Three-dimensional radiation dose test method based on water ionization and radiation dosimeter

Abstract

The invention provides a three-dimensional radiation dose detection method based on water ionization, and the method comprises the following steps: constructing a detection region through light guide fluid, radiating a radiation beam to the detection region, enabling the light guide fluid to generate ionization to generate an ionization product, and enabling a light signal to enter the detection region, at least one part of the light signal in the detection area is absorbed by the ionization product, the light signal which is not absorbed is emitted from the detection area, the light signal emitted from the detection area is collected to form a light intensity distribution two-dimensional image, the light intensity distribution two-dimensional image is converted into a dose distribution two-dimensional image based on the mapping relation between the light intensity and the radiation dose, and the dose distribution two-dimensional image is obtained. Performing three-dimensional image reconstruction by using the dose distribution two-dimensional image, and representing the three-dimensional distribution condition of the radiation dose absorbed by the detection area by using the obtained three-dimensional image; wherein the light guide fluid is pure water or an aqueous solution. The detection method has the advantages of radiation resistance and high spatial resolution, and can efficiently and reliably monitor the multi-dimensional dynamic distribution condition of the radiation dose in the detection area.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of radiation dose measurement, and in particular, relates to a three-dimensional radiation dose testing method based on water ionization and a radiation dose meter. BACKGROUND

[0002] Radiotherapy is one of the three major means of treating tumors, and its purpose is to kill tumor cells as much as possible and effectively protect surrounding normal tissues and important organs. In order to achieve this purpose, modern radiotherapy technology is developing towards more refined and customized treatment plans, and more accurate and complex treatment implementation. This trend is particularly evident in new technologies such as intensity-modulated radiotherapy (IMRT), stereotactic ablative radiotherapy (SABR), proton and heavy ion therapy, microbeam radiotherapy, and FLASH radiotherapy. These radiotherapy technologies produce complex dose distributions that match the patient's anatomy and tumor shape, posing challenges for dose measurement. For example, the ultra-high dose rate irradiation produced in FLASH radiotherapy, proton and heavy ion therapy requires radiation-resistant dosimeters, and the small field irradiation in microbeam radiotherapy and stereotactic ablative radiotherapy requires high spatial resolution. In particular, all radiotherapy methods require accurate measurement of the three-dimensional distribution of the dose.

[0003] Currently, conventional dose measurement methods such as two-dimensional and three-dimensional detector arrays, electronic portal imaging devices (EPID) can only provide sparse three-dimensional data, and the only 3D gel dosimeter on the market has a long processing time and is a disposable consumable, limiting its widespread use in clinical settings. The three-dimensional dose detection methods based on Cerenkov radiation light and fluorescence being developed have not yet been commercialized due to their own defects such as energy threshold, ionization quenching, afterglow effect, and irradiation damage.

[0004] The prior art CN113260878A provides a radiation dose meter based on a resonant cavity and an optical fiber, which detects the dose by detecting the absorption of hydrated electrons in a water solution to an external optical signal. However, this device can only measure the dose at a certain point and is more suitable for real-time monitoring of radiation dose in the human body during radiotherapy, and cannot provide the three-dimensional spatial distribution of the dose.

[0005] In summary, the development of modern radiotherapy technology and its safe use require an accurate, practical, and economical 3D dose measurement method with high spatial resolution and radiation resistance. SUMMARY

[0006] In order to achieve efficient and reliable multi-dimensional detection of radiation dose, the present application provides a three-dimensional radiation dose testing method based on water ionization and a radiation dose meter.

[0007] According to a first aspect of the present application, a method for detecting three-dimensional radiation dose based on water ionization is provided, comprising the following operations: constructing a detection area by using a light-guiding fluid, radiating a radiation beam to the detection area so that the light-guiding fluid is ionized to generate ionized products, projecting a light signal to the detection area, at least a part of the light signal being absorbed by the ionized products in the detection area, the unabsorbed light signal being projected out of the detection area, collecting the light signal projected out of the detection area to form a two-dimensional image of light intensity distribution, converting the two-dimensional image of light intensity distribution into a two-dimensional image of dose distribution based on the mapping relationship between light intensity and radiation dose, and reconstructing a three-dimensional image by using the two-dimensional image of dose distribution, so as to obtain a three-dimensional distribution of radiation dose absorbed by the detection area; wherein the light-guiding fluid is pure water or an aqueous solution.

