JP2008099807A - Radiotherapy planning apparatus and radiotherapy planning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable an operator to change and set a required irradiation condition in details and in a short period of time before an apparatus re-practices second and succeeding repeated calculations and to enable the operator to efficiently perform repetitive work until obtaining a desirable dose distribution result. <P>SOLUTION: After calculating an in vivo dose distribution (step 104 and step 206), three-dimensional position information of a region pertinent to a dose value specified beforehand is automatically registered (step 105 and step 207), and the operator adds the condition change of a prescription dose or the like to the registered regions 601 and 602. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radiotherapy planning apparatus and method for creating a treatment plan for performing treatment by irradiating an affected area with radiation such as particle beams or X-rays.

  Radiotherapy is performed by irradiating target tumor cells with radiation. Excessive irradiation or insufficient dose leads to side effects on normal tissues other than tumors and tumor recurrence. Therefore, it is required to concentrate and irradiate a designated dose of radiation as accurately as possible to the tumor region, and the process of creating a plan using a treatment planning apparatus before actual irradiation becomes extremely important.

  The treatment planning apparatus simulates the dose distribution in the patient by numerical calculation based on information obtained from CT images and the like. The operator determines irradiation conditions such as the irradiation direction, beam energy, and collimator shape while referring to the calculation result of the treatment planning apparatus.

  In the treatment using X-rays called IMRT (Intensity Modulated Radiation Therapy), even if a target area with a complicated shape is irradiated by irradiating from multiple directions while changing the shape of the collimator, the surrounding normal tissue is irradiated. Doses can be minimized. Even in treatment using particle beams, a technique called scanning irradiation has been realized in which a uniform dose distribution is formed in a target region by irradiating a number of thin beams with adjusted intensities.

  Such an advanced irradiation method can cope with a target region having a complicated shape, but the number of parameters to be determined by the treatment planning apparatus included in the irradiation condition increases, and the process until the irradiation condition is determined becomes complicated.

  Patent Documents 1 and 2 describe techniques for efficiently determining these parameters.

  In the technique described in Patent Document 1, a constraint condition is input based on a prescription, an evaluation function is set based on the constraint condition, and irradiation is performed by iterative calculation so that the evaluation function is minimized so as to achieve optimal radiation irradiation. In a control apparatus for a radiation treatment apparatus for radiation therapy that determines a beam weight and outputs an optimal beam weight solution to the radiation irradiation apparatus, a new evaluation function based on the changed restriction condition is changed by changing the restriction condition. When the irradiation beam weight is determined so as to be set and optimal radiation irradiation, the optimal solution of the irradiation beam weight obtained before changing the constraint condition is used as the initial solution of the irradiation beam weight.

  The technique described in Patent Document 2 makes a treatment plan using a human body image obtained from an image diagnostic apparatus and an input value of an operator, and based on this treatment plan, positions and directions of a gantry, an irradiation head, a treatment bed, and In a radiation therapy system that controls the energy of an accelerator, the constraint is interactively determined when determining the optimal value of the radiation source intensity by imposing a constraint on the objective function of linear programming and solving the linear programming problem. By changing, the linear programming problem is repeatedly solved, and the intensity of the radiation source is determined to an optimum value.

Japanese Patent No. 3530072 Japanese Patent No. 2551734

  In advanced irradiation methods such as IMRT for X-ray therapy and scanning irradiation for particle beam therapy, there are a wide range of methods that use objective functions (evaluation functions) that quantify deviations from prescription doses in order to determine irradiation parameters efficiently. It has been adopted. The objective function is defined so that the dose distribution becomes small enough to satisfy the prescription dose, and an optimum irradiation condition is calculated by searching a parameter set that minimizes the dose distribution by iterative calculation. A specific example of the calculation contents is detailed in Patent Document 1.

  By repeating the iterative calculation, the result gradually approaches the result. However, in a plan in which the shape of the region is complicated, it is often impossible to obtain a result that satisfies all the conditions even after iterative calculation is repeated until it sufficiently converges. In that case, iterative calculation is performed again after modifying the irradiation condition while referring to the calculation result. Examples of the change in the irradiation condition include a change in the irradiation direction or a change in the prescription dose imposed on the target area or the important organ.

  These changes are made while estimating the calculation results after the iterative calculation. However, when there are many parameters to be determined, the results do not necessarily converge to the assumed results. Often, the process of changing conditions and performing iterative calculations must be repeated several times until the desired result is obtained.

  As a device for reducing the labor required for this work, for example, in Patent Document 1, when the iterative calculation is performed again, the calculation is started with the previous convergence result as an initial value, so that the convergence is performed in the second and subsequent iterations. Can be shortened.

