JP2616595B2 - Three-dimensional volume dose estimation device for radiation therapy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional volume dose estimating apparatus for radiation therapy, and more particularly to a method for simulating the state of absorption of radiation dose to the human body when planning an optimal irradiation method in cancer radiation therapy. The present invention relates to a three-dimensional volume dose estimation apparatus for radiation therapy, which serves as an index for determining the suitability or unsuitability of a planned irradiation method from a plurality of simulation results.

[0002]

2. Description of the Related Art Heretofore, this kind of volume dose planning system has performed volume dose planning only for a CT slice including a point (isocenter) which is a center of radiotherapy.

[0003] This kind of volume dose planning system is
When one treatment plan is set for one patient, volume dose calculation is performed for the treatment plan, and the result is CR
It was output to T and a printer.

[0004]

In the above-mentioned conventional volume dose estimation system, the volume dose is calculated only for a CT slice including a point (isocenter) which is the center of radiotherapy. An area is a single organ or lesion, and although it is a solid with a certain size, volumetric dose is calculated for one section of the solid. There is a drawback that only is calculated.

In the conventional system, when one treatment plan is set for a certain patient, volume dose calculation is performed on the treatment plan, and the result is output to a CRT or a printer. Therefore, in order to make a plurality of treatment plans for the same patient and use each volume dose calculation result as one index, and to compare which plan is optimal, the physician stores the printer paper on which the results are output. However, since comparisons can only be made by comparing printer papers with the eyes, management is cumbersome and accurate comparisons are difficult.

[0006]

SUMMARY OF THE INVENTION A three-dimensional volume dose estimating apparatus for radiotherapy according to the present invention solves the above-mentioned problems, three-dimensionally obtains a volume dose of a region of interest, and uses the volume dose as an index. It is intended to facilitate the comparison of a plurality of treatment plans.

Therefore, the apparatus for estimating three-dimensional volume dose of radiotherapy according to the present invention determines whether or not the irradiation method planned for a target area where radiotherapy is to be performed when simulating the absorption state of radiation dose to the human body. In a radiotherapy three-dimensional volume dose estimating apparatus for estimating a volume dose of at least one region of interest that does not want to be irradiated with a radiation serving as an index to be determined, an absorbed dose is estimated on a CT slice in the region of interest for obtaining a volume dose. Among the matrices, an inner / outer determination unit that determines which calculation matrix is included, and a two-dimensional processing unit that obtains each absorbed dose using the calculation matrix included in the area obtained by the inner / outside determination unit, The absorbed dose of the matrix in the CT slice (two-dimensional) area where the region of interest for obtaining the volume dose found by the two-dimensional processing unit is A three-dimensional addition unit that creates volumetric dose calculation base data by performing a three-dimensional addition process on all CT slices in which a region of interest exists, and a volumetric dose created by the three-dimensional addition unit for the region of interest. Statistical processing unit that calculates the volume dose of the relevant area from the calculation base data and calculates at least one statistical value, and directory management that manages the treatment plan for each patient by converting the volume dose calculation results and volume dose calculation data into a database And an input unit for inputting the region of interest and the instruction, and an output unit for displaying a graph of the volume dose planning result and a numerical display of a statistical value.

[0008]

Next, the present invention will be described with reference to the drawings.

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

In the treatment plan simulation section 1, a doctor looks at a CT image of a patient and determines an area to be irradiated (hereinafter referred to as a target). Then, while drawing the radiation absorbed dose distribution into the patient on the CT image, the treatment angle,
Parameters related to the treatment machine (hereinafter, referred to as “treatment parameters”), such as the size of the irradiation field, are determined. Thereafter, the inside / outside determination unit 2 to the output unit 9, which are components of the three-dimensional volume dose estimation apparatus of the present invention, calculate the volume dose for the treatment method planned by the treatment plan simulation unit 1, and Create a database.

In the treatment plan simulation section 1, if there is a region for performing volumetric dose calculation other than the set region of interest, the input means 8 inputs its outline from the digitizer. It is assumed that a first region of interest (hereinafter, referred to as “roi1”) is input to the treatment plan simulation unit 1 and a new second and third region of interest (hereinafter, “roi2, roi2,
oi3 "). When you do that,
Volumetric dose is determined for the target, roi1 to roi3, and five regions within the body contour of the patient by the following method, that is, the inside / outside determination unit 1 to the statistical processing unit 5. Hereinafter, for convenience, a description will be given as a method of calculating the volume dose only for the region n.

First, the inside / outside determination unit 2 shown in FIG. 1 determines which calculation matrix is included in a region obtained based on the outline information of the region as shown in FIG. Is determined based on whether the middle point of the calculation matrix is within the region. For example, in the case of FIG. 2, it is assumed that a hatched portion is a calculation matrix that is included in the region n with respect to the thick solid line region n. And the middle point of the calculation matrix is
The following algorithm may be used as an algorithm for determining whether or not the area is within the area n. That is, all the intersections with the contour of the area n when the half line is drawn in an arbitrary direction with the middle point of the calculation matrix as the starting point are obtained. Depending on whether the number of intersections is an even number or an odd number, it can be determined that an even number is outside the contour and an odd number is within the outline. 4 shows an example of the inside / outside determination of the middle point in FIG. That is, in the diagram (A) of FIG. 3, both the case where the number of intersections with the half-line is one and the case where the number of intersections is five are illustrated.
The midpoint is determined to be within the contour. In addition, in the diagram (B) of FIG. 3, since the number of intersections with the half line is an even number, it is determined that the middle point is outside the contour. When the contour touches the half line, it is promised that there are two intersections.

