JPH11319123A - Radiotherapy system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To confirm that the respiration information of an object phase is resting information and to improve safety by providing a means for displaying the result of simulating whether or not irradiation can be intermittently performed by an extracted irradiation control period. SOLUTION: A treatment schedule device is provided with the means for displaying the respiration information, the means for displaying the start point and end point of an irradiation period and the means for displaying the result of simulating whether or not the irradiation can be intermittently performed by the extracted irradiation control period and a monitor for displaying the object by the means is disposed. As the processing flow of the three means, between a step 20 for deciding the start point and the end point and the step 21 for outputting the points, the step 100 for displaying the respiration information, the step 101 for displaying the start point and end point of the irradiation control period and the step 102 for displaying the result of simulating whether or not the irradiation can be intermittently performed by the extracted irradiation control period are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiotherapy system for performing radiotherapy on the basis of image diagnostic information of a lesion of a subject.

[0002]

2. Description of the Related Art In radiation therapy, it is important to irradiate only a lesion with an electron beam and a radiation beam while suppressing exposure of normal tissues around the lesion. In particular, it is important that the respiratory movement of the treatment target can accurately irradiate only the lesion that moves with the respiration.
In that sense, it is significant to use the respiratory-gated irradiation method.

[0003] Here, the respiratory-gated irradiation method is a method of irradiating a lesion with the above-mentioned beam in synchronization with the rest period of the lesion moving by respiratory movement. For the period during which the lesion is stationary, see "Study on respiratory phase-synchronized irradiation."
(Kiyoshi Ohara, 6 others: Journal of the Japan Society for Medical Radiology, No. 47
Vol. 3, No. 3, 488-496, 1987), and the lesion is located at a fixed position during end expiration (when exhaling) of about 2 seconds out of about 5 seconds in one cycle of breathing. .

According to such a respiratory-gated irradiation method, more ideal radiotherapy can be performed as compared with a general irradiation method in which an irradiation field is set to be wide so as to include the entire moving range of a lesion. .

[0005]

In order to perform respiratory-gated irradiation, it is important to accurately determine an irradiation control period corresponding to a stationary respiratory phase of a lesion. However, the patient's breathing is not always breathing at rest, and may suddenly cause abnormal breathing, which cannot be predicted. Due to this abnormal respiration, an erroneous irradiation control period may be obtained.

For example, there is a problem when the irradiation control period is determined for an abnormal respiratory waveform of the respiratory information 81 in FIG. 5 as shown in FIG. The irradiation control period is obtained by associating the rest period obtained from the CT image with the respiration information. In the case of FIG. 13, the start point 40 and the end point 41 correspond to abnormal respiration information in which the value of the respiration information at the end expiration is lower than that at the time of rest breathing.
That is, the irradiation control period is determined.

When performing respiratory-gated irradiation, irradiation is performed intermittently based on the irradiation control period. In this case, as shown in FIG. 14, the respiration information 83 shown in FIG. Since the light does not pass through the threshold value 40 'of the point 40, there is no irradiation control period. For this reason, it can be said that setting of such an irradiation period is inappropriate.

For example, in the case of a respiratory synchronization plan, FIG.
There is a problem when the irradiation control period is obtained for an abnormal respiration waveform of the respiration information 81 as shown in FIG. FIG.
In the case of, the irradiation control period of the start point 40 and the end point 41 is obtained for abnormal respiration information in which the value of the respiration information at the time of end-expiration is lower than that at the time of rest breathing.

When performing respiratory-gated irradiation, irradiation is performed intermittently based on this irradiation control period.
As shown in FIG. 16, the breathing information 83 does not pass through the threshold value 41 'of the end point 41 at the time of rest breathing, so that the irradiation control period continues beyond the period during which the lesion rests. Therefore, such setting of the irradiation period is inappropriate.

An object of the present invention is to provide a radiotherapy system capable of ensuring safety by confirming that respiration information of a target phase is rest information in order to accurately determine an irradiation control period. It is in.