  In Patent Document 2, the constraint condition can be changed interactively when the constraint condition (constraint point) is changed in order to redo the calculation of the linear programming method, and thereby the dose distribution obtained as a result of the previous calculation. The work can be performed while overlapping the position of the restriction point and displaying it on the screen.

  However, in the apparatuses described in Patent Documents 1 and 2, before the apparatus re-executes the second and subsequent iterations, the irradiation conditions necessary for the operator and the change and setting of the conditions related to the prescription dose can be changed in detail and in a short time. It is not necessarily sufficient in terms of making it possible. For example, in Patent Document 1, the apparatus itself shortens the time until convergence when performing the second and subsequent iterations, and the condition setting of the operator is performed before the device re-executes the second and subsequent iterations. It is not something that can be done in detail. In Patent Document 2, by changing the constraint condition interactively, the operator can set the condition in some detail before the apparatus re-executes the second and subsequent iterations. However, since the dose distribution displayed on the screen is for one slice of the CT image, in order to set the condition for the entire CT image, the operator repeatedly performs the condition setting work for all the slice images. It must be a lot of time.

  The object of the present invention is to allow the operator to change and set the necessary irradiation conditions in detail and in a short time before the apparatus re-executes the second and subsequent iterative calculations. It is an object of the present invention to provide a radiotherapy planning apparatus and method capable of efficiently performing repetitive work until results are obtained.

  In order to achieve the above object, the present invention provides a radiation treatment planning apparatus for creating a treatment plan for performing treatment by irradiating radiation, an input device, a display device, a storage device, and a display on the display device. First means for storing, in the storage device, three-dimensional position information of a first region in which radiation to be irradiated is controlled based on the medical image information that has been performed and the input information from the input device; Based on the displayed medical image information and information input by the input device, second means for storing the first irradiation condition for the first region in the storage device, and medical image information displayed on the display device And a third means for storing in the storage device a selection criterion for the second region to be automatically registered based on the input information from the input device, the first region position information, and the first region relative to the first region. A fourth means for performing a calculation based on the irradiation condition to determine a second irradiation condition for the first region, and calculating a dose distribution when the first region is irradiated with radiation under the first and second irradiation conditions; And extracting three-dimensional position information that matches the second region selection criteria from the calculation result of the dose distribution, and storing the three-dimensional position information in the storage device as position information of the second region. And 5th means and sixth means for displaying the first region and the calculation result of the dose distribution superimposed on the medical image information displayed on the display device.

  In order to achieve the above object, the present invention creates a treatment plan for performing treatment by irradiating radiation using a radiation treatment planning apparatus having an input device, a display device, and a storage device. In the radiotherapy planning method, based on medical image information displayed on the display device and input information from the input device, three-dimensional position information of a first region in which radiation to be irradiated is to be controlled is stored in the storage device. A first procedure for storing, a second procedure for storing the first irradiation condition for the first region in the storage device based on the medical image information displayed on the display device and the input information by the input device; A third procedure for storing, in the storage device, selection criteria for the second region to be automatically registered based on the medical image information displayed on the display device and information input by the input device; A calculation is performed based on the position information of the region and the first irradiation condition for the first region to determine the second irradiation condition for the first region, and the first region is irradiated with radiation under the first and second irradiation conditions. The fourth procedure for calculating the dose distribution in the case of the above, and extracting the three-dimensional position information that matches the selection criterion of the second area from the calculation result of the dose distribution, and using this three-dimensional position information as the second area And a sixth procedure for displaying the calculation result of the first region and the dose distribution superimposed on the medical image information displayed on the display device. And

  Furthermore, in the radiation treatment planning method, if necessary, the third irradiation condition for the second region is stored in the storage device based on medical image information displayed on the display device and information input by the input device. The calculation is performed based on the seventh procedure to be stored, the position information of the first area, the first irradiation condition for the first area, the position information of the second area, and the third irradiation condition for the second area, An eighth procedure for correcting the second irradiation condition, and recalculating the dose distribution when the first region is irradiated with radiation under the first irradiation condition and the corrected second irradiation condition; and the recalculated dose distribution. New three-dimensional position information that matches the selection criterion for the second region is extracted from the result of the calculation, and this new three-dimensional position information is stored as new position information after recalculation of the second region. Remember to device Further comprising a ninth procedure, and a tenth step of causing displayed over the display device the first region in the displayed medical image information and the dose distribution calculation result to.

  The concept of the present invention configured as described above is as follows.

