JP3932667B2 - Proton therapy planning system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The system of the present invention is based on the assumption that a proton beam having a Bragg peak at a certain depth from the body surface is used, so that exposure to normal tissue is suppressed as much as possible, and dose is effectively applied to the lesion. It is used for the planning of a proton therapy plan.
[0002]
[Prior art]
In radiation therapy, it is necessary to minimize the exposure to normal tissues and provide a sufficiently therapeutic dose to the lesion. Therefore, by using image data taken by an image diagnostic apparatus such as an X-ray CT apparatus, it is determined based on the simulation result of the dose distribution, etc., from which direction and how much radiation should be irradiated before treatment. A treatment plan is required. In particular, radiation called proton rays has a characteristic called “Bragg peak”. When a substance is irradiated with a proton beam, the dose rapidly increases at a certain depth from the surface and has a maximum value, and at a depth deeper than that, the dose rapidly decreases to zero. The position where this dose has the maximum value is called the Bragg peak. Therefore, if the position of the Bragg peak is controlled, it is possible to give a high dose almost in accordance with the shape of the lesion, and hardly give a dose behind the lesion. Therefore, in the treatment plan, it is important to determine the irradiation direction by well understanding the shape of the lesion and the positional relationship between the surrounding normal tissue and the lesion.
[0003]
The treatment plan is implemented by software implemented on a computer system. In the treatment plan, first, a three-dimensional region of normal tissue to be noticed around the lesion is set using image data, and the coordinates are stored in the memory. Next, calculate the 3D dose distribution inside the human body using image data according to a physical model based on the irradiation intensity determined according to the size of the lesion (called irradiation field) and the irradiation direction temporarily determined based on the irradiation intensity. To do. Various evaluation means are used for the evaluation of the results. That is, DVH (Dose Volume Histogram) which is a graph showing the relationship between the dose and the tissue volume having the dose value for a lesion or each normal tissue, a two-dimensional isodose diagram in which a dose distribution is superimposed on a tomogram, or For example, a three-dimensional display in which the dose distribution is superimposed on the human tissue as it is in the three-dimensional data, and is displayed in a three-dimensional translucent manner. If it is determined that the dose distribution is desirable, the tentatively determined irradiation direction and irradiation intensity are adopted for treatment. Otherwise, the irradiation direction and irradiation intensity are determined again, and dose distribution calculation is performed. Reassess the results. In the treatment plan, generally, the irradiation direction and the irradiation intensity adopted for the treatment are determined by such a repeated process.
[0004]
It is a very time-consuming task for a person to plan a treatment through this repeated process. Thus, several methods for calculating the irradiation direction and irradiation intensity by mathematical processing have been proposed. For example, A.Brahme, P.Kallman, B.lind: “Optimization of the Probability of Achieving Complication Free Ymor Control Using a 3D Pencil Beam Scanning Technique for Protons and Heavy Ions”, Proceedings form the NIRS international workshop on heavy charged particle therapy and related subjects. Chiba, Japan, 124/142, 1991, B. Lind, A. Brahme: “Photon Field Quantities and Units for Kernel Based Radiation Therapy Planning and Treatment Optimization”, Phys. Med. Biol., Vol. 37, 891/909, 1992. These calculate the irradiation direction and irradiation intensity so as to give an optimum dose distribution based on the least square method. These methods adopt a so-called inverse problem form in which the irradiation direction and the irradiation intensity are obtained from a desired dose distribution inside the human body. Since it uses a general-purpose calculation algorithm, it can be applied to proton therapy planning, but it has the disadvantages that the calculation is complicated and the calculation time is long. Since it is a premise that a desired dose distribution inside the human body is given as an input, when dealing with a three-dimensional treatment plan, there is also a problem that the effort required for the input becomes enormous. That is, it can be said that there has been no means in the past in order to determine the irradiation direction and irradiation intensity in a short time by actively utilizing the Bragg peak characteristic unique to the proton beam.
[0005]
[Problems to be solved by the invention]
A means for automatically determining the irradiation direction of the proton beam by utilizing the Bragg peak characteristic is provided.
[0006]
[Means for Solving the Problems]
As described above, the proton beam has a characteristic called a “black peak” in which the dose has a peak value at a certain depth in the medium. How to use this during the treatment will be described.
[0007]
The characteristic can be controlled so that the Bragg peak due to the scatterer installed in the irradiation device is enlarged and a flat region having a certain width is provided. This flat region having a certain width is called an extended black peak (SOBP). Further, the position of the SOBP can be controlled by adjusting the incident energy of the proton beam with the irradiation device. Therefore, if the water equivalent depth from the body surface to the lesion and the water equivalent thickness in the depth direction of the lesion are known, the SOBP can be matched well with the lesion. The water equivalent depth from the body surface to the lesion and the water equivalent thickness in the depth direction of the lesion are determined using image data taken with an X-ray CT apparatus. This is illustrated in FIG. A lesion 302 is present inside the human body 301, and a proton beam 303 is irradiated toward the lesion 302. However, a bolus 304, which is a type of distance compensation filter, is inserted in the middle. The bolus 304 serves to match the rear end of the SOBP 308 with the rear end of the lesion 302. The shape of the bolus 304 is determined so that the water equivalent depth from the bolus 304 to the trailing edge of the lesion 302 has a constant value. Then, in the deep dose distribution 307 when the proton beam 303 is irradiated, the SOBP 308 matches the lesion 302. Here, the dose 306 is expressed as a relative dose D [%] when the dose at SOBP 308 is 100%, and the depth 307 is expressed as z.
[0008]
When the lesion is irradiated with a proton beam by the above-described method, the SOBP can be completely matched with the lesion only at the position where the water equivalent thickness of the lesion is maximum, and at other positions, the SOBP is in front of the lesion. It will protrude in the edge direction. That is, a dose of 100% is given to some normal tissue near the lesion. Since this irradiation method was born in accordance with the policy that “the lesion must be given a high dose throughout the entire area even if the normal tissue near the lesion becomes larger”, such a protruding portion is Although it is unavoidable that it exists, it is certainly desirable that the amount be small. Therefore, a method of determining the irradiation direction from the viewpoint of minimizing the protruding portion will be considered.
[0009]
First, consider proton beam irradiation in a two-dimensional section for simplicity. When the irradiation direction 401 is determined as shown in FIG. 4, the length in the irradiation direction is equal to the maximum vertical length 403 of the lesion 402 in the SOBP region covering the lesion 402. Do Again, the spread in the direction perpendicular to the irradiation direction is equal to the lateral length 404 of the lesion. Therefore, the area of SOBP is equal to the product of the maximum longitudinal length 403 and the lateral length 404 of the lesion. On the other hand, the area of the lesion is known by the extraction process and is a constant value. If the latter is subtracted from the former, it becomes the area of the protruding portion 405. After all, the area of the protruding portion 405 is minimized because of the maximum length 403 in the direction of the lesion and the lateral length 40 perpendicular thereto. 4 This is when the irradiation direction is selected in such a direction as to minimize the product of. As another example, FIG. 4 shows a case where the lesion is a circle and a case where the lesion is a rectangle. When the lesion is a circle, the maximum longitudinal length 407 and the maximum lateral length 408 of the lesion are equal to the diameter of the circle and are constant regardless of the irradiation direction selected. Therefore, the protruding portion 409 has a constant value regardless of the irradiation direction. When the lesion is rectangular, the protruding portion 413 is completely zero in the irradiation direction perpendicular to each side. From this, it is generally considered that the closer the lesion is to a circle, the smaller the effect of minimizing the amount of protrusion, and the closer to a rectangle the greater the effect.
[0010]
When this is expanded to three dimensions, it is as shown in FIG. That is, the protrusion portion is minimized when the irradiation direction 501 is selected in such a direction that the product of the maximum length 503 in a certain direction of the lesion 502 and the projected area 504 of the lesion in that direction is minimized.
[0011]
Although an approach using a mathematical search algorithm can be considered to find the direction in which the protruding portion is minimized, the following method has been devised.
[0012]
The direction is represented by a pair of latitude and longitude, and candidate points for the direction are obtained in advance at certain angular intervals with respect to the latitude and longitude. The value of the above product is obtained for all of these candidate points, and the direction in which it is minimized is selected. If the candidate points are considered as points on the unit sphere, this minimization problem has symmetry in at least a certain direction and the opposite direction, so that the candidate points need only be considered for the hemisphere. However, since there are at least two candidates for the obtained solution due to this symmetry, it is necessary to examine which of them applies to actual irradiation from another viewpoint.
[0013]
Considering the situation at the clinical site, it is not necessary to make this angular increment so small that the number of candidate points to be calculated does not become enormous, and a minimum solution can be obtained in a practical processing time. At this time, if the distribution of the product is displayed as a contour line on the map using latitude and longitude, the validity of the obtained solution can be easily confirmed visually. You can also use the search algorithm to find the true minimum point using the minimum point selected on the map as the initial point. Ru It is also possible to reduce the angle increment only in the vicinity of the initial point and obtain the minimum point with higher resolution.
[0014]
The above method can be applied when the number of irradiation directions is one. If there are multiple candidates, that number of candidate points on this map The The one that you choose and minimizes the sum can be the final solution.
[0015]
In order to select any one of at least two candidates from the symmetry of the solution, it is effective to confirm with a three-dimensional display. That is, some normal tissues are three-dimensionally displayed around the lesion, and proton beams corresponding to irradiation direction candidates found by the above-described minimization method are superimposed and displayed in three dimensions. An appropriate irradiation direction is selected by alternately displaying the proton beam to be selected or observing the entire display target from an arbitrary direction. Alternatively, after determining the irradiation direction by three-dimensional display, it is also an effective means to display these irradiation directions on the above map and confirm the validity of the direction. A state of the three-dimensional display is shown in FIG. This is an example in which a spinal column 602, a heart 603, a left lung 604, a right lung 605, and a lesion 606 are displayed inside the body surface 601. A proton beam 608 extends from the lesion 606 to the body surface 601 corresponding to the irradiation direction 607. When observing for confirming the irradiation direction, it is assumed that the whole can be rotated in a three-dimensional space and observed from an arbitrary direction. When determining the irradiation direction using a three-dimensional image, the direction is set by dragging the proton beam 608 with a mouse cursor or the like. When determining the irradiation direction in multiple directions, the designated number of proton beams 608 are displayed and moved to an appropriate place with a mouse cursor or the like as in the case of only one.
[0016]
Since the following means are required to realize the above contents in the proton beam treatment planning system of the present invention, they are provided.
[0017]
1. Organization area setting method
In the system of the present invention, a semi-automatic extraction method such as a method using an image density threshold or a region expansion method using tissue connection information from 3D image data stored in a 3D array of voxels. Alternatively, a means for obtaining the three-dimensional coordinates of the whole human tissue, the lesion, and the important tissue is provided by a region designation method in which a person traces the tissue region of interest in each slice image output to the display device. One lesion and multiple important tissues can be set. The above operations can be executed interactively and the results can be seen immediately.