[0008] The detection principle of the method for detecting radiation dose is that the light-guiding fluid is ionized by the radiation beam, and the ionized products generated thereby absorb the light signal, so that the light intensity of the light signal changes before and after entering the detection area. Based on the fact that different regions in the detection area have different dose distribution, the light signal projected out of the detection area will form a two-dimensional image of light intensity distribution with different light intensity levels, and the two-dimensional image of light intensity distribution can reflect the deposition of the radiation dose in the detection area. Based on the above detection principle, the light path length in the detection area is controlled, so that the two-dimensional image of light intensity distribution has excellent imaging quality, and the radiation dose distribution in a wide dose range can be collected in the form of a two-dimensional image of light intensity. The three-dimensional model obtained by three-dimensional reconstruction based on the two-dimensional image can accurately reflect the three-dimensional distribution of the radiation dose, thereby realizing real-time and high-reliability three-dimensional radiation dose detection. Moreover, the raw material of water or an aqueous solution is easy to obtain, and the cost is relatively low and easy to replace. Using water or an aqueous solution as the light-guiding fluid can reduce the detection cost, and the physicochemical indicators of the light-guiding fluid can be flexibly adjusted according to the actual situation, so that different test requirements can be well met. In addition, the dose can be detected by using an optical method, and high time and spatial resolution can be achieved. In summary, the method for detecting radiation dose based on water ionization provided by the present application has excellent time resolution and spatial resolution, and can efficiently and reliably monitor the multi-dimensional dynamic distribution of the radiation dose in the detection area.

[0009] Preferably, the light path length in the detection area is 3 cm to 2 m.

[0010] Preferably, the ionized products include at least one of hydrogen ions, hydroxyl ions, hydrated hydrogen ions, hydrated hydroxyl ions, ionized water molecules, secondary excited electrons, hydrated electrons, hydrogen radicals, hydroxyl radicals, excited state water molecules, hydrogen gas, and hydrogen peroxide.

[0011] Preferably, the ionized product comprises hydrated electron. Based on the three-dimensional radiation dose detection method proposed in the present solution, the lifetime of the hydrated electron can be regulated within the range of 0.5 μs-660 μs in the application process, which can flexibly adapt to different detection requirements. In order to balance the detection efficiency and the reliability of the detection results, preferably, in the application process of the above-mentioned three-dimensional radiation dose detection method, the lifetime of the hydrated electron belongs to the range of 1 μs-100 μs.

[0012] Preferably, the wavelength range of the light signal belongs to 100 nm-2 μm.

[0013] Preferably, the wavelength range of the light signal belongs to 400 nm-1000 nm. Further controlling the wavelength of the light signal within the above range, the absorbed amount of the hydrated electron to the first light signal presents a linear relationship with the radiation dose in a relatively wide dose range and dose rate range (dose dynamic range 0.5 mGy-500 Gy, dose rate dynamic range 0.1 cGy / s-1×10 10 Gy / s), so that the optical intensity two-dimensional image with obvious light and dark partition can be obtained in the detection area due to the different distribution amounts of the radiation dose in different local parts, the resolution of the optical intensity two-dimensional image is improved, and the imaging quality of the optical intensity two-dimensional image is better improved.

[0014] Preferably, the wavelength range of the light signal belongs to 600 nm-800 nm.

[0015] Preferably, the pH of the light-guiding fluid is 5-12. According to the actual situation, if it is necessary to regulate the pH of the light-guiding fluid, one or a combination of the following materials can be selected: acidic materials such as hydrochloric acid (HCl), nitric acid (HNO3), sulfuric acid (H2SO4), etc.; basic materials such as sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonia (NH3·H2O), etc.; buffer solutions such as acetic acid / sodium acetate buffer solution, phosphate buffer solution, bicarbonate buffer solution, etc.; other pH regulators such as boric acid, ethylenediaminetetraacetic acid (EDTA).

[0016] Preferably, the pH of the light-guiding fluid is 6-8.5. Within the above pH range, the hydrated electron has higher stability, so that the imaging quality of the optical intensity two-dimensional image is improved.

[0017] Preferably, the light-guiding fluid contains sodium sulfite.

[0018] Preferably, the light signal is a parallel beam, a quasi-parallel beam, or a conical beam, which can better realize the 3D reconstruction of the dose spatial distribution.

[0019] Preferably, the light intensity distribution two-dimensional image is collected from different positions respectively, and the time difference between the triggering of the beam pulse and the collection of the light intensity distribution two-dimensional image is 10 ns to 1001 ms.

[0020] Preferably, the time difference between the triggering of the beam pulse and the collection of the light intensity distribution two-dimensional image is 500 μs to 1001 ms.