  When the objective function is set and the iterative calculation is repeated, the result may be improved by specifying the region more finely than the unit of the first registered target region and important organ and setting the irradiation condition and prescription dose. For example, there are regions that are easily deviated from the prescription dose as a result of calculation, such as a portion with a complicated target region shape and a portion close to an important organ in the target region. In this case, it is conceivable that the next calculation is performed after specifying only the region and re-weighting the objective function.

  The effect of improving the dose distribution can be expected not only by changing the weight but also by changing the irradiation condition only for a specific region. For example, in particle beam therapy using the scanning irradiation method that irradiates a large number of thin beams, the irradiation position can be set for each beam, so this irradiation position can be adjusted only within a specific area as described above. Better results may be obtained.

  However, it has been very difficult to perform such operations with conventional devices. Usually, the result of the dose distribution is displayed superimposed on the CT image, so that the operator can confirm on the screen an area that does not satisfy the condition given by the prescription dose. However, if you try to change the settings of irradiation conditions and prescription doses only for a specific area, you should adjust the settings after identifying the area to be changed while viewing the screen display for each slice. Must be repeated.

  In the present invention, as described above, the selection criterion for the second region to be automatically registered with respect to the first region is input (third means), and the positional information that matches the selection criterion for the second region from the calculation result of the dose distribution Is extracted and stored in the storage device, and using this function, if the device is set so that the device automatically registers the second region as a region where the irradiated dose greatly deviates from the prescription dose, The operator can easily change the irradiation condition and prescription dose for the region. This is because the area automatically registered by the device (second area) can be read from the storage device in the same manner as the target area and important organ (first area) registered by the operator. This is because the setting can be made separately from the area. As a result, before the repetitive calculation is performed again, the operator can change and set the necessary irradiation conditions in detail and in a short time until the operator obtains the desired dose distribution result. Work can be performed efficiently.

  In order to solve such a problem, the present invention extracts the three-dimensional position information that matches the selection criterion of the second area from the calculation result of the dose distribution as described above, and uses the three-dimensional position information as the second area. Having the function (fifth means) to be stored in the storage device as the positional information of the device, and using this function, the device automatically registers the region where the irradiated dose is largely deviated from the prescription dose as the second region. If it is set to, the operator can easily change the irradiation condition and the prescription dose for the region. This is because the area automatically registered by the device (second area) can be read from the storage device in the same manner as the target area and important organ (first area) registered by the operator. This is because the setting can be made separately from the area. As a result, the operator can change and set the necessary irradiation conditions in detail and in a short time before re-running the second and subsequent iterations. It is possible to efficiently perform the repetitive work until it is obtained.

  In the radiotherapy planning apparatus according to the present invention, preferably, the fifth means extracts three-dimensional position information that matches the selection criterion for the second area, and then, in advance, out of the areas related to the position information. An area having a volume larger than the set threshold is extracted, and position information of the area is stored in the storage device as position information of the second area.

  With this function, a large number of small areas are not registered, and it is possible to reduce the trouble for the operator to set a prescription dose or the like for the area.

  In the radiotherapy planning apparatus according to the present invention, after the fifth means extracts three-dimensional position information that matches the selection criterion for the second area, a margin in which an area related to the position information is set in advance is extracted. The position information of the enlarged or reduced area may be stored in the storage device as the position information of the second area.

  In this way, an enlarged or reduced area can be obtained, so that a plurality of areas can be registered together. As a result, regions can be registered without increasing the number of regions, and the labor required for operator settings can be reduced.

  According to the present invention, it is possible for the operator to change and set the necessary irradiation conditions in detail and in a short time before the apparatus re-executes the second and subsequent iterations, and the operator can obtain a desired dose distribution. It is possible to efficiently perform the repetitive work until the result is obtained.

  Hereinafter, an embodiment of the present invention will be described in the case where a treatment plan for particle beam therapy by IMRT or scanning irradiation method in X-ray therapy is made using the radiation therapy planning apparatus of the present invention.

  FIG. 1 is a diagram showing an outline of equipment of a radiotherapy planning apparatus according to an embodiment of the present invention. The radiotherapy planning apparatus according to the present invention includes a display device 301, an input device 302, an arithmetic processing device 303, and a memory 304. The input device 302 is, for example, a keyboard or a mouse.

  FIG. 2 shows a flow of treatment planning using the apparatus according to the embodiment of the present invention, and FIG. 3 is a flowchart showing processing functions performed by the apparatus of the present embodiment at the time of treatment planning in FIG. is there.

  The display device 301 has an area input screen, and medical image information (tomographic image information) obtained by imaging the affected part of the patient such as a CT image is displayed on the area input screen. The image information is stored in the memory 304 of the treatment planning apparatus, for example.

