WO2018004052A1

WO2018004052A1 - Method for optimization of planning phase in respiratory guided radiotherapy using geometric relationship of patient

Info

Publication number: WO2018004052A1
Application number: PCT/KR2016/007874
Authority: WO
Inventors: 강성희; 김시용; 김태호; 김동수; 신동석; 조민석; 김경현; 노유윤; 서태석
Original assignee: 가톨릭대학교 산학협력단
Priority date: 2016-06-30
Filing date: 2016-07-20
Publication date: 2018-01-04
Also published as: KR101796868B1

Abstract

The present invention relates to a method for obtaining an optimized irradiation time point of radiation by finding out the time point at which radiation is least irradiated to general tissue during the respiration of a patient. Specifically, the present invention relates to a method for obtaining the time point at which radiation is least irradiated to general tissue during the respiratory period of a patient by defining a three-dimensional geometric relationship between peripheral tissue and a target volume using biological characteristics of general tissue, such as esophagus or spine, where tumors are not formed, for radiation and an overlap volume histogram. In a method for irradiating radiation to a tumor of a patient according to an aspect of the present invention, the method comprises: a first step for determining an irradiation timing of the radiation using the radiation sensitivity of at least one first organ within a predetermined distance from the tumor among a plurality of organs and the geometric overlapping degree between the first organ and the tumor; and a second step for irradiating the radiation to the tumor at the irradiation timing, wherein the radiation sensitivity and the geometric overlapping degree may vary according to the respiration of the patient.

Description

Optimization of Planning Phase in Respiratory-Linked Radiation Therapy Using Patient Geometric Relationships

The present invention relates to a method for finding an optimal irradiation time point by finding a time when radiation is irradiated to general tissues in the respiration of a patient. Specifically, the present invention defines the three-dimensional geometrical relationship between the surrounding tissue and the target volume using the biological characteristics and the overlap volume histogram of the radiation of general tissues such as the esophagus and the spine where tumors do not occur, and then, into the general tissues in the patient's respiration cycle. It relates to a method of obtaining the point of time when the radiation is least irradiated.

Radiation therapy is a method of clinical medicine that treats patients with very short-wavelength, high-energy radiation, and is one of the three major cancer treatments along with surgery and chemotherapy. It usually treats malignant tumors called cancer, but it also treats benign tumors and some benign diseases.

Radiation therapy can be divided into external radiation therapy and brachytherapy, depending on the location of the irradiator.

External radiation therapy is a treatment method for irradiating radiation by using various equipments outside the body, and may be classified into photo-ray therapy, electron beam therapy, and particle beam therapy (neutron therapy, proton therapy, etc.) according to the type of radiation used. Accordingly, various radiation generating devices can be used, but the most widely used radiation generating device is a linear accelerator.

Proximity treatment is a method of irradiating radiation to a limited area by placing a radiation generating device or isotope in the body or surface, and it can be divided into intraluminal treatment, intraluminal treatment, tissue treatment, and contact treatment according to the space or method to be inserted. have.

The simulation and treatment planning process is necessary before full-scale radiation therapy begins. For this purpose, CT for radiotherapy planning is often performed. Determine the exact location and proper posture to receive treatment and mark areas of the body to be treated. If necessary, a device to fix the movement of the patient or a shielding device may be manufactured to prevent radiation from being irradiated to a normal part. Afterwards, it may be necessary to prepare meals or control urination / dungary conditions to maintain the same posture and body parts as planned during the treatment planning phase.

The patient is taken to a room for radiation therapy, lying on a bed with a treatment machine, posing, and being treated. Treatment is usually assessed on the first or second day of treatment and on a periodic basis.

The time taken depends on the method of treatment. Conventional radiation therapy takes about 10 minutes once, but in the case of intensity controlled radiation therapy, image guided radiation therapy, etc., it may take about 30 minutes. It may take more than a few hours when there is a need to maintain a low dose rate due to a large dose of radiation or a wide range of treatment, such as stereotactic or systemic radiation therapy.

The schedule is determined according to the type of disease, stage, and the general condition of the patient, and is usually received five times a week for five to eight weeks. However, in the case of stereotactic radiotherapy, treatment is performed 1 to 5 times unlike other treatment methods.

