 3 is a diagram showing temporal changes in control signals output to an ion source power source, a high frequency power source, and an electromagnet power source in the synchronous control device constituting the first embodiment of the medical radionuclide production apparatus of the present invention. is there.
FIG. 4 is a characteristic diagram showing the change over time of the positive ion beam output from the positive ion source constituting the first embodiment of the medical radionuclide production apparatus of the present invention, and the time change of the high frequency power output from the high frequency power supply. A characteristic diagram representing a time-dependent change of a high-frequency electric field generated by the linac, a characteristic diagram representing a time-dependent change of a positive ion beam output from the linac, a characteristic diagram representing a time-dependent change of a magnetic field generated by the deflecting electromagnet, and It is a characteristic view showing the time-dependent change of the positive ion beam which injects into a target container.
5 is a diagram for explaining details of a part A in FIG. 4 and a diagram for explaining details of a part B in FIG. 4;
FIG. 6 is a sectional view showing a detailed structure of a target container constituting the first embodiment of the medical radionuclide production apparatus of the present invention.
FIG. 7 is a block diagram showing a schematic configuration of the second embodiment of the medical radionuclide production apparatus of the present invention.
FIG. 8 is a diagram showing temporal changes in control signals output to the ion source power source, the high frequency power source, and the electromagnet power source in the synchronous control device constituting the second embodiment of the medical radionuclide production apparatus of the present invention. is there.
FIG. 9 is a characteristic diagram showing a time-dependent change of a positive ion beam output from a positive ion source constituting a second embodiment of the medical radionuclide production apparatus of the present invention, and a time-dependent change of high-frequency power output from a high-frequency power source A characteristic diagram representing a time-dependent change of a high-frequency electric field generated by the linac, a characteristic diagram representing a time-dependent change of a positive ion beam output from the linac, a characteristic diagram representing a time-dependent change of a magnetic field generated by the deflecting electromagnet, and It is a characteristic view showing the time-dependent change of the positive ion beam which injects into a target container.
[Explanation of symbols]
1 Medical radionuclide production equipment
2 Positive ion source
4 High frequency power supply (electric power supply means)
5 Linac
6 Target substance
7A Target container
7B Target container
7C target container
8 Power supply for electromagnet (magnetic field generation means)
9 Bending electromagnet (magnetic field generating means)
11A Beam position detector (beam position detection means)
11B Beam position detector (beam position detection means)
19 Vacuum passage (incident part)
26 Medical radionuclide production equipment

Claims (4)

A positive ion source for generating a positive ion beam;
An ion source power source that outputs pulsed power to the positive ion source and emits a pulsed positive ion beam from the positive ion source;
A high frequency power supply that outputs pulsed high frequency power; and
A pulsed high-frequency electric field is generated based on the pulsed high- frequency power supplied from the high-frequency power source, the pulsed positive ion beam incident from the positive ion source is accelerated by the high-frequency electric field, and the high-frequency period interval A linac that outputs the gathered beam group as a beam lump for each period of the pulse of the supplied pulsed high-frequency power while gathering at a gathering interval according to
A plurality of target containers for storing the target material and introducing the beam mass output from the linac to irradiate the target material;
An electromagnet power source for generating AC power;
A magnetic field is formed based on the electric power supplied from the electromagnet power source, the beam masses sequentially output from the linac are deflected by the temporal change of the magnetic field , and each beam mass is sequentially applied to the plurality of target containers. and sorting Ru deflection electromagnet so as to be equal,
A synchronous control device for controlling the power output of the ion source power source, the high frequency power source and the electromagnet power source,
The synchronous control device outputs a control signal for outputting the high-frequency power of the high-frequency power source in a pulsed manner to the high-frequency power source, and in synchronization with the control signal output to the high-frequency power source, the power of the ion source power source A control signal to be output in a pulse shape is output to the ion source power source, and the electromagnet power source is set such that a time-varying magnetic field period of the deflection electromagnet is an integral multiple of a pulse period of power of the high frequency power source. An apparatus for producing a radionuclide for medical use, which outputs a control signal to be controlled . 2. The medical radionuclide manufacturing apparatus according to claim 1 , wherein the synchronous control device includes a period of the temporal change of the deflection magnetic field generated by the deflection electromagnet , and a period of the pulse of the electric power supplied to the linac. The medical radionuclide production apparatus is characterized in that the ratio is equal to the number of the target containers. Apparatus for manufacturing a medical radionuclide any one of claims 1 or 2, apparatus for producing a medical radionuclide, wherein the time variation of the magnetic field of the deflection electromagnet is substantially sinusoidal. Apparatus for manufacturing a medical radionuclide any one of claims 1 to 3, a beam position detection means provided on the incident portion of the target vessel, the electromagnet based on the detection result of the previous SL beam position detecting means An apparatus for producing a radionuclide for medical use , further comprising an irradiation position control device for controlling a power value of a power source for power supply and controlling an intensity of a magnetic field generated by the deflection electromagnet .

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