[0021] According to a second aspect of the present application, a radiation dosimeter is provided, which comprises: a water tank, the water tank being provided with an inner cavity for containing a light-guiding fluid, the light-guiding fluid being pure water or an aqueous solution, a detection region being constructed by the light-guiding fluid, and the optical path length in the detection region being 3 cm to 2 m; a light source, the light source being configured to emit a light signal to the detection region, the light signal being configured to be at least partially absorbed by ionized products, and the unabsorbed light signal being emitted from the detection region; and an image collection module, the image collection module being configured to collect a light intensity distribution two-dimensional image formed by the light signal emitted from the detection region. In application, the radiation dosimeter can collect the light intensity distribution two-dimensional image, and the image data can be transmitted or copied to an external three-dimensional reconstruction system for three-dimensional reconstruction, and the three-dimensional distribution of the radiation dose can be reliably evaluated based on the result of the three-dimensional reconstruction.

[0022] The radiation dosimeter has the following advantages:

[0023] (1) high spatial resolution, the spatial resolution being micron-level; high temporal resolution, the temporal resolution being microsecond-level; and real-time dynamic monitoring of the distribution of the radiation dose during operation;

[0024] (2) good accuracy and precision, the accuracy being within 3%, and the precision being within 1%;

[0025] (3) high physical stability of the device, and the device is less affected by temperature, humidity, pressure and radiation.

[0026] Preferably, the inner cavity of the water tank comprises an entrance side and an exit side, and the distance between the entrance side and the exit side is 3 cm to 40 cm.

[0027] Preferably, the material of the water tank is quartz glass, crystal glass or acrylic.

[0028] Preferably, the material of the water tank is quartz glass.

[0029] Preferably, the thickness of the tank wall of the water tank is 5 mm to 3 cm.

[0030] Preferably, the thickness of the tank wall of the water tank is 5 mm.

[0031] Preferably, the radiation dosimeter further comprises an image processing module, which is configured to perform three-dimensional image reconstruction based on the two-dimensional image of the light intensity distribution. When the radiation dosimeter itself comprises the image processing module with the function of three-dimensional image reconstruction, the three-dimensional image reconstruction can be performed rapidly after the two-dimensional image of the light intensity distribution is acquired, which is beneficial to realize real-time detection of the dose distribution, and in addition, makes the integration of the radiation dosimeter higher.

[0032] Preferably, the radiation dosimeter further comprises a rotating driving device, which is configured to cause the light source and the image acquisition module to rotate and displace. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The basic structure schematic diagram of the radiation dosimeter provided for the embodiment 1, 2, 3, 4 is shown in Figure 1 In the figure, the black solid line connecting the light source 1, the concave lens 3-3, the first convex lens 3-1, the water tank 2, the second convex lens 3-2 and the image acquisition module 4 in sequence represents the light path propagation path of the light signal emitted by the light source 1 between the above components, and the arrow below the rotating platform 5 represents the rotating direction of the rotating platform 5.

[0034] Figure 2 The top view of the radiation dosimeter in the case that the total reflection mirror 7 is applied in the embodiment 1 is shown in Figure 2 In the figure, the arrow represents the light path propagation path of the light signal.

[0035] Figure 3 The basic structure schematic diagram of the radiation dosimeter provided for the embodiment 5 is shown in Figure 3 In the figure, the arrow represents the light path propagation path of the light signal. DETAILED DESCRIPTION

[0036] In order to make the personnel in the technical field better understand the present application scheme, the technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments.

[0037] Embodiment 1

[0038] 1. Basic structure of the radiation dosimeter

[0039] The radiation dosimeter used in the embodiment comprises a water tank 2, a light source 1, a lens group, an image acquisition module 4, a rotating platform 5 and a computer 6. The water tank 2 is square in shape and made of quartz glass. The water tank 2 is provided with a square inner cavity with an open end for accommodating light-guiding fluid, which can be water or water solution. After the light-guiding fluid is injected into the square inner cavity, a detection area is formed. The light source 1 is a laser light source capable of emitting laser light. The lens group comprises a concave lens 3-3 and a first convex lens 3-1 and a second convex lens 3-2. The concave lens 3-3 is used to diffuse the light signal emitted from the light source 1 into a large-area light signal. The first and second convex lenses are convex lenses with the same shape and material. The first convex lens 3-1 is used to convert the large-area light signal passing therethrough into parallel light signal. The second convex lens 3-2 is used to converge the parallel light signal passing through the water tank 2. In the embodiment, the image acquisition module 4 is a CMOS camera. The computer 6 is provided with an image processing module having a three-dimensional image reconstruction function for three-dimensional reconstruction based on the two-dimensional image of the dose distribution.