Most radiation treatments are given over several weeks and, if necessary, to mark the treatment area on the body, it is necessary to maintain this marking. It is also important to maintain your posture during treatment. In the case of respiratory synchrotherapy, maintaining the breath at the planned respiratory cycle is essential for the reappearance of the treatment as it was at the planning stage.

Depending on the treatment site and the combined treatment method, it may be necessary to adjust the type, method, and urination habits of the meal. If you treat the head and neck or digestive system, including the oral cavity, eating too much irritation may damage the mucous membranes, so be careful. When combined with chemotherapy, immunity can be lowered, so it's good to cook food with water. In the case of prostate treatment, the treatment area may vary depending on the degree of urination, so that drinking and urination may be adjusted according to the treatment time.

In the conventional radiotherapy plan, although the amount of radiation is irradiated to the general tissues around the tumor, the change is not taken into account according to the breathing, the degree of movement of the general tissues according to the breathing of the patient and the dose to receive the radiation This was not considered. Therefore, the destruction of the general tissue that should not be irradiated has a problem, a solution for this situation is required.

It is an object of the present invention to provide a user with a method of finding the optimal irradiation time point by finding the time when radiation is irradiated to the general tissues in the breath of the patient.

Specifically, the present invention defines the three-dimensional geometrical relationship between the surrounding tissue and the target volume using the biological characteristics and the overlap volume histogram of the radiation of general tissues such as the esophagus and the spine where tumors do not occur, and then, into the general tissues in the patient's respiration cycle. It is an object of the present invention to provide a user with a method of obtaining the point of time when the radiation is least irradiated.

On the other hand, the technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems that are not mentioned are clearly to those skilled in the art from the following description. It can be understood.

In the method of irradiating a tumor of a patient of one aspect of the present invention for achieving the above technical problem, at least one first organ of a plurality of organs within a predetermined distance from the tumor A first step of determining the irradiation timing of the radiation using a radiation sensitivity of and a degree of geometric overlap between the first organ and the tumor; And a second step of irradiating the radiation to the tumor at the irradiation timing. The radiation sensitivity and the degree of geometric overlap may vary according to breathing of the patient.

In addition, the irradiation timing may be a point in time where the degree of geometric overlap with the radiation sensitivity is minimal.

In addition, the irradiation timing is in the following equation

It may be determined as the time point when the minimum.

Equation

In the formula, i is an identification symbol for each of the first institutions, I is the total number of the first institutions,

Represents the degree of geometric overlap between the i organ and the tumor,

Represents the radiation sensitivity of the organ, i, at the time the patient breathes.

In addition, the respiratory period of the patient in one cycle may be divided by a constant N, and the time point at which the degree of geometric overlap with the radiation sensitivity is minimal among the time points from 1 / N to N / N may be determined as the irradiation timing.

In addition, the plurality of organs may include the esophagus, the heart and the spinal cord.

Also, before the first step, the step 0.5 of the plan for irradiating the tumor of the patient further comprises; wherein the step 0.5, end- is the point at which the patient exhales the most end- It may be performed using at least one image of the tumor at exhalation or end-inhalation, at which point the patient inhales most.

Further, based on the plan established in step 0.5, the radiation can be irradiated at a point when the degree of geometric overlap with the radiation sensitivity is minimal.

On the other hand, in the device for irradiating the tumor of the patient (tumor) of another aspect of the present invention for achieving the above technical problem, at least one agent within a predetermined distance from the tumor of the plurality of organs (organic) A control unit for determining an irradiation timing of the radiation using a radiation sensitivity of one organ and a degree of geometric overlap between the first organ and the tumor; And a radiation irradiator for irradiating the radiation to the tumor at the irradiation timing. The radiation sensitivity and the degree of geometric overlap may vary according to breathing of the patient.

In addition, the control unit may determine, as the irradiation timing, a point in time where the degree of geometric overlap with the radiation sensitivity is minimum.

In addition, the control unit in the following equation

The time at which the minimum becomes can be determined as the irradiation timing.

