JPH07255718A - Radiation treatment planning device, radiation treatment device and radiation treatment method - Google Patents

Abstract

PURPOSE:To make it possible to easily form an irradiation field of radiations while lessening the burden on an operator by calculating the error areas formed by end line parts of respective leaves and the lines of a target while rotating a collimator by a rotating means, then selecting the rotating angle of this collimator to minimize the error areas. CONSTITUTION:A control section 35 reads-in the opening degree set mode data and target data sent from an input section 34, virtually sets the rotating angle of the MLC 8 at 0 deg. and sets the leaf opening angle in compliance with the opening degree set mode. In succession, the control section calculates the error areas of this time and holds the error areas in a storage section 36. The rotating angle of the MLC is increased by a predetermined step theta deg.. The smallest error area is selected from the error areas stored in the storage section 36 when the rotating angle of the MLC attains 360 deg.. The irradiation field forming data is then formed to meet the selected rotating angle of the MLC and the leaf angle and is displayed in superposition on the target shape on a display section 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation treatment planning apparatus, a radiation treatment apparatus and a radiation treatment method for irradiating a lesion such as cancer with radiation to treat the lesion. The present invention relates to a radiation treatment planning apparatus, a radiation treatment apparatus, and a radiation treatment method each including a collimator that determines a radiation irradiation range.

[0002]

2. Description of the Related Art Radiation therapy for irradiating a lesion such as cancer with radiation to treat it is a root treatment method for treating the lesion itself, unlike chemotherapy, and its significance is being reconsidered in recent years. In particular, in early lung cancer, early breast cancer and the like, it has been recognized that radiation therapy is most effective, and it has been attracting attention.

In such radiation therapy, what is particularly important in terms of safety is to irradiate radiation in conformity with the shape of the lesion and avoid irradiating other normal tissues such as important organs as much as possible. is there. Therefore, in the radiotherapy device,
It is necessary to generate an irradiation range of the radiation on the body surface (corresponding to the irradiation range on the lesion, hereinafter referred to as irradiation field) in accordance with the shape of the lesion. In order to generate this irradiation field, conventionally, there is a method in which a plurality of lead blocks (hereinafter, also referred to as concealment blocks) are combined in a desired shape and placed in a radiation path, but at present, a diaphragm (also referred to as an aperture) is used. It is common to install a diaphragm device (also called collimator) whose opening can be adjusted automatically in the radiation path to generate an irradiation field. Here, an example of a procedure for generating an irradiation field using a collimator Will be described with reference to FIGS. 33 to 34.

FIG. 33 shows a main part of the radiation treatment apparatus.
The radiotherapy apparatus 100 includes an electron beam generator 101 having a radiation irradiation function, an electron beam deflector 102, and a target 103, a collimator 104 having a diaphragm, and a console 105 having a function of adjusting the opening of the diaphragm. Is equipped with.

Further, the radiation treatment apparatus 100 has an irradiation site (hereinafter also referred to as a target) including a lesion part of a subject.
A visible light source 106 such as a lamp and a half mirror 107 are provided for recognizing.

In order to determine an irradiation field in this radiation therapy apparatus (hereinafter also referred to as a therapy apparatus) 100, an operator moves a lead line on a shadow tray while performing fluoroscopy with an X-ray simulator in advance to determine an irradiation site. , Take X-ray pictures.

Then, light is projected from the X-ray source, and the shadow of the lead wire, that is, the shape of the irradiation site is marked on the body surface.

Then, when performing a treatment, the treatment device 1
The subject H is placed on the bed 108 of 00, and the operator
Light is emitted from the visible light source 106 onto the subject H, and the opening of the diaphragm of the collimator 104 is adjusted by the console 105 while observing the body surface of the subject H. Then, as shown in FIG. 34, the irradiation site by the light projected on the body surface of the subject H through the diaphragm of the collimator 104 and the area within the mark drawn on the body surface are matched. Then, the irradiation site on the body surface through the collimator 104, that is, the irradiation field of the radiation is determined.

At the time of treatment, a photograph was taken with radiation for treatment as needed, and the position of the irradiation site was confirmed by comparing this photograph with the X-ray photograph. On the other hand, recently, among the collimators, a multi-leaf collimator equipped with a multi-segment conformer diaphragm; Multi-Leaf C
ollimator (hereinafter referred to as MLC) is increasing.

This MLC is shown in FIG. FIG. 35 is a diagram of the opening (a rectangular shape when viewed from the radiation source side) 110a of the MLC 110 viewed from the radiation source side. This MLC110
Is a multi-leaf type composed of a plurality of leaves. That is, as shown in FIG. 36, a pair of leaf groups 1
11A and 111B are arranged to face each other with a radiation path in between. Each leaf group 111A, 111B is composed of a plurality of plate-shaped leaves 111, and each leaf 11
1 is movable in the x direction shown in FIG. A pair of upper diaphragms (leafs) 112, 112 are erected on both sides of the leaf groups 111A, 111B.
2, 112 are movable in the y direction shown in FIG. Further, the entire MLC 110 is configured to be rotatable about the center o of the opening 110a (arrow m).
reference).

In generating an irradiation field using the MLC 110, the operator preliminarily uses an MLC suitable for the target shape.
The rotation angle of the entire 100 is set. Then, after the entire MLC 110 has rotated to that angle, each leaf 111 is moved to adjust the opening degree of the openings formed by these leaves 111 (hereinafter referred to as irradiation openings; see FIG. 35).
That is, the shape of the irradiation opening forms the irradiation range of the radiation on the body surface, that is, the irradiation field.

In particular, a large number (eg 11 pairs) of leaves 1
Since 11 can be freely moved, the shape of the irradiation opening, that is, the irradiation field can be set finely,
It is possible to generate an irradiation field that is very close to the target shape.

Depending on the target, normal tissue may exist inside the target as shown in FIG. At this time, as described above, the collimator (or MLC) is used to once generate an irradiation field in conformity with the shape of the entire target, and then the operator selects the shadow tray 109 or the body surface of the subject H shown in FIG. A shield (for example, a lead block) having a size enough to completely hide the important organ was placed in a portion corresponding to normal tissue to shield it from radiation.

[0014]

The following problems have occurred in the generation of the radiation irradiation field described above.

(1) The operator looks at the body surface of the subject, that is, by visual inspection, the irradiation site on the body surface and the subject H.
The collimator diaphragm aperture was adjusted so that the area inside the mark was matched. Therefore, the operator has to perform console operations based on the control of the opening of the collimator and the recognition of the body surface of the subject one by one, and it takes a lot of time and effort to form the diaphragm opening of the collimator, that is, the radiation irradiation field. It took a while. (2) When shielding the normal tissue in the target, the operator manually placed a lead block matching the size of the normal tissue on the shadow tray or the body surface, so the placement position was not exactly accurate. In some cases, it could not be irradiated to the part to be irradiated with radiation, and there was a possibility that it would be irradiated to the part to be unirradiated (In the present invention, the part to be irradiated could not be irradiated. In that case, the area of the area that could not be irradiated (hereinafter referred to as the non-irradiated area) and the area of the area that was not irradiated (irradiated area) Together defined as the error area).

Therefore, there is a problem that the effect of the treatment is reduced and the possibility of affecting other normal tissues may occur. Further, when normal tissues of different sizes are present in different targets, the heavy shield must be carried and replaced once according to the size of the normal tissues, which is an excessive burden on the operator. Was there. (3) Even when the irradiation field is generated using MLC, the error area may change depending on the preset rotation angle of MLC. This is because the shape of the diaphragm surface of each leaf of the MLC is rectangular, so that the contour line of the target shape appears particularly in the curved portion.

By comparing FIGS. 37 and 38 with each other, it can be seen that the error areas are considerably different. Since the change of the error area depending on the rotation angle of the MLC is a serious problem from the viewpoint of the therapeutic effect and safety, the error area is minimized, that is, the optimum therapeutic effect is obtained. It is desired to set a rotation angle that can be achieved.

However, conventionally, the operator visually recognizes the target shape and only presets the rotation angle of the MLC which seems to match the target shape from experience and intuition, and sets the error area in consideration. Therefore, it was difficult to set the optimum rotation angle.

Since the MLC has a large number of leaves,
The rotation angle of the MLC must be set in consideration of the moving position of each leaf, which requires the operator to perform a trial and error operation, which imposes an excessive burden.

