KR101411055B1 - Particle beam irradiation system and charged particle beam correcting method - Google Patents

Abstract

An object of the present invention is to provide a particle beam irradiation system capable of increasing beam utilization efficiency without lowering the irradiation dose uniformity.
A synchrotron 13 for accelerating and outputting the ion beam 10 and an irradiation device 30 for irradiating the ion beam 10 emitted from the synchrotron 13 and irradiating one unit from the irradiation device 30 The accumulated beam charge amount measuring means 15 for measuring the accumulated beam charge amount Q _{meas in the} synchrotron 13 and the accumulated beam charge amount measuring means 15 for measuring the accumulated beam charge amount _Qmeas measured by the accumulated beam charge amount measuring means, A target current setting means for setting a target beam current value I _fb to be emitted from the synchrotron 13 based on a target current value I _fb of a beam current And an emission beam current correction control means for controlling the emission current control means.

Description

TECHNICAL FIELD [0001] The present invention relates to a particle beam irradiation system and a method for correcting a charged particle beam,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a particle beam irradiation system and a method for correcting a charged particle beam, and particularly to a particle beam therapy apparatus for treating cancer by irradiating a charged particle beam (ion beam) An appropriate particle beam irradiation system and a method for emitting a charged particle beam.

As radiation therapy for cancer, particle beam therapy is known in which an ion beam such as a proton or a heavy ion is irradiated to a cancerous part of a patient to be treated. As the irradiation method of the ion beam, there is a uniform injection irradiation method as disclosed in Patent Documents 1 to 3 and Non-Patent Documents 1 and 2. [

Japanese Patent No. 2596292 Japanese Patent Application Laid-Open No. 2009-28500 Japanese Patent No. 4158931 Japanese Patent Application Laid-Open No. 2010-238463 Japanese Patent No. 4691583

MEDICAL PHYSICS VOLUME 36 NUMBER 8 (AUGUST 2009) P3560-3567, MEDICAL PHYSICS 36, 8 (August 2009) REVIEW OF SCIENTIFIC INSTRUMENTS VOLUME 64 NUMBER 8 (AUGUST 1993) P2074-2093 of the Review of Scientific Instruments Vol. 64, No. 8 (August 1993)

In the uniform scanning irradiation method, in order to maintain the uniformity of the irradiation dose, it is necessary not to deplete the beam in the course of irradiation of one unit of the predetermined area. On the other hand, the charge amount of the ion beam accumulated in the synchrotron is not constant but fluctuates in accordance with the current fluctuation of the ion beam supplied from the shear accelerator.

In the case where the accumulated charge amount does not reach one unit irradiation, the beam is exhausted in the middle of the irradiation, and the irradiated dose uniformity is lowered. On the other hand, if the accumulation beam not irradiated by one unit is not used, it is disadvantageous in terms of beam utilization efficiency.

An object of the present invention is to provide a particle beam irradiation system capable of increasing the beam utilization efficiency without lowering the irradiation dose uniformity.

1. A particle beam irradiation system comprising a synchrotron for accelerating and emitting an ion beam and an irradiation device for irradiating the ion beam emitted from the synchrotron and irradiating one unit of the beam from the irradiation device a plurality of times, the amount of charge (Q _meas) on the basis of the accumulated beam charge amount measuring unit and a storage beam charge amount (Q _meas) measured at the accumulated beam charge amount measuring means for measuring, setting the target beam current value (I _fb), which emitted from the synchrotron And an emission beam current correction control means for controlling the beam current based on the target value I _fb of the emission beam current obtained from the target current setting means .

According to the present invention, it is possible to provide a particle beam irradiation system capable of increasing the beam utilization efficiency without lowering the irradiation dose uniformity.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a configuration of a particle beam irradiation system which is an embodiment of the present invention. Fig.
Fig. 2 is a diagram showing a change in energy of a main beam and an amount of accumulated beam charge in an operation cycle of a synchrotron according to an embodiment of the present invention. Fig.
3 is a view showing a configuration of an irradiation apparatus which is an embodiment of the present invention.
4 is a view showing a scanning path of a beam in a uniform scanning irradiation method, which is an embodiment of the present invention.
5 is a view showing a control preparation flow before irradiation control, which is an embodiment of the present invention.
6 is a view showing a flow during beam irradiation control, which is an embodiment of the present invention;
FIG. 7 is a graph showing a change in target beam current value and a change in the accumulated beam charge amount with the target beam current value at the time of beam irradiation control by the beam irradiation control flow according to the embodiment of the present invention. FIG.
8 is a view showing a configuration of a feedback control system for an outgoing beam current, which is an embodiment of the present invention.
9 is a view showing an irradiation control flow of a beam to which a lifting irradiation control, which is an embodiment of the present invention, is added.
Fig. 10 is a diagram showing a temporal change of a target beam current value and an accumulation beam charge amount accompanying the beam irradiation control by the irradiation control flow of the beam with the raising irradiation control added as an embodiment of the present invention. Fig.

The particle beam irradiation apparatus used for particle beam therapy includes an ion beam generator, a beam transport system, and an irradiation apparatus. The ion beam generator has a synchrotron or a cyclotron that accelerates an ion beam traveling along a main trajectory to a desired energy.

The synchrotron is a high-frequency accelerator (acceleration cavity) that accelerates to a target energy by applying a high-frequency voltage to an ion beam traveling along a main circuit track, an output high-frequency electrode that increases the betatron oscillation amplitude of the circulating ion beam, (For example, Patent Document 1). When a high-frequency magnetic field or high-frequency electric field (hereinafter referred to as a high-frequency signal) is applied to the output high-frequency electrode to output the ion beam accelerated to the target energy from the synchrotron to the beam transport system, a betatron oscillation Thereby increasing the amplitude. The ion beam having the increased beta -tron oscillation amplitude travels outside the stability limit, is emitted from the synchrotron to the beam transport system, and is transported to the irradiation device.

The irradiation device shapes the ion beam derived from the ion beam generator according to the depth from the body surface of the patient and the shape of the affected part and irradiates the affected part of the patient on the treatment bed. As an irradiation method, there is a uniform irradiation method (Non-Patent Document 1, page 3561, Fig. 1).

In the uniform scanning irradiation method, since the ion beam is scanned on the irradiation plane by the scanning electromagnet, the energy loss is smaller than that of the dual scattering body irradiation system that diffuses the beam to the entire irradiation surface with the two scattering bodies, It has a characteristic that the beam can be made longer.