  First, the operator displays medical image information on the region input screen, and uses a device such as a mouse of the input device 302 to specify a region (target region: first region) to be specified for each slice of the CT image. Input (step 101). When the input in each slice is completed, the operator performs an instruction operation for registering the input area in the apparatus (step 101). The region input by the operator through this instruction operation is stored in the memory 304 as three-dimensional position information (step 201). If there are other areas that need to be evaluated and controlled, such as when there is an important organ in the vicinity of the target area where the irradiation dose should be suppressed as much as possible, the operator also registers the positions of those important organs (first area) as well. (Step 101), the three-dimensional position information is also stored in the memory 304 (Step 201).

  FIG. 4 shows an example in which the operator inputs and registers the target region 401 and the important organs 402 and 403 on a slice with a CT image on the region input screen of the display device 301.

  Subsequently, the operator inputs an irradiation condition for the registered target area 401 (step 102). That is, based on the positions of the target region 401 and the important organs 402 and 403, the number of irradiation gates and the irradiation direction are determined, and a necessary instrument shape such as a collimator is also determined. In some cases, the apparatus is automatically determined, such as the shape of the collimator, rather than the operator determining everything. When the scanning irradiation method is adopted in the particle beam therapy, the irradiation positions of many beams must be determined, and the beam energy and the irradiation interval at each irradiation position can also be set.

  In addition to this, the operator inputs a prescription dose serving as a target dose value for each of the registered regions 401 to 403 (step 102). If the prescription dose is the target region 401, the minimum value and the maximum value of the dose to be received in the region are often input. Here, one dose value to be irradiated to the target region 401 is designated. The value is set to 100. Since the contents of the present embodiment are not affected, the unit is arbitrary. On the other hand, for the important organs 402 and 403, an allowable dose is often set as the maximum tolerable dose value. In this example, the allowable dose 20 is designated for both the important organs 402 and 403.

  When the input of the irradiation conditions (including the prescription dose) is completed, the operator performs an instruction operation for registering (setting) the input irradiation conditions (step 102). The irradiation conditions input by this instruction operation are stored in the memory 304 of the treatment planning apparatus (step 202).

  Thereafter, in general, the apparatus calculates the dose distribution in the body using the arithmetic processing unit 303 in accordance with an instruction operation by the operator, so that the parameters of the irradiation conditions (beam dose, etc.) to be determined using the treatment planning apparatus are calculated. The remaining parameters). In this case, the treatment planning apparatus defines an objective function in which the deviation from the prescription dose is quantified (step 104, step 204), and calculates the remaining parameters by minimizing this by repeated calculation (step 104). , Step 205).

  Further, when there are a plurality of regions in which the prescription dose is defined, the magnitude of the relative influence (relative importance) on the objective function when deviating from the prescription dose can be designated as the weight. In the example shown in FIG. 4 as well, since a plurality of regions of the target region 401 and the important organs 402 and 403 are set, the operator can specify which part of the setting has priority by setting the weight. Here, as an example, the regions 401, 402, and 403 are given the same weight.

  Here, the objective function will be specifically described. The objective function is defined so that the dose distribution becomes small enough to satisfy the prescription dose, and the optimum irradiation condition is calculated by searching the parameter set that minimizes this by iterative calculation. It is.

  As an example of the parameter determined by the objective function, there is an irradiation amount for each spot in the particle beam scanning irradiation. When the operator inputs the position of the target region 401 and the important organs 402 and 403 and their irradiation conditions (including prescription dose), the treatment planning apparatus generates (defines) an objective function as follows.

The apparatus sets m and n points for calculating doses in the target area 401 and important organs 402 and 403, respectively. The dose values at these points must meet the prescription dose entered by the operator as much as possible. Here, it is assumed that the target dose value p is set for m points corresponding to the target region 401 and the allowable dose value l is set for n points corresponding to the important organs 402 and 403. A vector having each spot irradiation amount as a parameter of the objective function as an element is written as x ^→ . The dimension of x ^→ is the total number of spots. Next, when a vector having dose values at m points in the target area 401 as elements is expressed by d ^{→ (1)} , the relationship between the dose x ^→
d ^{→ (1)} = Ax ^→
It can be expressed. The matrix A represents the contribution of the beam irradiated to each spot to the points in the target area, and is calculated by the treatment planning apparatus based on the information in the body based on the irradiation direction and CT images. Similarly, when a vector d ^{→ (2)} having dose values at n points in the important organs 402 and 403 as elements,
d ^{→ (2)} = Bx ^→
It can be expressed as. After calculating A and B, the treatment planning device generates the following objective function.

wi ⁽¹⁾ and wi ⁽²⁾ are weights (weights) corresponding to the respective points, and are values input by the operator together with the prescription dose. The first term is a portion corresponding to the target region 401, and F (x ^→ ) becomes smaller as the dose values at m points are closer to the prescription dose value p set as a target. The second term is a term relating to the important organs 402 and 403, and any dose that does not exceed the allowable dose l is sufficient. Therefore, if w ⁽²⁾ is d ^{→ (2)} <l, this term is set to zero. After generating the objective function of Equation (1), the apparatus searches for x ^→ where F (x ^→ ) is the smallest by repeating iterative calculation. An example of specific contents of the iterative calculation is detailed in Patent Document 1.