As described above, the optimal generation of the radiation irradiation field causes an excessive amount of labor and burden on the operator. Therefore, the treatment time is increased, the treatment efficiency is lowered, and erroneous operation is caused due to the labor and burden. There was a risk that it would affect safety.

The present invention has been made in view of the above circumstances, and a radiation treatment planning apparatus, a radiation treatment apparatus, and a radiation treatment method capable of easily generating a radiation irradiation field while significantly reducing the burden on the operator. The purpose is to provide.

[0022]

In order to achieve the above object, the invention described in claim 1 is a radiation path from a radiation source to a pair of leaf groups formed by a radiation shielding member. With a multi-leaf type collimator capable of independently driving each leaf in the facing direction, and rotating the entire pair of leaf groups. In a radiation treatment planning apparatus for planning a treatment plan for a radiation treatment apparatus that irradiates a lesion with radiation treatment, specifying means for specifying a target shape for the lesion on an image taken of the subject, and Rotating means for rotating the entire collimator in a state in which each leaf of the collimator is brought close to the target in a desired opening setting mode, The calculation means for calculating the error area formed by the end line portion of each leaf and the target line while rotating the collimator by means of, and the collimator rotation angle that minimizes the error area calculated by this calculation means are selected. And selection means.

Particularly, in the radiation treatment planning apparatus according to the second aspect, the opening setting mode is any one of a circumscribing mode, an inscribing mode, a midpoint mode, an optimum mode, and a perfect optimization mode.

In order to achieve the above object, the invention according to claim 3 is such that a pair of leaf groups formed of a plurality of leaves formed of a radiation shielding member are opposed to each other with a radiation path from the radiation source interposed therebetween. In addition, each leaf can be independently driven in the opposite direction, and a multi-leaf type collimator that can rotate the entire pair of leaves is provided, and the collimator irradiates the lesion area of the subject while narrowing the radiation. In a radiotherapy apparatus for performing radiotherapy, when normal tissue is present inside the lesioned portion, designating means for designating the shape and position of the normal tissue and the designated normal tissue are shielded by the leaf. A radiation irradiation means for irradiating radiation while rotating the collimator by a predetermined angle in this state, the radiation irradiation means is based on the shape and position of the normal tissue. Te, comprising a shielding means for at least one leaf close to the position is moved to shield the normal tissues.

Furthermore, in order to achieve the above-mentioned object, claim 4
In the invention described in 1 above, a pair of leaf groups formed of a plurality of leaves formed by a radiation shielding member are opposed to each other with a radiation path from a radiation source interposed therebetween, and each leaf is independently driven in the opposing direction. A multi-leaf collimator capable of rotating the entire pair of leafs is provided, and the collimator is provided in a radiotherapy method for irradiating a lesion area of a subject with radiation while narrowing the radiation with the collimator. Radiation is irradiated while rotating by a predetermined angle.

Further, in order to achieve the above object, claim 5
In the radiotherapy apparatus for irradiating a lesion area of a subject with radiation while narrowing the radiation with a collimator to perform radiotherapy, a shield for shielding the radiation having a shape suitable for the lesion area is used as the collimator. A shield insertion mechanism that is inserted between the subject and the subject is provided.

In particular, in the invention described in claim 6, the shield insertion mechanism is installed on the pedestal of the treatment device.

Particularly, in the invention described in claim 7,
A shield storage unit for storing the shield when not in use is installed on the pedestal of the treatment device.

Further, in the invention described in claim 8, when a normal tissue exists in the target shape of the subject, a designating means for designating the shape and position of the normal tissue and the designating means are designated. Based on the shape and position of the normal tissue, comprising a specifying means for specifying the insertion position of the shield at the spatial position between the collimator and the subject, the shield insertion mechanism, by the specifying means It is configured to include an automatic transporting unit that automatically transports the shield stored in the shield storage unit to the insertion position based on the identified insertion position of the shield.

On the other hand, in order to achieve the above-mentioned object, claim 9
The invention described in 1 is a radiotherapy apparatus for performing radiation therapy by irradiating the irradiation site while narrowing the radiation with a collimator based on a mark showing the shape of the irradiation site of the radiation drawn on the body surface of the subject in advance. The image pickup means for picking up the shape of the irradiation portion based on the mark drawn on the body surface of the subject, and the opening degree of the collimator using the image based on the shape of the irradiation portion picked up by the image pickup means And means for automatically moving.

In particular, in the invention according to claim 10, the collimator is arranged such that a pair of leaf groups formed of a plurality of leaves formed of a radiation shielding member are opposed to each other with a radiation path from the radiation source interposed therebetween. Further, it is a multi-leaf type collimator capable of independently driving each leaf in the opposite direction and rotating the entire pair of leaf groups.

[0032]

The present invention is used when performing treatment by irradiating a lesion with radiation while squeezing the radiation with a collimator, or when making a treatment plan. Here, as a collimator, a pair of leaf groups made up of a plurality of leaves formed by a radiation shielding member are opposed to each other with a radiation path from a radiation source interposed therebetween, and each leaf is independent in its opposing direction. It will be described that a multi-leaf type collimator that can be driven by the above-mentioned method and that can rotate the entire pair of leaf groups is used.

That is, according to the first and second aspects of the present invention, the specifying means specifies the target shape for the lesion on the image taken of the subject. The target shape is specified. At this time, of the opening setting modes including various modes of the circumscribing mode, the inscribing mode, the midpoint mode, the optimum mode, and the perfect optimization mode, for example, when the circumscribing mode is designated in advance, the entire collimator becomes
By the rotating means, each leaf is rotationally driven in a state of circumscribing the target according to the circumscribing mode.

The error area formed between the end line portion of each leaf and the target line according to the rotation of the collimator is calculated by the calculating means, and the error area calculated by the calculating means is calculated by the selecting means. The minimum collimator rotation angle is selected.

Therefore, the collimator rotation angle thus set is selected so that the error area is minimized in the designated opening setting mode.

According to the third and fourth aspects of the present invention, when a normal tissue exists inside the lesion, the designating means designates the shape and position of this normal tissue. Then, the shielding means included in the radiation irradiating means shields the normal tissue by moving at least one leaf near the position based on the shape and the position of the normal tissue. In this shielded state, the radiation irradiating means radiates the radiation while rotating the entire collimator by a predetermined angle.

That is, it is possible to irradiate the radiation while automatically shielding the normal tissue by the collimator.

Further, according to the present invention as defined in claims 5 to 6, it is suitable for a lesion portion stored in a shield storage unit also installed on the gantry, for example, by a shield insertion mechanism installed on the gantry. Since the shield having a different shape and configured to shield radiation is configured to be insertable between the collimator and the subject, the operator operates the insertion mechanism,
The shield can be easily inserted into a position where normal tissue is shielded.

In particular, according to the invention of claim 8, for example, when a normal tissue exists in the target shape of the subject, the shape and position of the normal tissue is specified by the specifying means, and the specified normal shape is specified. Based on the shape and position of the tissue, by the specifying means, the insertion position of the shield at the spatial position between the collimator and the subject is specified, and by the automatic transfer means included in the shield insertion mechanism, The shield stored in the shield storage unit is automatically conveyed to the insertion position specified by the specifying means.

According to the invention described in claims 9 to 10, it is assumed that a mark is drawn in advance on the body surface of the subject, the mark showing the shape of the radiation irradiation site.

At this time, the imaging means images the shape of the irradiation site based on the mark drawn on the body surface of the subject. Then, using the image based on the imaged shape of the irradiation site, the automatic opening control means automatically controls the opening of the collimator so that the shape of the irradiation site and the opening of the collimator match. .

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a radiation treatment planning apparatus and a radiation treatment system using the radiation treatment apparatus according to the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) First Embodiment FIGS. 1 to 10
It will be described based on.

FIG. 1 is a schematic block diagram of a radiation treatment system according to this embodiment, and FIG. 2 is a perspective view of a radiation treatment apparatus according to this embodiment.

This radiotherapy system comprises a radiotherapy device (hereinafter, simply referred to as a therapy device) 1. In this embodiment, the treatment apparatus 1 treats using X-rays, and as shown in FIGS. 1 and 2, the bed 2 on which the subject H is placed and the body axis (Z) direction of the subject H. It includes a pedestal 3 rotatable about the rotary shaft, a gantry support 4 rotatably supporting the gantry 3, and a console 5.