[0040] The radiation dosimeter provided in the embodiment is assembled in the following manner. The radiotherapy system, the light source 1, the CMOS camera, the rotating platform 5 and the computer 6 are electrically connected respectively, so that the computer 6 can control the opening and closing of the light source 1, can receive the control of the rotating speed of the rotating platform 5 and can receive the two-dimensional image of the light intensity distribution collected by the CMOS camera. The light source 1, the concave lens 3-3, the first convex lens 3-1, the second convex lens 3-2 and the CMOS camera are sequentially arranged in order. The first convex lens 3-1 and the second convex lens 3-2 are arranged opposite to each other so that the principal axes of the two coincide. The center of the light source 1, the center of the concave lens 3-3, the center of the first convex lens 3-1, the center of the second convex lens 3-2 and the lens center of the CMOS camera are all located on the principal axis of the first convex lens 3-1 and the second convex lens 3-2. A spacing position is reserved between the first convex lens 3-1 and the second convex lens 3-2. Then, the water tank 2 is arranged at the spacing position between the first convex lens 3-1 and the second convex lens 3-2. Pure water (pH = 7) is injected into the square open cavity of the water tank 2 as light-guiding fluid. The area occupied by the light-guiding fluid is the detection area. The rotating platform 5 is configured to enable the light source 1, the CMOS camera and the water tank 2 to make angular motion together. The three are kept relatively stationary with respect to each other in the process of making angular motion. Figure 1 As shown in FIG. 6, the propagation path of the light signal emitted by the light source 1 is as follows. The light source 1 emits a light signal. The light signal first reaches the concave lens 3-3, which diffuses the light signal into a large-area light signal. The diffused light signal then reaches the first convex lens 3-1, which converts the large-area light signal into parallel light. The parallel light enters the detection area. After passing through the detection area, the parallel light exits the detection area and then reaches the second convex lens 3-2, which converges the parallel light.

[0041] The three-dimensional radiation dose detection is performed by using the above radiation dosimeter, and the specific method is as follows:

[0042] S1. The computer 6 controls the light source 1 to be turned off, the computer 6 receives a radiation beam current trigger signal, the computer 6 controls the CMOS camera to collect a light intensity distribution two-dimensional image of the light signal emitted from the detection area, takes the light intensity distribution two-dimensional image collected as a background image, and transmits and stores the background image in the computer 6;

[0043] S2. The radiotherapy system emits a radiation beam current pulse to the detection area in a direction directly above the detection area, the radiation pulse ionizes the light guide fluid in the detection area and makes the light guide fluid generate hydrated electrons, and the hydrated electrons are taken as ionization products;

[0044] S3. When the computer 6 receives the radiation beam current trigger signal, the light source 1 is controlled to be turned on to emit a light signal, the light signal enters the detection area after being regulated by the concave lens 3-3 and the first convex lens 3-1 in turn, at this time, the light guide fluid in the detection area contains a certain amount of ionization products, the ionization products have an absorption effect on the light signal passing through the detection area, part of the light signal entering the detection area is absorbed by the ionization products, and the other part is not absorbed by the ionization products and can be emitted from the detection area, the latter reaches the second convex lens 3-2 after being emitted from the detection area, and reaches the CMOS camera after being converged by the second convex lens 3-2, the CMOS camera collects the light signal emitted from the detection area to form a light intensity distribution two-dimensional image, and transmits the obtained light intensity distribution two-dimensional image to the computer 6;

[0045] S4. The computer 6 subtracts the light intensity distribution two-dimensional image from the above background image to obtain a light intensity distribution two-dimensional image, and converts the light intensity distribution two-dimensional image into a dose distribution two-dimensional image based on the mapping relationship between the light intensity and the radiation dose;

[0046] S5. The computer 6 controls the rotating platform 5 to rotate by 1°;

[0047] S6. Then, steps S1-S5 are repeated until the angle of the rotating platform 5 is accumulated to 360°;

[0048] S7. The computer 6 performs three-dimensional reconstruction from the dose distribution two-dimensional images at each angle by using an image processing module, so as to represent the three-dimensional distribution of the radiation dose absorbed by the detection area.

