JPH04317665A - Three-dimensional volumetric dose estimating device for radiation treatment - Google Patents

Abstract

PURPOSE:To allow the immediate viewing of the results in the dose calculations of all the treatment plans made for patients by determining the volumetric quantity which three-dimensionally considers a concern region, making the results of the volumetric dose calculations to a data base and building the treatment plan for each of the patients. CONSTITUTION:The contour of the concern region is inputted to all of the CT slices, where the region exists by a two-dimensional processing section 3 which determines the accumulated dose of the region estimated by an inside and outside discrimination section 2 inputted from an input means 8. Statistical processing is executed by a statistical processing section 5 which determines the volumetric dose three-dimensionally considering the concern region by a three-dimensional calculating section 4 which executes addition processing by considering the spacings between the CT slices, after determining the two-dimensional volumetric dose on the respective CT slice planes. The data base 7 is formed from the results of the volumetric dose calculations by a directory management section 6. The treatment plans are managed by the directory management section 6 for each of the patients by utilizing such data base.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a three-dimensional volumetric dose estimating device for radiotherapy, and in particular, when planning an optimal radiation irradiation method in cancer radiotherapy, the present invention is used to simulate the state of absorption of radiation dose into the human body. The present invention relates to a radiation therapy three-dimensional volumetric dose estimator that serves as an indicator to determine the appropriateness or unsuitability of a planned irradiation method based on multiple simulation results.

0002

BACKGROUND OF THE INVENTION Conventionally, this type of volumetric dose planning system has a C
Volumetric dose planning was performed only for T slices.

[0003] Also, this type of volumetric dose planning system:
When one treatment plan is created for a certain patient, volume dose calculation is performed for that treatment plan, and the results are used as CR.
It was output to T or printer.

0004

[Problem to be Solved by the Invention] The conventional volume dose estimation system described above calculates the volume dose only for CT slices that include the center point (isocenter) of radiation therapy. A region is an organ or a lesion, etc., and although it is a three-dimensional object with a certain size, the volume dose is calculated for one cross section of the three-dimensional object, so it is a guideline for the volume dose of the region of interest. The disadvantage is that it only calculates

[0005] Furthermore, in conventional systems, when one treatment plan is established for a certain patient, volume dose calculation is performed for that treatment plan, and the results are output to a CRT or printer. Therefore, in order to create multiple treatment plans for the same patient, use the volume dose calculation results of each as one index, and compare which plan is optimal, doctors must keep the printer paper on which the results are printed. However, the comparison can only be made by visually comparing the printer paper, which is cumbersome in terms of management and difficult to make accurate comparisons.

[0006]

[Means for Solving the Problems] The three-dimensional volume dose estimating device for radiation therapy of the present invention aims to solve the above-mentioned problems, and is capable of three-dimensionally determining the volume dose of a region of interest, and using the volume dose as an index. The purpose is to easily compare multiple treatment plans.

[0007] Therefore, the three-dimensional volumetric dose estimating device for radiotherapy of the present invention determines the suitability or unsuitability of the irradiation method planned for the target area for radiotherapy when simulating the state of radiation dose absorption into the human body. In a three-dimensional volume dose estimator for radiation therapy that estimates the volume dose of at least one region of interest that is not desired to be exposed to radiation, which serves as an index for determining the amount, the absorbed dose is estimated on a CT slice within the region of interest for which the volume dose is to be determined. an inside/outside determining section that determines which calculation matrix is included among the calculated matrices; a two-dimensional processing section that calculates each absorbed dose using the calculation matrix included in the area determined by the inside/outside determining section; Three-dimensionally adds the absorbed dose of the intra-regional matrix of the CT slice (two-dimensional) in which the region of interest for which the volume dose is to be obtained, determined by the two-dimensional processing unit, exists for all CT slices in which the region of interest for which the volume dose is to be obtained exists. a three-dimensional addition unit that creates volumetric dose calculation basis data by performing the above-mentioned operations; a statistical processing unit that calculates statistical values; a directory management unit that creates a database of volume dose calculation results and volume dose calculation data and manages treatment plans for each patient; and input means for inputting the region of interest and the instructions; The device is configured to include an output means for displaying a graph of the volume dose planning results and a numerical display of statistical values.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