The bed 2 is provided with a top plate 2a for placing a subject on the upper side thereof. Further, the bed 2 is provided with a bed driving unit 6 inside thereof. The bed driving unit 6 moves up and down the top plate 2a (Y axis phrase) and its longitudinal direction (X direction).
In addition to having the function of moving to the top, it also has the function of rotating the top support and rotating around the isocenter. The operation of these beds 2 is performed by the top plate 2 of the subject H.
Required for positioning and irradiation on a,
It is controlled by a control signal from the console 5.

On the other hand, the gantry 3 is provided with a radiation generator 7 including a klystron and a radiation source in the irradiation head 3a. The radiation generator 7 deflects the accelerated electrons from the klystron to impinge them on the radiation source, and generates X from the radiation source.
The subject H is irradiated with a line beam. In addition, the irradiation head 3a includes, between the radiation source and the irradiation port,
A collimator that determines the irradiation field on the body surface of the subject H is built in. In this embodiment, as this collimator, a multi-leaf collimator (hereinafter, referred to as MLC) 8 having a multi-division conformer structure is mounted.

A schematic structure of the MLC 8 is shown in FIG. The MLC 8 is a multi-leaf type configured by a plurality of leaves. That is, as shown in FIG. 3, a pair of leaf groups 9A and 9B are arranged to face each other with a radiation path interposed therebetween. Each leaf group 9A, 9B is composed of a plurality of plate-shaped leaves 9, and each leaf 9 is individually equipped with a leaf driving unit 12 in which a lead screw 10 and a step motor 11 are combined, as shown in the figure. And
It is driven by a control signal supplied to the step motor 11. Therefore, by rotating the step motor 11, each leaf 9 can move independently along the X direction shown in FIG. Further, a pair of upper diaphragms (leafs) 13 and 13 are erected on both sides of the leaf groups 9A and 9B, and these upper diaphragms 13 and 13 are Z-shaped by a similar leaf driving unit 12.
It can be moved in any direction.

The leaf driving unit 12 is driven according to a control signal supplied from the console 5, and the two leaf groups 9A,
The size and shape of the irradiation opening formed by 9B (that is,
The size and shape of the irradiation field on the body surface) can be changed in real time.

Further, the MLC 8 is connected to the rotation driving unit 14 including, for example, a stepping motor. M
The LC 8 is driven by the rotation driving unit 14 to drive the LC 8 shown in FIGS.
Is rotated by a predetermined rotation angle (hereinafter referred to as MLC rotation angle) θ in the m direction. Note that FIG.
As shown in, when the moving direction of each leaf 9 of the MLC 8 is located in the direction orthogonal to the z axis in FIG.
The rotation angle of C8 is 0 °, that is, the initial position.

Further, the gantry support 4 can be rotated by the built-in gantry driving section 15 in both the clockwise direction and the counterclockwise direction of the gantry 3 as a whole. The operation of the gantry drive unit 15 is performed based on a control signal from the console 5.

The console 5 is a treatment device 1 as shown in the figure.
In addition to the main control unit 16 that manages the whole, the irradiation control unit 17, the bed control unit 18, the gantry control unit 19, the collimator control unit 20, which perform the processes individually assigned under the instruction of the main control unit 16, And a projector drive unit 21. The projector drive unit 21 drives three projectors (not shown) attached to the gantry 3. By positioning the subject H on the top plate 2a so that the positions designated by these three light projectors and the positions of, for example, a cross-shaped marker representing the isocenter marked on the body surface of the subject H are aligned, the isocenter is positioned. Will coincide with the center of rotation of the treatment device 1.

Each control unit is functionally composed of, for example, one computer, and performs processing according to a program previously stored in its memory. The main controller 16 is also connected to a treatment planning device described later via an interface circuit (hereinafter referred to as an I / F circuit) 22 so that the irradiation field data based on the shape of the treatment target can be received. It has become. The main control unit 16 is further connected to an input device 23 such as a keyboard and a display device 24 including a CRT, and is also connected to a handheld operation device 25. The handheld operation device 25 is hung near the bed 2 to improve operability.

The irradiation controller 17 turns on / off the gate signal.
The FF controls the radiation irradiation timing from the radiation treatment apparatus. In addition, the gantry control unit 18
Is the rotational position of the stepping motor of the gantry drive unit 15,
The rotation speed and the like are controlled to control the rotation speed and rotation amount of the gantry 3. Further, the bed control unit 19
Has a function of sending a control signal to the bed driving unit 6 to control the vertical movement of the table 2a by the bed driving unit 6 and the movement amount in the longitudinal direction, and the column rotation amount and the isocenter rotation amount.

The collimator controller 20 includes the leaf driver 1
2, the control signal is sent to the rotary drive unit 14, and each leaf 9
Of the MLC 8 and the rotation angle of the MLC 8 can be controlled.

On the other hand, when carrying out radiation treatment with this treatment apparatus 1, treatment plan data is required. In this embodiment,
As shown in FIG. 1, a radiotherapy CT apparatus (hereinafter, simply referred to as a CT apparatus) 30 and a radiotherapy planning apparatus (hereinafter, referred to as a CT apparatus)
31) and X-ray simulator 3
2 (may be omitted if necessary), the treatment plan data can be supplied to the treatment apparatus 1.

The CT device 30 is a normal CT scanner. Further, the radiation treatment planning device 31 is used to perform a radiation treatment planning based on the image data obtained by the CT device 30, and has a computer function. That is, as shown in FIG. 2, a display unit 33 having a CRT, a rectangular ROI, a polyline, and a cross R
An input unit 34 having an input device such as an OI, a keyboard, a trackball, and the like, a control unit 35 that controls the whole and performs the process of FIG. 8 to be described later, and a procedure of the process performed by the control unit 35. And data necessary for the processing thereof are stored in advance, and a storage unit 36 for temporarily storing the data calculated by the control unit 35 is provided.

In the treatment planning device 31, the actual M
In order to plan the position of each leaf 9 of the LC 8, the input section 3
5, it is possible to specify five types of modes (hereinafter referred to as opening degree setting modes): an inscribed mode, a circumscribed mode, a midpoint mode, an optimum mode, and a perfect optimization mode.

In the circumscribing mode, an end line portion (edge) of each leaf 9 is circumscribed with a target-shaped line (outer frame) (see FIG. 4).

In the inscribed mode, the end line portion of each leaf 9 is inscribed in the target shape line (see FIG. 5).

In the midpoint mode, the midpoint of the width of the end line portion of each leaf 9 is made to coincide with the target shape line (see FIG. 6).

The optimum mode is to calculate the error area in advance in the circumscribing mode, the inscribing mode, and the midpoint mode, and select the optimum mode (the smallest error area) from among these modes.

In the perfect optimization mode, the leaf 9 is moved so that its end line portion comes to a position where the ratio of the non-irradiated area to the erroneous irradiated area by each leaf 9 becomes optimum (approximately 1: 1). Full optimization mode; see FIG. 7).

The X-ray simulator 32 has a function of marking on the body surface based on the isocenter position data set by the treatment device 33, a function of photographing a target shape on a film, and the like.

Next, the overall operation will be described.

To start radiation therapy, the operator first places the subject H on the bed 2 of the CT apparatus 30,
The CT device 30 is driven to capture a scan image, an axial image, and the like of the subject H.

Image data based on the scano image and the axial image are sent to the treatment planning device 31. In the treatment planning device 31, an image (scano image, axial image) based on this image data is displayed on the CRT of the display unit 33. The lesion of the subject H appears in this scanogram.

While looking at this CRT, the operator specifies the target shape and its position in consideration of the lesion and the safety margin, for example, by a polyline of the input section 34, and then sets the desired opening degree from the input section 34. A mode (in the present embodiment, described as a midpoint mode) is designated.

The target shape and position data (hereinafter simply referred to as target shape data) designated by the operator and the opening setting mode data are sent to the control unit 35.

At this time, control unit 35 performs the processing shown in FIG.