[0049] 2. Design and construction of the experimental group

[0050] To explore the influence of the optical path length of the light signal in the detection area on the detection result, based on the basic structure of the radiation dosimeter provided in the embodiment, the optical path length of the light signal passing through the detection area is changed by setting a mirror, and the optical path length of the light signal passing through the detection area is taken as a variable. The experimental groups provided in the embodiment are numbered as experimental group 1, experimental group 2, experimental group 3, experimental group 4, and experimental group 5. The numbering and specific variable setting of each experimental group are shown in Table 1. Except for the variables shown in Table 1, the other components of the radiation dosimeter used in each experimental group and the connection mode and parameter setting thereof are strictly kept consistent. The light guide fluid used in the experimental groups shown in Table 1 is pure water with pH = 7, and nitrogen is passed into the light guide fluid to reduce the oxygen concentration of the light guide fluid to 1.7 mg / L. The light source 1 used is a laser light source with an emission wavelength of 660 nm, and the water tank 2 used is provided with a square open cavity with a size of 5 cm x 5 cm x 5 cm. The calculation method of the optical path length OPL involved in Table 1 is OPL = n x S, wherein n is the refractive index of water, n = 1.333, and S is the geometric length of the light signal passing through the detection area.

[0051] Table 1. Experimental group setting with optical path length as a variable

[0052]

[0053]

[0054] The experimental groups shown in Table 1 are subjected to three-dimensional radiation dose testing using the respective radiation dosimeters according to the three-dimensional radiation dose testing method provided in the embodiment. The radiation pulse dose emitted to the detection area by each group during testing is controlled to be the same, i.e., 5 Gy.

[0055] 3. Test items and test methods

[0056] Test items: signal-to-noise ratio of radiation dose testing and lifetime of hydrated electrons.

[0057] Test method: the radiation dosimeter is operated for radiation dose testing according to the above-mentioned radiation dose testing method. During the radiation dose testing, the radiotherapy system emits a radiation beam pulse to the detection area in the direction directly above the detection area. The water in the detection area is ionized and generates ionized products such as hydrated electrons by the ionization of the radiation pulse. The signal-to-noise ratio and the lifetime of the water and electrons can be calculated by the degree and speed of the weakening of the laser light intensity detected by the detector.

[0058] The calculation formula of the signal-to-noise ratio is:

[0059]

[0060] where A signal and A noise are the root mean square signal and noise, which are calculated as:

[0061]

[0062] x i and y i are the ith values of the measured signal and noise, respectively, for a total of N values.

[0063] The results of the signal-to-noise ratio test can be used to characterize the imaging quality of the radiation dose test, and the lower the signal-to-noise ratio, the higher the corresponding imaging quality.

[0064] The method for testing the signal-to-noise ratio is that the laser generated by the single-energy laser passes through the 5 cm wide water tank 2 and is detected by the detector, which is used to measure the change in laser intensity. The electron pulse beam generates a 5 cm x 5 cm uniform irradiation field in the water tank 2. The length of the optical path can be adjusted by the total reflection mirror 7, as shown in Figure 2 two total reflection mirrors 7 are installed on both sides of the water tank 2, and the mirror surface is perpendicular to the light so as not to block the initial incident light and the final emitted light.

[0065] After the above test, the test results show that the optical path length has no obvious effect on the hydration electron lifetime, and the hydration electron lifetime is about 2 μs; while the signal-to-noise ratio increases with the increase of the optical path length, and when the optical path length is 33.325 cm, the signal-to-noise ratio reaches 2.

[0066] Example 2

[0067] 1. Basic structure of the radiation dosimeter

[0068] The structure of the radiation dosimeter used in this embodiment is basically the same as that used in experimental group 1 of example 1, the difference is that the pH value of the light guide fluid used in this embodiment is different from that of the light guide fluid used in experimental group 1 of example 1, and nitrogen gas is introduced into the light guide fluid to adjust the oxygen concentration of the light guide fluid in this embodiment. Therefore, according to the content recorded in experimental group 1 of example 1, the assembly of the radiation dosimeter and the preparation before the test are carried out, and according to the variable setting mode of the experimental group, the water solution meeting the requirements of each experimental group is injected into the water tank 2 of the radiation dosimeter as the light guide fluid.

[0069] 2. Design and construction of experimental groups

[0070] The experimental group 1 of Example 1 is taken as a reference, and the pH value of the light guide fluid in the radiation dosimeter and the oxygen concentration in the light guide fluid are taken as variable settings for the experimental groups of the present example. The experimental groups of the present example are numbered as experimental group 6, experimental group 7, experimental group 8, and experimental group 9, respectively. Different concentrations of NaOH solution are used as the light guide fluid for each experimental group in Table 2. The numbers of the experimental groups of the present example and the corresponding pH values of the light guide fluid used are shown in Table 2. The oxygen concentration in the light guide fluid of each experimental group of the present example is maintained at 6.5 mg / L. Except for the variables shown in Table 2, the other components of the radiation dosimeter used in each experimental group in Table 2 and the connection mode and parameter settings thereof are strictly consistent with those of experimental group 1 of Example 1.