Equation

Represents the degree of geometric overlap between the i organ and the tumor,

The controller may classify the respiratory period of the patient in one cycle into a constant N, and determine, as the irradiation timing, a time point at which the degree of geometric overlapping with the radiation sensitivity is minimum among time points 1 / N to N / N. have.

In addition, a plan for radiating the tumor of the patient is established through the control unit, and when end-exhalation is the point at which the patient exhales the most or end-inhalation is the point at which the patient inhales the most. The plan can be formulated using at least one image of the tumor of.

The control unit may control the radiation irradiator to irradiate the radiation at a time when the degree of geometric overlap with the radiation sensitivity is minimum based on the established plan.

The present invention can provide a user with a method of finding the optimal irradiation time point by finding the time when radiation is irradiated to the general tissues in the breath of the patient.

Specifically, the present invention defines the three-dimensional geometrical relationship between the surrounding tissue and the target volume using the biological characteristics and the overlap volume histogram of the radiation of general tissues such as the esophagus and the spine where tumors do not occur, and then, into the general tissues in the patient's respiration cycle. The user can be provided with a way to find out when the radiation is least irradiated.

According to the present invention, the radiation treatment plan is considered in consideration of the radiation sensitivity of the general tissue as well as the dose to the general tissue during the radiation treatment, thereby enabling safe radiation treatment.

On the other hand, the effect obtained in the present invention is not limited to the above-mentioned effects, other effects that are not mentioned will be clearly understood by those skilled in the art from the following description. Could be.

1 is a view for explaining the operation of CT imaging and reconstruction.

2 is a schematic diagram of a general CT system 100.

3A and 3B illustrate specific examples of geometric relationships of the esophagus, spinal cord, and heart in the planning target volume in relation to the present invention.

4 is a view for explaining the degree of overlapping the normal tissue (normal tissue) in relation to the tumor (tumor).

FIG. 5 illustrates the results of a Dose Volume Histogram (DVH) evaluation between a phase (10%) when inhaling the breath and a phase (50%) when inhaling the most breath in relation to the present invention.

6 illustrates specific examples of optimized values in each phase in connection with the present invention.

FIG. 7 illustrates an example of a table summarizing mean doses of normal tissues in relation to the present invention.

8 illustrates an example of a table comparing maximum doses in a plurality of cases in connection with the present invention.

9 shows an example of a table comparing average and maximum doses in a plurality of cases in connection with the present invention.

10A to 10J illustrate a comparison of a dose volume histogram (DVH) between a low value and a high value for each case in relation to the present invention.

11A to 11J illustrate specific examples of Pearson Correlation coefficients according to sensitivity analysis (SPSS) for each case in relation to the present invention.

FIG. 12 is a table showing the normal tissue complication probability (NTCP) separated for each case and organized according to the present invention.

FIG. 13 summarizes the summary of the possibility of normal tissue complications of FIG. 12 in a table.

FIG. 14 summarizes the summary of mean dose reduction in a table in connection with the present invention.

15 summarizes the maximum dose summary contents in a table in relation to the present invention.

The medical imaging apparatus is a device for acquiring an internal structure of an object as an image.

The medical image processing apparatus is a non-invasive inspection apparatus, which photographs and processes structural details, internal tissues, and fluid flow in the body and shows them to the user.

A user such as a doctor may diagnose a health state and a disease of a patient by using the medical image output from the medical image processing apparatus.

A device for photographing an object by radiating a patient is typically a computed tomography (CT) device.

Computed tomography (CT) device of the medical image processing apparatus may provide a cross-sectional image of the object, and the internal structure of the object (for example, organs such as kidneys, lungs, etc.) do not overlap as compared to a general x-ray device. As an advantage, it is widely used for the precise diagnosis of the disease. Hereinafter, the medical image acquired by the computed tomography apparatus is called a CT image.

In acquiring a CT image, CT data of an object is performed by using a computed tomography apparatus to obtain raw data. The CT image is reconstructed using the obtained ru data. Here, the data may be a sinogram that is a projection data or a collection of projection data obtained by projecting radiation onto an object.

For example, in order to acquire a CT image, an image reconstruction operation must be performed using a sinogram obtained by CT imaging.

1 is a view for explaining the operation of CT imaging and reconstruction.