That is, the control unit 35 reads the opening setting mode data and the target shape data sent from the input unit 34 (step 101). And virtually M
The rotation angle of LC8 is set to 0 °, that is, the initial position (step 102). Then, the leaf opening is set according to the opening setting mode (midpoint mode). Now, as shown in FIG. 9, the target shape T is at the center of the MLC 8,
If it has a square shape and has an area of 5 cm × 5 cm and is tilted at an angle of approximately 45 ° from the moving direction of the leaves 9, each leaf 9 has the target line and the midpoint of the width of the end line portion of the leaf 9 coincident with each other. The position is virtually moved to such a position (see FIG. 9. The arrival position of each leaf 9 at this time is referred to as a leaf opening).

Subsequently, the control unit 35 calculates the error area at this time. As shown in the figure, the error area S ₁ is

## EQU1 ## S ₁ = 0.5 × 0.5 / 2 × 28 = 3.5 cm ² is calculated. This error area S ₁ is held in the storage unit 36 (step 104).

Then, the control unit 35 increases the MLC rotation angle by a predetermined step θ ° (for example, 1 °) (step 105). Next, the current MLC rotation angle is 36
It is determined whether 0 °, that is, whether the MLC 8 has virtually rotated once (step 106). Currently, the MLC rotation angle is 1
Since the result is NO, the result of this determination is NO, and the process returns to step 103 and the above-described steps 103 to 105 are performed. That is, the MLC rotation angle is 1
Error area S ₁ for each of 2 °, 2 °, 3 °, ...
S _2, S _3, ... are determined, will have been stored in the storage unit 36.

Thus, when the MLC rotation angle is 360 °, that is, when the MLC 8 makes one rotation, the result of the determination in step 106 is YES, and the process proceeds to step 107. In step 107, the minimum error area S _min is selected from the error areas S _{1 to} S ₃₆₀ stored in the storage unit 36.
Select. In the case of this embodiment, as shown in FIG.
LC rotation angle is 45 ° (135 °, 225 °, 315 °
Since it is minimized when the same applies to) cases, S _min
= S ₄₅ , that is, the MLC rotation angle is selected to be 45 °.

Next, the control unit 35 creates irradiation field shape data in accordance with the selected MLC rotation angle (45 °) and leaf opening, and displays this irradiation field shape on the target shape T (step 108). It is displayed on the CRT of the unit 33 (step 109).

At this time, the operator determines whether or not the created irradiation field shape is suitable for the target shape T while observing the CRT. As a result, for example, when it is considered that the position of a certain leaf is not suitable, a trackball is used to send a signal (fine adjustment signal) indicating the position of the leaf and the position to be moved (fine adjustment signal) to the control unit 35. In addition, when it is determined to be suitable, a signal indicating that (hereinafter,
An OK signal) is sent by, for example, a keyboard.

The control unit 35 waits for whether or not this fine adjustment signal is sent (step 110). When the fine adjustment signal is sent, the determination at step 110 is YES and this fine adjustment signal is sent. It is read and the corresponding processing is performed (step 111). After this fine adjustment is made, or when an OK signal is directly input from the keyboard, it is determined that no further fine adjustment is made (step 11).
The determination of 0 is NO), and the process proceeds to step 112.

In step 112, the control unit 35 determines whether the irradiation field shape created by the processing up to step 111 described above is acceptable. As a result, when it is determined that there is another more optimal irradiation field shape, step 112
Is NO, the process returns to step 111, and the above-described process is repeated according to the opening degree setting mode newly designated by the operator.

On the other hand, if it is determined that this irradiation field shape is acceptable, the determination in step 112 is YES, and the process ends.

The leaf opening data and rotation angle data of the MLC 8 thus obtained are stored in the storage unit 36.

After the treatment plan is made in this way, radiation treatment is performed, for example, after one week has passed. In this treatment, when the main control unit 16 is activated using the input device 23 of the console 5 of the treatment apparatus 1, the main control unit 16 causes the main controller 16 to open the leaf stored in the storage unit 36 of the treatment planning apparatus 31 up to that point. Degree data and rotation angle data are read. When these data are passed to the collimator control unit 20, the collimator control unit 20 controls the leaf drive unit 12 according to the leaf opening data and also controls the rotation drive unit 14 according to the rotation angle data.

By driving the leaf driving unit 12 and the rotation driving unit 14, each leaf 9 of the MLC 8 is treated by the treatment planning device 31.
And the entire MLC 8 rotates to the position planned by the treatment planning device 31. That is, MLC8 is applied to a square-shaped lesion inclined at 45 °.
When a treatment is planned by designating the opening degree setting mode of 2 as the midpoint mode, the control is performed as shown in FIG. Therefore,
The radiation emitted from the radiation generating unit 7 is narrowed down along the irradiation opening of the MLC 8 and finally becomes an optimum irradiation field (irradiation range) that is closest to the planned area. Therefore, effective treatment will be performed.

In this embodiment, the processing of step 101 of the input section 34 and the control section 36 forms the specifying means according to claim 1, and steps 101 to 10 of the control section 36.
3. The process of step 105 forms a rotating means. Further, the processing of step 104 of the control unit 36 forms a calculating means, and the processing of step 107 forms a selecting means.

Further, in the present embodiment, the opening setting mode is designated as the midpoint mode, but the present invention is not limited to this, and the above-mentioned circumscribing mode, inscribing mode, etc. are selected according to the shape of the target. The same effect can be obtained by specifying the other mode.

Further, although the target shape is designated by using the polyline in this embodiment, the present invention is not limited to this, and the target shape may be designated by using the above-mentioned rectangular ROI or voxel data. Good.

Furthermore, in the present embodiment, the radiation treatment system includes a treatment device 1, a CT device 30, and a treatment planning device 3.
1. The X-ray simulator 32 is composed of
The radiation treatment system is not limited to this, and the treatment device 1, the CT device 30, and the treatment planning device 3 are used as a radiation treatment system.
1 and an X-ray CT simulator having the functions of the X-ray simulator 32.

(Second Embodiment) The configuration of the second embodiment is shown in FIG.
And the description thereof will be omitted. In the second embodiment, it is assumed that the normal tissue D exists inside the target T as shown in FIG.

Next, the overall operation will be described centering on the processing of the irradiation control section 17 and the collimator control section 20. The description of the same operation as that of the first embodiment will be omitted or simplified.

In the second embodiment, as in the first embodiment, the opening setting mode data (in this embodiment, the contact mode is set) and the target shape data are input from the input unit 34 of the treatment planning apparatus 31. At the same time, the shape data and the position data of the normal tissue D existing inside the target (hereinafter, simply referred to as the shape data of the normal tissue) are rectangular ROIs.
Input with or polyline. Then, it is assumed that the optimum rotation angle (0 ° in the case of the present embodiment) is obtained based on the opening setting mode data and the target shape data. At this time, the storage unit 36 of the treatment planning device 31
In addition to the leaf opening data and the rotation angle data (0 °) based on the circumscribing mode, are input the shape data of the normal tissue D inside the target T.

When the treatment is performed after the treatment plan is made in this way, the main controller 16 is activated by using the input device 23 of the console 5 of the treatment apparatus 1. The main control unit 16 that has started
Reads the leaf opening data, the rotation angle data, and the shape data of the normal tissue D stored in the storage unit 36 of the treatment planning device 31 up to that point and passes them to the irradiation control unit 17 and the collimator control unit 20.

At this time, the irradiation controller 17 and the collimator controller 20 perform the processing shown in FIG. That is,
The collimator control unit 20 reads data such as leaf opening data sent from the main control unit 16 into the internal buffer (step 201). Then, it is determined whether or not the shape data of the normal tissue D is input (step 20).
2). If the shape data of the normal tissue D is not input, the normal processing described in the first embodiment (the leaf drive unit 12 is controlled according to the leaf opening data, and the rotation drive unit 14 according to the rotation angle data). Are controlled) (step 203), and the process ends. Since the shape data of the normal tissue D is input now, step 20
The process of 2 is YES, and the process proceeds to step 204.

Subsequently, the collimator control section 20 controls the leaf drive section 12 according to the input leaf opening data to move each leaf 9 (step 204). As a result, as shown in FIG. 11, each leaf 9 moves so as to circumscribe the target shape T. And normal tissue D
The leaf 9a that is closest to the position is moved to a position that shields the normal tissue D (step 205; FIG. 13).
reference).