[0071] Table 2. Experimental group setting with light guide fluid pH value as a variable

[0072] Group Optical light fluid pH Oxygen concentration of optical light fluid Example 2 Experiment Group 6 7 6.5 mg / L Example 2 Experiment Group 7 9 6.5 mg / L Example 2 Experiment Group 8 11 6.5 mg / L Example 2 Experiment Group 9 13 6.5 mg / L

[0073] 3. Test items and test methods

[0074] Test items: signal-to-noise ratio and hydrated electron lifetime of radiation dose test.

[0075] Test method: The test method used in the present example is consistent with the test method for the corresponding index in Example 1.

[0076] After the above tests, the test results show that when the pH value is less than 11, the hydrated electron lifetime and the signal-to-noise ratio increase with the increase of the pH value; when the pH value is greater than 11, the hydrated electron lifetime and the signal-to-noise ratio remain basically unchanged. When the pH value is 11, the hydrated electron lifetime is 2 μs, and the signal-to-noise ratio is 2.

[0077] Example 3

[0078] 1. Basic structure of radiation dosimeter

[0079] The structure of the radiation dosimeter used in the present example is basically consistent with that of the radiation dosimeter used in experimental group 1 of Example 1. The difference lies in that the light source 1 used for the present example to incident light signal to the detection area of the radiation dosimeter is different from the light source 1 used in experimental group 1 of Example 1. Based on the corresponding light signal wavelength requirements of the radiation dosimeter provided by each experimental group of the present example, a suitable light source 1 is selected, and the assembly of the radiation dosimeter and the preparation before the test are carried out according to the contents recorded in experimental group 1 of Example 1.

[0080] 2. Design and construction of experimental groups

[0081] The experimental groups of this embodiment are set with the laser wavelength (wavelength of the light signal incident on the detection area) emitted by the light source 1 in the radiation dose meter as a variable, and the experimental groups set in this embodiment are respectively numbered as experimental group 10 and experimental group 11. Table 3 uses the light source 1 capable of emitting light signals of different wavelengths as the light source 1 of each experimental group, and the numbers of the experimental groups of this embodiment and the wavelengths of the light signals emitted by the corresponding light source 1 during the test are shown in Table 3. In addition, “experimental group 1” in Table 3 refers to the experimental group 1 set in Example 1. Except for the variable shown in Table 3, the other components of the radiation dose meter used in each experimental group and the connection mode and parameter setting thereof are strictly consistent with those of experimental group 1 of Example 1.

[0082] Table 3. Experimental group setting with the wavelength of the light signal for radiation dose detection as a variable

[0083] Group Light signal wavelength Example 1 Experiment Group 1 660 nm Example 3 Experiment Group 10 530 nm Example 3 Experiment Group 11 808 nm

[0084] 3. Test items and test methods

[0085] Test items: signal-to-noise ratio of radiation dose test and lifetime of hydrated electron.

[0086] Test method: The test method used in this embodiment is consistent with the test method of the corresponding index in Example 1.

[0087] After the above test, the test results show that the wavelength of the light has no significant effect on the lifetime of the hydrated electron, and the lifetime of the hydrated electron is about 2 μs.

[0088] Example 4

[0089] 1. Basic structure of the radiation dose meter

[0090] The structure of the radiation dose meter used in this embodiment is basically consistent with that of the radiation dose meter used in experimental group 1 of Example 1, and the difference lies in that this embodiment uses a sodium sulfite solution (prepared by adding sodium sulfite to pure water) as the light guide fluid. Therefore, the assembly of the radiation dose meter and the preparation before the test are carried out according to the content recorded in experimental group 1 of Example 1, and the sodium sulfite solution meeting the requirements of each experimental group is injected into the water tank 2 of the radiation dose meter as the light guide fluid according to the variable setting mode of the experimental group.