The uniform scanning irradiation apparatus includes two scanning electromagnets (horizontal scanning electromagnets, vertical scanning electromagnets) for scanning the beam on the irradiation plane, and an absorbed dose range (enlargement (Hereinafter referred to as "SOBP (Spread-0ut Bragg Peak)"), and a ball screw and a collimator for forming an irradiation area in accordance with the shape of the affected part. In a uniform irradiation apparatus, a ridge filter (non-patent reference 2, page 2078, Fig. 31) is used for an energy absorber forming SOBP. The ridge filter is a structure in which a plurality of wedge-shaped energy absorbing members having different thicknesses in the region through which the ion beam passes are arranged on a plane. The energy of the beam passing through the ridge filter is attenuated according to the thickness of the passing portion of the ridge filter. This energy forms the SOBP by overlapping of the attenuated ion beam.

In the uniform scanning irradiation method, a predetermined dose uniformity is achieved by repeatedly irradiating the ion beam on the irradiation plane a plurality of times (hereinafter referred to as re-painting), as described in Non-Patent Document 2, after the beam current value is suppressed to be low. Therefore, by controlling the beam current value to a constant value, deterioration of the dose uniformity on the irradiation plane can be suppressed, so that the number of repainting can be reduced and the dose rate can be improved.

A method of scanning a beam in the uniform scanning irradiation method will be described with reference to Fig. In the uniform scanning irradiation method, there can be used a unit and a blur method (for example, described in Patent Document 2), a spiral and blur method (for example, described in Patent Document 3), a raster scanning method (non-patent reference 1, page 3564, ) And line scanning methods are considered. The unit and blur method forms a flat uniformity by overlapping the Gaussian distribution of the scanned beam by scanning the irradiation beam by the scanning electromagnet, as shown in Fig. 4 (a). The spiral and blur method (not shown) scans the irradiation plane by superimposing scan trajectories whose initial phase is changed by a scanning method designed to improve the beam utilization efficiency, after securing an edge than the unit and blur method. The raster scanning method is a method of scanning the beam linearly and continuously, as described in Fig. 4 (b), unlike the above-described blur method. In the line scanning method, as shown in Fig. 4 (c), the irradiation of the beam is stopped during scanning in the single scanning direction, which is irradiated by the raster scanning method, thereby increasing the effective use efficiency of the beam.

Here, beam scanning required for irradiation of one unit will be described. First, when it is the same as the range of the beam scanning necessary for irradiation of one unit, the trajectory is scanned from the scanning start point to the end point. As shown in Fig. 4, the scanning starting point and the ending point are the same point in the unit, the blurring method, and the spiral and blurring method (not shown). Further, in the raster scanning method and the line scanning method, the scanning starting point and the ending point are different. The scanning time necessary for irradiation of these units is from 10 to 100 milliseconds per one week, so that it is sufficiently short for the emission control time (about 0.5 sec to several seconds) of the synchrotron.

Next, we explain the matters that need to be reviewed while using the description of each document. In the uniform scanning irradiation method, in order to maintain the uniformity of the irradiation dose, it is desired to irradiate the irradiation area without exhausting the beam until irradiation of the predetermined area is completed during the irradiation control. Non-Patent Document 1 employs a cyclotron as an ion beam generating apparatus. In the case of a cyclotron, the ion beam supplied to the irradiation apparatus becomes a direct current beam. However, when employing a synchrotron in the ion beam generator, the ion beam accumulated in the synchrotron is supplied to the irradiation device in accordance with the operation cycle of the synchrotron. Thereby, there is a fear that the ion beam accumulated in the synchrotron is exhausted by continuing the emission control. Therefore, when the accumulation beam of the synchrotron is depleted, the emission control is stopped and the beam scanning control of the scanning electromagnet is stopped. Thereafter, the accumulation and emission control of the ion beam and the beam scanning control of the scanning electromagnet are repeated We need to continue.

The current value of the ion beam supplied from the synchrotron to the irradiation device is set to be low and repaint is performed about 100 times so that the dose uniformity is not affected even if the irradiation of the beam accompanying the depletion of the accumulation beam charge is stopped Thereby suppressing the deterioration of the dose uniformity at the beam irradiation stop position (described in Non-Patent Document 1, page 3562). As a result, it takes a long time to irradiate a predetermined dose, so that the treatment time becomes long.

Further, outgoing beam current feedback control is devised as means for suppressing time variation of the ion beam supplied from the synchrotron. The emission beam current feedback control is performed by converting the amount of ionized charge detected by a dose monitor or the like installed in the irradiation apparatus into a current value of the ion beam and correcting the deviation of the detected current value and the target current value by the amplitude value of the output high- Correct it with the beam current value. When applying the emission beam current feedback control to the uniform scanning method, the target beam current value is controlled to a constant value. However, it is known that the charge amount of the ion beam accumulated in the synchrotron fluctuates due to the current fluctuation of the ion beam supplied from the shear accelerator of the synchrotron. Therefore, when the outgoing beam current feedback control is performed, the amount of the ion beam charge accumulated in the synchrotron decreases with respect to the outgoing beam charge amount expressed by the product of the time required for one unit of irradiation and the target current value of the outgoing beam, The beam current waveform of the latter half of the emission control is generated and the uniformity of the dose is likely to be deteriorated although the beam current feedback control is performed in accordance with the depletion of the beam charge amount.

In Patent Document 4, as a countermeasure for suppressing the beam depletion during emission control, the amount of accumulated beam charge is measured after the emission control of the beam from the synchrotron, and when the amount of accumulated beam charge does not become the amount of charge necessary for irradiation of one unit, The purpose of transition is described. By performing such control, there is a problem that the exhaustion of the beam does not occur during irradiation of one unit, but the utilization efficiency of the beam charge amount accumulated in the synchrotron is lowered.

Patent Document 5 discloses that the accumulated beam charge amount is measured before emission control to correct the target value of the emission beam current feedback control. In the correction of the target value of the feedback control, a standard value of the accumulated charge amount of the ion beam circling around the synchrotron is set in advance, and based on the comparison result between the accumulated beam charge amount measured immediately before the emission control of the synchrotron and the standard value of the accumulated charge amount, The correction of the current value is described. In Patent Document 5, since it is premised that the accumulated ion beam charge amount is emitted efficiently by one emission control, the current value of the ion beam to be supplied to the irradiation apparatus is set to be low as in the uniform scanning irradiation method, And there is no method of survey to investigate the problem.

In each of the embodiments of the present invention described below, even if the amount of accumulated beam charge in the synchrotron fluctuates, the beam depletion does not occur during irradiation of one unit, and the flatness of the irradiation dose can be ensured. Further, by efficiently using the accumulated beam charge amount in the synchrotron, the time required for irradiation with a predetermined dose can be shortened, and the treatment time can be shortened.

Each of the embodiments described below relates to a uniform irradiation method in which irradiation of one unit is performed plural times from the irradiation device. A plurality of times of irradiating one unit, that is, remapping means typically repeating irradiation of one surface to a certain irradiation plane a plurality of times. In each of the embodiments, " irradiation on one surface " in the uniform irradiation method is expressed as " irradiation in one unit ", which means that irradiation of one surface of the ion beam accumulated in the synchrotron is performed only once To clarify the difference between the two.

[First Embodiment]

A particle irradiation system, which is a preferred embodiment of the present invention, will be described with reference to Figs. 1, 2, and 3. Fig. 1, the particle beam irradiating system 1 of the present embodiment includes an ion beam generator 11, a beam transport device 14, an irradiation area forming device (a charged particle beam irradiating device, ) 30, and the beam transport device 14 makes contact with the ion beam generator 11 and the irradiation device 30 disposed in the treatment room.

The control system of the particle beam irradiation system 1 includes an accelerator control device 40 for controlling the ion beam generator 11 and the beam transport device 14, The synchrotron 13 and the beam transport device 14, which are the information planned by the treatment planning device 43 and the ion beam generating device, A timing system 50 for realizing synchronous control of the devices constituting the synchrotron 13, an interlock 41 independent of the general control device 41 for securing the safety of the patient, System 60 shown in Fig. Further, the emission control device 20 controls the high-frequency voltage used when emitting the beam from the ion beam generator 11 to the beam transport device 14. [

The ion beam generator 11 includes an ion source (not shown), a shear accelerator 12, and a synchrotron 13. The ion source is connected to the shear accelerator 12, and the shear accelerator 12 is connected to the synchrotron 13. [ The shear accelerator 12 accelerates the ion beam 10 generated from the ion source up to the energy that can be incident on the synchrotron 13. The ion beam 10a accelerated by the shear accelerator 12 is incident on the synchrotron 13.

2 (a) shows the change of energy of the main beam in the operation cycle of the synchrotron 13, and FIG. 2 (b) shows the change of the accumulated beam charge amount. The synchrotron 13 performs a series of operation control such as incidence, acceleration, emission, and deceleration at intervals of 2 to 3 seconds. In the emission control, emission preparation control is performed in advance.

The beam 10b incident on the synchrotron 13 is energized by a high-frequency voltage applied to an accelerating cavity (not shown), thereby accelerating to a desired energy. At this time, the deflecting electromagnet 18, the quadrupole electromagnet (not shown), and the like (not shown) are arranged in accordance with the increase of the circumference energy of the ion beam 10b so that the orbit of the ion beam 10b circulating in the synchrotron 13 becomes constant. The frequency of the high frequency voltage applied to the accelerating cavity is increased.

The ion beam 10b accelerated to the desired energy is subjected to irradiation control under the condition that the main beam 10b can be emitted by the energization amount of the quadrupole electromagnet and the hexagonal electromagnet Condition). After the emission preparation control is finished, a high frequency voltage is applied from the yarn use control device 20 to the output high frequency electrode 16 to increase the Bettron oscillation amplitude of the beam 10b which circulates in the synchrotron 13. The main beam 10b exceeding the stability limit condition is emitted from the synchrotron 13 to the beam transport device 14 and transported to the irradiation device 30 by the increase of the amplitude of the vibration of the betatron. The beam emission control from the synchrotron 13 can be realized at high speed by controlling ON / OFF of the high-frequency voltage applied to the output high frequency electrode 16 by the emission control device 20.

The accumulated beam charge amount 70 in the synchrotron 13 changes as shown in Fig. 2 (b) in accordance with the operation sequence of the synchrotron 13 (Fig. 2 (a)). When the ion beam 10a is incident on the synchrotron 13, the amount of accumulated beam charge gradually increases. In the initial stage of the acceleration control, the ion beam is lost due to the space charge effect and the like, so that the amount of charge of the accumulation beam is attenuated. The synchrotron 13 emits the ion beam 10b from the synchrotron 13 every amount of charge Q _scan necessary for irradiation of one unit. When irradiation of one unit is completed, emission of the beam is stopped for preparation of movement of the irradiation device 30 to be described later to the irradiation starting point of the scanning electromagnet 32 to be described later. The beam charge amount Q _loss remaining in the synchrotron 13 without repeating the emission and stop of such a beam so as to be completely emitted to the emission control period is decelerated to a low energy by the subsequent deceleration control and is destroyed.

Fig. 3 shows the configuration of the irradiation apparatus. The irradiating device 30 scans the irradiation plane with the scanning electromagnet 32 and measures the irradiation dose of the beam 10d irradiated to the patient by using a dose monitor 31 or a beam shape monitor , The beam intensity of the beam 10d to be irradiated and the beam shape are checked in order. The beam 10d scanned by the scanning electromagnet 32 passes through the energy absorbing member 33 to form an SOBP adapted to the thickness in the ring depth direction. The beam formed with the SOBP is irradiated with an intrinsic jig matching the annular shape 37 of the patient 36, such as the collimator 34 or the bolus 35,

A method of controlling the output high frequency voltage in the emission control device 20 will be described with reference to FIG. The high-frequency oscillator 21 outputs a high-frequency signal having a center frequency Fc of an output high-frequency voltage controlled by energy. The high-frequency signal output from the high-frequency oscillator 21 is mixed with the band-limited high-frequency signal output from the band-limited high-frequency signal generator 22 and the high-frequency mixer 221. Thus, a band-limited high-frequency signal having a center frequency Fc and a frequency width of 2Fw is obtained. The mixed-band limited high-frequency signal controls the amplitude value of the high-frequency voltage in the beam current feedback control circuit 24 so as to realize the beam current intensity waveform (the target value of the beam current intensity) obtained by the target beam current correction calculating section 29 . The beam current feedback control circuit 24 is constituted by an amplitude modulator 23, a feedback loop gain adjuster 241, a feedback loop gain adjuster 242, an addition operation circuit 243 and a high frequency switch 25. First, the deviation between the dose monitor detection signal 311 detected by the dose monitor 31 and the target beam current value I _fb set by the target beam current correction calculating section 29 is calculated by the feedback loop gain adjuster 241 . The feedback loop gain adjuster 241 calculates the feedback correction signal based on the feedback gain. The addition operation circuit 243 adds the amplitude modulation signal Am and the feedback correction signal to correct the amplitude modulation signal. By setting the addition result in the amplitude modulator 23, beam current feedback control is realized.

The high frequency signal whose amplitude value is controlled by the beam current feedback control circuit 24 is transmitted to the high frequency power amplifier 17 through the high frequency switch 26 controlled by the interlock system 60. The band-limited high-frequency signal amplified by the high-frequency power amplifier 17 is applied to the output high-frequency electrode 16. Frequency signal applied to the output high frequency electrode 16 increases the amplitude of the Bettron oscillation of the beam 10b circulating in the synchrotron 13 and is emitted from the synchrotron 13 to the beam transport device 14. [

5, 6, 7, and 8, a description will be given of a calculation processing method of the target beam current in the target beam current correction arithmetic unit 29 constituting the output control device 20, which is a feature of the present embodiment Explain. Fig. 5 shows a control preparation flow before irradiation control is started, and Fig. 6 shows a flow at the time of beam irradiation control. Fig. 7 shows the change of the target beam current value during the beam irradiation control according to the control flow at the time of beam irradiation shown in Fig. 6 and the accumulation beam charge amount with time. Fig. 8 shows a configuration of a feedback control system for an emission beam current.