Specifically, FIG. 1A is a diagram for describing a CT imaging operation of a computed tomography apparatus that acquires data by moving at predetermined angular intervals. 1B is a diagram for describing a sinogram and a reconstructed CT image obtained by CT imaging.

The computed tomography apparatus generates an X-ray and irradiates the object to an X-ray, and detects the X-ray passing through the object by an X-ray detector (not shown). The X-ray detector generates ru data corresponding to the detected X-rays.

Specifically, referring to FIG. 1A, the X-ray generator 20 included in the CT apparatus irradiates an X-ray to the object 25. In the CT imaging, the X-ray generating unit 20 rotates around the object and acquires a plurality of

rub data

30, 31, and 32 corresponding to the rotated angle. In detail, the first ruler data 30 is obtained by detecting the X-ray applied to the object at the P1 position, and the second ruler data 31 is obtained by detecting the ray applied to the object at the P2 position. Then, the X-ray applied to the object is detected at the P3 position to obtain the third rudata P3. In this case, the data may be projection data.

Referring to FIG. 1B, as described in FIG. 1A, the plurality of

ruble data

31, 31, and 32 are obtained by moving the X-ray generator 20 at predetermined angular intervals. One sinogram 40 can be obtained.

In addition, the sinogram 40 is back-projected to restore the CT image 50.

If there is an error in the reconstructed CT image 50, the reconstructed CT image 50 is forward-projected to obtain a simulated sinogram, and the simulated sinogram and CT images are obtained. By compensating for the error between the sinograms 40, an error existing in the reconstructed CT image 50 may be corrected.

Since the CT system may provide a cross-sectional image of the object, an internal structure of the object (for example, an organ such as a kidney and a lung) may be overlapped with each other, compared to a general X-ray imaging apparatus.

For example, the CT system may provide a relatively accurate cross-sectional image of an object by acquiring and processing image data having a thickness of 2 mm or less tens or hundreds per second. Conventionally, there has been a problem that only the horizontal cross section of the object is expressed, but it is overcome by the appearance of various image reconstruction techniques as follows. Three-dimensional reconstruction imaging techniques include the following techniques.

SSD (Shade surface display): A technique for displaying only voxels having a certain HU value as an initial three-dimensional imaging technique.

Maximum intensity projection (MIP) / minimum intensity projection (MinIP): A 3D technique showing only those having the highest or lowest HU value among the voxels constituting the image.

VR (volume rendering): A technique that can adjust the color and transmittance of the voxels constituting the image for each region of interest.

Virtual endoscopy: A technique that allows endoscopic observation in three-dimensional images reconstructed by the VR or SSD technique.

MPR (multi planar reformation): An image technique for reconstructing different cross-sectional images. It is possible to reconstruct freedom in the direction desired by the user.

Editing: Various techniques for arranging surrounding voxels to make it easier to observe the point of interest in VR.

VOI (voxel of interest): A technique for representing only a selected area in VR.

Computed tomography (CT) system 100 according to an embodiment of the present invention can be described with reference to the accompanying FIG. CT system 100 according to an embodiment of the present invention may include various types of devices.

2 is a schematic diagram of a general CT system 100.

Referring to FIG. 2, the CT system 100 may include a gantry 102, a table 105, an X-ray generator 106, and an X-ray detector 108.

The gantry 102 may include an X-ray generator 106 and an X-ray detector 108.

The object 10 may be located on the table 105.

The table 105 may move in a predetermined direction (eg, at least one of up, down, left, and right) during the CT imaging process.

In addition, the table 105 may be tilted or rotated by a predetermined angle in a predetermined direction.

In addition, the gantry 102 may also be inclined by a predetermined angle in a predetermined direction.

However, in the conventional radiotherapy plan such as CT scan, although the amount of radiation is irradiated to the general tissues around the tumor was not considered, the change was not taken into account according to the breathing. The resulting radiation dose was not taken into account.

Therefore, the problem of destruction of general tissue that should not be irradiated.

Therefore, in order to solve such a problem, an object of the present invention is to provide a user with a method of finding an optimal irradiation time point by finding a time when radiation is irradiated to the general tissues in the patient's breath.

In general, CT imaging is performed on the assumption that the patient is fixed.

Unexpectedly, however, the patient is difficult to remain stationary at all times, and breathing occurs little by little, which eventually leads to blur in the CT image.

Therefore, the present invention basically uses a radiation method in consideration of the patient's breathing.

That is, it is possible to reconstruct the image using only the image when the specific position based on the breath of the patient, through which it is possible to establish the treatment plan of the patient.

For example, assuming that the time when the patient inhales the most breath is called end-inhalation, and the time when the patient exhales the most is called end-exhalation, the image is reconstructed using only the image of the end-inhalation. Or reconstruct the image using only the image at the end-exhalation.

In addition, in consideration of the patient's breathing it is also possible to apply a predetermined cycle in the reconstruction of the image.

That is, when the patient exhales and inhales for an average of X hours, it is possible to divide the image into N sections and to reconstruct the image by collecting only the images in the divided sections.

In the present invention, based on the configuration of reconstructing the image in each of the above-described specific location and divided the section to reconstruct the image for each section, find the point of time when the radiation is irradiated to the general tissue least in the patient's breathing and optimized irradiation time I would like to suggest a way to get it.

It is very important to properly consider the geometric relationship between the tumor and the organ at risk (OAR) in treatment, and for each phase the geometric relationship between the tumor and the OAR is respiratory. The doses of the OAR can be different for each phase because they can be different.

Therefore, in this specification, in order to find the optimal phase to obtain the dosimetric benefit in the radiation treatment considering the respiration, the geometric relationship between the OAR and the Planning Target Volume (PTV) in each phase (geometric relationship) We propose a method that can be reflected in the treatment plan by using a factor that can be expressed quantitatively.

Here, the planning target volume (PTV) is difficult to irradiate the radiation only to the target area, which may mean a plan for the minimum area capable of irradiating the radiation including the target.

Specifically, in the present invention, a result value (Cost Value) is obtained for each phase by using radiation sensitivity and geometric overlap of each tissue (organ, organ), and the irradiation is performed at the moment (or phase) of which the result value is the smallest. We propose a method, apparatus, and irradiation planning method.

In the present specification, OVH (Overlap Volume Histogram) indicates the degree of geometric overlap. That is, OVH means the degree of overlapping in the dorsal direction about the tumor (tumor).

Tolerance dose is the value obtained by subtracting the radiation sensitivity from TD50 (Tolerance Dose). In other words, the Tolerance dose can be seen as indicating 50% probability of necrosis when receiving radiation.

In addition, OAR (organ at risk) relates to normal tissue (radiation sensitivity) is different for each tissue (normal tissue), this sensitivity should be taken into account. Geometric factors (OVH) and biological factors ( TD) can be combined to determine at which phase the radiation should be good, which will be the point at which the influence of radiation on the normal tissue is minimal.

Patient data and image acquisition may require 4DCT image data of lung cancer patients with tumors located relatively near the esophagus, heart, and spinal cord.

In addition, for contour delineation and treatment planning, target volumes and normal tissue volumes (e.g., esophagus, heart, spinal cord) are determined by ICRU 62. Determined according to definitions, contouring can be performed in all phases for all patients.

In addition, in order to consistently perform treatment planning for each patient phase, the same beam energy, the number of beams, the beam directions, and the use of wedges may be equally applied.

In addition, peripheral OARs and particles such as esophagus, heart, and spinal cord can be traced using overlap volume histograms in the Lung cancer case for the planning phase optimization process for each patient. Three dimensional geometric relationships of a planning target volume (PTV) may be defined.

In addition, the biological index can be included in the process to properly reflect the biological characteristics of the relatively radiation-sensitive OAR in the score.

As a result, in the present invention, a result value (Cost Value) is obtained for each phase by using the radiation sensitivity and geometric overlap of each tissue (organ, organ), and the radiation is irradiated at the moment (or phase) having the smallest result value. We propose a method, device, and radiation planning method.

Such a result value (Cost Value) according to the present invention can be calculated by the following equation (1).

In Equation 1

Means OAR (organ at risk) for the organs around the targeting tumor.