In a plan in which the shape of the region is complicated, a result that satisfies all the conditions is often not obtained even after iterative calculation is repeated until it sufficiently converges. In that case, the irradiation condition is changed with reference to the calculation result, the objective function is reset, and the iterative calculation is performed again. Examples of the change of the irradiation condition include a change of the irradiation direction, a change of the prescription dose imposed on the target region 401 and the important organs 402 and 403, and a change of the weight. Changing the irradiation direction corresponds to changing A and B in the equation (1), changing changing the prescription dose corresponds to changing p and l in the equation (1), and weighting. Changing this corresponds to changing wi ⁽¹⁾ and wi ⁽²⁾ in equation ⁽¹⁾ . Thus, based on the modified objective function becomes again F a (x ^→) to explore a x ^→ minimized.

  These changes are made while estimating the calculation results after the iterative calculation. However, when there are many parameters to be determined, the results do not necessarily converge to the assumed results. It is often necessary to repeat the process of changing conditions (resetting the objective function) and performing iterative calculations several times until a desired result is obtained.

  In the apparatus of the present invention, in order to reduce the labor required for the work, before the generation of the objective function and the iterative calculation, the selection criteria for the area (second area) to be automatically registered in response to the result of the iterative calculation are set. Input and define (step 103). The selection criteria defined by the operator is stored in the memory 304 in the apparatus by the operator's instruction operation (step 203). In the present embodiment, as selection criteria, a region where the dose exceeds 120 in the target region 401 and a region irradiated with a dose exceeding the allowable dose 20 in the important organs 402 and 403 are automatically registered. Set. Here, it is possible not only to specify a region exceeding a certain dose value, but also to specify a region where the dose is insufficient, such as a region where the dose is 80 or less.

  Next, when the start of the process is instructed by the operator's instruction operation, the apparatus generates an objective function and repeats calculation, and sets irradiation condition parameters (remaining parameters such as beam irradiation amount) to be determined using the apparatus. Then, the dose distribution is calculated based on the irradiation condition, and the result is stored in the memory 304 (step 206).

  At this point, the apparatus of the present invention automatically extracts the three-dimensional position information of the new area according to the selection criteria predetermined by the operator, and stores the position information of the extracted area in the memory 304 (step 105). Step 207). The result is displayed on the display device 301 together with the necessary isodose line (step 105, step 208).

  A display example is shown in FIG. In FIG. 5, the isodose lines 501 and 502 corresponding to the dose values 120 and 100 and the isodose line 503 corresponding to the allowable dose value 20 set for the important organ are superimposed on the display of the regions 401 to 403 on the CT image. Has been drawn. The dose distribution display in the actual treatment planning apparatus is not only an isodose line display but also a solid display or a three-dimensional display, but is omitted because it is not directly related to the present invention.

  The state of the area registered by the apparatus is shown in FIG. The apparatus includes a region 601 having a dose of 120 or more in the target region 401 (a region surrounded by a dotted line and filled with diagonal lines: a second region) and a region 602 that exceeds the allowable dose in the important organs 402 and 403. (Second area) is registered. When there are a plurality of areas satisfying the condition such as the area 601, a plurality of areas are registered. Although only a certain slice is shown in FIG. 6, these areas are actually registered as three-dimensional position information. Note that the registration area illustrated in FIG. 6 may be displayed on the display device 301.

  After a new area is registered in step 105 and step 207, the operator changes the selection criteria set in step 103 and step 203 while confirming the result on the display device 301, so that the step 105 and step 207 are performed. It is also possible to modify the area registered with. For example, in FIG. 6, an area 601 having a dose of 120 or more is registered, and in FIG. 5, the area 501 is displayed on the display device 301, but the selection criterion of the dose 120 or more set by the operator in steps 103 and 203 is illustrated. By changing to the state 6, the shape of the area 601 (area 501) also changes accordingly, and the position information of the area is stored again in the memory 304 (step 105, step 207) and displayed. It is displayed on the device 301 (step 105, step 208).