[0091] 2. Design and construction of experimental groups

[0092] The experiment group 1 of the embodiment 1 is taken as a reference, and the sodium sulfite content in the light guide fluid in the radiation dosimeter is taken as a variable to set the experiment groups of the embodiment. The experiment groups of the embodiment are numbered as experiment group 12, experiment group 13, experiment group 14 and experiment group 15 respectively, and different concentrations of sodium sulfite solution are used as the light guide fluid of each experiment group in table 4. The numbers of the experiment groups of the embodiment and the corresponding pH values of the light guide fluid used are shown in table 4. In addition, “experiment group 1” in table 4 refers to the experiment group 1 set in the embodiment 1. Except for the variable shown in table 4, the other parts of the radiation dosimeter used in each experiment group and the connection mode and parameter setting thereof are strictly consistent with those of the experiment group 1 of the embodiment 1.

[0093] Table 4. Setting of experiment groups with the sodium sulfite content in the light guide fluid as a variable

[0094]

[0095]

[0096] 3. Test items and test methods

[0097] Test items: signal-to-noise ratio of radiation dose test and lifetime of hydrated electron.

[0098] Test method: the test method used in the embodiment is consistent with the test method of the corresponding index in the embodiment 1.

[0099] After the above test, the test results show that, compared with using pure water as the light guide fluid, the lifetime of the hydrated electron can be prolonged by adding sodium sulfite to the pure water, and the detection signal intensity can be enhanced and the signal-to-noise ratio can be increased.

[0100] Embodiment 5

[0101] The radiation dosimeter used in the embodiment includes a water tank 2, a light source 1, a reflector 8, an image acquisition module 4, a rotating platform 5 and a computer 6. The water tank 2 is square in shape and is made of quartz glass. The water tank 2 is provided with a square inner cavity with an open end, and the size of the square inner cavity is 10 cm x 10 cm x 10 cm, which is used to accommodate the light guide fluid. Water or aqueous solution can be selected as the light guide fluid, and the detection area is constructed after the light guide fluid is injected into the square inner cavity. The light source 1 is an LED panel, and the LED panel is provided with LED light sources capable of emitting 650 nm light, which are arranged in an array. In the embodiment, the image acquisition module 4 is specifically a CMOS camera. The computer 6 is provided with an image processing module, and the image processing module has a three-dimensional image reconstruction function for three-dimensional reconstruction based on the two-dimensional image of the dose distribution.

[0102] The radiation dosimeter provided by the embodiment is assembled in the following manner: the light source 1, the CMOS camera, the rotating platform 5 and the computer 6 are respectively electrically connected, so that the computer 6 can control the opening and closing of the light source 1, can receive the rotating speed of the rotating platform 5, and can receive the light intensity distribution two-dimensional image collected by the CMOS camera; the CMOS camera, the light source 1 and the mirror 8 are sequentially arranged in order, and a spacing position is reserved between the light source 1 and the mirror 8; then the water tank 2 is arranged at the spacing position between the light source 1 and the mirror 8, pure water (pH = 7) is injected into the square inner cavity of the water tank 2 as a light guide fluid, and the area occupied by the light guide fluid is the detection area; the rotating platform 5 is connected with the bottom surface of the water tank 2 to achieve the effect that the rotating platform 5 can drive the water tank 2 to perform corner motion. Figure 3 As shown in FIG. 1, the propagation path of the light signal of the radiation dosimeter provided by the embodiment during operation should satisfy: the light signal emitted by the LED panel of the light source 1 propagates upward to the semi-transmissive reflective element 9 of the light source 1, the light signal after being emitted is incident on the detection area perpendicularly to the side wall of the water tank 2, reaches the mirror 8 after passing through the detection area for the first time, is reflected by the mirror 8 and then is incident on the detection area perpendicularly to the side wall of the water tank 2 again, and reaches the CMOS camera after passing through the detection area again, and is collected by the CMOS camera. The three-dimensional radiation dose detection is performed by using the above-mentioned radiation dosimeter, and the specific method is as follows:

[0103] S1. The computer 6 controls the light source 1 to be closed, the computer 6 receives a radiation beam current trigger signal, the computer 6 controls the CMOS camera to collect the light intensity distribution two-dimensional image of the light signal emitted from the detection area, and the light intensity distribution two-dimensional image thus collected is used as a background image, and the background image is transmitted and stored in the computer 6;

[0104] S2. The radiotherapy system emits a radiation beam pulse to the detection area in the direction directly above the detection area, the radiation pulse ionizes the light guide fluid in the detection area and makes the light guide fluid generate hydrated electrons, and the hydrated electrons are used as ionization products;

