1. An ion beam three-dimensional dose distribution detection apparatus, comprising:

the device comprises a luminescent material, a position moving device, an optical image acquisition unit and an image processing unit;

the position moving device is fixedly provided with the luminescent material and is used for sequentially translating the luminescent material in the direction vertical to the beam current according to a preset measuring position track; the ion beam to be detected enters along the direction vertical to the thickness of the luminescent material and interacts with the luminescent material to generate fluorescence;

the optical image acquisition unit is used for measuring the generated fluorescence in real time and sending a cross section image of the luminescent material containing the two-dimensional dose distribution of the ion beam current to be detected, which is obtained by measurement, to the image processing unit;

the image processing unit is used for obtaining the three-dimensional dose distribution of the ion beam current to be detected according to the cross section image of the luminescent material obtained through measurement and a preset measurement position track.

2. The apparatus of claim 1, wherein the lateral length of the luminescent material is greater than the size of the irradiation field of the ion beam current to be detected, the longitudinal length of the luminescent material is greater than the depth of the irradiation field of the ion beam current to be detected, and the thickness of the luminescent material is not less than the minimum thickness of the optical image acquisition unit, which can obtain the fluorescence intensity generated by the interaction between the ion beam current to be detected and the luminescent material.

3. The apparatus of claim 1, wherein the luminescent material is a scintillator or a crystal luminescent material.

4. The apparatus of claim 1, wherein the optical image acquisition unit is a video camera or a still camera.

5. The apparatus of claim 1, wherein the predetermined measurement position trajectory is formed by a series of phosphor measurement positions, and the distance between the phosphor measurement positions is set according to actual requirements.

6. The apparatus of claim 1, wherein the optical image acquisition unit, the position shifting device and the luminescent material are disposed in a closed housing; the optical image acquisition unit is arranged on the inner wall of the closed shell and is arranged in a direction capable of detecting all fluorescence; the moving device is arranged on a sliding track of the inner wall of the closed shell.

7. A method for detecting a three-dimensional dose distribution of an ion beam using the apparatus of any one of claims 1 to 6, comprising the steps of:

1) before beam irradiation is started, the luminous material is placed at a preset initial position through a position moving device, and an optical image acquisition unit and an image processing unit are started to ensure that the image processing unit can normally acquire images from the optical image acquisition unit;

2) after the beam starts to irradiate, translating the luminescent material by a position moving device according to a preset measuring position track, and acquiring a two-dimensional section structure diagram of the ion beam to be detected at each measuring position;

3) and performing three-dimensional reconstruction on the obtained two-dimensional profile structure chart of the ion beam current to be detected at each measuring position to obtain three-dimensional dose distribution of the ion beam current to be detected.

8. The method of claim 7, wherein the method comprises: in the step 2), the method for translating the luminescent material through the position moving device according to the preset measuring position track and acquiring the two-dimensional profile structure diagram of the ion beam current to be detected at each measuring position comprises the following steps:

2.1) moving the luminescent material to a first measuring position, and measuring the light intensity distribution at the first measuring position through an optical image acquisition unit to obtain a two-dimensional profile structure chart of the ion beam current to be detected in the depth direction at the first measuring position;

2.2) after the first measuring position is measured, the luminescent material is moved to a second measuring position through the position moving device, and the light intensity distribution at the second measuring position is measured to obtain a two-dimensional profile structure chart of the ion beam current to be detected in the depth direction at the second measuring position;

2.3) repeating the step 2.2), and so on, measuring the two-dimensional section structure diagram of the ion beam current to be detected in the depth direction of each measuring position.

9. The method of claim 8, wherein the method comprises: in the step 3), the method for performing three-dimensional reconstruction on the obtained two-dimensional profile structure diagram of the ion beam current to be detected at each measurement position to obtain three-dimensional dose distribution of the ion beam current to be detected comprises the following steps:

3.1) converting the obtained two-dimensional profile structure chart of the ion beam to be detected at each measuring position into beam two-dimensional dose distribution according to the relative relation between the light intensity and the dose;

and 3.2) generating the three-dimensional dose distribution of the ion beam current to be detected by using a three-dimensional image reconstruction method according to the measurement interval of each measurement position in the preset measurement position track.

Background

In ion beam radiotherapy: firstly, obtaining three-dimensional anatomical structure information of a patient through CT scanning; secondly, delineating the tumor target area and surrounding organs at risk in the CT image; thirdly, designing a reasonable irradiation field direction and optimizing the irradiation parameters to obtain three-dimensional dose distribution of the target area and the organs at risk; and finally, transmitting the irradiation parameters verified by the plan to an accelerator control system to realize accurate irradiation on the tumor target area. It can be seen that the implementation of radiotherapy involves a plurality of links, and the final treatment effect is affected when a problem occurs in each link, so that a set of reliable quality assurance measures is required to ensure that each link of radiotherapy can be accurately executed. From the angle of beam current, a treatment planning system needs the cross section distribution of the beam spot in the transverse direction and the longitudinal direction as basic machine parameters for establishing a beam current model and calculating the dose. Daily beam quality assurance requires measuring the transverse and longitudinal profile distribution of the beam spot to ensure that it is consistent with the data stored in the treatment planning system. Before patient treatment begins, the patient treatment plan needs to be validated to ensure that the measured dose distribution is consistent with the dose distribution calculated at the time of plan design. Therefore, the rapid and accurate beam dose distribution measurement is a precondition for realizing accurate radiotherapy. Meanwhile, in other fields of ion beam measurement, such as ion accelerator beam diagnosis, spatial ion beam radiation measurement and the like, it is also important to quickly and accurately obtain the three-dimensional profile structure and dose distribution of the beam.

Currently, the measurement methods of the ion beam lateral dose distribution include: the ionization chamber is matched with a three-dimensional water tank for measurement, film measurement, two-dimensional ionization chamber matrix measurement and scintillator detector measurement. The measurement of the longitudinal dose distribution of the ion beam is as follows: the ionization chamber is matched with a three-dimensional water tank for measurement, film measurement, a depth dose distribution detector and the like. The ionization chamber is a parallel plate ionization chamber or a finger-shaped ionization chamber with small sensitive volume, and the position of the ionization chamber is accurately controlled in the three-dimensional water tank, so that the dosage measurement at different spatial positions is realized. For example, a lateral dose distribution can be obtained by moving a plurality of measurement positions in the vertical beam direction; the longitudinal dose distribution can be obtained by moving a plurality of measurement positions along the beam direction. The method has high accuracy and the defects that only one point of dosage can be measured at a time, and the time for obtaining complete dosage distribution is long and the efficiency is low. The film measuring method is widely applied, can directly measure and obtain the dose distribution in the transverse direction and the longitudinal direction, and has the defects of high cost due to incapability of recycling, position error due to manual position arrangement and long time spent on post-processing. The two-dimensional ionization chamber matrix is generally applied to measurement of transverse dose distribution, and has the advantages of convenient positioning and high measurement speed, and has the disadvantages of low resolution and incapability of measuring longitudinal dose distribution. The depth dose distribution detector is used for measuring longitudinal dose distribution, has the advantages of quickly obtaining a complete longitudinal dose distribution curve and has the disadvantages of measuring integral dose and being incapable of reflecting the dose distribution curve of beam current in the transverse direction. The scintillator detector utilizes the characteristic that the beam current and the fluorescent target mutually act to emit light, detects light signals through the camera and converts the light signals into dose distribution, thereby realizing rapid dose distribution detection. Therefore, the current dose distribution detection method cannot achieve the ideal state in terms of detection accuracy, efficiency, and convenience at the same time.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide an ion beam three-dimensional dose distribution detection apparatus and method, which achieve accurate, fast and convenient ion beam three-dimensional dose distribution detection, and provide powerful means for obtaining ion radiotherapy basic data, detecting daily beam state, and rapidly verifying patient treatment plan.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect of the present invention, there is provided an ion beam three-dimensional dose distribution detection apparatus, comprising: the device comprises a luminescent material, a position moving device, an optical image acquisition unit and an image processing unit; the position moving device is fixedly provided with the luminescent material and is used for sequentially translating the luminescent material in the direction vertical to the beam current according to a preset measuring position track; the ion beam to be detected enters along the direction vertical to the thickness of the luminescent material and interacts with the luminescent material to generate fluorescence; the optical image acquisition unit is used for measuring the generated fluorescence in real time and sending a cross section image of the luminescent material containing the two-dimensional dose distribution of the ion beam current to be detected, which is obtained by measurement, to the image processing unit; the image processing unit is used for obtaining the three-dimensional dose distribution of the ion beam current to be detected according to the cross section image of the luminescent material obtained through measurement and a preset measurement position track.

Further, the luminescent material is a rectangular thin sheet, the transverse length of the luminescent material is larger than the size of the irradiation field of the ion beam current to be detected, the longitudinal length of the luminescent material is larger than the depth of the irradiation field of the ion beam current to be detected, and the thickness of the luminescent material is not smaller than the minimum thickness which can be obtained by the optical image acquisition unit and is generated by the interaction between the ion beam current to be detected and the luminescent material.

Further, the luminescent material is a scintillator or a crystal luminescent material.

Further, the optical image capturing unit employs, but is not limited to, a video camera or a still camera.

Further, the preset measuring position trajectory is formed by a series of luminescent material measuring positions.

Further, the optical image acquisition unit, the position moving device and the luminescent material are arranged in the closed shell; the optical image acquisition unit is arranged on the inner wall of the closed shell and is arranged in a direction capable of detecting all fluorescence; the moving device is arranged on a sliding track of the inner wall of the closed shell.

In a second aspect of the present invention, there is provided a method for detecting a three-dimensional dose distribution of an ion beam, comprising the steps of:

1) before beam irradiation is started, the luminous material is placed at a preset initial position through a position moving device, and an optical image acquisition unit and an image processing unit are started to ensure that the image processing unit can normally acquire images from the optical image acquisition unit;

2) after the beam starts to irradiate, translating the luminescent material by a position moving device according to a preset measuring position track, and acquiring a two-dimensional section structure diagram of the ion beam to be detected at each measuring position;

3) and performing three-dimensional reconstruction on the obtained two-dimensional profile structure chart of the ion beam current to be detected at each measuring position to obtain three-dimensional dose distribution of the ion beam current to be detected.

Further, in the step 2), the method for translating the luminescent material by the position moving device according to the preset measuring position track and obtaining the two-dimensional profile structure diagram of the ion beam current to be detected at each measuring position comprises the following steps:

2.1) moving the luminescent material to a first measuring position, and measuring the light intensity distribution at the first measuring position through an optical image acquisition unit to obtain a two-dimensional profile structure chart of the ion beam current to be detected in the depth direction at the first measuring position;

2.2) after the first measuring position is measured, the luminescent material is moved to a second measuring position through the position moving device, and the light intensity distribution at the second measuring position is measured to obtain a two-dimensional profile structure chart of the ion beam current to be detected in the depth direction at the second measuring position;

2.3) repeating the step 2.2), and so on, measuring the two-dimensional section structure diagram of the ion beam current to be detected in the depth direction of each measuring position.

Further, in the step 3), the method for performing three-dimensional reconstruction on the obtained two-dimensional profile structure diagram of the ion beam current to be detected at each measurement position to obtain three-dimensional dose distribution of the ion beam current to be detected includes the following steps:

3.1) converting the obtained two-dimensional profile structure chart of the ion beam to be detected at each measuring position into beam two-dimensional dose distribution according to the relative relation between the light intensity and the dose;

and 3.2) generating the three-dimensional dose distribution of the ion beam current to be detected by using a three-dimensional image reconstruction method according to the measurement interval of each measurement position in the preset measurement position track.

Due to the adoption of the technical scheme, the invention has the following advantages: (1) the rapid measurement of the two-dimensional structure of the beam spot and the reconstruction of the three-dimensional structure can be realized, and convenience is provided for the acquisition of basic machine parameters of a treatment planning system; (2) the beam state detection can be realized quickly, and powerful means is provided for detecting the accelerator beam every morning; (3) through two-dimensional distribution measurement and three-dimensional dose reconstruction, the irradiation dose of each position of the irradiation field can be obtained, so that the rapid and accurate verification of the treatment plan of the patient is realized; (4) the device is light and convenient to install, and the efficiency and the precision of beam detection are improved; (5) the application range is not limited to the field of ion beam radiotherapy, and can be widely applied to other fields of ion beam detection.

Drawings

FIG. 1 is a schematic structural diagram of a dose distribution detecting device provided in an embodiment of the present invention;

FIG. 2(a) is a two-dimensional structure of a measured beam spot;

FIG. 2(b) is a three-dimensional dose distribution of the beam spot obtained after three-dimensional reconstruction;

FIG. 3(a) is a two-dimensional cross-sectional view of a field measured under a regular irradiation field;

FIG. 3(b) is the three-dimensional dose distribution in the regular irradiation field obtained after three-dimensional reconstruction;

FIG. 4(a) is a two-dimensional cross-sectional structure of an irradiation field in the depth direction measured under the patient treatment plan verification condition;

FIG. 4(b) is a three-dimensional measured dose distribution of a patient treatment plan resulting from a three-dimensional reconstruction;

the respective symbols in the figure are as follows:

1. luminescent material measurement position 1; 2. a luminescent material measurement position n-3; 3. a luminescent material measurement position n-2; 4. a luminescent material measurement position n-1; 5. a luminescent material measurement position n; 6. a position moving device; 7. a luminescent material measurement position n + 1; 8. a luminescent material measurement position n + 2; 9. a luminescent material measurement position n + 3; 10. measuring the end point position of the luminescent material; 11. the beam incident direction; 12. an optical image acquisition unit; 13. a closed housing; 14. measuring the resulting two-dimensional dose distribution; 15. cross section of luminescent material; 16. an image processing unit.

Detailed Description

The invention is described in detail below with reference to the figures and examples.

The ion beam three-dimensional dose distribution detection device provided by the invention can accurately measure the two-dimensional profile structure information of the beam in the longitudinal direction, and the three-dimensional dose distribution of the whole irradiation field is obtained by a three-dimensional reconstruction method through measuring the two-dimensional depth dose distribution of the beam at different positions in the transverse direction, so that the measurement of an accurate three-dimensional beam spot structure and the three-dimensional rapid verification of a patient treatment plan can be realized, the purpose of accurate radiotherapy is achieved, and the guarantee is provided for clinical treatment. Meanwhile, the invention can also be applied to other fields of ion beam detection, is used for detecting the cross section structure of the beam in the transverse direction and the longitudinal direction and measuring the three-dimensional dose distribution, and improves the detection efficiency and the convenience.

As shown in fig. 1, the present invention provides an ion beam three-dimensional dose distribution detection apparatus, which includes: luminescent material, position shifting means 6, an optical image acquisition unit 12 and an image processing unit 16. The position moving device 6 is provided with a luminescent material, and the luminescent material is used for successively translating the luminescent material in the direction vertical to the beam current according to a preset measuring position track so as to achieve the purpose of measuring two-dimensional dose distribution of different sections in the depth direction of the beam current; the ion beam to be detected enters along a direction perpendicular to the thickness of the luminescent material (shown as a beam entering direction 11 in fig. 1), and the ion beam to be detected interacts with the luminescent material to generate fluorescence; the optical image acquisition unit 12 is used for measuring the generated fluorescence in real time and sending the obtained image of the cross section 15 of the luminescent material containing the two-dimensional dose distribution 14 to the image processing unit 16; the image processing unit 16 is configured to obtain a three-dimensional dose distribution of the ion beam current to be detected according to the two-dimensional dose distribution 14 obtained through measurement and a preset measurement position trajectory.

Further, the luminescent material includes, but is not limited to, a scintillator, a crystal luminescent material, and the like.

Further, the optical image pickup unit 12 includes, but is not limited to, a video camera, a still camera, and the like.

Further, the length and width of the luminescent material need to meet the requirements of actual measurement, such as the transverse direction (i.e. perpendicular to the beam direction) needs to be larger than the size of the irradiation field, the longitudinal direction (i.e. along the beam direction) needs to be larger than the depth of the irradiation field, the thickness of the luminescent material is fixed, and the requirement needs to be larger than the minimum thickness of the fluorescence intensity generated by the interaction between the ion beam to be detected and the luminescent material, which can be acquired by the optical image acquisition unit.

Further, the preset measuring position track is formed by a plurality of luminous material measuring positions 1-5 and 7-10. The distance between the measuring positions of the luminescent materials is set according to actual needs.

Further, the optical image acquisition unit 12, the mobile device 6 and the luminescent material are arranged in the closed shell 13, and the optical image acquisition unit 12 is arranged on the inner wall of the closed shell 13 and is installed at a position capable of detecting all fluorescence; the moving device 6 is arranged on a track on the inner wall of the closed shell and used for sequentially translating the luminescent material in the direction vertical to the beam current according to a preset measuring position track. The closed shell can avoid the influence of external illumination on the fluorescent signal.

Based on the ion beam three-dimensional dose distribution detection device, the invention also provides an ion beam three-dimensional dose distribution detection method, which comprises the following steps:

1) before beam irradiation begins, the luminous material is placed at a preset initial position through the mobile device, the optical image acquisition unit and the image processing unit are started, and the image processing unit is ensured to be capable of normally acquiring images from the optical image acquisition unit. The preset initial position is set according to measurement requirements, for example, if the irradiation field range of the ion beam current to be detected is large, the preset initial position is far from the central position, and vice versa.

2) After the beam starts to irradiate, the luminescent material is translated through the position moving device according to the preset measuring position track, and a two-dimensional section structure diagram of the ion beam to be detected at each measuring position is obtained.

Specifically, the method comprises the following steps:

2.1) moving the luminescent material to a first measuring position according to the measurement requirement, and measuring the light intensity distribution at the first measuring position through an optical image acquisition unit to obtain a two-dimensional profile structure diagram of the ion beam current to be detected in the depth direction at the first measuring position.

2.2) after the first measuring position is measured, the luminescent material is moved to a second measuring position through the moving device, and the light intensity distribution at the second measuring position is measured to obtain a two-dimensional profile structure chart of the ion beam current to be detected at the second measuring position in the depth direction.

2.3) repeating the step 2.2), and so on, measuring the two-dimensional section structure diagram of the ion beam current to be detected in the depth direction of each measuring position.

3) And performing three-dimensional reconstruction on the obtained two-dimensional profile structure chart of the ion beam current to be detected at each measuring position to obtain three-dimensional dose distribution of the ion beam current to be detected.

Specifically, the method comprises the following steps:

and 3.1) converting the obtained two-dimensional profile structure chart of the beam at each measuring position into beam two-dimensional dose distribution according to the relative relation between the light intensity and the dose.

And 3.2) generating the three-dimensional dose distribution of the ion beam current by using a three-dimensional image reconstruction method according to the measurement interval of the two-dimensional image.

Example 1

FIG. 2(a) shows a two-dimensional cross-sectional structure of a beam spot at a position in the horizontal direction in the depth direction, which is obtained by the dose distribution detecting device of the present invention. It can be seen that the detection device of the present invention can accurately obtain the structural information of the irradiation field in the depth direction, so that some basic information of the beam spot, such as the size distribution of the beam spot at different positions in the depth direction, can be obtained. Fig. 2(b) is a three-dimensional dose distribution of the beam spot obtained after three-dimensional reconstruction. Fig. 3(a) shows a two-dimensional cross-sectional structure of a certain slice in the depth direction in the regular irradiation field. The device can be used for quickly obtaining the two-dimensional dose distribution of the irradiation field. Fig. 3(b) is a three-dimensional dose distribution in a regular irradiation field obtained after reconstruction. Fig. 4(a) shows two-dimensional radiation field structure information in the depth direction of a certain slice measured by the apparatus of the present invention under the patient treatment plan verification condition, and fig. 4(b) shows a three-dimensional dose distribution obtained after three-dimensional reconstruction. The dose detection device and the three-dimensional dose reconstruction method can be used for obtaining the irradiation dose of each position of the irradiation field, so that the accurate and rapid verification of the treatment plan of the patient is realized, and the realization of accurate radiotherapy is guaranteed. The ion beam three-dimensional dose distribution detection device and method provided by the invention can be applied to ion beam radiotherapy and can be widely applied to other fields of ion beam detection, and are used for detecting the cross section structure of the beam in the transverse direction and the longitudinal direction and reconstructing the three-dimensional dose distribution, so that the detection efficiency and the convenience are improved.

The above embodiments are only used for illustrating the present invention, and the structure, connection mode, manufacturing process, etc. of the components may be changed, and all equivalent changes and modifications performed on the basis of the technical solution of the present invention should not be excluded from the protection scope of the present invention.