  The area automatically registered by the apparatus is automatically given a name, and the operator can display the result in a list. As for the regions registered by the apparatus, the position information is stored in the memory 304 of the apparatus in the same manner as the target areas and important organs registered by the operator, and a prescription dose or the like can be set for each area. Further, when the same setting is desired for a plurality of areas, the operator can collectively set the areas by grouping the areas.

If the operator determines that the dose distribution obtained as a result of the iterative calculation satisfies the condition specified as the prescription dose, the condition is confirmed, and the irradiation is obtained by the iterative calculation. The conditions (irradiation parameters) are stored in the memory 304 together with the input irradiation conditions. (Step 107, Step 209). The irradiation condition (irradiation parameter) obtained by the iterative calculation is the irradiation amount for each spot in the setting example of the particle beam scanning irradiation described above, and the irradiation amount x ^→ for each spot obtained by the objective function.

  When the operator determines that the condition is not satisfied, for example, when an area greatly different from the prescribed dose is confirmed, it is necessary to make a plan again (step 106). In the dose distribution result shown in FIG. 5 as an example, there is a region that greatly exceeds the prescription dose 100 in the target region 401, and a high dose has also been irradiated to the important organs 402 and 403, so the irradiation conditions are changed. It is necessary to repeat the iterative calculation.

When the operator repeats the iterative calculation, the conditions can be individually changed for the area automatically registered by the apparatus if necessary. For example, the weight for the newly registered area 601 in the objective function is reset so as to be larger than the weight set for the area 401 (steps 102 and 202). As a result, in the above-described setting example of particle beam scanning irradiation, the objective function generated by the treatment planning apparatus is obtained by adding a term corresponding to the region 601 in addition to the equation (1) (step 104). Step 204). Specifically, when the dose of k points in the region 601 is expressed as di ⁽³⁾ (i = 1, 2,..., K), wi ⁽¹⁾ <wi ⁽³⁾ set by the operator. Using the weight wi ⁽³⁾ that becomes

The objective function is changed as follows. In addition, for example, when the irradiation position is changed in a newly registered region, it is necessary to change the element of x ^→ that is the parameter of the equation (1).

  Since the area 601 exists inside the target area 401, the setting made for the target area 401 is also applied to the area 601. When the setting is changed for the area 601, this setting may be added to the setting of the existing target area 401, but it can also be set so that the newly set setting is given priority in the area 601. Similarly to the setting of the region 602, the setting of the important organ 402 may be compatible, and the setting of the region 602 may be prioritized.

  After the setting is completed, a new dose distribution result is obtained by causing the apparatus to perform the iterative calculation again by an instruction operation by the operator (step 103, steps 205 and 206). When a new dose distribution is obtained, the areas 601 and 602 that are automatically registered in the memory 304 based on the previous calculation result are automatically deleted by the apparatus, and the new dose distribution result and the selection criteria set by the operator are used. The three-dimensional position information of the new area is extracted and stored in the memory 304, so that the position information of the new area is automatically registered (steps 105 and 207). The result is displayed on the display device 301 together with the necessary isodose line (step 105, step 208).

  If the result is insufficient, the operator returns to step 102 and further changes the prescription dose or the like. This process is repeated until the operator determines that a reasonable dose distribution has been obtained.

  As described above, in the present embodiment, the area in which the dose to be irradiated is greatly deviated from the prescription dose is set so that the apparatus automatically registers as the second areas 601 and 602. Can easily change the irradiation conditions and prescription dose for the second area, and change the conventional irradiation conditions and prescription dose changes and settings required before re-running the second and subsequent iterations. Means are provided for doing in more detail than the apparatus. As a result, it is possible to efficiently perform the repetitive work until the operator obtains a desired dose distribution result.

  It should be noted that the selection criteria for the area automatically registered by the apparatus can be changed every time the operator repeats the iterative calculation (step 103, step 203). In this embodiment, the registration standard is determined based on the dose value in each region (the dose in the target region is 120 or more, the dose in the important organ is 20 or more), but the prescription dose exceeds 20%. It can also be set by the ratio of prescription doses.

  FIG. 7 is a flowchart showing processing functions according to another embodiment of the present invention.

  In general, the dose distribution has a complicated shape as indicated by reference numeral 601 in FIG. 6, and an area defined based on the dose value is subdivided, and many small areas may appear. However, the original purpose of the present invention is to improve the distribution by applying individual settings to regions where the dose tends to deviate from the prescription dose. That is, the area 601 registered in FIG. 6 indicates that the area in the vicinity tends to have a higher dose than other areas, and the fine shape of the area is not so important. . Therefore, instead of registering all the areas that meet the selection criteria set by the dose value, the operator may set a threshold for the volume of the area to be registered and automatically remove the excessively subdivided areas by the device. it can. The flowchart of FIG. 7 shows the flow of this function, and is a flowchart of a portion corresponding to step 207 of FIG.

