JP4256127B2 - Intensive irradiation type radiotherapy device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an intensive irradiation type radiotherapy apparatus having an X-ray computed tomography function.
[0002]
[Prior art]
An X-ray computed tomography apparatus that irradiates a subject with X-rays and reconstructs image data from transmission data is known. This X-ray computed tomography apparatus can be improved to a specification that allows high-dose irradiation, and the collimator (X-ray diaphragm) can be trimmed to an arbitrary shape so that no radiation other than the treatment target is irradiated. By adopting a multi-leaf collimator, there is a movement to try to combine it with intensive irradiation type radiotherapy.
[0003]
This dual-purpose machine eliminates the need to transfer the subject from the X-ray computed tomography apparatus to the radiation therapy apparatus in a series of operations from image generation for positioning to treatment, and is placed on a single device. The treatment time can be shortened and the positioning accuracy can be improved by reducing the chance that the subject will be displaced during the period from positioning to treatment start. It has the advantage of being able to plan. This advantage is exceptional, and this type of dual-purpose machine is considered to be more popular.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to provide an intensive irradiation type radiotherapy apparatus capable of confirming an area to be treated together with an irradiation concentration area with an image during treatment.
[0005]
[Means for Solving the Problems]
The concentrated irradiation type radiotherapy apparatus according to the first aspect of the present invention includes a radiation source that generates therapeutic radiation toward a subject, a multi-channel radiation detector that detects radiation transmitted through the subject, A moving mechanism that moves a radiation source with respect to the subject together with the radiation detector, an image reconstruction unit that reconstructs image data based on the output of the radiation detector, and for arbitrarily trimming the radiation A plurality of strip-shaped leaves disposed between the radiation source and the subject and provided so as to be individually movable forward and backward, wherein at least one leaf of the plurality of leaves transmits radiation to other leaves And a multi-leaf collimator having a high rate.
A concentrated irradiation type radiotherapy apparatus according to a second aspect of the present invention includes a radiation source that generates therapeutic radiation toward a subject, a multi-channel radiation detector that detects radiation transmitted through the subject, A moving mechanism that moves a radiation source with respect to the subject together with the radiation detector, an image reconstruction unit that reconstructs image data based on the output of the radiation detector, and for arbitrarily trimming the radiation A plurality of strip-shaped leaves disposed between the radiation source and the subject and provided so as to be able to advance and retreat individually, and at least one of the plurality of leaves has a width relative to other leaves narrow and multi-leaf collimator, and set individually in accordance with the other leaf opening to the shape of the treatment area, the multi-leaf to fully open the narrow least one leaf of the width In order to control a remeter and execute detection of radiation transmitted through the subject and reconstruction of the image data in parallel with generation of the therapeutic radiation from the radiation source, the radiation detector and the And a control unit that controls the image reconstruction unit .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an intensive irradiation type radiotherapy apparatus according to the present invention will be described below with reference to the drawings. The therapeutic radiation is described as a general X-ray, but is not limited thereto. Intensive irradiation type radiotherapy equipment dynamically controls the aperture of the collimator in conjunction with the continuous movement of the radiation source relative to the subject (patient), so that finely focused radiation is always directed to the treatment site of the subject. By concentrating, it is a treatment device that selectively gives a treatment effect with high energy to a treatment site and suppresses exposure to other healthy sites as much as possible. Here, the radiation source is described as an example of moving on a circumferential trajectory, but the moving trajectory of the radiation source is not limited thereto.
[0007]
In this example, the intensive irradiation type radiotherapy apparatus has a basic structure common to the X-ray computed tomography apparatus. Similar to the X-ray computed tomography apparatus, the intensive irradiation type radiotherapy apparatus includes a rotation / rotation type in which an X-ray tube and a radiation detector are rotated as one body, and a large number of detection elements in a ring shape. There are various types such as a fixed / rotation type in which only the X-ray tube rotates around the subject, and the present invention can be applied to any type. Here, the rotation / rotation type will be described. Further, to reconstruct one slice of tomographic image data, projection data for about 360 ° around the subject and about 360 ° is required, and projection data for 180 ° + fan angle is also required in the half scan method. . The present invention can be applied to any reconstruction method. Here, a half scan method that is advantageous in terms of time resolution will be described as an example. In addition, the mechanism for converting incident X-rays into electric charges is based on an indirect conversion type in which X-rays are converted into light by a phosphor such as a scintillator and the light is further converted into electric charges by a photoelectric conversion element such as a photodiode. The generation of electron-hole pairs in semiconductors and their transfer to the electrode, that is, the direct conversion type utilizing a photoconductive phenomenon, is the mainstream. Any of these methods may be employed as the X-ray detection element, but here, the former indirect conversion type will be described. In recent years, so-called multi-tube type devices in which a plurality of pairs of X-ray tubes and X-ray detectors are mounted on a rotating ring have been commercialized, and peripheral technologies have been developed. The present invention can be applied to both a conventional single-tube type device and a multi-tube type device. Here, a single tube type will be described.