At this time, it is judged whether or not the normal tissue D is completely shielded by the leaf 9a (step 20).
6). If it is not completely shielded, it is calculated which other leaf should be moved to which position to shield it, and the other leaf is moved and shielded based on the calculation result (step 207). In this way, when the normal tissue D is completely shielded, the result of the determination in step 206 is YES, and the process proceeds to step 208.

In step 208, the collimator controller 20 sends the radiation irradiation timing data to the irradiation controller 17 via the main controller 16. The irradiation controller 17 turns on / off the gate signal based on the timing data.
FF control is performed to generate radiation for S time (step 208). Then, the irradiation control unit 17 sends data indicating that the irradiation of the radiation has ended to the collimator control unit 20 via the main control unit 16. In addition, this S time is
For example, the rotation angle θ of the MLC8 is 1 °,
If you want to make one rotation (360 °), "S = 1/3
60 × normal radiation irradiation time ”.

When the collimator control unit 20 receives the data indicating that the irradiation of the radiation is completed, the collimator control unit 20 proceeds to step 20.
9, the MLC 8 is rotated by θ ° (1 ° in this embodiment) at a required speed. Then, it is determined whether the MLC 8 has rotated to a predetermined angle (for example, 360 °) (step 210). Since the result of this judgment is NO now,
Before returning to the execution of Step 204, the above-mentioned Steps 204 to 210 with the MLC 8 rotated by 1 °.
Repeat the process of.

In this way, the MLC 8 is rotated by 1 ° from the initial position (0 °), and radiation is emitted in the rotated state. For example, FIG. 14 shows the position of each leaf 9 of the MLC 8 when the rotation angle of the MLC 8 reaches 90 ° in total. In FIG. 14, since the normal tissue D cannot be shielded by one leaf 9a (corresponding to the case where the determination in step 207 is NO), it is shielded by the two leaves 9a and 9b. Hereinafter, similarly, the position of each leaf 9 when the total rotation angle of the MLC 8 is 180 ° (see FIG. 15) and 270 ° (see FIG. 16) is shown.

In this way, the MLC 8 makes the predetermined angle (3
If the MLC 8 has rotated up to 60 ° (that is, the MLC 8 has rotated once), the collimator controller 20 determines YES in step 210, and proceeds to step 211.

In step 211, the collimator controller 20 sends the data indicating the end of radiation irradiation to the irradiation controller 17 via the main controller 16, and as a result, the irradiation of radiation is completed (step 211). Then, the MLC 8 is moved to the initial position (0 °, but in the case of the present embodiment, the predetermined angle is 360 °).
The leaf drive unit 12 sends a command to return the leaf 9 to the original position.
And to the rotation drive unit 14 to end the process (step 212).

In this manner, the radiation treatment can be performed while the normal tissue D existing in the target T is automatically and completely shielded by the MLC 8. Therefore, since it is unnecessary to put or remove the shield such as a lead plate, the treatment time for the patient is shortened and the burden on the operator is reduced.

Further, since the normal tissue in the target is shielded automatically rather than manually, human error is eliminated and the reliability of the treatment apparatus is relatively improved.

Further, since the radiation is radiated every time the MLC 8 is rotated by θ °, it is possible to reduce the reduction of the radiation efficiency of the radiation to the target T by the leaf 9a itself which shields the normal tissue.

In this embodiment, the treatment planning device 3
The input unit 1 forms the designating unit according to claim 2, and the irradiation control unit 17 and the collimator control unit 20 perform steps 201 to 210, the radiation generation unit 7, the leaf drive unit 12,
The rotation drive unit 14 forms a radiation irradiation unit. In particular, the processes of steps 204 to 206 of the collimator control unit 20 and the leaf driving unit 12 form the shielding means.

In this embodiment, the rotation angle θ of the MLC 8 is set to 1
However, the present invention is not limited to this, and in consideration of the dose rate and the like in the treatment apparatus 1, M
The optimum rotation angle may be set based on the rotation speed required for the LC8.

Further, in the present embodiment, the above-described processing of FIG. 8 is performed by the treatment apparatus 1, but the present invention is not limited to this. For example, the treatment planning apparatus 31 performs the processing of FIG. It may be configured to be virtually performed and to send the result to the treatment device 1.

Furthermore, in the present embodiment, the radiation treatment system comprises a treatment device 1, a CT device 30, a treatment planning device 31,
Although it is composed of the X-ray simulator 32, the present invention is not limited to this, and as a radiation treatment system, the treatment apparatus 1, the CT apparatus 30, the treatment planning apparatus 31,
X-ray CT having the functions of the X-ray simulator 32
It may be configured with a simulator.

(Third Embodiment) The treatment apparatus 1 according to the present embodiment.
17 and a side view and a front view thereof are shown in FIGS. 18 and 19, respectively. The same or equivalent configurations as those of the first and second embodiments are designated by the same reference numerals, and the description thereof will be omitted or simplified.

In the present embodiment, the treatment apparatus 1 includes a shield insertion mechanism 50 for inserting and placing a shield for shielding normal tissue existing in the target shape from radiation between the collimator 8 and the subject H. A shield storage unit 52 for storing the shield 51 is provided.

The shield insertion mechanism 50 is provided on one side surface of the gantry 3. The shield insertion mechanism 50 includes a cylindrical support column 50a that is expandable and rotatable and is attached to the support column 50a.
An arm 50b is provided so as to protrude substantially vertically from the side surface of the arm. This arm 50b is also extendable and retractable, and the arm 5b
A hand 50c with two fingers that can be opened and closed is provided at the tip of 0b.

Stretching and rotating of the column 50a, the arm 50b
The expansion and contraction and rotation of, and the opening and closing of the two fingers of the hand 50c are performed by a shield insertion mechanism drive unit described later. This shield insertion mechanism drive unit has a power source such as an electric motor and a drive mechanism such as a worm gear and a rack and pinion for each of the column 50a, the arm 50b, and the hand 50c, and the power supplied from the power source. Has the function of converting the linear motion, the rotary motion, and the opening / closing motion.

As shown in FIGS. 17 to 19, the shield housing portion 52 is provided on one side surface of the gantry 3 (shield insertion mechanism 50).
Is provided). The shield storage unit 52 includes storage chambers divided into, for example, five chambers from above, and each storage chamber has a circular shield (hereinafter also referred to as a block) 51 (No. 1
~ No. 5) are stored in order from the top.

Next, FIG. 20 is a schematic block diagram of this embodiment.
Shown in. The same or equivalent configurations as those of the first and second embodiments are designated by the same reference numerals, and the description thereof will be omitted or simplified.

In this embodiment, in addition to the configuration of FIG. 1, the above-mentioned shield insertion mechanism 50 and the shield insertion mechanism drive unit 53 for driving this shield insertion mechanism are provided. The shield insertion mechanism drive unit 53 is driven in response to a control signal from the shield insertion mechanism control unit 54 provided in the console 5, and expands and contracts and rotates the support column 50a of the shield insertion mechanism 50, and moves the arm 50b. Expansion and contraction, rotation, and hand 50
The opening / closing operation of c is performed.

A memory 55 is provided in the console 5. This memory 55 has a look-up table, and the look-up table has a diameter of each block 51 inserted by the shield insertion mechanism 50 and a shield insertion height d from the radiation source P (see FIG. 21). When,
The shielding range (diameter) on the body surface corresponding to this diameter and the height d from the target is stored. For example, in FIG.
As shown in FIG. 1 (diameter 10 mm) to NO. Up to 5 (diameter 24.41 mm),
When the distance from the target T to the body surface (isocenter (I / C)) is 1000 mm, d is a predetermined length (for example, 400 mm and 500) in this lookup table.
mm), the shielding range on the body surface of each block 51 (NO. 1 to NO. 5) is stored. For example, block No. In 1, when d = 400 mm, on the body surface,
It can shield a circular area with a diameter of 25 mm.
Block No. In No. 3, when d = 500 mm, a circular range having a diameter of 31.25 mm can be shielded on the body surface.

Next, the overall operation will be described.

Also in this embodiment, as shown in FIG. 23, it is assumed that the normal tissue D (the normal tissue D is substantially circular) exists in the target T.