  In step 103 in FIG. 2, the operator inputs the minimum value of the volume of the region to be automatically registered and stores it in the memory 304. The apparatus performs objective function generation and iterative calculation in step 104 in FIG. 2 and steps 204 and 205 in FIG. 3, and after calculating the dose distribution in step 206 in FIGS. The position information is extracted (step 802), and the volume of each region is calculated (step 803). Next, the apparatus deletes an area having a volume less than the previously input minimum value (step 804), and stores only the position information of the remaining area, that is, an area having a volume greater than or equal to the previously set minimum value in the memory 304. (Step 805).

  FIG. 8 is a diagram showing an area automatically registered by the apparatus according to the present embodiment. In this embodiment, since the fine area as represented by 603 in FIG. 6 is less than the threshold volume, it is removed from the target of automatic registration, and three areas 701, 702, and 703 shown in FIG. Register only the area. With this function, a large number of small areas are not registered, and it is possible to reduce the trouble for the operator to set a prescription dose or the like for the area.

  FIG. 9 is a flowchart showing processing functions according to still another embodiment of the present invention.

  In step 103 of FIG. 2, the operator inputs and sets a margin for the region that is automatically registered, and after repeated calculation, the region where the dose value matches the selection criterion is set to the size of the set margin. It is also possible to register after the apparatus has automatically expanded or reduced according to the above. The flowchart of FIG. 9 shows the flow of this function, and like FIG. 7, only the part corresponding to step 207 of FIG. 2 is shown.

  In step 103 of FIG. 2, the operator inputs a margin for the area to be automatically registered and stores it in the memory 304. The apparatus performs objective function generation and iterative calculation in step 104 in FIG. 2 and steps 204 and 205 in FIG. 3, and after calculating the dose distribution in step 206 in FIGS. The position information is extracted (step 902), and the area is enlarged or reduced by the size of the margin set by the operator (step 903). When a region where adjacent regions overlap each other due to the expansion of this region, the sum of these regions is integrated as one region (step 904), and the three-dimensional position information of this integrated region is obtained. It is saved in the memory 304 and newly registered (step 905).

  Also according to the present embodiment, an enlarged area 701 similar to the area 701 shown in FIG. 8 is obtained, so that the portions where the high dose areas such as the areas 601 and 603 in FIG. it can. As a result, the range to be specified can be expanded without increasing the number of areas, and the labor required for operator setting can be reduced.

It is a figure which shows the equipment outline | summary of the radiotherapy planning apparatus concerning one embodiment of this invention. It is a flowchart which shows the flow of the treatment plan planning using the apparatus by one embodiment of this invention. It is a flowchart which shows the processing function which the apparatus of this Embodiment performs in the case of the treatment plan planning of FIG. It is a figure which shows the state which the operator input and registered the target area | region and the important organ on the slice with a CT image on the area | region input screen of a display apparatus. It is a figure which shows dose distribution of the calculation result displayed on the CT screen of a display apparatus by this Embodiment. It is a figure which shows the area | region automatically registered by the apparatus of this Embodiment. It is a flowchart which shows the processing function which the apparatus in other embodiment of this invention performs. It is a figure which shows the area | region automatically registered by the processing function of FIG. It is a flowchart which shows the processing function which the apparatus in further another embodiment of this invention performs.

Explanation of symbols

301 ... Display device 302 ... Input device 303 ... Arithmetic processing device 304 ... Memory (storage device)
401... Target area (first area)
402, 403 ... important organ (first region)
501... Dosage 120 isodose line obtained as a result of repeated calculation 502... Dose 100 isodose line obtained as a result of repeated calculation 503... Dose 20 obtained as a result of repeated calculation 601. Area where the irradiation dose is 120 or more in the target area (second area)
602... An area where the irradiation dose is 20 or more in the automatically registered vital organ (second area)
603 ... A portion 701 of the area 601, 702 ... A target area automatically registered after providing a volume threshold value 703 Area 703 with an irradiation dose of 120 or more ... In a vital organ automatically registered after providing a volume threshold value In areas where the irradiation dose is 20 or more

Claims (8)

In a radiotherapy planning apparatus for creating a treatment plan for performing treatment by irradiating radiation,
An input device;
A display device;
A storage device;
First means for storing, in the storage device, three-dimensional position information of a first region in which radiation to be irradiated is to be controlled based on medical image information displayed on the display device and information input by the input device; ,
Second means for storing the first irradiation condition for the first region in the storage device based on the medical image information displayed on the display device and the input information by the input device;
A third means for storing, in the storage device, selection criteria for the second region to be automatically registered based on the medical image information displayed on the display device and the input information by the input device;
A calculation is performed based on the position information of the first region and the first irradiation condition for the first region to determine a second irradiation condition for the first region, and the first region is subjected to the first and second irradiation conditions. A fourth means for calculating a dose distribution when irradiated with radiation;
Fifth means for extracting three-dimensional position information that matches the selection criterion for the second area from the calculation result of the dose distribution and storing the three-dimensional position information in the storage device as position information for the second area When,
A radiotherapy planning apparatus comprising: sixth means for displaying the first region and the calculation result of the dose distribution superimposed on the medical image information displayed on the display device. The radiotherapy planning device according to claim 1,
The fifth means, after extracting the three-dimensional position information that matches the selection criteria of the second area, from among the areas related to the position information, extract an area having a volume larger than a preset threshold, The radiation treatment planning apparatus, wherein the storage device stores position information of the area as position information of the second area. The radiotherapy planning device according to claim 1,
The fifth means extracts the three-dimensional position information that matches the selection criteria for the second area, and then enlarges or reduces the area related to the position information by a preset margin, and enlarges or reduces the area. The radiation treatment planning apparatus, wherein the storage device stores the position information of the region thus obtained as the position information of the second region. The radiotherapy planning device according to claim 1,
The fourth means generates an objective function in which the deviation from the first irradiation condition is quantified based on the three-dimensional position information of the first area and the first irradiation condition for the first area. A radiation treatment planning apparatus for obtaining an irradiation parameter that minimizes a deviation from the first irradiation condition by performing an iterative calculation using the method, and determining the second irradiation condition. In the radiotherapy planning device according to any one of claims 1 to 4,
The three-dimensional position information of the first area stored by the first means includes position information of the target area and position information of an important organ, and the first irradiation condition for the first area stored by the second means is , Including a dose value to be received by the target area, an allowable dose for the important organ, and a weight indicating a priority level of the target area and the important organ, and a selection criterion for the second area to be stored by the third means includes: A radiotherapy planning apparatus, comprising: a dose value that is excessive or small with respect to a dose value to be irradiated to a target region; and a maximum dose value that exceeds an allowable dose of the important organ. In the radiotherapy planning device according to any one of claims 1 to 4,
The treatment plan is based on particle beam scanning irradiation,
The first irradiation condition for the first region stored by the second means includes a dose value and spot position information to be received by the first region,
The second irradiation condition determined by the fourth means includes an irradiation parameter for each spot position. In a radiation treatment planning method for creating a treatment plan for performing treatment by irradiating radiation using a radiation treatment planning device having an input device, a display device, and a storage device,
A first procedure for storing, in the storage device, three-dimensional position information of a first region in which radiation to be irradiated is to be controlled based on medical image information displayed on the display device and information input by the input device; ,
A second procedure for storing the first irradiation condition for the first region in the storage device based on the medical image information displayed on the display device and the input information by the input device;
A third procedure for storing, in the storage device, selection criteria for the second region to be automatically registered based on the medical image information displayed on the display device and the input information by the input device;
A calculation is performed based on the position information of the first region and the first irradiation condition for the first region to determine a second irradiation condition for the first region, and the first region is subjected to the first and second irradiation conditions. A fourth procedure for calculating a dose distribution when irradiated with radiation;
Fifth procedure for extracting three-dimensional position information that matches the selection criteria for the second region from the calculation result of the dose distribution and storing the three-dimensional position information in the storage device as the position information of the second region When,
A radiotherapy planning method comprising: a sixth procedure for displaying the first region and the calculation result of the dose distribution superimposed on the medical image information displayed on the display device. The radiotherapy planning method according to claim 7,
A seventh procedure for storing the third irradiation condition for the second region in the storage device based on the medical image information displayed on the display device and the input information by the input device;
The second irradiation condition is corrected by performing calculations based on the position information of the first area, the first irradiation condition for the first area, the position information of the second area, and the third irradiation condition for the second area. An eighth procedure for recalculating a dose distribution when the first region is irradiated with radiation under the first irradiation condition and the modified second irradiation condition;
New three-dimensional position information that matches the selection criteria for the second region is extracted from the recalculated calculation result of the dose distribution, and the new three-dimensional position information is extracted after the recalculation of the second region. A ninth procedure to be stored in the storage device as correct position information;
A radiotherapy planning method, further comprising: a tenth procedure for displaying the first region and the calculation result of the dose distribution superimposed on the medical image information displayed on the display device.

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