In other words,

Means the degree of overlap of the tumor (tumor) and the surrounding organs (organ), the case of 1 may be the worst timing at the time of irradiation.

Here, r is a value that the user specifies the degree of overlap of the tumor (tumor) and the surrounding organs (organ), for example, the user can specify the r value to 1mm or 2mm.

That is, the r value becomes a constant determined by the user's specification.

therefore

It can be said that represents the degree of overlap of the tumor (tumor) and the surrounding organs (organ) above the constant r value determined by the user.

Also,

Is a value that indicates the degree of necrosis with a 50% chance of receiving radiation.

That is, it may mean a radiation acceptance standard allowed for each organ.

In addition, in Equation 1, i means a situation when each organ (organ).

For example, if i is 1 in the esophagus

or

In the case of i = 2

or

If i is 3, the spinal cord

or

May mean a value of.

As a result, the optimum effect may be generated by irradiating radiation at a point when the cost value is minimized.

Through this planning phase optimization method, better dosimetric effect can be confirmed in the proposed phase.

Figure 4 (a) shows the OVH of the heart (heart), (b) shows the OVH of the esophagus (Esophagus), (c) shows the OVH of the spinal cord (spinal cord).

Dose Volume Histogram (DVH) evaluation was performed between the phase (10%) when inhaling the most breath and the phase (50%) when inhaling the most breath using Equation 1, and FIG. In relation to this, the results of the Dose Volume Histogram (DVH) evaluation are shown between the phase of inhaling breath (10%) and the phase of inhaling breath (50%).

6 illustrates specific examples of optimized numerical values in each phase in connection with the present invention.

7 illustrates an example of a table in which mean doses of normal tissues are summarized in relation to the present invention.

8 shows an example of a table comparing maximum doses in a plurality of cases in connection with the present invention.

9 illustrates an example of a table comparing average and maximum doses in a plurality of cases in connection with the present invention.

Also, FIGS. 10A to 10J illustrate a comparison of the Dose Volume Histogram (DVH) between a low value and a high value for each case in relation to the present invention.

10A to 10J show the results of each case in the DVH (Dose Volume Histogram) between the phase of inhaling the breath (10%) and the phase of inhaling the breath (50%). .

FIG. 11A shows the Pearson Correlation coefficient between the organ and the dose that contributed most to score formation in Case 1 in the Esophagus.

FIG. 11B shows the Pearson Correlation coefficient between the organ and dose that contributed most to score formation in case of heart 2 in case of heart.

FIG. 11C shows the Pearson Correlation coefficient between the organ and dose most contributing to score formation in case 3 of heart.

FIG. 11D shows the Pearson Correlation coefficient between the organ and dose most contributing to score formation in Case 4 in the Esophagus.

FIG. 11E shows the Pearson Correlation coefficient between the organ and dose most contributing to score formation in case of heart 5 in heart.

FIG. 11F shows the Pearson Correlation coefficient between the organ and dose that contributed most to score formation in Case 6 in the Esophagus.

FIG. 11G illustrates a Pearson Correlation coefficient between the organ and the dose most contributing to the score formation in case of spinal cord (case 7).

FIG. 11H shows the Pearson Correlation coefficient between the organ and dose most contributing to score formation in case of heart 8 in case of heart.

FIG. 11I shows the Pearson Correlation coefficient between the organ and the dose that contributed most to the score formation in case of case 9 in the heart.

FIG. 11J illustrates a Pearson Correlation coefficient between the organ and the dose most contributing to score formation in case 10 of the spinal cord.

In addition, FIG. 12 illustrates a normal tissue complication probability (NTCP) according to the present invention.

In addition, FIG. 13 summarizes the summary contents of the normal tissue complications of FIG. 12 in a table.

Referring to FIG. 13, p value of Cord may also be significant when Wilcoxon code rank verification is performed.

14 can be seen to show the p-Values by paired t-test.

After all, the present invention defines a three-dimensional geometrical relationship between the surrounding tissue and the target volume using the biological characteristics and the overlap volume histogram of the normal tissues such as the esophagus and the spine where the tumor has not occurred, thereby radiating the general tissues in the patient's respiratory cycle. This is how to find the least investigated time.