[0008]
FIG. 1 is a diagram showing a configuration of an intensive irradiation type radiotherapy apparatus according to an embodiment of the present invention. The focused irradiation type radiotherapy apparatus has a gantry 100. The gantry 100 includes a rotating ring 102 that is held rotatably about a rotation center axis RA. The rotating ring 102 has an X-ray tube 101 that generates a relatively high dose of therapeutic radiation in a direction facing the rotation central axis RA, that is, a central axis (X-ray central axis) XC of the X-ray bundle from the X-ray tube 101. Is attached at a position orthogonal to the rotation center axis RA. A multi-channel X-ray detector 103 is attached at a position on the rotary ring 102 facing the X-ray tube 101 across the rotation center axis RA. The X-ray detector 103 includes a plurality of X-ray detection elements arranged along a direction substantially orthogonal to the rotation center axis RA and the X-ray center axis XC, in practice, on an arc centered on the X-ray focal point. The X-ray detector 103 has a single X-ray detection element array or a plurality of X-ray detection element arrays. The former is called a single-slice X-ray detector, and the latter is called a multi-slice or two-dimensional array X-ray detector.
[0009]
In addition, the rotation coordinate system about the Z axis is defined by the XY coordinate system with the rotation center axis RA as the Z axis. In this case, the X-ray central axis XC is defined as the Y axis, and the axis orthogonal to the ZY axis is defined as the X axis. The XYZ axes are used as appropriate below.
[0010]
A multi-leaf collimator 108 is disposed between the X-ray tube 101 and the rotation center axis RA. In practice, the multi-leaf collimator 108 is attached to the X-ray emission window of the X-ray tube 101. The multi-leaf collimator 108 is a component unique to a treatment apparatus provided for trimming X-rays emitted from the focal point of the X-ray tube 101 to an arbitrary shape and an arbitrary size at an arbitrary position.
[0011]
As shown in FIG. 2A, the multi-leaf collimator 108 includes a plurality of strip-shaped leaves 201 having a width of 1 mm in terms of a converted value on a rotation center axis RA that is individually movable along the X axis. 203. Actually, with the X-ray central axis XC as the center line, two leaves 201 and 203 form a pair by opening both sides of the center line, and a plurality of these leaf pairs are arranged in the Z-axis direction, here nine in parallel Has been.
[0012]
As shown in FIG. 2C, at least one pair of leaves 203 in the center with respect to the Z-axis is different from other leaves 201 arranged in pairs on both sides thereof, as shown in FIG. The X-ray transmittance is defined by the ratio (Iout / Iin) of the transmitted X-ray dose Iout to the incident X-ray dose Iin. The other leaf 201 has an X-ray transmittance indicating zero or an approximate value thereof. For this reason, the other leaves 201 substantially shield X-rays. On the other hand, the central leaf 203 has a transmittance that is higher than the other leaves 201 and does not pass through without attenuation, that is, an X-ray transmittance that exceeds zero and is less than 1.0. Therefore, as shown in FIG. 2D, the two leaves 203 in the center are attenuated to a low dose according to the X-ray transmittance and the dose of incident X-rays without completely blocking the X-rays. It has a function of leaking X-rays. The X-ray transmittance of the two leaves 203 in the center is that the dose of leaked X-rays satisfies the safety standard at the time of imaging under the dose of therapeutic X-rays, and at the time of general imaging The value is almost the same as the dose.
[0013]
The other leaf 201 is a shield made of a material having a high source weak coefficient such as lead having a thickness necessary for obtaining an X-ray transmittance of zero or an approximate value thereof, as shown in FIG. It has a structure in which a plate 205 and, for example, an iron plate 207 for compensating its rigidity are bonded together. On the other hand, the central leaf 203 has a structure in which a plate (semi-transmissive plate) 209 made of a material such as Mo whose source weakness coefficient is lower than that of lead and the same iron plate 207 are bonded together. In order to make the moving mechanism common, the semi-transmissive plate 209 of the leaf 203 is preferably set to the same thickness as the shielding plate 205 of the leaf 201.
[0014]
Even if the translucent plate 209 and the shielding plate 205 are not composed of different metals, for example, each is composed of an alloy containing lead, and the composition ratio of lead is set so that the transflective plate 209 is lower than the shielding plate 205. Thus, the X-ray transmittance relationship between the leaf 201 and the leaf 203 may be realized. 3A and 3B, the shielding plate 205 is, for example, a lead plate, while the semi-transmissive plate 213 of the leaf 203 is also a lead plate of the same material, and The X-ray transmittance relationship between the leaf 201 and the leaf 203 may be realized by configuring the semi-transmissive plate 213 to be thinner than the shielding plate 205.
[0015]
In the above description, the leaf 203 having a high X-ray transmittance has one pair at the center. However, as shown in FIG. 4, a plurality of sheets on both sides of the center, three here, that is, a plurality of pairs at the center, three pairs here. May be configured with a leaf 203 having a high X-ray transmittance.
[0016]
Returning to FIG. The X-ray detector 103 is connected to a data acquisition circuit 104 generally called a DAS (data acquisition system). The data acquisition circuit 104 has a function of converting the output (current signal) of each channel of the X-ray detector 103 into a voltage signal, amplifying it, and converting it into a digital signal. The DAS 104 is connected to a pre-processing device 106 that corrects non-uniformity between channels of the DAS output through a non-contact data transmission device 105 using light or magnetism as a medium. Data that has undergone preprocessing (projection data) is stored in the auxiliary storage device 112.
[0017]
The auxiliary storage device 112 includes an image reconstruction device 114 for reconstructing image data from projection data, a display device 116, an input device 115 equipped with an X-ray irradiation emergency stop button together with a pointing device such as a mouse and a keyboard, and an X Based on the radiation output dose characteristic data and tomographic image data, the radiation dose distribution in the body is calculated, and the relationship between the opening of the multi-leaf collimator 108 and the X-ray tube rotation angle with respect to the treatment area set from the input device 115 A treatment planning system 113 with a treatment specialist support function for performing optimal irradiation such as calculation, and a treatment / control for controlling the gantry 100 and the high-voltage generator 109 to perform treatment according to the treatment plan. System controller via scan / control bus and data / control bus It is connected to the 111.
[0018]
FIG. 5 shows a flow of a series of operations required for the treatment of this embodiment. Prior to the treatment, first, scanning is performed under the control of the treatment / scan controller 110 (S1). Scanning is an operation for acquiring in-vivo tomographic image data of a subject, and the greatest difference from treatment is that the X-ray dose generated from the X-ray tube 101 is low. Therefore, the therapy / scan controller 110 supplies the high voltage generator 109 with control signals corresponding to a relatively low tube voltage and a relatively low tube current. Further, the treatment / scan controller 110 supplies a control signal necessary for completely opening the central leaf 203 at the maximum opening and completely closing the other leaves 201 to the multi-leaf collimator driving unit 107. . In this state, the rotating ring 102 is continuously rotated to continuously or intermittently emit X-rays, and the detector 103 repeatedly detects transmitted X-rays at a predetermined sampling frequency.
[0019]
Based on the projection data collected by this scanning, the tomographic image data is reconstructed by the image reconstruction device 114 (S2) and displayed on the display device 116 under the planning support function of the treatment planning system 113. FIG. 6 shows an example of the displayed tomographic image. On the image, the treatment area indicated by the oblique lines is set by tracing the outline of the treatment site by operating the input device 115 by the operator (S3).
[0020]
Based on the set position, size, and shape of the treatment area, the treatment planning system 113 calculates the opening degree of each leaf 201, 203 of the multi-leaf collimator 108 for each minute rotation angle of the X-ray tube 101. (S4). The opening degree of the leaves 201 and 203 is defined as a moving distance from the center line. By setting the opening degree of each leaf 201, 203 individually, an opening corresponding to the outer shape of the treatment area can be set.
[0021]
Along with these operations, although not shown, the setting of irradiation conditions during treatment is completed, and the opening degree of each leaf 201, 203 is initialized (S5), and then treatment is started at an arbitrary time (S6). The therapy / scan controller 110 supplies a control signal corresponding to a relatively high tube voltage and a relatively high tube current so that the high voltage generator 109 is exposed to X-rays at a relatively high dose for therapy. To do. In this state, the rotating ring 102 is continuously rotated to continuously expose a high dose of X-rays for treatment, and the leaves 201 and 203 calculated in advance according to the rotation angle of the X-ray tube 101 are used. Is dynamically changed (S7). As a result, as shown in FIGS. 7 (a), 7 (b), 7 (c), and 7 (d), the opening of the collimator 108 is always shaped in accordance with the outer shape of the treatment site during the rotation period. A site to be treated is irradiated with a high-dose X-ray beam that is thinly trimmed.
[0022]
During this treatment period, high-dose X-rays emitted from the X-ray tube 101 pass through the aperture of the collimator 108 without being attenuated, and at the same time, the leaf 203 whose central X-ray transmittance is not zero. Transmits after being attenuated. The X-ray that has become a low dose due to attenuation is irradiated onto the subject together with a high-dose X-ray for treatment, and the X-ray transmitted through the subject is detected by the X-ray detector 103. Thereby, projection data is collected (S8). Note that a high dose of X-rays is irradiated through the opening of the multi-leaf collimator 108, and after being attenuated by the subject, the transmitted X-rays similarly have a relatively high dose. On the other hand, after a low dose of X-rays is irradiated through the central leaf 203 of the multi-leaf collimator 108 and the subject is attenuated, the transmitted X-rays have a relatively low dose. Here, the dynamic ranges of the detector 103 and the DAS 104 are set based on a low-dose X-ray similar to that of scanning. Therefore, a relatively high dose of X-rays is detected as its maximum value, saturating the dynamic range.
[0023]
The image reconstruction device 114 reconstructs tomographic image data based on the projection data set for 180 ° + α (S9). This reconstruction processing is real-time processing, that is, the image reconstruction device 114 reconstructs tomographic image data in substantially real time in parallel with generation of therapeutic radiation. The reconstructed tomographic image data is immediately displayed on the display device 116 (S10). This reconstruction and display process is repeated continuously during the treatment, with the time required to rotate the angle range of 180 ° + α as a cycle, thereby imaging the cross-sectional form including the treatment site as a moving image. Can do.
[0024]
FIG. 8 shows an example of the displayed tomographic image. As described above, the X-rays irradiated through the openings of the multi-leaf collimator 108 have a high dose, and are thus detected as the maximum value of the dynamic range of the detector 103 and the DAS 104. Accordingly, an area where X-rays are concentrated with rotation (concentrated area) is imaged with the maximum density. On the other hand, the X-rays irradiated through the central leaf 203 of the multi-leaf collimator 108 have a low dose, and the tissue reflecting the difference in the X-ray absorption rate by effectively utilizing the dynamic range of the detector 103 and the DAS 104. The form can be imaged. The operator (operator) can recognize the portion showing the maximum density as a region (concentrated region) where X-rays concentrate, and can observe a tissue form other than the concentrated region with it.
[0025]
Here, during the treatment period, a situation may occur in which the concentrated region is detached from the treatment site due to body movement of the subject. FIG. 9 shows an example of a tomographic image corresponding to this situation. It can be observed that the concentrated area is displayed in black with a high density, and at the same time, an image of the treatment site is shown deviating from the concentrated area. From this image, the surgeon confirms the degree of positional deviation of the site to be treated with respect to the concentrated area, and presses the irradiation emergency stop button of the input device 115 as necessary. In accordance with the operation of the irradiation emergency stop button, the treatment / scan controller 110 recognizes that an emergency stop command has been input (S11), and takes necessary measures to stop X-ray irradiation on the subject in an emergency. (S12). In general, the application of the tube voltage and the supply of the tube current from the high voltage generator 109 to the X-ray tube 101 is urgently stopped, but instead of the application of the tube voltage and the supply of the tube current, it is stopped. Alternatively, when the X-ray tube 101 is equipped with a shutter device, it may be dealt with by closing the shutter.
[0026]
In addition, even if the site to be treated is misaligned with respect to the concentration area, if the misalignment is slight, or if the misalignment has disappeared and the tendency to return to the original position can be seen, emergency stop In some cases, it may be desirable to continue treatment without doing so. In that case, the opening degree of each leaf 201, 203 is specified by the surgeon specifying the approximate center position of the treatment site that has become partially visible outside the high concentration concentration area on the tomographic image. Can be immediately recalculated by the treatment planning system 113, and the control can be switched to the opening control according to the calculation result.
[0027]
If the position of the treatment site with respect to the concentrated area on the tomographic image does not shift or is insignificant, the process of S7 to S11 is performed until the treatment end condition expires in S13 without inputting an emergency stop command. Is repeated. When the treatment end condition expires in S13, the treatment wave is ended (S14).
[0028]
As described above, according to the present embodiment, the treatment site is displayed as a morphological image together with the surrounding tissue during the treatment period, and the irradiation concentration area is displayed at a high density on the image, and thus the positional deviation between the two. Etc. can be monitored immediately, and an emergency stop can be made if necessary. For this reason, the safety | security at the time of a treatment can be improved.
[0029]
In the above description, among the leaves constituting the multi-leaf collimator 108, the central leaf 203 has been described as having higher X-ray transmittance than the other leaves 201. This is intended to realize morphological imaging accompanying avoidance of saturation of the dynamic range and to reduce exposure of healthy sites other than the site to be treated. A similar object may be realized by configuring the width of the central leaf 215 of the multi-leaf collimator 108 to be narrower than the other leaves 201, as shown in FIGS. 10 (a) and 10 (b). The width of the two leaves 215 in the center is that the X-ray dose that passes through the slit of that width avoids the saturation of the dynamic range under the X-ray dose for treatment, and is a safety standard for imaging. And is determined to be a value that substantially matches the dose during general imaging.
[0030]
The plate 219 of the central leaf 215 is made of the same material as the shielding plate 205 of the other leaf 201, for example, lead and has the same thickness. In this configuration example, the central leaf 215 has zero X-ray transmittance equivalent to the other leaves 201, that is, has shielding properties.
[0031]
During treatment, the central leaf 215 is fully open. By reducing the width of the central leaf 215, the X-rays that are thinly formed through the slit and pass through the subject and enter the detector 103 become a substantially low dose. And does not saturate the dynamic range of the DAS 104. Thereby, visualization of the form of the treatment site and the surrounding tissue can be ensured. When video monitoring is not required during treatment, unnecessary exposure can be avoided by controlling the opening of the central leaf 215 in accordance with the treatment area. In addition, the central leaf 215 is completely opened, and a structure is adopted in which the rotating ring 102 is inclined with respect to the rotation center axis RA in order to reduce the exposure of a healthy site when image monitoring is performed during treatment. May be.
[0032]
This configuration example can be developed as shown in FIGS. 11 (a) and 11 (b). That is, all the leaves constituting the multi-leaf collimator 108 may be constituted by the leaves 215 having the same narrow width as that at the center. In this case, the collimator opening can be approximated by the outer shape of the non-treatment area.
[0033]
(Modification)
The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention at the stage of implementation. Furthermore, the above embodiment includes various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, some constituent requirements may be deleted from all the constituent requirements shown in the embodiment.
[0034]
【The invention's effect】
According to the present invention, an area to be treated can be confirmed with an image together with an irradiation concentration area during treatment.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an intensive irradiation type radiotherapy apparatus according to an embodiment of the present invention.
FIG. 2 is a view showing the structure of the multi-leaf collimator shown in FIG.
FIG. 3 is a view showing a first modification of the multi-leaf collimator in FIG. 1;
FIG. 4 is a view showing a second modification of the multi-leaf collimator in FIG. 1;
FIG. 5 is a flowchart showing a series of flow from a treatment plan to the end of treatment in the present embodiment.
6 is a view showing an example of an image displayed in S3 of FIG.
FIG. 7 is a supplementary diagram for explaining the opening control in S7 of FIG. 5;
FIG. 8 is a diagram showing an example of an image displayed in S10 of FIG.
FIG. 9 is a diagram showing an example of an image when the positional shift displayed in S10 of FIG. 5 occurs.
FIG. 10 is a view showing a third modification of the multi-leaf collimator shown in FIG.
FIG. 11 is a view showing a fourth modification of the multi-leaf collimator in FIG. 1;
[Explanation of symbols]
100 ... Gantry,
101 ... X-ray tube,
102 ... rotating ring,
103 ... X-ray detector,
104: Data collection circuit,
105 ... non-contact data electrical equipment,
106: Pretreatment device,
107 ... multi-leaf collimator driving unit,
108 ... multi-leaf collimator,
109 ... Output switching type high voltage generator,
110 ... treatment / scan controller,
111 ... System controller,
112 ... Auxiliary storage device,
113 ... Treatment planning system,
114 ... reconstructing device,
115: Input device.

Claims (12)

A radiation source for directing therapeutic radiation toward the subject;
A multi-channel radiation detector for detecting radiation transmitted through the subject;
A moving mechanism for moving the radiation source with the radiation detector relative to the subject;
An image reconstruction unit for reconstructing image data based on the output of the radiation detector;
A plurality of strip-shaped leaves disposed between the radiation source and the subject for arbitrarily trimming the radiation and provided to be freely advanced and retracted; and at least one of the plurality of leaves And a multi-leaf collimator having a high radiation transmittance with respect to other leaves.   2. The concentrated irradiation type radiotherapy apparatus according to claim 1, wherein the other leaf is designed to have a radiation transmittance of zero or an approximate value for the therapeutic radiation.   The intensive irradiation type radiotherapy apparatus according to claim 1, wherein the at least one leaf is made of a material having a lower radiation attenuation coefficient than a material constituting the other leaf.   The intensive irradiation radiation therapy apparatus according to claim 1, wherein the at least one leaf is thinner than the other leaves.   In parallel with the generation of the therapeutic radiation from the radiation source, the radiation detector and the image reconstruction unit are controlled to execute detection of radiation transmitted through the subject and reconstruction of the image data. The intensive irradiation type radiotherapy apparatus according to claim 1, further comprising a control unit that performs the control.   The intensive irradiation radiation therapy apparatus according to claim 5, wherein the image reconstruction unit reconstructs the image data substantially in real time in parallel with the generation of the therapeutic radiation.   The display unit for immediately displaying the reconstructed image data, and a manual operation unit corresponding to an emergency stop of the irradiation of the therapeutic radiation to the subject are further provided. Intensive irradiation type radiotherapy device. A radiation source for directing therapeutic radiation toward the subject;
A multi-channel radiation detector for detecting radiation transmitted through the subject;
A moving mechanism for moving the radiation source with the radiation detector relative to the subject;
An image reconstruction unit for reconstructing image data based on the output of the radiation detector;
A plurality of strip-shaped leaves disposed between the radiation source and the subject for arbitrarily trimming the radiation and provided to be freely advanced and retracted; and at least one of the plurality of leaves Is a multi-leaf collimator that is narrower than other leaves,
The opening of the other leaf is individually set according to the shape of the treatment area, the multi-leaf collimator is controlled so that the at least one narrow leaf is fully opened, and the treatment from the radiation source is performed. In parallel with the generation of the radiation for use, the radiation detector and the control unit for controlling the image reconstruction unit are provided to execute the detection of the radiation transmitted through the subject and the reconstruction of the image data. Intensive irradiation type radiotherapy apparatus characterized by the above.   The concentrated irradiation type radiotherapy apparatus according to claim 8, wherein at least one of the narrow leaves has a shielding property against the therapeutic radiation, like the other leaves.   The intensive irradiation type radiotherapy apparatus according to claim 8, wherein the at least one narrow leaf is made of the same material as the other leaves. The intensive irradiation radiation therapy apparatus according to claim 8 , wherein the image reconstruction unit reconstructs the image data substantially in real time in parallel with the generation of the therapeutic radiation. 12. The display apparatus according to claim 11 , further comprising: a display unit that immediately displays the reconstructed image data; and a manual operation unit that responds to an emergency stop of irradiation of the therapeutic radiation on the subject. Intensive irradiation type radiotherapy device.

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