[0011]

The object of the present invention is to provide an image diagnostic apparatus for obtaining an image capturing the movement of a lesion moving with respiration, a respiratory detecting means for detecting respiratory information,
Based on the irradiation control period extraction means for extracting the irradiation control period from the image capturing the movement of the lesion and the respiration information, and the respiration information obtained by the respiration detection means during treatment,
In a radiotherapy system comprising a radiotherapy device intermittently performing irradiation in synchronization with an irradiation control period, a respiration information display means for displaying the detected respiration information, and a start point and an end point of the extracted irradiation control period And a simulated irradiation display means for displaying an irradiation period simulating whether or not irradiation can be performed intermittently by the extracted irradiation control period.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 5 shows a system configuration of the radiotherapy system. The X-ray CT apparatus 60 (image diagnostic apparatus) collects image data of a lesion of a treatment target using dynamic scan, spiral scan, or the like. Image the lesion while measuring. The respiratory synchronization device 61 (respiration detection means) is connected to a strain gauge for detecting the abdominal pressure of the body to be treated and a lamina for detecting the ventilation volume in order to obtain respiration information, displays the detected respiration information, and displays the respiration information. An irradiation start point and an irradiation end point of radiation to the body are set (22 in FIG. 1 described later). This respiratory synchronization device 61
At the time of treatment, it is connected to a treatment device 70 composed of a control unit 65, an accelerator 66, a gantry 67, and a treatment table 68, and takes breathing information 83 from the treatment target 90 while breathing based on the set irradiation start point and irradiation end point. The synchronization signal 84 is created (23 in FIG. 1) and the control unit 65
Output to

The treatment planning device 62 includes image information 80 from the X-ray CT device 60 and respiration information 8 from the respiratory synchronization device 61.
The operator inputs 1 and plans how to radiate radiation to the subject to be treated based on these two pieces of information. This device 62 has a subtraction function (FIG. 2).
10), an area calculation function (13 in FIG. 2), a focus still area extraction function (17 in FIG. 2), a collation function (18 in FIG. 2), etc., and image information 80 from the X-ray CT apparatus 60. To extract an image of the still range of the lesion (17 in FIG. 2). Further, respiratory information 81 from the respiratory synchronizer 61 is input, and this information 81 is compared with the image of the still range (FIG. 2). 1
8) Then, the irradiation start point and the irradiation end point are determined from the both (20 in FIG. 2), and the data is output (21 in FIG. 2).

The control unit 65 controls the respiratory synchronization signal 8
4 to output control signals 86, 87 and 88,
6, the gantry 67, the treatment table 68, and the like are controlled to perform respiratory-gated irradiation.

The collation device 63 inputs data 85 planned by the treatment planning device 62, sends the data 85 to the control unit 65, and is constantly communicating with the control unit 65. The information that moves the gantry 67 and the treatment table 68 is received, and it is confirmed whether or not the plan made in the treatment plan is executed as it is.

Next, a specific example will be described in detail with reference to FIGS. In FIG. 2, the numbers in parentheses correspond to the device numbers.

At the same time, the collection of image information by the X-ray CT apparatus 60 (step 2) and the collection of respiration information on the subject to be treated by the respiratory synchronization apparatus 61 (step 3) are started (step 1).
At the same time, time measurement (step 1) is performed at the same time.
The time is stored as data at the time of image acquisition in the X-ray CT apparatus, and the respiration information can be obtained as a time axis.

When the collection of image information by the X-ray CT apparatus 60 is completed (step 4), image data is output (step 5). On the other hand, when the collection of the respiration information by the respiratory synchronization device 61 is completed (Step 4 ′), the respiration information is output (Step 6).

From the images obtained by X-ray CT, a plurality of original images near the end-expiration where the lesion rests are shown in FIGS.
The subtraction function is started based on the plurality of pieces of image data (step 10), and the subtraction image between the images is obtained as shown in FIG. 3 (ab-f-f).
Collect as shown in g) (step 11). If the focus is moving, the moving part appears as a difference in gradation (black part 51 or white part 52) in the subtraction image. However, in the range where the lesion is stationary, there is no difference in the gradation in the subtraction image, and the gradation is almost 0.
It is a nearby image. The black portion 51 has a minus gradation, and can be regarded as a gradation range where the gradation is −50 or less, for example. The white portion 52 has a positive gradation, and can be regarded as a gradation range of, for example, a gradation of +50 or more. The gradation range of the black portion 51 and the white portion 52 is specified in advance (for example, when the gradation is minus 50).
The following range and the range of plus 50 or more are designated as the gradation range), the subtraction images obtained as shown in FIG. 3 are calculated one by one, and the area of the black portion 51 and the white portion 52 is calculated. (Step 13). In the case where there are many portions 53 near the gray level of approximately 0 between black and white, or in the case of all intermediate portions, the calculated area of the combined black portion 51 and white portion 52 is substantially zero. That is, the image range in which the area is substantially zero is the still period.

Alternatively, by taking the absolute value of the gradation of the subtraction image, by taking the absolute value of the black portion where the gradation is minus and making it positive by taking the absolute value, all the moving portions of the lesion are displayed as white portions. can do.
In addition, by inverting the plus and minus of this image, all the portions where the lesion is moving can be displayed as black portions. By displaying in this way, the operator can clearly know the part where the lesion is moving. In the subtraction image having the absolute value as described above, for example, in a case where all the moving portions of the lesion are displayed as white portions, the gradation range of the white portion is designated in advance (for example, the gradation is plus 50). The above range is designated as a gradation range), the subtraction images are calculated one by one, and the area of the white portion is calculated (step 13). If there are many parts 53 whose gradation is near zero or all of them are intermediate parts, the calculated area of the white part is substantially zero. That is, the image range in which the area is substantially zero is the still period.

From the result, an image range (c, d, e in FIG. 3) in which the area is substantially zero is output (steps 15, 16).
Then, the range of this image is extracted as a range where the lesion is stationary (step 17). The stationary range shows an image at the start point (c in FIG. 3) and an image at the end point (e in FIG. 3) of the stationary range. The extracted image has time data at the time of image acquisition as described above, and the extracted image information is input to the treatment planning device 62 (step 31). At the same time, the respiratory information of the object to be treated, which is acquired at the time of imaging by X-ray CT, is input from the respiratory synchronization device 61 to the treatment planning device 62 (step 32). The respiration information is waiting for data as a continuous time, and the imaging performed by the X-ray CT starts at the same time as the acquisition of the respiration information of the respiratory synchronizer,
In the treatment planning device 62, the time of the image at the start point of the still range and the time of the image at the end point of the still range can be compared with the time of the breathing information. The starting point and the ending point can be determined on the respiration information (steps 19 and 20), and the data of the starting point and the ending point are output to the respiratory synchronizer 61 (step 21). 4 of 40)
And the end point is set as the irradiation end point (41 in FIG. 4) (step 22). The area between the irradiation start point (40 in FIG. 4) and the irradiation end point (41 in FIG. 4) is a range where the lesion is stationary and is an irradiation range. Therefore, a respiratory synchronization signal (84 in FIG. 4) can be created in this range (step 23).

The setting of the irradiation start point and the irradiation end point and the generation of the respiratory synchronization signal will be described in detail with reference to FIG. The image data 100 is the X-ray CT device 60
, And a plurality of images are continuously collected. This raw data is acquired, for example, with a scan time of one second per image.

The original image 110 is the output of the image data in step 5 of FIG. 1 and includes the image data a to g of FIG. The original image 110 is reconstructed based on the image data 100 (raw data).
Minute time (eg 0.1 seconds) over a range of 00
This is an image obtained by shifting. Image 1 of focus rest area
20 is extracted in step 17 in FIG. 1, and the images c, d, and e are, as described above, image data a in FIG.
This is an image showing a range in which the area of the white part and the black part is determined to be substantially 0 as a result of mutual subtraction of 病 g and the lesion is stationary. That is, the start point of the still range is at the start point of the image c, and its end point coincides with the end point of the image d. This image 120 is input to the treatment planning device 62 for collation (step 18) in step 31. The respiratory information 81 is the output in step 6, where two convex waves indicate that the lesion moves due to respiration of the object to be treated is large, and a concave wave sandwiched between them indicates that the lesion moves little. Is shown. This respiration information 81 is input to the treatment planning device 62 in step 32. The treatment planning device 62 collates the image 120 of the focus rest range with the respiration information 81 (step 18), extracts the irradiation control range 46 in step 19, and determines the start point of the irradiation control range (start point of the image c) in step 20. Irradiation start point P
1. The end point (end point of the image e) is set to the irradiation end point P2.
And outputs the P1 and P2 data to the respiratory synchronizer 61 in step 21. The respiratory synchronization device 61 sets the respective points where the respiration information 81 intersects the points P1 and P2 as the irradiation start point 40 and the irradiation end point 41 in step 22, and stores the set values in the memory. The area between the points 40 and 41 is the area where the lesion is stationary, which is the irradiation area. At the time of treatment, the respiratory synchronizer 61 in which the irradiation range is set is connected to the treatment device 7.
Connect to 0. The respiratory synchronization device 61 collects the current respiration information (83 in FIG. 5) of the treatment target (step 28),
Start point 4 of irradiation range already stored in memory
A respiration synchronization signal 84 is created from 0 and the end point 41 (step 23). That is, as shown in FIG. 4, the respiratory synchronization signal 84 is a high level between the irradiation start point 40 and the irradiation end point 41.
And an off signal 43 which is low in a range other than the on signal 42. The respiratory synchronization device 61 outputs the respiration synchronization signal 84 to the control unit 65 (step 2).
5) When the respiration information 83 is in the irradiation control range 46, the treatment device 70 is operated by the ON signal 42 to emit radiation to the treatment target 90. When the respiration information 83 is outside the irradiation control range 46, the off signal 43 is output to the control unit 65, and the irradiation of the therapy device 20 is prohibited.
After a lapse of a predetermined time, the treatment is terminated (step 3).
0).

In the present invention, the treatment planning device 6 shown in FIG.
2. Respiration information display means for displaying respiration information, irradiation control period display means for displaying the start point and end point of the irradiation control period, and simulation of whether or not irradiation can be performed intermittently by the extracted irradiation control period. Simulated irradiation means for displaying the results obtained are provided, and a monitor 62 'for displaying an object by these means is provided. The processing flow of the three means includes a step 20 for determining an irradiation start point and an end point shown in FIG.
During step 21 for outputting these points, FIG.
Step 100 for displaying respiratory information as shown in
A step 101 for displaying a start point and an end point of the irradiation control period and a step 103 for displaying a result of simulating whether or not irradiation can be performed intermittently by the extracted irradiation control period are provided. That is, in step 100, the waveform of the respiration information 81 shown in FIG. 4 is displayed on the monitor 62 ', in step 101, the irradiation start point 40 and the irradiation end point 41 are displayed on the monitor 62', and further, in step 103 The waveform of the irradiation control period 46 is displayed on the monitor 62 'so that it can be specially identified, and whether the setting of the irradiation control period is not for abnormal breathing but for resting breathing is performed. Can be confirmed, and if the displayed irradiation control period is set for abnormal breathing, the irradiation period is set again in resting breathing, and irradiation is performed for resting breathing. Make it possible to confirm that the control period has been set.

Next, the object displayed on the monitor 62 'is displayed by the display by the respiration information display means (step 100), the display by the irradiation control period display means (step 101), and the display by the simulated irradiation display means (step 103). explain.

FIG. 6 shows the breath information 81. The amount of change in the respiratory information 81 is proportional to the amount of movement of the affected part that moves with respiration, and the amount of change in the value of the respiratory information is large in the phase range in which the affected part is moving. The amount of change in the value is also displayed small. Thus, the movement of the affected part can be visually grasped by the breathing information 81. In FIG. 6, in the part of the phase range r, a change in the value of the respiration information is large, indicating that the affected part is moving.
In the part of the phase range s, the change of the value of the respiration information is small,
This indicates that the affected area is almost stationary. This respiration information 81 is displayed on the monitor 62 'in step 100. Step 102 for such breathing information 81
, The start point 40 and the end point 41 of the irradiation control period are changed to a monitor 62 ′, for example, as shown in FIG.
To be displayed. In addition, the start point 40 and the end pointer 41 can be displayed as crosshairs as in the example shown in FIG. In addition, as in the example shown in FIG. By displaying the start point and end point of the irradiation control period in this way, it is possible to confirm which phase of the respiration information the irradiation control period was set to, and thereby, the phase of the respiration information can be reduced. It is possible to determine whether the waveform is a breathing waveform.