The calculation setting flow of the target beam current value used for the emission beam current feedback control before irradiation will be described with reference to Fig. First, a method of setting the initial value of the target beam current value I _fb used for the emission beam current feedback control will be described before starting the irradiation treatment to the patient. The treatment planning device 43 calculates the total irradiation dose to the patient 36 and registers it in the storage device 42. [ In the storage device 42, conversion table data of the irradiation charge amount with respect to the irradiation dose is prepared in advance. The general control device 41 reads out the total irradiation dose calculated by the treatment planning device 43 based on the irradiation condition from the treatment scheduler (not shown), and outputs the total irradiation dose calculated by the treatment planning device 43 The total irradiation charge amount Q _target necessary for obtaining the dose is calculated from the conversion table data prepared in advance in the overall control device 41. [ The collective control device 41 transmits the total irradiation amount Q _target and the setting condition of the irradiation device to the irradiation control device 44 and the irradiation control device transmits information such as the total irradiation charge amount Q _target .

The irradiation control device 44 calculates the reference beam current value I _scan at one unit of irradiation based on the beam current control range that can be emitted from the synchrotron and, based on the scanning speed of the scanning electromagnet 32, A scan time (T _scan ) necessary for irradiation of one unit is set (801).

Next, the amount of charge (Q _scan ) necessary for one unit of irradiation and the number of times of repainting (N _r ) are calculated (802). The amount of charge Qscan required for irradiation of one unit can be obtained by _multiplying the reference beam current value I _scan in one unit of irradiation and the scanning time T _scan necessary for irradiation in one unit, . ≪ / RTI > The number of repaints (N _r ) can be calculated by dividing the total irradiation charge amount (Q _target ) by the amount of charge (Q _scan ) necessary for irradiating one unit, as shown in (2).

(803) by setting the total irradiation charge amount (Q _target ) to the remaining irradiation irradiation amount (Q _rest ) in the irradiation area. The remaining irradiation charge amount Q _rest is obtained by subtracting the accumulated value (accumulated irradiation electric charge amount Q _sum ) of the electric charge amount irradiated to the affected part from the total irradiation electric charge amount Q _target . Further, initialization is performed by setting 0 to the accumulated irradiation charge amount Q _sum (804).

The reference beam current value I _scan at the irradiation of one unit is set as the initial value of the target beam current value I _fb of the emission beam current feedback control in the emission control device 20 (805). The above-described control flows 801 to 805 are executed by the irradiation control device 44. The irradiation preparation control shown in Fig. 5 is performed only in the operation cycle at the start of irradiation to the patient, and not in the second and subsequent operation cycles.

The irradiation control flow of the beam will be described with reference to Fig. The synchrotron 13 accelerates the beam incident from the shear accelerator 12 to a predetermined energy (811). After the beam acceleration control is completed, the accumulated beam charge amount Q _meas accumulated in the synchrotron is measured (812). The accumulation beam charge amount Q _meas is measured using the accumulated beam charge amount detecting means 15 such as DCCT provided in the synchrotron 13. [ The measurement results of the accumulated beam charge amount _Qmeas are stored in the emission controller 20 and the target beam current correction calculator 29 constituting the emission controller 20 performs the processing shown in the following control flow do.

The target beam current correction calculating unit 29 first determines whether the accumulated beam charge amount Q _{meas in the} synchrotron 13 is exhausted (813). When the accumulation beam charge amount is exhausted (Q _{meas? 0} ), the control proceeds to deceleration control of the beam (814).

(Q _meas > 0), the remaining charge quantity Q _rest is compared with the accumulated beam charge quantity Q _meas to determine the charge quantity to be set as the compared charge quantity Q _comp (815). The comparative charge amount Q _comp refers to the amount of charge that becomes a reference at the time of correction control of the reference beam current value I _scan in irradiation of one unit, which will be described later. The accumulated beam charge amount Q _meas is set (816) in the compared charge amount Q _comp , and the accumulated beam charge amount Q _meas is set to the measured beam charge amount Q _meas in the case where the remaining irradiation amount Q _rest is larger than the accumulated beam charge amount Q _meas for the remaining amount of charge and sets a residual irradiation irradiation charge (Q _rest) is the, compared to the amount of charge (Q _comp), if (Q _rest) is less (817). That is, the smaller one of the remaining irradiation charge amount Q _rest and the accumulation beam charge amount Q _meas is set as the comparison charge amount Q _comp .

Next, the comparative charge amount Q _comp is compared with the charge amount Q _scan necessary for irradiation in one unit (818). Comparing the amount of charge (Q _comp) is in many cases than the amount of charge (Q _scan) required for irradiation of the first unit (Q _comp ≥Q _scan), the emitted beams of the current feedback control to the target value, the target beam current value (I _fb) of No correction is made (819). In Comparative amounts if (Q _comp) is less than the amount of charge (Q _scan) required for irradiation of the first unit (Q _comp <Q _scan), the target beam current value (I _fb) the reference beam current in one unit of irradiation Is corrected to be smaller than the value I _scan (820).

As described above, the target beam current correction calculating unit 29, which is the target current setting unit, determines the target value I _fb of the beam current based on the reference beam current value I _scan in one unit irradiation, It is possible to perform control in which the variation of the beam current caused by the accelerator is properly adjusted by the correction. In this embodiment, it is checked in advance whether or not the amount of charge necessary for one unit of irradiation is stored in the synchrotron before the irradiation of one unit. If the amount of accumulated beam charge in the synchrotron is small, the value of the outgoing beam current is corrected Thereby suppressing beam depletion during one unit irradiation, thereby ensuring uniformity of irradiated dose.

The target beam current value I _fb is calculated by _subtracting the reference beam current value I _scan in one unit of irradiation from the comparison electric charge amount Q _scan required for irradiation of one unit, (Q _comp ).

In this manner, the comparison charge quantity Q _comp is used to determine the target value I _fb of the target beam current by the target beam current correction calculation section 29 as the target current setting means. As a result, the beam current can be appropriately set so as to increase the beam utilization efficiency without generating beam depletion during irradiation of one surface. By efficiently using the accumulated beam charge amount in the synchrotron, the time required for irradiation with a predetermined dose can be shortened and the treatment time can be shortened. If beam depletion can be suppressed during irradiation of one unit, the beam current value at the time of irradiation of one unit can be increased to reduce the number of repainting, so that the time required for irradiation with a predetermined dose is shortened and the treatment time is shortened .