[0010] In the treatment planning simulation section 1, a doctor looks at a CT image of a patient and determines an area (hereinafter referred to as a target) to which radiation will be applied. After that, while drawing the radiation absorption dose distribution inside the patient's body on the CT image, the treatment angle,
Parameters related to the treatment machine, such as the size of the irradiation field (hereinafter referred to as “
(referred to as "treatment parameters"). Thereafter, the treatment plan simulation unit 1
Volume dose calculations are performed for the treatment method planned in , and the results are compiled into a database.

In the treatment planning simulation section 1, if there is a region to be subjected to volume dose calculation other than the set region of interest, the input means 8 inputs its contour from a digitizer. Suppose that a first region of interest (hereinafter referred to as "roi1") is input in the treatment planning simulation unit 1, and new second and third regions of interest (hereinafter referred to as "roi2, roi") are input.
3) is added. In such a case, the volumetric dose is determined for the target, roi1 to roi3, and five regions within the patient's body contour using the following method, that is, the inside/outside determination unit 1 to the statistical processing unit 5. From now on, for convenience,
This will be explained as a method for determining the volume dose only for region n.

First, the inside/outside determining unit 2 in FIG. 1 determines which calculation matrices are included in the area by determining calculation matrices included in area n based on the contour information of the area, as shown in FIG. It is determined whether the midpoint of the calculation matrix is within the area. For example, in the case of FIG. 2, it is assumed that with respect to the region n indicated by the thick solid line, the shaded portion is the calculation matrix included within the region n. Then, the midpoint of the calculation matrix is
The following algorithm may be used to determine whether it is within region n. That is, when a half-line is drawn in an arbitrary direction starting from the midpoint of the calculation matrix, all the points of intersection with the outline of region n are determined. Depending on whether the number of intersections is even or odd, it can be determined that if the number is even, it is outside the contour, and if it is odd, it is inside the contour. An example of inside/outside determination of the midpoint in FIG. 3 is shown. That is, the subdiagram of Fig. 3 (
In A), both the case where the number of intersections with the half line is one and the case where there are five are exemplified, and since the number of intersections is an odd number in both cases, it is determined that the midpoint is within the contour. Also, the partial diagram (B) in Figure 3
Since the number of intersections with the half line is an even number, the midpoint is determined to be outside the contour. Note that when a contour touches a half-line, there are two points of intersection.

[0013] In this way, the inside/outside determination is performed using the above method for all CT slices into which region n has been input. For example, referring to FIG. 4, when the patient receives No. 1~No
．． Five CT slices of No. 5 were taken. 2~No. 4
If region n is found in three slices, and if region n is input to these three slices, then no. 2~No. The inside/outside judgment operation is performed for slice No. 4. However, if region n is within the body contour, the inside/outside determination is performed for all photographed slices.

Next, in the two-dimensional processing section 3, the inside/outside determining section 2
Obtain the absorbed dose data of each calculation matrix of each CT slice within the region n obtained in . Since this absorbed dose data has already been calculated by the treatment plan simulation section 1, it is sufficient here to read the data of the corresponding calculation matrix.

[0015] Next, the three-dimensional addition section 4 adds the data of the calculation matrix within the region n for each CT slice into which the region n obtained up to the two-dimensional processing section 2 is input, over all the corresponding CT slices. to add. According to FIG. 4, slice No. 2 to slice no. The dose data in area n up to 4 are added up, but at this time, the dose data of slice i (i is 2 to 4) is added in the body axis direction,
Assuming that the CT slice has a thickness up to the midpoint of adjacent CT slices, the two-dimensional calculation matrix in the region n up to now is recognized as a thick three-dimensional voxel (pixel having a thickness).

[0016] Here, both ends n are recognized as a collection of a plurality of voxels, and each voxel has absorbed dose data. A plurality of pairs of the voxel size in the region n and the dose data of the voxel will be hereinafter referred to as volumetric dose calculation base data, as shown in FIG.