In planning treatment, the treatment planning device 3
The opening setting mode data (in the present embodiment, the circumscribing mode) and the target shape data are input from the input unit 34 of No. 1 and the shape data and the position data of the normal tissue D existing in the target T (hereinafter , Simply referred to as shape data of normal tissue) is also input by a rectangular ROI, a polyline, or the like. Then, it is assumed that the optimum rotation angle (0 ° in the case of the present embodiment) is obtained based on the opening setting mode data and the target shape data. At this time, the leaf opening data and the rotation angle data (0 °) based on the circumscribing mode are stored in the storage unit 36 of the treatment planning device 31.
Is input, and normal tissue D in the target T
The shape data of is also entered.

When the treatment is carried out after the treatment plan is made in this way, the main controller 16 is activated by using the input device 23 of the console 5 of the treatment apparatus 1. The main control unit 16 that has started
Reads the leaf opening data and the rotation angle data that have been stored in the storage unit 36 of the treatment planning device 31 up to that point, and also reads the shape data of the normal tissue D.

The main controller 16 passes the shape data of the normal tissue D to the shield insertion mechanism controller 54.

At this time, the shield insertion mechanism control unit 54
The processing shown in FIG. 24 is performed. That is, the shield insertion mechanism control unit 54 reads the shape data of the normal tissue D sent from the main control unit 16 (step 401). Next, the area of the normal tissue is calculated from the read shape data of the normal tissue D (step 402). Then, the diameter of the normal tissue D is obtained from the obtained area of the normal tissue D (step 403).

After that, the shield insertion mechanism control unit 54 looks up the memory 55 (step 404), and based on the diameter of the normal tissue D from the look-up table, the normal tissue D can be completely shielded. Block is selected, and its insertion position (height) d is selected (step 405). For example, if the diameter of the normal tissue D is 30 mm, the block No. 2 is the height of d = 400 mm, the center position of the normal tissue D, and the block No. The block No. 2 is inserted at a position that coincides with the center position of the block 2 (referred to as a shield insertion position). 3 with a height of d = 500 mm, the center position of the normal tissue D and the block No. It should be inserted at a position where the center position of 3 matches.

In this way, the shield (corresponding to No. 3, for example) corresponding to the size of the normal tissue D and the shield insertion position are obtained, and therefore the shield insertion mechanism control unit 54
Is the shield insertion mechanism drive command and the shield insertion mechanism drive unit 5
Then, the process is terminated by sending the result to step 3 (step 406).

The shield insertion mechanism drive section 53 drives the shield insertion mechanism 50 to take out the shield from the storage section 52 and automatically convey it to the shield insertion position. That is,
The support column 50a of the shield insertion mechanism 50 is connected to the height of the arm 50b and the block No. of the shield storage unit 52. 3 is moved along the axial direction to a position where the storage position (height) of No. 3 matches, and then the column 50a is moved to the hand 50c of the arm 50b.
Is the block number of the shield storage unit 52. Rotate to the position facing 3.

Then, the two fingers of the hand 50c block the arm 50b. 3 is extended to a position surrounding the block 50, and then the two fingers of the hand 50c are driven so as to be closed so that the block No. 3 can be grasped by the two fingers.

Then, the arm 50b is rotated while being contracted in the opposite direction to the block No. held by the hand 50c of the arm 50b. The center position of 3 is matched with the center position of the shield insertion position. Then, the column 50a is moved by moving the column 50a in the axial direction. The height of 3 is made to coincide with the height d of insertion of the shield.

When the insertion of the shield 51 by the drive of the shield insertion mechanism 50 is completed as described above, the main controller 16 collimates the leaf opening data and the rotation angle data as in the first embodiment. It is passed to the control unit 20. The collimator control unit 20 controls the leaf drive unit 12 according to the leaf opening data, and controls the rotation drive unit 14 according to the rotation angle data.

By driving the leaf drive unit 12 and the rotation drive unit 14, each leaf 9 of the MLC 8 is transferred to the treatment planning device 31.
Moves to the position planned in (in this embodiment, the position circumscribing the target shape), and the entire MLC 8 rotates to the position planned in the treatment planning device 31 (0 ° in this embodiment). .

Therefore, as shown in FIG.
The irradiation field shape is automatically created by each leaf 9 of No. 8 and the normal tissue D is the block No. It can be seen that the number 3 is automatically and completely shielded. That is, the normal tissue in the target shape can be easily shielded without bothering the operator.

Therefore, the time for carrying the shield such as the lead plate and the like is eliminated, and the time for restraining the patient to the treatment is greatly reduced.

The processing of step 401 of the input unit 34 and the shield insertion mechanism control unit 54 in this embodiment forms the designating means according to claim 8, and the shield insertion mechanism control unit 5
The processing of steps 402 to 405 in step 4 forms the identifying means. In addition, step 40 of the shield insertion mechanism control unit 54
The process 6 and the shield insertion mechanism drive unit 54 form an automatic transfer unit.

In the present embodiment, the structure of the shield insertion mechanism 50 is shown in FIGS. 17 to 19, but the present invention is not limited to this, and the shield can be gripped and conveyed to the shield insertion position. Any structure may be used as long as it is one.

Further, in the present embodiment, the normal tissue has a substantially circular shape, but the present invention is not limited to this, and can be applied to various rectangular shapes.
In this case, various shapes of the shield can be prepared, or the maximum length in normal tissue can be used instead of the diameter.

Further, in this embodiment, the shield insertion mechanism 5
However, the present invention is not limited to this. For example, the shield insertion mechanism 5
The support column 50a, the arm 50b, and the hand 50c of 0 may be manually moved.

Furthermore, in this embodiment, the shield storage unit 5 is used.
Although 2 is provided on the gantry 3, the present invention is not limited to this and may be attached to, for example, the bed 2 or the like.

On the other hand, in this embodiment, the collimator is a multi-leaf type collimator, but the present invention is not limited to this. For example, a collimator having a structure in which a concealment block or the like is combined, or a collimator having any structure is used. But it's okay.

Further, in the present embodiment, the radiation treatment system comprises a treatment device 1, a CT device 30, a treatment planning device 31, X.
Although it is configured by the line simulator 32, the present invention is not limited to this, and as a radiotherapy system,
It may be composed of the treatment apparatus 1, the CT apparatus 30, the treatment planning apparatus 31, and the X-ray CT simulator having the functions of the X-ray simulator 32.

(Fourth Embodiment) The treatment device 6 according to the present embodiment.
The main part of 0 is shown in FIG. The treatment device 60 includes an electron beam generator 61 such as a klystron, an electron beam deflector 62 that deflects the electron beam output from the electron beam generator 61 to make it a straight line, and a radiation source 63. . The electron beam generator 61, the electron beam deflector 62, and the radiation source 63.
Form the radiation generating part.

The treatment device 61 has a MLC 64 having a multi-division conformal diaphragm structure, and a film table (shadow tray) on which a radiation field film obtained by a laser printer (not shown) of the treatment planning device 31 is placed. 65 and a bed 66 on which the subject H is placed.

Further, the treatment device 60 is provided on a visible light source 67 such as a light, a first half mirror 68 arranged in the optical path of the visible light emitted from the visible light source 67, and a path of a radiation path. The second half mirror 69 is provided. The distance from the second half mirror 69 to the radiation source 63 and the distance from the second half mirror 69 to the visible light source 67 are arranged to be equal.

As shown in FIG. 26, the center of the first half mirror 68 passes through the central axis (z axis in FIG. 26) of the visible light emitted from the visible light source 67, and is approximately 45 from the central axis. As shown in FIG. 26, the second half mirror 69 is arranged at a tilted angle, and the center of the second half mirror 69 is the central axis of the visible light emitted from the visible light source 67 and the radiation source 6.
They are arranged so as to pass through the central axes of 3 and be inclined by about 45 degrees from the respective central axes.

Further, as shown in FIG. 26, the treatment device 61 has a C on the lower side (x direction side) of the first half mirror 68.
A CD camera 70 is provided. This CCD camera 70
Is provided so that the distance between the CCD camera 70 and the first half mirror 68 is equal to the distance between the first half mirror 68 and the visible light source 67.

Next, FIG. 27 is a system configuration diagram of this embodiment.
Shown in. The description of the same or equivalent constituent elements as those of the first to third embodiments will be omitted or simplified.