Further, the result of simulating whether or not the irradiation can be performed intermittently by the extracted irradiation control period is monitored by changing the color of the respiration information waveform 46 during the irradiation control period in step 103 as shown in FIG. 10, for example. 62 '
To be displayed. Further, as in the example shown in FIG. 11, the display can be performed by changing the color of the entire range 46 ′ of the irradiation control period. Also, as shown in the example shown in FIG.
Can be displayed by a rectangle 46 "falling.
Thus, the irradiation control period at an arbitrary phase is displayed,
By confirming that the irradiation control period substantially matches the phase range in which the affected part is stationary, it is possible to confirm whether the setting of the irradiation control period is appropriate for any phase. The determination as to whether or not the waveform is abnormal is made using the result of simulating the irradiation control period. When the irradiation period is extremely short or extremely longer than the cycle of the respiration information, it is regarded as an abnormal waveform, and the process of determining the irradiation control period is performed again.

Specifically, when an abnormal waveform of the respiration information 81 shown in FIG. 13 or FIG. 15 is displayed on the monitor 62 ', the irradiation control period is not determined for this abnormal waveform.
An irradiation control period is determined for the quiet breathing of the breath information 81.

[0029]

According to the present invention, for any organ including a lesion, it is possible to grasp the period during which the lesion moving with respiration stops, and confirm whether the extracted irradiation control period is appropriate. Can improve safety,
In addition, since the irradiation period is accurate, safe treatment capable of minimizing exposure to normal tissues around the lesion can be performed.

[Brief description of the drawings]

FIG. 1 is a flowchart of a radiotherapy system according to an embodiment of the present invention.

FIG. 2 is a flowchart of a radiotherapy system according to another embodiment of the present invention.

FIG. 3 is an explanatory diagram of a subtraction function according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram of irradiation control period setting according to the embodiment of the present invention.

FIG. 5 is a configuration diagram of a radiotherapy system according to an embodiment of the present invention.

FIG. 6 is an explanatory diagram of respiratory information according to the embodiment of the present invention.

FIG. 7 is an explanatory diagram showing a display method of a start point and an end point according to the embodiment of the present invention.

FIG. 8 is an explanatory diagram illustrating a method of displaying a start point and an end point according to the embodiment of this invention.

FIG. 9 is an explanatory diagram showing a display method of a start point and an end point according to the embodiment of the present invention.

FIG. 10 is an explanatory diagram showing a method of displaying an irradiation control period at an arbitrary phase according to the embodiment of the present invention.

FIG. 11 is an explanatory diagram showing a method of displaying an irradiation control period at an arbitrary phase according to the embodiment of the present invention.

FIG. 12 is an explanatory diagram showing a method of displaying an irradiation control period at an arbitrary phase according to the embodiment of the present invention.

FIG. 13 is an explanatory diagram showing a case where an inappropriate irradiation control period is set in the embodiment of the present invention.

FIG. 14 is an explanatory diagram showing a case where an inappropriate irradiation control period is set in the embodiment of the present invention.

FIG. 15 is an explanatory diagram showing a case where an inappropriate irradiation control period is set in the embodiment of the present invention.

FIG. 16 is an explanatory diagram showing a case where an inappropriate irradiation control period is set in the embodiment of the present invention.

[Explanation of symbols]

 40 Irradiation start point 40 'Irradiation start point threshold 41 Irradiation end point 41' Irradiation end point threshold 45 Respiration synchronization signal 46 Irradiation control period 60 X-ray CT apparatus 61 Respiration synchronization apparatus 62 Treatment planning apparatus 62 'Treatment Device monitor 70 Therapeutic device

Claims (1)

[Claims] 1. An image diagnostic apparatus for obtaining an image capturing the movement of a lesion moving along with respiration, a respiration detecting means for detecting respiration information, and an image capturing apparatus for capturing the motion of the lesion and respiration information. An irradiation control apparatus comprising: an irradiation control period extracting unit for extracting an irradiation control period; and a radiation therapy apparatus for performing intermittent irradiation in synchronization with the irradiation control period based on respiration information obtained by a respiration detecting unit during treatment. In the treatment system, respiratory information display means for displaying the detected respiratory information;
Irradiation control period display means for displaying a start point and an end point of the extracted irradiation control period, and simulated irradiation display means for displaying an irradiation period simulating whether or not irradiation can be performed intermittently by the extracted irradiation control period. Radiation therapy system.