In this manner, the inside / outside determination is performed by the above method for all the CT slices to which the region n has been input.
For example, referring to FIG. 1 to N
o. No. 5 CT slices were taken. 2-No.
Region n is seen in three of the four slices, and region n is input to these three slices. 2-No. The inside / outside determination operation is performed for slice 4. However, when the region n is within the body contour, the inside / outside determination is performed for all slices taken.

Next, in the two-dimensional processing section 3, the inside / outside determination section 2
Absorbed dose data possessed by each of the calculation matrices of each CT slice in the area n obtained by the above is obtained. Since the absorbed dose data has already been calculated by the treatment plan simulation unit 1, the data of the corresponding calculation matrix may be read here.

Next, in the three-dimensional addition unit 4, the data of the calculation matrix in the region n for each CT slice to which the region n obtained up to the two-dimensional processing unit 2 is input is applied to all the corresponding CT slices. to add. According to FIG. 2 to slice No. 2 The dose data in the region n up to 4 is added. At this time, the dose data of the 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 the adjacent CT slice, the two-dimensional calculation matrix in the region n up to this point is recognized as a thick three-dimensional voxel (pixel having a thickness).

Here, both ends n are recognized as a group 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 are hereinafter referred to as volume dose calculation base data as shown in FIG.

In the next statistical processing unit 5, the volume of the region n, the volume dose value, the dose and the volume dose frequency distribution are obtained from the volume dose base data. Further, the average dose value and the maximum / minimum dose value in the area n are calculated as needed. The volume of the region n is assumed to be the sum of the sizes of the respective voxels in the region n, and the volume dose value is assumed to be the sum of the product of the voxel size and the dose value of the voxel. The frequency distribution is created with one voxel as one frequency. The average dose value is a weighted average of the voxel dose values in consideration of the voxel volume, 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 inside / outside judgment section 2
From the database, the volumetric dose calculation base data and the volumetric dose calculation result obtained by a series of operations of the statistical processing unit 5 are compiled into a database, and for each patient (if a plurality of plans are made for one patient, each plan) Manage. As shown in FIG. 7, the management table includes a patient name, a patient number, a plan number, a plan date,
Comments and the like are displayed, and the doctor inputs the patient number and the plan number with the input means 8 while viewing this management table for the treatment plan performed in the past, and outputs the result of the volume dose calculation of the relevant plan for the relevant patient. It can be displayed and viewed by means 9.

Finally, the output means 9 displays the frequency distribution of the dose and the volume dose obtained by the statistical processing section 5 as a graph, and also displays numerical values of statistical values.

[0020]

As described above, according to the present invention, the contour of the region of interest is input to all the CT slices in which the region of interest exists, and a two-dimensional volume dose is calculated on each CT slice plane. By taking into account the interval and performing addition processing, a volumetric dose that considers the region of interest three-dimensionally is obtained, the results of volumetric dose calculation are compiled into a database, and a treatment plan is managed for each patient. When comparing treatment plans based on the results of dose calculation as one index, the patient name (or patient I)
By simply specifying D), there is an effect that the dose calculation results of all the treatment plans planned for the patient can be immediately viewed.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram of an inside / outside determination criterion of an inside / outside determination unit.

FIG. 3 is an explanatory diagram of a contour inside / outside determination algorithm of an inside / outside determination unit.

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

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

FIG. 6 is an explanatory view showing dose calculation base data.

FIG. 7 is an explanatory diagram showing directory management.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Treatment plan simulation part 2 Interior / external judgment part 3 Two-dimensional processing part 4 Three-dimensional addition part 5 Statistical processing part 6 Directory management part 7 Database 8 Input means 9 Output means

Claims (1)

(57) [Claims] At least one interest that does not want to be irradiated with radiation serving as an index for determining suitability of a planned irradiation method for a target area to be subjected to radiation treatment when simulating a state of absorption of a radiation dose to a human body. In a radiotherapy three-dimensional volume dose estimating apparatus for estimating a volume dose of a region, a matrix (hereinafter referred to as a “calculation matrix”) is used for estimating an absorbed dose on a CT slice in a region of interest for obtaining a volume dose. An inside / outside determination unit for determining whether a calculation matrix is included, a two-dimensional processing unit for obtaining each absorbed dose using the calculation matrix included in the region obtained by the inside / outside determination unit, and a calculation performed by the two-dimensional processing unit The absorbed dose of the matrix in the region of the CT slice (two-dimensional) where the region of interest for which the volume dose is to be determined exists. A three-dimensional addition unit that creates volumetric dose calculation base data by performing a three-dimensional addition process on all CT slices; and a volume dose calculation base data created by the three-dimensional addition unit for the region of interest. A statistical processing unit that performs volumetric dose calculation and calculates at least one statistical value; a directory management unit that manages a treatment plan for each patient by converting a volumetric dose calculation result and volumetric dose calculation data into a database; An apparatus for estimating a three-dimensional volume dose of radiotherapy, comprising: input means for inputting the instruction; and output means for displaying a graph of a volume dose planning result and a numerical value of a statistical value.