Next, the statistical processing section 5 calculates the volume of region n, the volume dose value, the dose, and the volume dose frequency distribution from the volume dose basis data. Furthermore, the average dose value and maximum/minimum dose value within region n are calculated as necessary. The volume of region n is the sum of the sizes of each voxel in region n, and the volumetric dose value is the sum of the products of each voxel size and voxel dose value. Further, the frequency distribution is created with one voxel as one frequency. The average dose value is a weighted average of the voxel dose values taking into consideration the volume of the voxel, and the maximum/minimum dose value is the dose value of the voxel having the maximum/minimum dose value.

In the directory management section 6, the internal/external determining section 2
The volume dose calculation basis data and the volume dose calculation results obtained through a series of operations in the statistical processing unit 5 are created into a database for each patient (or for each plan if multiple plans are made for one patient). manage. As shown in Figure 7, the management table includes patient name, patient number, plan number, plan date,
Comments, etc. are displayed, and the doctor inputs the patient number and plan number using the input means 8 while looking at this management table for past treatment plans, and outputs the volume dose calculation results for the relevant plan for the patient. It can be displayed and viewed using means 9.

Finally, the output means 9 displays graphically the frequency distribution of the dose and volumetric dose obtained by the statistical processing section 5, as well as numerically displays the statistical values.

[0020]

As explained above, the present invention inputs the outline of the region of interest into all CT slices in which the region of interest exists, calculates the two-dimensional volume dose on each CT slice plane, and then calculates the volumetric dose of the CT slice. By taking the interval into consideration and performing addition processing, the volume dose that considers the region of interest three-dimensionally is calculated, the results of the volume dose calculation are compiled into a database, and the treatment plan is managed for each patient. When creating a treatment plan and comparing which plan is optimal using the dose calculation results as an indicator, the patient name (or patient ID)
By simply specifying , you can immediately view the dose calculation results for all treatment plans planned for that patient.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of the inside/outside determination criteria of the inside/outside determination section.

FIG. 3 is an explanatory diagram of the contour inside/outside determination algorithm of the inside/outside determining section.

FIG. 4 is an explanatory diagram of CT slices to be calculated by the inside/outside determination unit.

FIG. 5 is an explanatory diagram of a data range between slices in a three-dimensional addition unit.

FIG. 6 is an explanatory diagram showing dose calculation basis data.

FIG. 7 is an explanatory diagram showing directory management.

[Explanation of symbols]

1 Treatment plan simulation section 2 Internal/external determination section 3 Two-dimensional processing section 4 Three-dimensional addition section 5 Statistical processing section 6 Directory management section 7 Database 8 Input means 9 Output means

Claims (1)

[Claims] Claim 1: When simulating the absorption state of radiation dose to the human body, at least one interest in not wanting to be exposed to radiation serves as an index to determine the suitability of the irradiation method planned for the target area for radiotherapy. In a three-dimensional volume dose estimator for radiotherapy that estimates the volume dose of a region, which of the matrices (hereinafter referred to as "calculation matrix") used to estimate the absorbed dose on a CT slice within the region of interest for which the volume dose is to be calculated is used. an inside/outside determination section that determines whether a calculation matrix is included; a two-dimensional processing section that determines each absorbed dose using the calculation matrix included in the area determined by the inside/outside determination section; A CT slice (2
The absorbed dose of the intra-regional matrix of the dimension) is determined by a three-dimensional addition unit that creates volume dose calculation base data by performing three-dimensional addition processing on all CT slices in which the region of interest for which the volume dose is to be calculated, and the region of interest for which the volume dose is calculated. A statistical processing unit that calculates the volume dose of the corresponding area from the volume dose calculation base data created by the three-dimensional addition unit and calculates at least one statistical value, and a statistical processing unit that calculates the volume dose calculation result and the volume dose calculation data. A directory management unit that creates a database and manages treatment plans for each patient, an input means for inputting the region of interest and the instructions, and an output means for graphically displaying volume dose planning results and numerically displaying statistical values. A three-dimensional volumetric dose estimating device for radiation therapy, comprising: