KR101721798B1 - Assessment method for changing time of radiation therapy planning - Google Patents

Abstract

The present invention relates to a radiotherapy plan assessment method. The method for assessing the point in time of a change in radiotherapy plan according to an embodiment of the present invention includes: a step of receiving images acquired by CT equipment, MRI equipment, and a 3D scanner before radiotherapy for a patient; a step of calculating a dose distribution based on the images acquired by the CT equipment and the MRI equipment and calculating volume data based on the image acquired by the 3D scanner; a step of receiving images acquired by the MRI equipment and the 3D scanner during the radiotherapy for the patient; a step of analyzing a change in the patients anatomical intra-body structure and a change in the patients external volume based on the images acquired by the MRI equipment and the 3D scanner during the radiotherapy for the patient; a step of recalculating the dose distribution based on the image acquired by the MRI equipment during the radiotherapy for the patient; and a step of determining whether a change in radiotherapy plan is required or not by comparing the recalculated dose distribution to the previous dose distribution.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a radiation treatment plan,

The present invention relates to a method for evaluating the timing of a change in a radiotherapy plan, and more particularly, to a method for evaluating a change in a radiotherapy plan in order to determine the necessity of changing a radiotherapy plan according to a change in a patient's body shape, ≪ / RTI >

Radiation therapy is one of the three major cancer treatment methods in addition to surgery and chemotherapy, and is a treatment method of killing cancer cells by irradiating tumor volume. Generally, radiotherapy is performed according to diagnosis using medical imaging equipment such as CT, MRI, and PET, and treatment is performed by using ionizing radiation generated from a medical linear accelerator according to a treatment plan and treating the tumor .

In the course of radiation therapy, when the radiation is delivered to the tumor volume, its surrounding normal organs can also be exposed to radiation. Thus, in establishing a radiation treatment plan, it is important to minimize the radiation transmission to the normal organs around the tumor volume while delivering enough radiation to kill the cancer cells in the tumor volume. In particular, it is important to minimize the radiation transmission to the surrounding tissues when establishing the radiotherapy plan for head and neck cancer because the tissues that are sensitive to the radiation therapy are concentrated in the head and neck.

On the other hand, as patients continue to receive radiation therapy, most patients experience weight loss and body shape changes. FIG. 1 is a CT image showing changes in body shape (external volume) before and after radiotherapy in head and neck cancer patients undergoing radiation therapy. As shown in FIG. 1, the surface of the patient changes from A to B while the treatment is being performed. can confirm. In addition, it can be deduced that the body weight changes according to the external volume change.

FIG. 2 is a CT image showing the change in the anatomical structure of the patient before and after radiation therapy for head and neck cancer in the same manner as radiation therapy. Referring to FIG. 2, not only the volume change of the patient but also the anatomical structure, Size, location, and so on. In general, the internal structure may change in the direction of decreasing the size of the tumor while radiotherapy is being performed.

Depending on the volume and anatomical structure of these patients, the target dose of the initial radiation therapy plan can not be delivered and the treatment effect can be significantly reduced, and the exposure to the normal organs may be increased to cause side effects .

Therefore, in order to enhance the effectiveness of radiation therapy and improve the stability, it is necessary to change the treatment plan according to the body shape and weight change of the individual patient. Thus, it is necessary to determine whether the change of the radiation treatment plan is necessary, .

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art and it is an object of the present invention to provide a personalized medical service by determining the necessity of changing the radiation treatment plan in consideration of the state change of the patient, The purpose of the method is to provide.

The present invention has another object in minimizing unnecessary radiation exposure in evaluating a radiation treatment plan.

It is another object of the present invention to reduce the increase in medical costs while performing personalized radiation therapy.

The method of evaluating the change of the radiotherapy plan according to an embodiment of the present invention includes receiving an image acquired from a CT apparatus, an MRI apparatus and a 3D scanner before a radiation treatment of a patient, acquiring an image acquired from the CT apparatus, Calculating dose distribution based on one image, calculating volumetric data based on the image acquired from the 3D scanner, receiving image acquired from the MRI apparatus and the 3D scanner during the radiation treatment of the patient, Based on the images acquired from the MRI equipment and the images acquired from the 3D scanner, analysis of the patient's internal anatomical structure changes and external volume changes, and the dose distribution based on the images acquired from the MRI equipment during the patient's radiation treatment The calculation step and the recomputed dose distribution are compared with the existing dose distribution to determine whether a modification of the radiation treatment plan is required And a step of.

According to an embodiment of the present invention, in the step of calculating the dose distribution based on the image acquired by the CT apparatus and the image acquired by the MRI apparatus, Density information can be given and the dose distribution can be calculated using the electron density value assigned to each pixel of the image acquired by the MRI apparatus.

According to an embodiment of the present invention, the step of recalculating the dose distribution based on the image acquired by the MRI apparatus during the radiation treatment of the patient may be periodically performed.

According to one embodiment of the present invention, in the step of determining whether or not a change in the radiation treatment plan is required, in the case where the dose delivered to the tumor differs by more than a predetermined value from the existing dose distribution and the recalculated dose distribution, It is possible to judge that a change of Alternatively, it can be judged that it is necessary to change the radiation treatment plan when the dose delivered to the normal organ from the recalculated dose distribution exceeds the allowable value.

According to one embodiment of the present invention, it is possible to accurately calculate the dose distribution in the patient's body during the radiation treatment, evaluate the radiation treatment plan, and change the radiation treatment plan as needed in a timely manner, thereby establishing a patient-tailored radiation treatment plan.

According to one embodiment of the present invention, when evaluating a radiation treatment plan, unnecessary radiation exposure can be prevented from occurring in the patient.

In addition, according to the embodiment of the present invention, it is possible to reduce the cost burden on the patient even in evaluating the radiation treatment plan from time to time.

FIG. 1 is a CT image showing changes in body shape before and after radiotherapy in head and neck cancer patients receiving radiation therapy.
FIG. 2 is a CT image showing changes in anatomical structure and dose distribution of a patient with head and neck cancer after radiation therapy before and during radiotherapy.
3 is a conceptual diagram illustrating a system for evaluating a radiation treatment plan according to an embodiment of the present invention.
4 is a flowchart sequentially illustrating a process of evaluating a radiation treatment plan according to an embodiment of the present invention.
5 is a test photograph for analyzing a volume change of a patient according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In order to clearly illustrate the present invention, parts that are not related to the present invention are omitted, and the same components are denoted by the same reference numerals throughout the specification. The sizes and the like of the respective components shown in the drawings are arbitrarily shown for convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings.

That is, the specific shapes, structures, and characteristics described in the specification can be implemented by changing from one embodiment to another embodiment without departing from the spirit and scope of the present invention. It is to be understood that changes may be made without departing from the scope. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of the present invention should be construed as encompassing the scope of the appended claims and all equivalents thereof.

As described above, the body shape of the patient, that is, the external volume and the anatomical structure, may change due to the progress of the radiation therapy, thereby failing to transmit the target radiation dose to the tumor volume, Increased exposure may cause side effects. In such cases, it is inevitable to change the radiation treatment plan initially decided.

In order to evaluate the radiation treatment plan and determine the necessity of the change, it is necessary to determine whether the radiation dose is exactly as required for the tumor volume and whether the exposure to the surrounding normal organ is excessive You need to check.

In general, a method of acquiring a patient's body image through a CBCT (cone beam computed tomography) apparatus or a CT simulator (computed tomography simulator), and calculating the dose of radiation therapy based on the acquired image is known. Therefore, it is possible to consider the method of calculating the radiation dose and determining whether the radiation treatment plan should be changed by acquiring the CT image of the patient every day during the course of the radiation therapy using such equipment.

However, CBCT equipment is expensive and often does not have such equipment in medical institutions that conduct actual radiation therapy. In addition, even when a CT simulator is used, there is a problem in that unnecessary exposure to radiation is increased as a patient conducts a CT scan every day, and the medical cost is still increased.

In consideration of this point, the present invention is characterized in that it is possible to confirm the state change of the patient according to the radiation therapy without evaluating the CT image every day, evaluate the treatment plan accordingly, and modify the treatment plan in a timely manner.

FIG. 2 is a conceptual diagram illustrating a system for evaluating a radiation treatment plan according to an embodiment of the present invention. Referring to FIG. 2, the radiation treatment plan evaluation system 100 according to the present embodiment includes: A data receiving unit 110, a data processing unit 120 for analyzing and processing the received data, a display unit 130 for visually confirming the received data and processed data, and a control unit 140.

The data receiving unit 110 of the radiation treatment plan evaluation system 100 receives the images of the patients acquired from the CT apparatus, the MRI apparatus, and the 3D scanner. In this example, in order to minimize unnecessary radiation exposure during radiotherapy, only the acquired images were taken before the start of radiation therapy, and MRI and 3D scan images were taken before and after radiation therapy Periodically during radiation therapy.

The data processing unit 120 analyzes a change in a body shape of a patient, that is, a change in an external volume and an internal anatomy of the body based on the image received by the data receiving unit 110, and calculates a dose distribution based on the image. Also, the data processing unit 120 can evaluate the appropriateness of the patient's currently applied radiation treatment plan based on the calculated dose distribution. The calculation of the dose distribution and the evaluation method of the radiation treatment plan will be described in detail later.

The display unit 130 displays the image received from the data receiving unit 110 or displays the result of analyzing and processing the data in the data processing unit 120 to the user.

The control unit 140 controls data and signal flow between each component of the radiotherapy plan evaluation system 100 as well as data and signal flow between the radiotherapy plan evaluation system 100 and the external device, And to perform predetermined functions.

The radiation treatment plan evaluation system 100 described above is illustrative and may further include other components necessary for evaluating the following radiation treatment plan.

FIG. 3 is a flowchart sequentially illustrating a process of evaluating a radiation treatment plan according to an embodiment of the present invention. Hereinafter, a method of evaluating a radiation treatment plan according to the present embodiment will be described in detail with reference to FIG.

Before the radiation therapy is started, the images of the patient obtained from the CT apparatus, the MRI apparatus, and the 3D scanner are received (S110). CT images, MRI images, and 3D scan images received from these devices are used to calculate the patient's dose distribution and analyze the patient's anatomical structural changes and external volume changes as described below.

Next, the in-vivo dose distribution is calculated based on the received CT image and MRI image (S120).

Basically, dose distribution calculations can be made to establish the initial radiotherapy plan with only pre-treatment CT images. However, it is necessary to calculate the dose distribution periodically to evaluate whether the current treatment plan is appropriate during the radiation therapy of the patient, and if the CT image is newly acquired every time, unnecessary radiation exposure is increased to the patient. Therefore, in this embodiment, the dose distribution is calculated based on the MRI image to solve this problem, and the CT image is utilized only for the one acquired before the radiation treatment.

To this end, the present embodiment uses a deformable image registration technique. Specifically, HU (Hounsfield Unit) values are designated for each voxel of an MRI image through a variable image matching technique, electron density information of a CT image is given, and the electron density assigned to each pixel of the MRI image The dose is used to calculate the dose distribution in the patient's body.

As described above, in the present embodiment, the dose distribution can be calculated through the MRI image and the 3D scan image, and the treatment plan can be evaluated without using the CT image with the risk of additional radiation exposure, thereby reducing unnecessary radiation exposure to the patient .

While calculating the dose based on the CT image and the MRI image, the external volume of the patient before the radiation treatment is analyzed based on the received 3D scan image (S120).

In this embodiment, since the volume information is analyzed and processed through the image received from the 3D scanner, the 3D scan image can be used irrespective of the color change depending on the brightness of the surroundings using the 3D scanner.

Meanwhile, in the present embodiment, since it is sufficient to scan a patient's body using a 3D scanner, a 3D scanned image can be acquired using a small-sized scanner that can be carried. In this case, the total scan time is less than 10 minutes, and the 3D scan image can be obtained quickly.

In the case of acquiring a 3D scan image using a portable small scanner, it is possible to smoothly scan and display to the user whether the external information of the patient is sufficiently scanned. For example, if the distance between the scanner and the patient, the moving speed of the scanner, and the like are sufficient, the green light is displayed when the patient's appearance information can be sufficiently obtained, and the yellow light is displayed if the patient's appearance information is not sufficient. Lt; / RTI > In the scanning process, the patient may have slight tremors or movements. Such minute movements may be compensated through data processing after the scan.

Next, the MRI image and the 3D scan image periodically acquired during the radiation treatment based on the treatment plan established according to the dose distribution calculated based on the CT image and the MRI image before the treatment are received (S130).

MRI images and 3D scanned images can be obtained before each radiotherapy of the patient, and the period of receiving them can be, for example, three times a week, but this may vary depending on the specific treatment plan.

Upon receiving the MRI image and the 3D scan image during the radiation treatment, the anatomical structure change and the external volume change of the patient are analyzed based on these images (S140).

It is possible to analyze the external volume change due to the progress of the radiation treatment through the 3D scan image. FIG. 5 is a photograph showing a 3D scan image acquired through a 3D scanner after attaching a virtual tumor to a human body model, according to an exemplary embodiment of the present invention. As shown in FIG. 5, according to the volume calculation using the 3D scan image, each calculated volume has a difference of less than 0.1% from the actual volume, and it is confirmed that the 3D scan image accurately reflects the actual volume, It is confirmed that the volume change of the patient can be analyzed accurately.

In this way, the external volume change of the patient can be analyzed through the 3D scan image, and the external volume and the anatomical structure information can be accurately analyzed by comparing with the MRI image. For example, 3D scan images and MRI images can be changed finely when acquiring images before acquisition of each radiological treatment. However, MRI images based on external volume information obtained from 3D scan images And the volume and the volume of the external surface in the MRI image are combined. Based on this, the anatomical structure information in the MRI image, that is, the position and size of the tumor and surrounding normal organ, It can be analyzed accurately.

Meanwhile, the 3D scan image and the MRI image data of the patient can be accumulated and the tendency can be grasped and the correlation between the external volume change and the anatomical structure change can be analyzed. This can be used to calculate and predict the radiation dose delivered to the patient in the radiation therapy of the patient.

Then, the dose distribution is recalculated based on the 3D scan image MRI image (S150). Then, the newly calculated dose distribution is compared with the existing dose distribution to evaluate the treatment plan and judge whether the treatment plan is to be changed (S160).

As described above, the external volume and anatomical structure of the patient may be changed as the radiation therapy proceeds. Therefore, if radiation therapy continues on the basis of a treatment plan, the amount of radiation irradiated to the patient, the amount of radiation delivered to the tumor, and the amount of radiation delivered to the surrounding normal organ may vary.

Therefore, in this embodiment, the change in the external volume and the anatomical structure are obtained through the 3D scan image and the MRI image acquired during the radiation treatment, and then the dose distribution reflecting the current treatment plan is recalculated based on the MRI image, Evaluate whether changes in the current treatment plan are necessary.

If the dose distribution is recalculated by reflecting the current treatment plan in newly received MRI images, the amount of radiation irradiated to the patient, the amount of radiation delivered to the tumor, and the amount of radiation delivered to the surrounding normal organ can be grasped. The current treatment plan is assessed by determining whether or not there is any difference in dose delivered to the tumor or surrounding normal organ compared with the time of establishing the initial treatment plan.

In this embodiment, it can be judged that it is necessary to change the treatment plan when the dose delivered to the tumor differs by more than a predetermined value. For example, if the dose delivered to the tumor differs by more than 5% compared to the dose distribution in the initial treatment plan, it can be judged that the treatment plan needs to be changed. In addition, even if the dose delivered to the normal organ exceeds the allowable value, it can be judged that the treatment plan needs to be changed.

As described above, according to this embodiment, the radiation treatment plan can be periodically evaluated and changed in a timely manner, so that the personalized radiation therapy can be performed, and the accurate radiation dose is delivered to the tumor and the radiation dose of the normal organ unnecessarily transmitted is reduced The stability of the radiation therapy can be improved.

According to the present embodiment, unnecessary radiation exposure during the radiation therapy of the patient can be suppressed by recalculating the patient's dose distribution based on the MRI image without acquiring additional CT images, The occurrence of secondary cancer can be minimized. In addition, it does not require costly CT equipment, which can improve patient access to medical services by reducing costs.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limited to the embodiments set forth herein. It can be understood that It is to be understood, therefore, that the embodiments described above are illustrative in all aspects and not restrictive.

100: Radiotherapy planning assessment system
110: Data receiving unit
120:
130:
140:

Claims (5)

Receiving an image acquired from a CT apparatus, an MRI apparatus, and a 3D scanner before the radiation therapy of the patient,
Calculating a dose distribution based on the image acquired from the CT apparatus and the image acquired from the MRI apparatus, calculating the volume data based on the image acquired from the 3D scanner,
Receiving an image acquired from an MRI apparatus and a 3D scanner during a radiation therapy of a patient,
Analyzing the patient's internal anatomical structure change and external volume change based on the image acquired from the MRI apparatus and the image acquired from the 3D scanner during the radiation therapy of the patient,
Recalculating the dose distribution based on the image acquired from the MRI apparatus during the radiation therapy of the patient, and
Comparing the recalculated dose distribution with the existing dose distribution to determine whether it is necessary to change the radiation treatment plan
Of the radiation therapy plan. The method according to claim 1,
In the step of calculating the dose distribution based on the image acquired by the CT apparatus and the image acquired by the MRI apparatus, the electron density information of the image acquired by the CT apparatus is given to the pixels of the image acquired by the MRI apparatus, And calculating a dose distribution using an electron density value assigned to each pixel of the obtained image. The method according to claim 1,
Wherein the step of recalculating the dose distribution based on the images acquired by the MRI apparatus during the radiation therapy of the patient is performed periodically. The method according to claim 1,
It is determined that it is necessary to change the radiation treatment plan when the dose delivered to the tumor differs by more than a predetermined value in the existing dose distribution and the recalculated dose distribution in the step of determining whether the change of the radiation treatment plan is necessary or not Of the radiation therapy plan. The method according to claim 1,
Characterized in that it is determined that a change in the radiation treatment plan is necessary when the dose transferred to the normal organ from the recalculated dose distribution exceeds the allowable value, How to evaluate the point of change of the plan.

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