In this embodiment, the CCD camera 70 described above is provided in addition to the configuration of FIG. An A / D converter 71, a bit map memory 72, and an arithmetic processing unit 73 are connected to the output side of the CCD camera 70. A /
The D converter 71 is adapted to convert a video signal obtained by the CCD camera 70 into digital data. Further, the bitmap memory 72 is set so that the coordinates of the bitmap correspond to the irradiation opening surface of the MLC 8, and A
It has a function of storing the digital data (bit data) converted by the / D converter 71 as black and white binary. The arithmetic processing unit 73 is adapted to perform processing shown in FIG. 28 described later based on the bit data stored in the bit map memory 72.

Next, the overall operation will be described centering on the processing of the arithmetic processing section 73.

In the present embodiment, a treatment plan is prepared in advance for a certain subject, and the mark indicating the irradiation site is previously set for the subject H.
Is marked with.

First, the subject H on which the mark indicating the irradiation site is drawn is placed on the bed 66, and the visible light from the visible light source 67 is reflected by the first half mirror 68 and the second half mirror 69.
The subject H is irradiated with (the diaphragm of the MLC 64 is fully opened) via the, and the irradiation site (irradiation field shape) is projected on the body surface.

In this state, the reflected light from the body surface is incident on the CCD camera 70 via the second half mirror 69 and the first half mirror 68 (see FIG. 26). At this time, the image obtained by the CCD camera 70 is the radiation source 6
3 is equivalent to the image seen through MLC8.

At this time, the bed 6 is taken by the CCD camera 70.
The subject H on 6 is imaged. The obtained analog image is A / D converted by the A / D converter 71 to set a threshold value for distinguishing between the skin and the mark, and binarized (body surface;
(White, mark; black) processing (see FIG. 28A).

The digital image data binarized by the A / D converter 71 is sent to the bit map memory 72. As a result, the body surface portion is stored as white (0) and the mark portion is stored as black (1) in the bitmap memory 72 (see FIG. 28B).

Next, the arithmetic processing unit 73 performs a process of inverting the black and white of the bit data stored in the bit map memory 72. As a result, bit data in which the mark portion is white and the body surface portion is black is stored in the bitmap memory 72 (see FIG. 28C).

Then, the arithmetic processing unit 73 receives white bit data (flag '0 from the outside of the bitmap memory 72).
If the flag '1' is set in the adjacent bit data in the area up to the bit position containing '),
A different flag ('
2 ') is set up. As a result, the flag on the mark is "0", and the bit on the inside of the mark is "1".
A flag "2" is set on the bit outside the mark "," (see FIG. 28D).

At this time, the arithmetic processing unit 73 sets the flag '0.
Find the coordinates of the bitmap where ´ is set,
The coordinate position is sent to the collimator control unit 20. The collimator controller 20 sends to the leaf driver 12 a command to move the actual leaf 9 according to the coordinate position. At this time, as shown in FIG. 29, even if the mark is thick, it is only necessary to preset in advance which coordinate position of the edge of each leaf 9 is moved to the inside, the outside, or the middle of the mark. Can be moved.

In this way, each leaf 9 is formed as shown in FIG. 28 (e).
As shown in, the irradiation field shape can be created by moving to a desired position. That is, the operator does not need to specify the actual movement position of the leaf 9 and automatically
Since the position of each leaf 9 of the LC 8 can be designated, the burden on the operator can be significantly reduced.

The contents stored in the bit map memory are
For confirmation, it may be displayed on a display or the like (not shown) if necessary.

Another example of the fourth embodiment will be described. 30. In the configuration of FIG. 27, the first half mirror 68 is removed, and the CCD camera 70 is photographed in a state of being inclined by α ° from the central axis of the radiation source, as shown in FIG.

In this case, as shown in FIG. 31, the mark appears to be short in the tilt (α) direction. Therefore, in this case, assuming that the apparent mark length is l'and the actual mark length is 1, the irradiation field shape is created by performing the above-described processing while correcting as "l = l'sin α". can do.

Further, the image taken by the CCD camera 70 is CR of the display 23 via the A / D converter 71, the bit map memory 72, the arithmetic processing section 73 and the main control section 16.
By sending to T and recognizing as an image on this CRT and moving the position of each leaf 9 of the actual MLC 8, the irradiation field shape can be automatically created from the change in brightness on the image. It is possible (this method can also be performed with the configuration of the fourth embodiment described above).

Further, as shown in FIG. 32, the CCD image pickup device 74 is placed on the extension line of the radiation path and its image pickup surface is ML.
It is also possible to perform the above-described processing at a position parallel to the irradiation opening surface of C8.

Further, instead of the CCD camera 70, a linear image sensor, a photodiode or the like can be used.

The visible light source 67, the first half mirror 68, the second half mirror 69, CC in this embodiment.
The D camera 70 forms an image pickup means, and the A / D converter 71,
The bitmap memory 72, the arithmetic processing unit 73, the leaf driving unit 12, the rotation driving unit 14, and the collimator control unit 20 form an automatic aperture control unit.

Further, in the present embodiment, the collimator is a multi-leaf type collimator, but the present invention is not limited to this, and a collimator in which each leaf is automatically moved to set the opening degree. Any structure of collimator can be applied as long as it is available.

Furthermore, in the present embodiment, the radiation treatment system includes a treatment device 1, a CT device 30, a treatment planning device 31,
Although it is composed of the X-ray simulator 32, the present invention is not limited to this, and as a radiation treatment system, the treatment apparatus 1, the CT apparatus 30, the treatment planning apparatus 31,
X-ray CT having the functions of the X-ray simulator 32
It may be configured with a simulator.

[0162]

As described above, according to the first and second aspects of the present invention, the rotation angle of the collimator that minimizes the error area is automatically set in the designated opening setting mode such as the midpoint mode. Since it is selected, the radiation field created under this condition always has the smallest error area, that is, the optimum field shape. Therefore, the effect and safety of treatment can be improved. Further, since the optimum rotation angle of the collimator can be automatically selected, it is possible to significantly reduce the treatment time and the burden on the operator due to the conventional setting of the rotation angle.

According to the third and fourth aspects of the present invention, when the normal tissue exists inside the lesion, if the shape and position of this normal tissue are specified, the normal tissue is based on the shape and position of the normal tissue. , At least one leaf of the collimator near that position can move to automatically shield the normal tissue, and in this shielded state,
Radiation can be emitted while the entire collimator is rotated by a predetermined angle.

Therefore, it is not necessary to carry a shield for shielding normal tissue, and the burden on the operator can be reduced. In addition, since the shape and position of normal tissue is accurately recognized and the normal tissue is automatically shielded on it, there is a significant difference in accuracy from the conventional manual operation of orthotopic tissue. Yes, further improvement in safety can be expected.

Furthermore, according to the fifth and sixth aspects of the present invention, the operator can easily operate the shield inserting mechanism to easily insert the shield into the position where the normal tissue is shielded. Therefore, it is not necessary to carry a shield for shielding normal tissue, and the burden on the operator can be reduced.

In particular, according to the invention of claim 8, when the shape and position of the normal tissue are specified, the spatial distance between the collimator and the subject is determined based on the specified shape and position of the normal tissue. The insertion position of the shield at the position is specified, and the shield is automatically conveyed to the specified insertion position.

That is, since the shape and position of the normal tissue is accurately recognized and the normal tissue is automatically shielded on the basis of the shape and position, the conventional manual shielding of the orthotopic tissue is not accurate. There is a marked difference, and further improvement in safety can be expected.

On the other hand, according to the inventions of claims 9 to 10, when the mark indicating the shape of the irradiation site drawn on the body surface of the subject is drawn in advance, an image based on the shape of the irradiation site is obtained. Since the collimator opening is automatically controlled so that the shape of the irradiation site and the collimator opening match, the operator operates the console based on the control of the collimator opening and the body of the subject. It is possible to create an optimum irradiation opening, that is, an optimum irradiation field, although it is not necessary to perform surface recognition. Therefore, it is possible to remarkably reduce the treatment time and the operator's burden associated with the conventional collimator opening control.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a radiotherapy system according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a radiation treatment apparatus according to this embodiment.

FIG. 3 is a perspective view showing a schematic configuration of MLC.

FIG. 4 is a diagram illustrating a circumscribing mode.

FIG. 5 is a diagram illustrating an inscribed mode.

FIG. 6 is a diagram illustrating a midpoint mode.

FIG. 7 is a diagram illustrating a complete optimization mode.

FIG. 8 is a schematic flowchart showing an example of processing of a control unit.

FIG. 9 is a diagram showing a positional relationship between a target shape and a leaf opening.