[0018]
2. 3D display
The system of the present invention provides a method of superimposing a tissue and a proton beam in a three-dimensional manner and displaying both on a two-dimensional projection surface in a semi-transparent manner. It is assumed that an arbitrary number of proton beams can be generated around a lesion, and each beam can be set in an arbitrary direction. The lesion center point is given as a diagonal intersection of a rectangular parallelepiped that circumscribes the lesion, and its position can be adjusted. It is assumed that display / non-display can be selected with respect to an arbitrary organization among the organizations in which the organization region is set. Assume that the display object can be displayed by rotating it arbitrarily, or the inside can be displayed by cutting along an arbitrary cross section. It is also possible to display a proton beam corresponding to the irradiation direction set on the protrusion amount distribution map. The above operations can be executed interactively and the results can be seen immediately. In the three-dimensional display, it is possible to intuitively grasp the positional relationship between the tissue and the proton beam in the three-dimensional space.
[0019]
3. Overflow amount distribution map
In the system of the present invention, based on the shape information of the lesion obtained in the tissue region setting, the amount of protrusion from the lesion in the 100% dose range in each direction is calculated and the distribution map is displayed, and the direction in which it is minimized A means for displaying a mark is provided. (There are two directions.) It is assumed that the direction in which the amount of protrusion is calculated can be set by adjusting the angular increments of latitude and longitude. The distribution map of the amount of protrusion is displayed by a method of painting colored contour lines or a certain color between contour lines. The number of contour lines can be arbitrarily set in color. It is also possible to calculate the true minimum direction by an exploratory algorithm using the minimum direction with the above mark as an initial position. However, since the algorithm itself is independent of the present invention, its contents are not described here. The projection amount distribution map can be linked to the three-dimensional display, and if the minimum direction of the projection amount is selected in either the forward or reverse direction, the three-dimensional display of the proton beam is switched accordingly. It is assumed that a plurality of irradiation directions can be set on this distribution map. At this time, it is assumed that the total amount of protrusion can be displayed. It is also possible to specify the number of irradiation directions and display the direction in which the total amount of protrusion is minimized. However, the smallest pair is selected from the set latitude / longitude grid points. Even when there are a plurality of irradiation directions, if one of the forward and reverse directions is selected for each direction, the three-dimensional display of the proton beam is also switched accordingly.
[0020]
The following examples explain how the above means can be used to solve the problem.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
First, an example of a proton beam treatment system and a treatment planning apparatus to which the present invention can be applied will be shown, and then a configuration example of a proton beam treatment system capable of realizing the present invention will be shown. Finally, some specific examples of the proton beam treatment planning system of the present invention will be described.
[0022]
FIG. 11 shows an example of a proton beam treatment system. A tomographic image of the human body obtained from the X-ray CT apparatus 1101 is input to the treatment planning apparatus 1102. The treatment planning apparatus 1102 calculates a dose distribution based on various parameters 1103 and evaluates / determines the result. These parameters 1103 are changed several times to determine the most optimal irradiation condition. The determined irradiation conditions are input to the control device 1105 in the treatment apparatus 1104, and the maximum proton beam range 1106, the proton beam SOBP 1107, the rotation angle of the gantry 1108, and various types of the irradiation nozzles 1109 installed in accordance with the irradiation conditions. The parameters of the device, the position and rotation angle of the treatment bed 1110 are controlled.
[0023]
The treatment planning apparatus 1102 indicates a computer system as shown in FIG. This system includes, in addition to the computer main body 1201, an input device 1202 for inputting data, a display device 1203 for displaying results, and a storage device 1204 for storing treatment planning software itself and output results. Composed.
[0024]
FIG. 13 shows an example of the contents of the treatment planning apparatus 1102. In the treatment planning apparatus 1102, calculation processing parts such as a tissue region setting 1302, a dose distribution calculation 1303, and a display calculation 1304 are performed via an interface 1301, which is an input / output unit, for image data 1305, extracted data 1306, parameters 1307, and result display. Input / output data in the storage device and display device such as 1308 and irradiation condition 1309 are connected. In the treatment plan, first, image data 1305 is input, and an extraction result is obtained using the extraction range as a parameter 1307 according to the processing of the tissue region setting 1302. The result is stored in the storage device as extracted data 1306. Next, every time the irradiation condition 1309 is input, the process of the dose distribution calculation 1303 is repeatedly performed to obtain the final irradiation condition 1309 and stored in the storage device. In this process, for example, the display calculation 1304 outputs the state of the dose distribution as a result display 1308.
[0025]
FIG. 14 shows an example of the operation screen of the proton beam treatment planning system of the present invention. This is an example of a screen for controlling the display contents of the protrusion amount distribution map 1401 and the three-dimensional display 1402 by a pick operation of the mouse cursor. The number of gates, the increment of latitude, and the increment of longitude are designated by the scroll bar 1403 for setting the number of gates, the scroll bar 1404 for setting the increment of latitude, and the scroll bar 1405 for setting the increment of longitude, respectively. If the initialization button 1406 is picked, these return to the initial values. By picking a contour line display type selection button 1407, a colored contour line or a method of painting with a certain color between contour lines is selected. The number of contour lines is set by a scroll bar 1408 for setting the number of contour lines, and an initialization button 1409 is used for initialization. The color of the contour line is set by selecting a color from the contour line color palette 1410 and placing it in the contour line color setting area 1411. If the resolution increment selection button 1412 is picked, the angle increment is made finer, the irradiation direction 1422 with the smallest protrusion amount is calculated again, and if the search algorithm start button 1413 is picked, the protrusion required at that stage is calculated. The irradiation direction 1422 with the smallest amount of protrusion is searched for and obtained using the irradiation direction 1422 with the smallest amount as the initial position. In either case, the result is displayed on the protrusion amount distribution map 1401 and the three-dimensional display 1402.
[0026]
When determining the final irradiation direction by adjusting the irradiation direction 1422 with the minimum amount of protrusion required at the present stage, first, the irradiation direction adjustment mode switching button 1414 is picked so that the direction can be adjusted. To do. Thereafter, the irradiation direction 1422 with the minimum protrusion amount is dragged with the mouse cursor, or the beam 1423 with the irradiation direction with the minimum protrusion amount is dragged with the mouse cursor in the three-dimensional image 1402 or the θ-direction moving scroll bar. 1415, the position is moved using the φ-direction moving scroll bar 1416. Finally, the irradiation direction adjustment mode is switched to a state where the direction adjustment cannot be performed by picking the switch button 1414.
[0027]
If the three-dimensional display mode button 1417 is picked, a three-dimensional display 1402 is displayed and interlocked with the protrusion amount distribution map 1401. If the 3D display mode button 1417 is picked again, the 3D display 1402 disappears. By operating the scroll bar 1418 for rotating the 3D image latitude and the scroll bar 1419 for rotating the 3D image longitude, the display object in the 3D display 1402 is rotated. A 3D image display target selection button 1420 is picked to specify which organ in the 3D display 1402 is to be displayed. If the 3D image display target selection button 1420 is picked again, the organ display disappears. By picking an irradiation direction selection button 1421, the beam 1423 in which irradiation direction is displayed three-dimensionally, and which irradiation direction 1422 mark in the protrusion amount distribution map 1401 is highlighted is selected.
[0028]
Four examples will be described below.
[0029]
1. Example 1
In this embodiment, when the number of irradiation directions is one, the final irradiation direction is determined on the basis of the irradiation direction indicated by the map display of the protrusion amount distribution. The result of the map display can be represented by a three-dimensional display, and the irradiation direction can be confirmed and the direction can be adjusted while linking them. If there is no important tissue around the lesion, if there are important tissues even if they are small, or if the important tissue is away from the lesion, a map display that determines the irradiation direction directly from the lesion shape is sufficient, and three-dimensional The display is mainly used for qualitative confirmation of the irradiation direction.
[0030]
[Step 701] Map display
Based on the shape information of the lesion obtained by the tissue region setting process, the protrusion amount distribution is displayed as contour lines on a map represented by a combination of latitude and longitude. The map can be selected from either colored contour lines or a method of filling a color between contour lines. When the map is displayed for the first time, the latitude / longitude angle increment, the number of contour lines, and the contour line color set in advance are used. Otherwise, the map is displayed with the value set immediately before. In addition, marks are displayed in two forward and reverse directions that minimize the protrusion amount.
[0031]
[Step 702] Determination of angle increment change
Specifies whether to change the latitude and longitude angle increments.
[0032]
[Step 703] Angle increment change
Change the latitude and longitude angle increments to the specified values. Latitude and longitude can be changed independently.
[0033]
[Step 704] Determination of Contour Line Number Change
Specify whether to change the number of contour lines.
[0034]
[Step 705] Change the number of contour lines
Change the number of contour lines to the specified value.
[0035]
[Step 706] Determination of Contour Line Color Change
Specifies whether to change the contour color.
[0036]
[Step 707] Contour line color change
Change the contour color to the color selected from the color palette.
[0037]
[Step 708] Judgment of three-dimensional display
Specify whether to perform 3D display in conjunction with map display.
[0038]
[Step 709] Three-dimensional display
A proton beam corresponding to the irradiation direction set in the map display or the irradiation direction specified in the three-dimensional display is superimposed and displayed on the human tissue in a three-dimensional manner. The proton beam displays only one of the two forward and reverse directions.
[0039]
[Step 710] Direction switching
Switch the forward and reverse irradiation directions alternately and select the appropriate direction. This function works with map display and 3D display.
[0040]
[Step 711] Determination of direction adjustment
Specify whether to adjust the irradiation direction.
[0041]
[Step 712] Direction adjustment
The irradiation direction is moved in the direction specified by the mouse cursor or key input.
[0042]
[Step 713] Determination of initial state transition
Specify whether to return the irradiation direction to the initial state before adjustment.
[0043]
[Step 714] Determination of preservation of direction
Specify whether to save the irradiation direction in the storage device.
[0044]
[Step 715] Save direction
The irradiation direction is stored in a storage device.
[0045]
2. Example 2
In this embodiment, when the number of irradiation directions is one, the final irradiation direction is determined with reference to the irradiation direction shown in the three-dimensional display. The result of the three-dimensional display can be represented by a map display, and the irradiation direction can be confirmed and the direction can be adjusted while linking them. If the important tissue is close to the lesion, or if the important tissue is large even if it is far from the lesion, the positional relationship between the lesion and their 3D space is important, so the direction of irradiation is determined by 3D display. Is efficient. The map display is mainly used for quantitative confirmation of the irradiation direction, and the irradiation direction with the smallest amount of protrusion is used as a standard role.
[0046]
[Step 801] Direction setting
In the three-dimensional display state in which only the tissue is displayed, the irradiation direction is set with a mouse cursor or key input.
[0047]
[Step 802] 3D display
Based on the irradiation direction set immediately before, a proton beam is superimposed and displayed on the human tissue in a three-dimensional manner.
[0048]
[Step 803] Map display
Based on the shape information of the lesion obtained by the tissue region setting processing, the distribution of the protrusion amount is displayed as a contour line on a map represented by a combination of latitude and lightness. The map can be selected from either colored contour lines or a method of filling a color between contour lines. When the map is displayed for the first time, the angle increments of latitude and longitude, the contour line main line, and the contour line color set in advance are used. Otherwise, the map is displayed with the value set immediately before. The set irradiation direction is displayed with a mark. Also, Is Marks are displayed in two forward and reverse directions that minimize the amount of protrusion.
[0049]
[Step 804] Determination of angle increment change
Specifies whether to change the latitude and longitude angle increments.
[0050]
[Step 805] Angle increment change
Change the latitude and longitude angle increments to the specified values. Latitude and longitude can be changed independently.
[0051]
[Step 806] Determination of change in the number of contour lines
Specify whether to change the number of contour lines.
[0052]
[Step 807] Change the number of contour lines
Change the number of contour lines to the specified value.
[0053]
[Step 808] Determination of Contour Line Color Change
Specifies whether to change the contour color.
[0054]
[Step 809] Change contour color
Change the contour color to the color selected from the color palette.
[0055]
[Step 810] Direction Adjustment Determination
Specify whether to adjust the irradiation direction.
[0056]
[Step 811] Direction adjustment
The irradiation direction is moved in the direction specified by the mouse cursor or key input.
[0057]
[Step 812] Determination of initial state transition
Specify whether to return the irradiation direction to the initial state before adjustment.
[0058]
[Step 813] Determination of saving direction
Specify whether to save the irradiation direction in the storage device.
[0059]
[Step 814] Save direction
The irradiation direction is stored in a storage device.
[0060]
3. Example 3
The present embodiment is a modified version of the first embodiment. The irradiation direction obtained by the map display of the protrusion amount distribution is used as an initial position, and a search algorithm is applied to find the true protrusion amount minimum direction or the vicinity of the initial position. This is a case where the angle increment is made finer and the minimum amount of protrusion is obtained at higher resolution. In this case as well, the map display result can be represented by a three-dimensional display, and the irradiation direction can be confirmed and the direction can be adjusted while linking them. As in Example 1, it is suitable when there is no important tissue around the lesion, when there is an important tissue even if they are small, or when the important tissue is away from the lesion, but the lesion shape is complicated Is particularly effective. In general, if the lesion shape is complicated, the amount of protrusion of the irradiation direction varies greatly with the change in the irradiation direction. Therefore, it is better to obtain the irradiation direction with the minimum protrusion amount at a considerably high resolution.
[0061]
[Step 901] Determination of angle increment change
Specifies whether to change the latitude and longitude angle increments.
[0062]
[Step 902] Angle increment change
Change the latitude and longitude angle increments to the specified values. Latitude and longitude can be changed independently.
[0063]
[Step 903] Map display
Based on the shape information of the lesion obtained by the tissue region setting process, the protrusion amount distribution is displayed as contour lines on a map represented by a combination of latitude and longitude. The map can be selected from either colored contour lines or a method of filling a color between contour lines. When the map is displayed for the first time, the latitude / longitude angle increment, the number of contour lines, and the contour line color set in advance are used. Otherwise, the map is displayed with the value set immediately before. In addition, marks are displayed in two forward and reverse directions that minimize the protrusion amount.
[0064]
[Step 904] Judgment of Change in Number of Contour Lines
Specify whether to change the number of contour lines.
[0065]
[Step 905] Change the number of contour lines
Change the number of contour lines to the specified value.
[0066]
[Step 906] Determination of Contour Line Color Change
Specifies whether to change the contour color.
[0067]
[Step 907] Contour line color change
Change the contour color to the color selected from the color palette.
[0068]
[Step 908] Determination of detailed map display
Specifies whether or not to obtain the irradiation direction with the smallest protrusion amount obtained at the present stage more accurately.
[0069]
[Step 909] Detailed map display
Do the same as the map display, but use the search algorithm to find the true minimum direction with the minimum amount of protrusion obtained at the current stage as the initial position, or limit the angle step to the vicinity of the initial position. It is finer, and with a higher resolution, the minimum amount of protrusion is found and the point is marked on the map for display.
[0070]
[Step 910] Determination of three-dimensional display
Specify whether to perform 3D display in conjunction with map display.
[0071]
[Step 911] Three-dimensional display
A proton beam corresponding to the irradiation direction set in the map display or the irradiation direction specified in the three-dimensional display is superimposed and displayed on the human tissue in a three-dimensional manner. The proton beam displays only one of the two forward and reverse directions.
[0072]
[Step 912] Direction switching
Switch the forward and reverse irradiation directions alternately and select the appropriate direction. This function works with map display and 3D display.
[0073]
[Step 913] Determination of direction adjustment
Specify whether to adjust the irradiation direction.
[0074]
[Step 914] Direction adjustment
The irradiation direction is moved in the direction specified by the mouse cursor or key input.
[0075]
[Step 915] Determination of transition to the initial state
Specify whether to return the irradiation direction to the initial state before adjustment.
[0076]
[Step 916] Determination of saving direction
Specify whether to save the irradiation direction in the storage device.
[0077]
[Step 917] Save Direction
The irradiation direction is stored in a storage device.
[0078]
4). Example 4
In this embodiment, when there are a plurality of irradiation directions (usually referred to as multi-port irradiation), the final irradiation direction is determined based on the irradiation direction indicated by the map display of the protrusion amount distribution. 2 is a second direction version of the first embodiment. Again, the map display result can be represented by a three-dimensional display, and the irradiation direction can be confirmed and the direction can be adjusted while interlocking these. If there is no important tissue around the lesion, if there are important tissues even if they are small, or if the important tissue is away from the lesion, a map display that determines the irradiation direction directly from the lesion shape is sufficient, and three-dimensional The display is mainly used for qualitative confirmation of the irradiation direction.
[0079]
[Step 1001] Setting the number of gates
Set the number of irradiation directions (called the number of gates).
[0080]
[Step 1002] Map display
Based on the shape information of the lesion obtained by the tissue region setting process, the distribution of the protrusion amount is displayed as a contour line on a map represented by a combination of latitude and longitude. The map can be selected from either colored contour lines or a method of filling a color between contour lines. When the map is displayed for the first time, the latitude / longitude angle increment, the number of contour lines, and the contour line color set in advance are used. Otherwise, the map is displayed with the value set immediately before. A set of irradiation directions that minimizes the total amount of protrusion for the set number of gates is selected and displayed on the map with a mark. At this time, the total amount is also displayed numerically. However, the same mark is attached to the two forward and reverse directions where the amount of protrusion is equal to distinguish the other directions.
[0081]
[Step 1003] Determination of angle increment change
Specifies whether to change the latitude and longitude angle increments.
[0082]
[Step 1004] Angle increment change
Change the latitude and longitude angle increments to the specified values. Latitude and longitude can be changed independently.
[0083]
[Step 1005] Determination of change in the number of contour lines
Specify whether to change the number of contour lines.
[0084]
[Step 1006] Change the number of contour lines
Change the number of contour lines to the specified value.
[0085]
[Step 1007] Determination of Contour Line Color Change
Specifies whether to change the contour color.
[0086]
[Step 1008] Contour line color change
Change the contour color to the color selected from the color palette.
[0087]
[Step 1009] Determination of three-dimensional display
Specify whether to perform 3D display in conjunction with map display.
[0088]
[Step 1010] Three-dimensional display
A proton beam corresponding to the irradiation direction set in the map display or the irradiation direction specified in the three-dimensional display is superimposed and displayed on the human tissue in a three-dimensional manner. It is assumed that an arbitrary number of proton beams can be generated around a lesion, and each beam can be set in an arbitrary direction. The lesion center point is given as a diagonal intersection of a rectangular parallelepiped that circumscribes the lesion, and its position can be adjusted. The proton beam displays only one of the two forward and reverse directions.
[0089]
[Step 1011] Alternate direction switching
A plurality of irradiation directions are independently switched between forward and reverse irradiation directions, and an appropriate direction is selected. This function works with map display and 3D display.
[0090]
[Step 1012] Direction Adjustment Determination
Specify whether to adjust the irradiation direction.
[0091]
[Step 1013] Direction adjustment
The irradiation direction is moved in the direction specified by the mouse cursor or key input. However, a plurality of irradiation directions can be adjusted independently.
[0092]
[Step 1014] Determination of Initial State Transition
Specify whether to return all irradiation directions to the initial state before adjustment.
[0093]
[Step 1015] Determination of gate number change
Specify whether to change the number of gates.
[0094]
[Step 1016] Determination of saving direction
Specify whether to save the irradiation direction in the storage device.
[0095]
[Step 1017] Save direction
The irradiation direction is stored in a storage device.
[0096]
【The invention's effect】
If the proton beam treatment planning system of the present invention is used, the proton beam is determined based on the policy of finding the direction in which the amount of protrusion outside the lesion in the high-dose area, which is the difference between the lesion and the enlarged Bragg peak area covering it, is minimized. It is possible to automatically determine the irradiation direction. The result can be confirmed on the two-dimensional map and in the three-dimensional display, and the irradiation direction can be corrected there.
[Brief description of the drawings]
FIG. 1 is a protrusion amount distribution map.
FIG. 2 is a coordinate system.
FIG. 3 shows the characteristics of proton beams.
FIG. 4 shows the relationship between the irradiation direction and the amount of protrusion (two-dimensional).
FIG. 5 shows the relationship between the irradiation direction and the amount of protrusion (three-dimensional).
FIG. 6 is a three-dimensional display.
FIG. 7 is a flowchart of the first embodiment.
FIG. 8 is a flowchart according to the second embodiment.
FIG. 9 is a flowchart according to the third embodiment.
FIG. 10 is a flowchart according to the fourth embodiment.
FIG. 11 shows the configuration of a proton beam treatment system.
FIG. 12 shows a computer system.
FIG. 13 shows an internal processing mechanism of a treatment planning apparatus.
FIG. 14 shows an example of an operation screen.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 101 ... Overflow amount distribution map, 102 ... Latitude, 103 ... Longitude, 104 ... Contour line, 105 ... Minimum amount of protrusion, 201 ... Human body, 202 ... Lesion, 203 ... Irradiation direction, 204 ... Latitude, 205 ... Longitude, 301 ... Human body , 302 ... lesion, 303 ... proton irradiation, 304 ... bolus, 305 ... depth, 306 ... relative dose, 307 ... dose distribution curve, 308 ... enlarged Bragg peak, 401 ... irradiation direction, 402 ... lesion (general form), 403 ... Maximum length in the vertical direction, 404 ... Maximum length in the horizontal direction, 405 ... Projection area, 406 ... Foci (circular), 407 ... Maximum length in the vertical direction, 408 ... Maximum length in the horizontal direction, 409 ... Projection area, 410 ... lesion (cuboid), 411 ... maximum length in the vertical direction, 412 ... maximum length in the horizontal direction, 413 ... protruding area, 501 ... irradiation direction, 502 ... lesion, 503 ... longitudinal direction Large length, 504 ... projection, 601 ... body, 602 ... 脊桂, 603 ... heart, 604 ... left lung, 605 ... right lung, 606 ... lesion, 607 ... illumination direction, 608 ... proton beam.

Claims (8)

An input device for inputting image data and an external command, a computer for processing the input image data by an external command, a treatment planning device for displaying the processing result, and a gantry based on the processing result Proton has a means to control the position and direction of the treatment bed, the maximum range that is the reach of the proton beam, and the extended Bragg peak width that is the peak region of the proton beam deep dose formed just before the maximum range. In a proton beam therapy system composed of a proton beam therapy device capable of installing a bolus, which is a type of distance compensation filter for matching the maximum range of a proton beam to the green after the lesion in the line passing path,
By using the shape information of the lesion in the human body where the tissue area is set using image data, the difference between the lesion and the area where the enlarged Bragg peak width covers the lesion and the area surrounding the lesion is minimized. Means for determining the direction of irradiation ;
The means for determining the irradiation direction of the proton beam expresses the irradiation direction by a pair of latitude and longitude centered on the lesion, and the lesion and the expanded Bragg peak width in the plurality of irradiation directions are the region covering the lesion and the lesion periphery. The difference is calculated, the distribution of the difference is displayed on the map with the latitude and longitude of the irradiation direction as coordinate axes, and the irradiation direction with the minimum difference is displayed on the map together with the minimum difference value. A proton beam treatment planning system characterized by An input device for inputting image data and an external command, a computer for processing the input image data by an external command, a treatment planning device for displaying the processing result, and a gantry based on the processing result Proton has a means to control the position and direction of the treatment bed, the maximum range that is the reach of the proton beam, and the extended Bragg peak width that is the peak region of the proton beam deep dose formed just before the maximum range. In a proton beam therapy system composed of a proton beam therapy device capable of installing a bolus, which is a type of distance compensation filter for matching the maximum range of a proton beam to the green after the lesion in the line passing path,
By using the shape information of the lesion in the human body where the tissue area is set using image data, the difference between the lesion and the area where the enlarged Bragg peak width covers the lesion and the area surrounding the lesion is minimized. Means for determining the direction of irradiation;
The means for determining the irradiation direction of the proton beam is a three-dimensional display of the irradiation beam in a three-dimensional display of the human tissue along the irradiation direction in which the difference between the lesion and the enlarged Bragg peak width is minimal between the lesion and the region surrounding the lesion. The proton beam treatment planning system is characterized in that the overlapping difference is displayed and the minimum difference value is displayed.   An input device for inputting image data and an external command, a computer for processing the input image data by an external command, a treatment planning device for displaying the processing result, and a gantry based on the processing result Proton has a means to control the position and direction of the treatment bed, the maximum range that is the reach of the proton beam, and the extended Bragg peak width that is the peak region of the proton beam deep dose formed just before the maximum range. In a proton beam therapy system composed of a proton beam therapy device capable of installing a bolus, which is a type of distance compensation filter for matching the maximum range of a proton beam to the green after the lesion in the line passing path,
  By using the shape information of the lesion in the human body where the tissue area is set using image data, the difference between the lesion and the area where the enlarged Bragg peak width covers the lesion and the area surrounding the lesion is minimized. Means for determining the direction of irradiation;
  The means for determining the irradiation direction of the proton beam expresses the irradiation direction as a set of latitude and longitude centered on the lesion, and the difference between the lesion and the area surrounding the lesion is minimized. On the map representing the distribution of the difference in a plurality of irradiation directions with the latitude and longitude of the irradiation direction as the coordinate axes, and the three-dimensional human tissue A proton beam treatment planning system, which can be selected on a three-dimensional display in which irradiation beams are superimposed and displayed in a three-dimensional manner along an irradiation direction in which the difference is minimized with respect to the display.   An input device for inputting image data and an external command, a computer for processing the input image data by an external command, a treatment planning device for displaying the processing result, and a gantry based on the processing result Proton has a means to control the position and direction of the treatment bed, the maximum range that is the reach of the proton beam, and the extended Bragg peak width that is the peak region of the proton beam deep dose formed just before the maximum range. In a proton beam therapy system composed of a proton beam therapy device capable of installing a bolus, which is a type of distance compensation filter for matching the maximum range of a proton beam to the green after the lesion in the line passing path,
  By using the shape information of the lesion in the human body where the tissue area is set using image data, the difference between the lesion and the area where the enlarged Bragg peak width covers the lesion and the area surrounding the lesion is minimized. Means for determining the direction of irradiation;
  The means for determining the irradiation direction of the proton beam expresses the irradiation direction as a set of latitude and longitude centered on a lesion, and represents the distribution of the difference in a plurality of irradiation directions with the latitude and longitude of the irradiation direction as coordinate axes. The irradiation direction in which the difference between the lesion marked on the map and the area where the enlarged Bragg peak width covers the lesion and the lesion periphery is minimized can be corrected in an arbitrary direction according to a command from the outside in the map, and In conjunction with the correction of the irradiation direction on the map, the three-dimensional display in which the irradiation beam is three-dimensionally superimposed and displayed along the irradiation direction that minimizes the difference with respect to the three-dimensional display of the human tissue. A proton beam treatment planning system, wherein the irradiation direction and the value of the difference in the irradiation direction are also changed.   An input device for inputting image data and an external command, a computer for processing the input image data by an external command, a treatment planning device for displaying the processing result, and a gantry based on the processing result Proton has a means to control the position and direction of the treatment bed, the maximum range that is the reach of the proton beam, and the extended Bragg peak width that is the peak region of the proton beam deep dose formed just before the maximum range. In a proton beam therapy system composed of a proton beam therapy device capable of installing a bolus, which is a type of distance compensation filter for matching the maximum range of a proton beam to the green after the lesion in the line passing path,
  By using the shape information of the lesion in the human body where the tissue area is set using image data, the difference between the lesion and the area where the enlarged Bragg peak width covers the lesion and the area surrounding the lesion is minimized. Means for determining the direction of irradiation;
  The means for determining the irradiation direction of the proton beam expresses the irradiation direction by a set of latitude and longitude centered on the lesion, and the irradiation beam along the irradiation direction that minimizes the difference with respect to the three-dimensional display of the human tissue. The three-dimensional irradiation direction in which the difference between the lesion displayed as the irradiation beam in the three-dimensional display in which the three-dimensional images are superimposed and the enlarged Bragg peak width between the lesion and the region surrounding the lesion is minimized The display can be corrected in an arbitrary direction according to a command from the outside, and in conjunction with the correction of the irradiation direction on the three-dimensional display, the latitude and longitude of the irradiation direction are used as coordinate axes in the plurality of irradiation directions. A proton beam treatment planning system, wherein an irradiation direction in a map representing a difference distribution and a value of the difference in the irradiation direction are also changed.   An input device for inputting image data and an external command, a computer for processing the input image data by an external command, a treatment planning device for displaying the processing result, and a gantry based on the processing result Proton has a means to control the position and direction of the treatment bed, the maximum range that is the reach of the proton beam, and the extended Bragg peak width that is the peak region of the proton beam deep dose formed just before the maximum range. In a proton beam therapy system composed of a proton beam therapy device capable of installing a bolus, which is a type of distance compensation filter for matching the maximum range of a proton beam to the green after the lesion in the line passing path,
  By using the shape information of the lesion in the human body where the tissue area is set using image data, the difference between the lesion and the area where the enlarged Bragg peak width covers the lesion and the area surrounding the lesion is minimized. Means for determining the direction of irradiation;
  The means for determining the irradiation direction of the proton beam expresses the irradiation direction by a set of latitude and longitude centered on the lesion, and the difference in the plurality of irradiation directions is expressed using the latitude and longitude of the irradiation direction as coordinate axes. In the map representing the cloth, the irradiation direction in which the difference between the lesion and the enlarged Bragg peak width between the lesion and the area surrounding the lesion is minimized is set as the initial position, and the value of the difference between the initial positions is determined using a predetermined search algorithm. Obtaining an irradiation direction having a small value of the difference, or increasing the resolution of the irradiation direction distribution on the map by reducing the angular increment of the irradiation direction near the initial position on the map, A proton beam treatment planning system characterized by obtaining an irradiation direction having a difference value smaller than the difference value of an initial position.   An input device for inputting image data and an external command, a computer for processing the input image data by an external command, a treatment planning device for displaying the processing result, and a gantry based on the processing result Proton has a means to control the position and direction of the treatment bed, the maximum range that is the reach of the proton beam, and the extended Bragg peak width that is the peak region of the proton beam deep dose formed just before the maximum range. In a proton beam therapy system composed of a proton beam therapy device capable of installing a bolus, which is a type of distance compensation filter for matching the maximum range of a proton beam to the green after the lesion in the line passing path,
  By using the shape information of the lesion in the human body where the tissue area is set using image data, the difference between the lesion and the area where the enlarged Bragg peak width covers the lesion and the area surrounding the lesion is minimized. Means for determining the direction of irradiation;
  The means for determining the irradiation direction of the proton beam expresses the irradiation direction by a set of latitude and longitude centered on the lesion, and the lesion and the expanded Bragg peak width for the given irradiation direction number The irradiation direction that minimizes the sum of the differences from the covered area is displayed on a map representing the distribution of the differences in a plurality of irradiation directions with the latitude and longitude of the irradiation direction as coordinate axes, and in a three-dimensional display of human tissue On the other hand, the proton beam therapy is characterized in that the radiation beam is displayed together with the sum of the smallest differences on a three-dimensional display in which the radiation beams are superimposed and displayed along the radiation direction in which the sum of the differences is minimized. Planning system.   An input device for inputting image data and an external command, a computer for processing the input image data by an external command, a treatment planning device for displaying the processing result, and a gantry based on the processing result Proton has a means to control the position and direction of the treatment bed, the maximum range that is the reach of the proton beam, and the extended Bragg peak width that is the peak region of the proton beam deep dose formed just before the maximum range. In a proton beam therapy system composed of a proton beam therapy device capable of installing a bolus, which is a type of distance compensation filter for matching the maximum range of a proton beam to the green after the lesion in the line passing path,
  By using the shape information of the lesion in the human body where the tissue area is set using image data, the difference between the lesion and the area where the enlarged Bragg peak width covers the lesion and the area surrounding the lesion is minimized. Means for determining the direction of irradiation;
  The means for determining the irradiation direction of the proton beam expresses the irradiation direction by a set of latitude and longitude centered on the lesion, and the lesion and the expanded Bragg peak width for the given irradiation direction number All directions of the irradiation direction in which the sum of the differences from the covered area is minimized are displayed on a map representing the distribution of the differences in the plurality of irradiation directions with the latitude and longitude of the irradiation direction as coordinate axes, and the human tissue The three-dimensional display is displayed on the three-dimensional display in which the irradiation beam is superimposed and displayed in a three-dimensional manner along the irradiation direction in which the sum of the differences is minimized, and both the map and the three-dimensional display are external. The irradiation direction in the other of the map and the three-dimensional display can be corrected in accordance with a command from the map and in conjunction with the correction of the irradiation direction with respect to one of the map and the three-dimensional display. Direction and so Proton therapy planning system characterized also by changing the total sum of the difference in the irradiation direction.

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