That is, in the present invention, a result value (Cost Value) is obtained for each phase by using radiation sensitivity and geometric overlap of each tissue (organ, organ), and the radiation is irradiated at the moment (or phase) having the smallest result value. We propose a method, device, and radiation planning method.

The detailed description of the preferred embodiments of the invention disclosed as described above is provided to enable those skilled in the art to implement and practice the invention. Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art will understand that various modifications and changes can be made without departing from the scope of the present invention. For example, those skilled in the art can use each of the configurations described in the above-described embodiments in combination with each other. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

The invention can be embodied in other specific forms without departing from the spirit and essential features of the invention. Accordingly, the above detailed description should not be interpreted as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention. The present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. In addition, the claims may be combined to form an embodiment by combining claims that do not have an explicit citation relationship or may be incorporated as new claims by post-application correction.

Claims

In the method of irradiating the tumor of the patient (tumor),

A first step of determining the irradiation timing of the radiation using the radiation sensitivity of at least one first organ within a predetermined distance from the tumor of the plurality of organs and the degree of geometric overlap between the first organ and the tumor ; And

And irradiating the radiation to the tumor at the irradiation timing.

The radiation sensitivity and the degree of geometric overlap change according to the breathing of the patient.
The method of claim 1,

And the irradiation timing is a point in time at which the degree of geometric overlap with the radiation sensitivity is minimal.
The method of claim 1,

The irradiation timing is expressed by the following equation
Irradiation method characterized in that it is determined as the time when the minimum.

Equation

In the formula, i is an identification symbol for each of the first institutions, I is the total number of the first institutions,
Represents the degree of geometric overlap between the i organ and the tumor,
Represents the radiation sensitivity of the organ, i, at the time the patient breathes.
The method of claim 1,

The patient's breathing period in one cycle is divided by a constant N,

And a time point at which the degree of geometric overlap with the radiation sensitivity is minimum among the time points from 1 / N to N / N is determined as the irradiation timing.
The method of claim 1,

Said plurality of organs comprises the esophagus (Esophagus), heart (heart) and spinal cord (spinal cord).
The method of claim 1,

Before the first step,

Step 0.5 of establishing a plan for irradiating the tumor of the patient;

The 0.5 step,

Irradiation method is performed using at least one image of the tumor when the end-exhalation is the time when the patient exhales most, or end-inhalation when the patient inhales the most .
The method of claim 6,

And the radiation is irradiated at a time point when the degree of geometric overlap with the radiation sensitivity is minimum based on the plan established in step 0.5.
In the device for irradiating the tumor of the patient (tumor),

A control unit for determining an irradiation timing of the radiation using a radiation sensitivity of at least one first organ within a predetermined distance from the tumor and a degree of geometric overlap between the first organ and the tumor; And

And a radiation irradiation unit for irradiating the radiation to the tumor at the irradiation timing.

The radiation sensitivity and the geometric overlapping degree is changed according to the breathing of the patient.
The method of claim 8,

And the control unit determines the point of time at which the degree of geometric overlap with the radiation sensitivity is minimum as the irradiation timing.
The method of claim 8,

The control unit in the following equation
And a time point at which is minimum is determined as the irradiation timing.

Equation

In the formula, i is an identification symbol for each of the first institutions, I is the total number of the first institutions,
Represents the degree of geometric overlap between the i organ and the tumor,
Represents the radiation sensitivity of the organ, i, at the time the patient breathes.
The method of claim 8,

The control unit,

The patient's breathing period in one cycle is divided by a constant N,

And a time point at which the degree of geometric overlap with the radiation sensitivity is minimum among the time points from 1 / N to N / N is determined as the irradiation timing.
The method of claim 8,

Wherein said plurality of organs comprises an esophagus, a heart and a spinal cord.
The method of claim 8,

A plan for radiating the tumor of the patient through the control unit is established,

Wherein said plan is formulated using at least one image of said tumor at the time of end-exhalation at which said patient exhales most or at end-inhalation at which time said patient exhales most Irradiation device.
The method of claim 13,

And the control unit controls the radiation irradiator to irradiate the radiation at a time point when the degree of geometric overlap with the radiation sensitivity is minimum based on the established plan.