Based on the target beam current value I _fb described above, the beam current feedback control circuit 24, which is a part of the yarn use control device 20, carries out the emission beam current feedback control and outputs the beam current feedback control from the synchrotron 13 to the irradiation device 30) (821). When irradiation of one unit is completed, the amount of charges irradiated on the accumulated irradiation charge amount (Q _sum ) is added (822). At this time, the cumulative irradiation charge quantity Q _sum is obtained by multiplying the cumulative irradiation charge quantity Q _sum by multiplying the target beam current value I _{fb by} the scanning time T _scan of one unit, as shown in the formula (4) . Along with this, the remaining irradiation charge amount Q _rest is updated (823). The remaining irradiation charge amount Q _rest is obtained by subtracting the cumulative irradiation charge amount Q _sum from the total irradiation electric charge amount Q _target as shown in (Equation 5).

Finally, the cumulative irradiation amount Q _sum is compared with the total irradiation amount Q _target (824). When the accumulated irradiation charge quantity Q _sum reaches the total irradiation charge quantity Q _target (Q _sum ? Q _target ), the beam irradiation control is terminated and the accumulated irradiation charge quantity Q _sum reaches the total irradiation charge quantity Q _target If not (Q _sum <Q _target ), control returns to the control flow 812 to continue the beam irradiation control.

Hereinafter, the reason for comparison between the remaining irradiation charge amount Q _rest and the accumulated beam charge amount Q _meas , which is also a feature of this embodiment, in the control flow 815 will be described.

First, when the second half of the emission control time T _ext of the synchrotron, the accumulated beam charge amount Q _meas is _smaller than the amount of charge Q _scan necessary for irradiation of one unit. The amount of charge required for the irradiation of the first unit (Q _scan) than the accumulated beam charge amount (Q _meas) is Continuing the output control in the low state, discarded the beam is depleted before completion of the irradiation of the first unit, the dose uniformity within the irradiation zone deteriorate . Therefore, conventionally, the beam current value at the time of irradiating one unit is made low, and the effect of unevenness of the dose uniformity occurring at the time of beam depletion is reduced by taking a sufficient number of repaints (N _r ). As a result, the dose rate did not increase and treatment time was required.

Further, when the end of the beam irradiation control is reached, the remaining irradiation charge amount Q _rest is reduced. That is, it approaches the total irradiation dose (Q _target ) that satisfies the required irradiation dose. In this state, on the basis of the amount of charge required for the irradiation of the first unit (Q _scan), it is smaller than the amount of charge (Q _scan) required for irradiation of the irradiation amount of charge remaining (Q _rest) by the lapse of the irradiation control unit 1. In the conventional technique, as described in Patent Document 4, when the accumulated beam charge amount Q _meas becomes smaller than the amount of charge ( _Qscan ) necessary for irradiation of one unit, since the transition to the deceleration control is made, The accumulated beam charge amount Q _{meas that} is smaller than the required charge amount Q _scan is decelerated without being used for irradiation, so that the beam utilization efficiency can not be increased.

When performing correction of the target beam current value I _{fb in the} outgoing beam current feedback control in accordance with these two situations (820), either of the remaining irradiation charge amount Q _rest and the accumulated beam charge amount Q _meas since either by correcting the smaller one as compared to the amount of charge (Q _comp), while satisfying the dose uniformity, can be accompanied by the improvement of the beam use efficiency improves dose rate, it is possible to reduce the treatment time.

The time variation of the target beam current value and the accumulated beam charge amount accompanying the beam irradiation control by the control flow at the time of beam irradiation will be described with reference to FIG. In this embodiment, the case where the accumulated beam charge amount Q _meas is measured five times within the emission control time T _ext and the emission control is performed, and the case where the remaining irradiation charge amount Q _rest is sufficiently large is assumed.

The accumulation beam charge amount (Fig. 7A) is set in the synchrotron 13 based on the accumulation beam charge amount confirmation signal 501 (Fig. 7B) after the acceleration control of the synchrotron 13 is finished And the accumulated beam charge amount detection means 15 measures the accumulated beam charge amount. At this time, the accumulated beam charge amount is Q _meas1 . Accumulated beam charge amount is more than Because of the high amount of charge (Q _scan) required for irradiation of the first unit, comparing the amount of charge (Q _comp) is in Q _meas1, and correcting the target beam current value (I _fb) is not carried out. Therefore, the target beam current value (Fig. 7 (c)) is set as the reference beam current value I _scan at the irradiation of one unit which is the initial set value.

Emission control based on the emission beam current feedback control is started based on the beam emission control signal (Fig. 7 (d)). As a result, a beam 10d of a constant current is supplied to the irradiation device 30, and the beam current value I _dose converted from the detection signal of the dose monitor 31 is confirmed (Fig. 7 (e) ). After the irradiation of the beam at the scanning time (T _scan ) of one unit is completed, the beam emission control is stopped and the accumulated beam charge amount is measured. In this embodiment, similarly, the steps from the beam measurement to the emission control are repeated three times (Q _{meas2 to} Q _meas4 ).

The accumulated beam charge amount Q _meas is measured based on the confirmation signal of the fifth accumulation beam charge amount. The accumulated beam charge amount is Q _meas5, since ever more than the amount of charge (Q _scan) required for irradiation of the first unit, comparing the amount of charge (Q _comp) is in Q _meas5 and, there is a need for correction of the target beam current value (I _fb) . Accordingly, correction of the target beam current value (I _fb) is, by carrying out on the basis of (Equation 3), the target beam current value (I _fb), the reference beam current value of the one unit of irradiation (I _scan) . By performing the emission control by the emission beam current feedback control based on the target beam current value I _fb , the beam current value I _dose converted from the dose monitor detection signal is irradiated.

Next, a method of operating the particle beam irradiating apparatus to which the present embodiment is applied will be described with reference to Fig. The doctor inputs patient information (position and size of the affected part, irradiation direction of the beam, and maximum irradiation depth) into the treatment planning device 43. The treatment planning device 43 calculates the SOBP width, the irradiation area size, and the target dose for the affected part based on the inputted patient information, using the treatment planning software.

The result calculated by the treatment planning device 43 is recorded in the storage device 42. [ The collective control device 41 transmits the total irradiation charge amount Q _target and the irradiation condition to the irradiation control device 44 based on the irradiation condition from the treatment scheduler (not shown). The irradiation control device 44 selects the setting conditions of the devices constituting the irradiation device and sets the irradiation conditions of the irradiation control device 20 to the irradiation control quantity Q _target or the reference beam current (I _scan ), the scan time (T _scan ) required for one unit of irradiation, the amount of charge (Q _scan ) required for one unit of irradiation, and the number of times of repainting (N _r ). The calculation and the like of the amount of charge (Q _scan ) required for irradiation of one unit, which is a feature of the present embodiment, are performed by the irradiation control device 44 based on the information from the treatment planning device 43. [

The treatment plan information is displayed on a display device (not shown) arranged in the control room of the treatment room preparing for treatment. The radiographer confirms the display screen and places the energy absorbing member 33 designated by the display in the irradiation device 30. [

In accordance with an instruction from the general control device 41, the treatment bed control device (not shown) moves the treatment bed to which the radiologist fixes the patient, Position.

The accelerator control device 40 determines the irradiation beam energy from the treatment plan information from the collective control device 41 and sets the operation control parameters of the devices constituting the synchrotron 13 and the beam transport device 14. [ For the output control device 20, in response to the exit beam energy, and sets the output operation using the control parameters, the center frequency Fc, the frequency width Fw of a high-frequency signal, the amplitude modulation data Am, the feedback gain G _fb.

The doctor instructs the collective control device 41 to start the irradiation from the operation panel in the above-mentioned control room. Based on the irradiation start instruction, the shear accelerator 12 accelerates an ion beam (for example, both ions (or carbon ions such as carbon ions)) generated from the ion source and supplies it to the synchrotron 13.

The synchrotron 13 accelerates the ion beam 10a incident from the shear accelerator while circulating the synchrotron 13 to a desired energy. The ion beam 10b is accelerated to the target beam energy and then is stored in the accumulation beam charge quantity detecting means 15 based on the accumulated beam charge quantity confirmation signal 501 outputted from the timing system 50 _meas . The target beam current correction calculating section 29 sets the target beam current value I _fb of the outgoing beam current feedback control circuit 24 on the basis of the accumulated beam charge amount Q _meas . Thereafter, the output high frequency signal is applied to the output high frequency electrode 16 by the beam output control signal 502 output from the timing system 50, thereby controlling the output voltage of the output high frequency electrode 16 based on the target beam current value I _fb A beam is emitted from the synchrotron (13).

In this embodiment, the detection of the accumulated beam charge amount is performed based on the accumulated beam charge amount confirmation signal 501 output from the timing system 50 to detect the accumulated beam charge amount corresponding to the irradiation of the first unit , The accumulation beam charge amount confirmation signal 501 after the next unit is generated based on the input of the beam emission control signal 502 input from the timing system 50 as a starting point and the scanning time T _scan and the irradiation stop time T _off) to, but is detected based on a signal calculated from the output control unit 20, the illumination control device (44) the accumulated beam charge amount corresponding to all the irradiation surface on the outside of the output control device 20, such as based on The effect is not changed even if a device for generating the confirmation signal 501 is installed.

The beam output control in the present embodiment is performed by inputting the beam output control signal 502 from the timing system 50 to the emission control device 20 and outputting the target beam current correction operation section Frequency switch 25 is opened based on the beam output control signal 252 from the synchrotron 13 to the irradiation device 30 during the irradiation stop time T _off between irradiation of one unit The supply is stopped.

The ion beam 10c emitted from the synchrotron 13 passes through the beam transport device 14 and arrives at the irradiation device 30. [ The ion beam 10d is advanced along the beam path in the irradiation device 30 and the ion beam 10d is scanned by the scanning electromagnet 32 to form SOBP in the energy absorbing member 33, The affected part is irradiated.

The dose of the ion beam irradiated to the affected part is measured by the dose monitor 31. [ The detection signal 311 from the dose monitor 31 is input to the emission beam current feedback control circuit 24 and the target beam current value I _fb and the detected beam current value I _dose in the dose monitor 31 The amplitude control value of the high-frequency voltage based on the deviation of the output beam current is controlled to a constant value by feedback correction.

When irradiation of one unit to the affected part is completed, the beam emission control is stopped, the excitation quantity of the scanning electromagnet is returned to the irradiation start position, and the cumulative irradiation charge quantity Q _sum is recorded. Thereafter, the accumulated beam charge amount is measured. Corrects the target beam current value according to the measurement result, and starts irradiation of one unit again. These controls are repeated to irradiate the beam until the accumulated irradiation charge amount Q _sum reaches the total irradiation charge amount Q _target .

In the apparatus constituting the particle beam irradiation system 1, when there is something obstructive to beam irradiation to the patient during the irradiation control, the interlock system 60 determines that the state of the apparatus is abnormal (Abnormality signal) 601 to the interlocking high-frequency switch 26 of the output control device 20 in parallel with the integrated control device 41. [ The yarn use control device 20 receives the abnormal signal 601 from the interlock system 60 as a beam emission stop command and immediately opens the interlocking high frequency switch 26. [ The interlocking high-frequency switch 26 is opened so that the application of the output high-frequency signal to the high-frequency electrode 16 is stopped. Thereby, the synchrotron 13 can realize the interlock control for stopping the emission of the ion beam 10b.

According to this embodiment, the following effects can be obtained.

(1) In the present embodiment, the scanning range from the irradiation starting position to the ending position in the irradiation area is set as a unit of scanning range, and the scanning range of this unit is managed as an irradiation unit. The accumulated beam charge amount Q _{meas in the} synchrotron 13 in turn is measured and the accumulated beam charge amount (hereinafter referred to as &quot; Q &quot;) with respect to the amount of charge Q _scan necessary for irradiation in one unit The target beam current correction arithmetic unit 29 corrects the target beam current value of the emergent beam current feedback control circuit 24 in accordance with the measured beam current value Q _meas . As a result, it is possible to suppress the occurrence of depletion of the accumulated beam charge amount in the synchrotron 13 during irradiation of one unit.

(2) In the present embodiment, as described above, the accumulated beam charge amount in the synchrotron 13 is sequentially measured before irradiating one surface, and the target beam current value of the outgoing beam current feedback control is corrected based on the measurement result , There is no depletion during irradiation of the first surface. Therefore, it is not necessary to lower the target beam current value of the emission beam current feedback control in consideration of the deterioration of the dose uniformity when the accumulation beam charge amount is depleted in the middle, as in the prior art. This makes it possible to increase the target beam current value of the outgoing beam current feedback control when one surface is irradiated, thereby improving the dose rate and further shortening the treatment time.

(3) In this embodiment, it is not necessary to continuously monitor the exhaustion charge amount 70 for exhaustion, and the beam emission control accompanying the depletion of the accumulated beam charge amount 70 and the stop processing of the beam scanning control become unnecessary, The configuration and control method of the control apparatus constituting the particle beam irradiation system can be simplified. In the system for continuously monitoring whether or not the accumulated beam charge amount 70 in the synchrotron 13 is exhausted during irradiation of the one surface, in the case where the beam 10b is depleted, the emission control of the beam 10b is stopped, The beam scanning control in the electromagnet 32 is stopped. Thereafter, it is necessary to start the beam emission control from the synchrotron 13 and the beam scanning control in the scanning electromagnet 32 after the beam is again incident on the synchrotron 13 and accelerated.

[Second Embodiment]

A second embodiment of the present invention is shown. The apparatus configuration of this embodiment is the same as that of the first embodiment, but the target beam current correction arithmetic unit 29 differs from the correcting method of the target beam current value I _fb .

The irradiation control flow of the beam will be described with reference to Fig. The difference from Fig. 6, compare the target amount of charge based on the target beam current value correction control in place of (818-820 in Fig. 6), the lifting amounts of irradiated (I _fb) (Q _carry) based on the (Q _comp) (825 to 828 in Fig. 9) of the beam current value I _fb .

In the case of the first embodiment, the accumulation beam charge amount Q _meas decreases with the elapse of the emission control time T _ext of the synchrotron. In the latter half of the emission control time T _ext , it is conceivable that the accumulated beam charge amount Q _meas is very small with respect to the amount of charge Q _scan required for irradiation of one unit. This is because, even when the irradiation control is advanced and the remaining irradiation charge amount Q _rest is decreased, it is necessary to irradiate a small amount of charge similarly. Therefore, it is necessary to perform irradiation control of one unit in order to effectively use the accumulated beam charge amount Q _meas or to satisfy the total irradiation charge amount Q _target .

This processing is, when the beam charge amount (Q _meas) accumulated in the synchrotron 13, after the acceleration control end is not an integral multiple of the first amount of charge (Q _scan) required for irradiation of the unit is, is generated and operation cycle at each of the synchrotron Throw away.

Therefore, in this embodiment, after the comparative charge amount Q _comp is set (the control flow of 815 to 817 in Fig. 9), the amount of charge for _carry- up Q _carry shown in (Equation 6) is calculated (825) .

The _carry-in charge quantity Q _carry shown in Equation (6) is obtained by subtracting the charge quantity ( _Qscan ) necessary for irradiation of one unit from the comparison charge quantity (Q _comp ). The charge quantity (Q _carry ) required for the irradiation of one unit is compared with the charge quantity (Q _scan ) required for irradiation of one unit (826).

When lifting irradiation amount of charge (Q _carry) is less than the amount of charge (Q _scan) required for irradiation of the first unit (Qcarry≤Qscan), the lifting of the correction target current value is not performed (827), lifting irradiation amount of charge ( when Q _carry) is larger than the amount of charge (Q _scan) required for irradiation of the first unit (Qcarry> Qscan) it is (is subjected to lifting the correction of the target current value shown in equation (7)) 828.

Rounded irradiation amount of charge (Q _carry) drag is, the first embodiment is to be pulled more the amount of charge (Q _scan) required for irradiation of the first unit from the comparison the amount of charge (Q _comp) were used for the determination of the correction of the target current value, . That is, when the non-second dose for a second by first subtracting the amount of charge (Q _scan) required for irradiation of a unit over the time, accumulated beam charge amount of charge (Q _scan) required for irradiation of the first unit (Q _meas), accumulation The irradiation time can be shortened by irradiating the beam charge quantity Q _meas by one irradiation.

The above can also be expressed as comparing the amount of charge (Q _scan ) necessary for irradiation of one unit by two times and the comparison charge amount (Q _comp ). The target beam current value I _fb is larger than the beam current value I _scan necessary for irradiation of one unit when the comparison charge quantity Q _comp is smaller than twice the charge Q _scan required for one unit irradiation It is possible to shorten the irradiation time by irradiating the wafer. Specifically, as shown in (Equation 7), the target beam current value I _fb is obtained by dividing the accumulated beam charge amount Q _meas by the scanning time T _scan required for irradiation of one unit .

In this way, as the determination criterion of the necessity of correction, compared to the amount of charge (Q _comp) and 1 by utilizing the comparison values of the amount of charge (Q _scan) required for irradiation of the unit, is possible proper control according to the accumulated beam charge amount (Q _meas) It becomes. I.e., the comparison the amount of charge as in the first embodiment (Q _comp) In this case, less than the amount of charge (Q _scan) required for irradiation of the first unit, can be controlled to be high beam efficiency while avoiding the beam depletion of the first surface irradiated have. Also can be shortened, compared to the amount of charge (Q _comp) yi irradiation time by a moderately high when compared with the first amount of charge (Q _scan) required for irradiation of the unit, the lifting irradiation as shown in the second embodiment. It is also possible to adopt a judgment criterion which is a combination of the judgment criterion of the first embodiment and the judgment criterion of the second embodiment. In this case, the merit of both can be enjoyed.

Also in the second embodiment, the effect of the charge amount, but to compare the comparison (Q _comp) the amount of charge (Q _scan) required for irradiation of the first unit two times that is greater than one time does not need to be doubled, the same can be obtained. The number of times can be determined depending on whether a certain amount of charge can be examined in one unit of irradiation. In the latter half of the emission control period, when the accumulated beam charge amount in the synchrotron is slightly larger than the amount of charge required for irradiation of one unit, when the irradiation of the beam is completed at one time by the irradiation charge amount increasing means, The time required for irradiation of a predetermined dose can be shortened and the treatment time can be shortened.

The time variation of the target beam current value and the accumulated beam charge amount accompanying the beam irradiation control by the control flow at the time of beam irradiation will be described with reference to Fig. In order to make the explanation easy to understand, the accumulated beam charge amount Q _meas1 after completion of the acceleration control shown in Fig. 10 and the amount of charge Q _scan necessary for irradiation of one unit are the same as those in Fig.

In Figure 10, by the first time from the accumulated beam charge amount in the third-time measurement (Q _meas1 ~Q _meas3), lifting irradiation does not conduct, the embodiment of the fourth measurement (Q _meas4) when, lifting irradiation, Fig. I am investigating the charge that I had been investigating divided by two times in seven by one. Therefore, as compared with Fig. 7, the target beam current value I _{fb for the} fourth irradiation is higher than the reference beam current value I _{scan for} one unit irradiation, and the fifth irradiation control is not performed The irradiation time can be shortened by the irradiation stop time (T _off ) between the scanning time (T _scan ) of one unit and the irradiation of one unit.

According to the present embodiment, the amount of charge Q _scan required for irradiation of one unit, which is generated when the accumulated beam charge amount Q _meas after completion of the acceleration control is not an integral multiple of the charge amount Q _scan required for irradiation of one unit ), The irradiation time can be shortened. Since this lifting process occurs every operation cycle of the synchrotron, the effect of shortening the irradiation time is large, and it is possible to shorten the treatment time of another layer.

Thus, in the latter half of the emission control period, when the accumulated beam charge amount in the synchrotron is slightly larger than the charge amount required for irradiation of one unit, the beam irradiation is divided into two, The time required for irradiation with a predetermined dose can be shortened and the treatment time can be shortened.

In the particle beam irradiation system of each embodiment described above, the irradiation control device 44 calculates the beam current value I _scan necessary for irradiation of one unit, and the accumulated beam charge amount measuring means calculates the cumulative beam charge amount Q _meas And the target current setting means corrects the beam current value I _scan necessary for one unit irradiation based on the accumulated beam charge amount Q _meas so that the target beam current value I set _fb), and by controlling the beam current based on an output using the control device 20 having the emission beam current correction control means, the target beam current value (I _fb), and corrects the charged particle beam. By correcting the charged particle beam in this manner, it is possible to realize the particle beam irradiation system capable of increasing the beam utilization efficiency without lowering the irradiated dose uniformity.

1: Particle irradiation system
10a, 10b, 10c, 10d: beam
11: An ion beam generator
12: shear accelerator
13: Synchrotron
14: beam transport device
15: accumulation beam charge quantity detection means
16: High-frequency electrode
17: High-frequency power amplifier
18: biased electromagnet
20: Output control device
21: High-frequency oscillator (high-frequency oscillator)
22: band-limited high-frequency signal generator
23: Amplitude modulator
24: beam current feedback control circuit
25, 26: High-frequency switch
27: Output high frequency signal processor
29: Target beam current correction operation section
30: Irradiation unit
31: Dose monitor
32: scanning electromagnet
33: Energy absorber
34: Collimator
35: Bolus
36: Patient
37:
38: Beam scanning path
4O: Accelerator control device
41: Integrated control device
42: storage device
43: Treatment planning device
44: Irradiation control device
50: Timing system
60: Interlock system
221: High frequency mixer
241, 242: feedback loop gain regulator
243: Addition operation circuit
252: beam emission control signal
311: The dose monitor detection signal
501: accumulation beam charge amount confirmation signal
502: beam emission control signal
Q _target : total charge
Q _scan : the amount of charge required for one unit of irradiation
Q _rest : Remainder charge
Q _sum : cumulative irradiation charge amount
Q _meas : accumulation beam charge quantity
Q _comp : comparative charge
Q _carry : the amount of charge to raise
Q _ext : the amount of outgoing beam charge from the synchrotron
T _ext : emission control time
T _scan : 1 unit scan time
T _off : the irradiation stop time between one unit of irradiation
N _r : Number of repaints
N _scan : the number of times of irradiation in one unit within the emission control time
I _scan : Reference beam current value in one unit of irradiation
I _fb : target beam current value
I _dose : beam current value

Claims (14)

1. A particle beam irradiation system comprising a synchrotron for accelerating and emitting an ion beam and an irradiation device for irradiating the ion beam emitted from the synchrotron,
Receiving means for receiving a total irradiation charge amount necessary for the plurality of irradiation,
An exit control device for calculating an accumulated irradiation charge amount,
An accumulation beam charge quantity measuring means for measuring an accumulation beam charge quantity in the synchrotron;
And a target beam current value for setting a target beam current value to be emitted from the synchrotron by using the comparison charge amount when the smaller of the remaining irradiation charge amount and the accumulation beam charge amount obtained by subtracting the accumulated irradiation charge amount from the total irradiation charge amount is a comparison charge amount, Setting means,
An output beam current correction control means for controlling the beam current based on the target beam current value obtained from the target current setting means
And the particle beam irradiating system. delete The method according to claim 1,
And an irradiation control device for calculating the amount of charge necessary for irradiation of one unit,
Wherein the target current setting means uses a comparison value between the comparison charge amount and the charge amount necessary for irradiation of the unit as a criterion for determining whether correction is necessary. The method according to claim 1 or 3,
And an irradiation control device for calculating a beam current value required for irradiation of one unit,
Wherein the target current setting means determines the target value of the beam current based on the beam current value required for irradiation of the unit. The method according to claim 1 or 3,
Wherein the target current setting means corrects the target beam current value so that the target beam current value becomes smaller than the beam current value required for irradiation of one unit when the comparison charge amount is smaller than the charge amount required for irradiation of the one unit Ray irradiation system. 6. The method of claim 5,
Wherein the target beam current value is obtained by correcting a beam current value required for irradiating the one unit with a ratio of the comparative charge amount to a charge amount necessary for irradiating the one unit. The method according to claim 1 or 3,
The target current setting means corrects the target beam current value to be larger than the beam current value required for irradiation in the unit of one when the comparison charge amount is smaller than two times the amount of charge required for irradiation of one unit The particle beam irradiation system. 8. The method of claim 7,
Wherein the target beam current value is obtained by dividing the accumulated beam charge amount by a scanning time necessary for irradiation of one unit. There is provided a method for correcting a charged particle beam in a particle beam irradiation system comprising a synchrotron for accelerating and emitting an ion beam and an irradiation device for irradiating the ion beam emitted from the synchrotron, As a result,
The receiving means receives the total irradiation charge amount necessary for the irradiation for the plurality of times,
The exit control device calculates the accumulated irradiation charge amount,
The irradiation control device calculates a beam current value required for irradiation of one unit,
The accumulated beam charge amount measuring means measures the accumulated beam charge amount in the synchrotron,
Wherein the target current setting means sets the target current to be used for the irradiation of the one unit by using the comparison charge amount when the smaller of the remaining irradiation charge amount and the accumulated beam charge amount obtained by subtracting the cumulative irradiation charge amount from the total irradiation charge amount is the comparison charge amount, A target beam current value to be emitted from the synchrotron is set by correcting the current value,
Wherein the emission beam current correction control means controls the beam current based on the target beam current value. 5. The method of claim 4,
Wherein the target current setting means corrects the target beam current value so that the target beam current value becomes smaller than the beam current value required for irradiation of one unit when the comparison charge amount is smaller than the charge amount required for irradiation of the one unit Ray irradiation system. 5. The method of claim 4,
The target current setting means corrects the target beam current value to be larger than the beam current value required for irradiation in the unit of one when the comparison charge amount is smaller than two times the amount of charge required for irradiation of one unit The particle beam irradiation system. 6. The method of claim 5,
The target current setting means corrects the target beam current value to be larger than the beam current value required for irradiation in the unit of one when the comparison charge amount is smaller than two times the amount of charge required for irradiation of one unit The particle beam irradiation system. The method according to claim 6,
The target current setting means corrects the target beam current value to be larger than the beam current value required for irradiation in the unit of one when the comparison charge amount is smaller than two times the amount of charge required for irradiation of one unit The particle beam irradiation system. The method according to claim 1,
The accumulation beam charge amount measuring means measures the accumulated beam charge amount every irradiation of one unit within the emission time and the target current setting means corrects the target beam current value every irradiation of one unit And the particle beam irradiation system.

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