FIG. 10 is a diagram showing a positional relationship between a target shape and a leaf opening when the MLC is rotated by 45 degrees.

FIG. 11 is a view showing a normal tissue inside a target.

FIG. 12 is a schematic flowchart showing an example of processing of an irradiation control unit and a collimator control unit.

FIG. 13 is a view showing a state in which normal tissue is shielded by a leaf.

FIG. 14 is a diagram showing the position of each leaf of the MLC when the rotation angle of the MLC reaches 90 ° in total.

FIG. 15 is a diagram showing the position of each leaf of the MLC when the rotation angle of the MLC reaches 180 ° in total.

FIG. 16 is a diagram showing the position of each leaf of the MLC when the rotation angle of the MLC reaches 270 ° in total.

FIG. 17 is a schematic perspective view showing a radiotherapy apparatus according to a third embodiment.

FIG. 18 is a schematic side view of the radiotherapy apparatus according to the third embodiment.

FIG. 19 is a schematic front view of the radiotherapy apparatus according to the third embodiment.

FIG. 20 is a block diagram showing a schematic configuration of a radiotherapy system according to a third embodiment.

FIG. 21 is a view for explaining the insertion height of the shield.

FIG. 22 is a diagram showing an example of a lookup table stored in a memory.

FIG. 23 is a view showing a normal tissue inside a target.

FIG. 24 is a schematic flowchart showing an example of processing of a shield insertion mechanism control unit.

FIG. 25 is a diagram showing an irradiation field shape including a shield that completely shields normal tissue.

FIG. 26 is a diagram showing a main part of a radiotherapy apparatus according to a fourth embodiment.

FIG. 27 is a schematic block diagram of a radiotherapy apparatus according to a fourth embodiment.

28A to 28D are views for explaining changes in stored contents in the bitmap memory in the arithmetic processing section.
(E) is a figure which shows an irradiation field shape.

FIG. 29 is a diagram illustrating the position of a leaf in the width of a mark on the body surface.

FIG. 30 is a side view of a treatment apparatus showing a modification of the fourth embodiment.

FIG. 31 is a diagram illustrating correction of mark length.

FIG. 32 is a side view of the treatment apparatus showing a modification of the fourth embodiment.

FIG. 33 is a perspective view showing a schematic configuration of a conventional radiotherapy apparatus.

FIG. 34 is a diagram for explaining generation of an irradiation field shape by an irradiation site by light projected on the body surface of the subject and an area inside a mark drawn on the body surface.

FIG. 35 is a diagram showing a schematic configuration of MLC.

FIG. 36 is a diagram illustrating a normal tissue in a target and a shield that shields the normal tissue.

FIG. 37 is a diagram showing an error area.

FIG. 38 is a diagram showing an error area when the MLC is rotated by θ.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Radiation therapy apparatus 2 Bed 2a Top plate 3 Platform 4 Platform support 5 Console 6 Bed drive part 7 Radiation generation part 8 MLC 9 Leaf 9A Leaf count 9B Leaf count 10 Lead screw 11 Step motor 12 Leaf drive part 14 Rotation drive part 16 Main control unit 17 Irradiation control unit 20 Collimator control unit 30 CT device 31 Treatment planning device 32 X-ray simulator 33 Display unit 34 Input unit 35 Control unit 36 Storage unit 50 Shield insertion mechanism 51 Shield 52 52 Shield storage 53 Shield Insertion mechanism drive unit 54 Shield insertion mechanism control unit 55 Memory 60 Treatment device 61 Electron beam generation unit 62 Electron beam deflection unit 63 Radiation source 64 MLC 65 Film stage (shadow tray) 66 Bed 67 Visible light source 68 First half mirror 69 Second half mirror 70 CCD camera 1 A / D converter 72 bit map memory 73 processing unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Endo 1385-1 Shimoishigami, Otawara, Tochigi Prefecture Toshiba Medical Engineering Co., Ltd. (72) Inventor Yukie Matsuki 1385-1 Shimoishi, Otawara, Tochigi Prefecture Stock Association Company Toshiba Nasu Factory

Claims (10)

[Claims] 1. A pair of leaf groups made up of a plurality of leaves formed of a radiation shielding material are opposed to each other with a radiation path from a radiation source interposed therebetween, and each leaf can be independently driven in the opposing direction. In addition, a multileaf type collimator capable of rotating the entire pair of leaf groups is provided, and a treatment plan for a radiotherapy apparatus for performing radiation treatment by irradiating a lesion area of a subject while narrowing the radiation with the collimator is prepared. In the radiation treatment planning apparatus for, a state in which the specifying unit that specifies the target shape of the lesion on the image taken of the subject and each leaf of the collimator are brought close to the target in the desired opening setting mode Rotation means for rotating the entire collimator, and the end line portion of each leaf and the target according to the rotation of the collimator by the rotation means. A radiation treatment planning apparatus comprising: a calculating unit that calculates an error area formed by the line of the gamma line and a selecting unit that selects a collimator rotation angle that minimizes the error area calculated by the calculating unit. 2. The radiation treatment planning apparatus according to claim 1, wherein the opening setting mode is one of a circumscribing mode, an inscribing mode, a midpoint mode, an optimum mode, and a complete optimization mode. 3. A pair of leaf groups made of a plurality of leaves formed of a radiation shielding material are opposed to each other with a radiation path from a radiation source interposed therebetween, and each leaf can be independently driven in the opposing direction. In a radiotherapy apparatus that includes a multi-leaf type collimator capable of rotating the entire pair of leaf groups, and irradiates a lesion area of a subject with radiation while narrowing the radiation with the collimator to perform radiotherapy, When normal tissue is present inside, radiation is applied while designating the shape and position of this normal tissue, and with the designated normal tissue shielded by the leaf, rotating the collimator by a predetermined angle. Radiation irradiation means for moving the at least one leaf near the position based on the shape and position of the normal tissue. A radiation treatment apparatus comprising a shielding means for shielding the normal tissue. 4. A pair of leaf groups made up of a plurality of leaves formed of a radiation shielding material are opposed to each other with a radiation path from a radiation source interposed therebetween, and each leaf can be independently driven in the opposing direction. In the radiation treatment method, which comprises a multi-leaf type collimator capable of rotating the entire pair of leaf groups, and irradiates a lesion area of a subject with radiation while narrowing the radiation with the collimator, the collimator is predetermined. A method for irradiating radiation, which comprises irradiating radiation while rotating it by an angle. 5. A radiotherapy apparatus for irradiating a lesion area of a subject with radiation while irradiating the lesion area with a collimator to perform radiation treatment, and a shield for shielding the radiation having a shape suitable for the lesion area and the collimator. A radiation treatment apparatus comprising a shield insertion mechanism that is inserted between a subject and a subject. 6. The radiation therapy apparatus according to claim 5, wherein the shield insertion mechanism is installed on a pedestal of the therapy apparatus. 7. The shield storage unit for storing the shield when not in use is installed on a pedestal of the treatment apparatus.
The described radiotherapy device. 8. When normal tissue exists in the target shape of the subject, based on the specifying means for specifying the shape and position of this normal tissue and the shape and position of the normal tissue specified by this specifying means. And a specifying unit that specifies an insertion position of the shield at a spatial position between the collimator and the subject, the shield inserting mechanism,
The radiotherapy apparatus according to claim 7, further comprising an automatic transporting unit that automatically transports the shield stored in the shield storage unit to the insertion position specified by the specifying unit. 9. A radiotherapy apparatus for performing radiotherapy by irradiating the lesion area while narrowing the radiation with a collimator based on a mark indicating the shape of the radiation irradiation site drawn on the body surface of the subject in advance, The opening degree of the collimator is determined by using an imaging unit that captures the shape of the irradiation site based on the mark drawn on the body surface of the subject and an image based on the shape of the irradiation site captured by the imaging unit. A radiation treatment apparatus comprising: an automatic opening degree control unit that automatically controls the shape to match the shape of the irradiation site. 10. The collimator is arranged such that a pair of leaf groups made up of a plurality of leaves formed of a radiation shielding material are opposed to each other across a radiation path from a radiation source, and each leaf is independent in its opposing direction. 10. The radiation treatment apparatus according to claim 9, which is a multi-leaf type collimator that can be driven by rotating the pair of leaf groups.