[0105] S3. When the computer 6 receives the radiation beam current trigger signal, the light source 1 is controlled to be turned on to emit a light signal, the light signal propagates in the direction perpendicular to the side wall of the water tank 2 after being controlled by the reflective element of the light source 1, at this time, the light guide fluid in the detection area contains a certain amount of ionization products, the ionization products have an absorption effect on the light signal passing through the detection area, and thus part of the light signal entering the detection area is absorbed by the ionization products, and the other part of the light signal is not absorbed by the ionization products and can be emitted from the detection area, the latter reaches the mirror 8 after being emitted from the detection area, is totally reflected by the mirror 8 and then is incident on the detection area in the direction perpendicular to the side wall of the water tank 2 again, sequentially passes through the detection area and the light source 1 and then reaches the CMOS camera, the CMOS camera collects the light signal emitted from the detection area to form a light intensity distribution two-dimensional image, and the obtained light intensity distribution two-dimensional image is transmitted to the computer 6.

[0106] S4. The computer 6 subtracts the two-dimensional image of the light intensity distribution from the above-mentioned background image to obtain a two-dimensional image of the light intensity distribution, and converts the two-dimensional image of the light intensity distribution into a two-dimensional image of the dose distribution based on the mapping relationship between the light intensity and the radiation dose;

[0107] S5. The computer 6 controls the rotation platform 5 to rotate by 1°;

[0108] S6. Then, steps S1-S5 are repeated until the rotation angle of the rotation platform 5 accumulates to 360°.

[0109] S7. The computer 6 performs three-dimensional reconstruction from the two-dimensional images of the dose distribution at each angle by using an image processing module, thereby obtaining a three-dimensional distribution of the absorbed radiation dose in the detection region.

[0110] The above embodiments are only used to illustrate the technical solutions of the present application but not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently, and these modifications or replacements are within the protection scope of the present application.

Claims

1. A three-dimensional radiation dose detection method based on water ionization, characterized in that, Includes the following operations: A detection region is constructed using a light-guiding fluid. A radiation beam is emitted into the detection region, causing the light-guiding fluid to ionize and generate ionization products. A light signal is incident into the detection region, and at least a portion of the light signal is absorbed by the ionization products. The unabsorbed light signal exits from the detection region. The light signal exiting from the detection region is collected to form a two-dimensional image of light intensity distribution. Based on the mapping relationship between light intensity and radiation dose, the two-dimensional image of light intensity distribution is converted into a two-dimensional image of dose distribution. The two-dimensional image of dose distribution is used to perform three-dimensional image reconstruction, and the resulting three-dimensional image characterizes the three-dimensional distribution of radiation dose absorbed by the detection region. Wherein: the light guiding fluid is pure water or an aqueous solution.

2. The three-dimensional radiation dose detection method based on water ionization as described in claim 1, characterized in that: The optical path length of the optical signal in the detection area is 3cm to 2m.

3. The three-dimensional radiation dose detection method based on water ionization as described in claim 1, characterized in that: The ionization products include at least one of hydrogen ions, hydroxide ions, hydrated hydrogen ions, hydrated hydroxide ions, ionized water molecules, secondary excited electrons, hydrated electrons, hydrogen free radicals, hydroxyl free radicals, excited-state water molecules, hydrogen gas, and hydrogen peroxide.

4. The three-dimensional radiation dose detection method based on water ionization as described in claim 3, characterized in that: The ionization products include hydrated electrons.

5. The three-dimensional radiation dose detection method based on water ionization as described in claim 4, characterized in that: The wavelength range of the optical signal is 100nm to 2μm.

6. The three-dimensional radiation dose detection method based on water ionization as described in claim 5, characterized in that: The wavelength range of the first optical signal is 400nm to 1000nm.

7. The three-dimensional radiation dose detection method based on water ionization as described in claim 4, characterized in that: The pH of the light-guiding fluid is 5 to 12.

8. The three-dimensional radiation dose detection method based on water ionization as described in claim 7, characterized in that: The pH of the light guide fluid is 6 to 8.

5.

9. The three-dimensional radiation dose detection method based on water ionization as described in claim 4, characterized in that: The light-guiding fluid contains sodium sulfite.

10. The three-dimensional radiation dose testing method for water ionization as described in claim 1, characterized in that: Two-dimensional images of the light intensity distribution are acquired from different locations. During any acquisition of the two-dimensional images of the light intensity distribution, the time difference between triggering the beam pulse and acquiring the two-dimensional images of the light intensity distribution is 10ns to 1001ms.

11. A radiation dosimeter, characterized in that, The radiation dosimeter includes: A water tank is provided with an inner cavity for containing a light-guiding fluid, which is pure water or an aqueous solution. A detection area is constructed using the light-guiding fluid, and the optical path length in the detection area reaches 3cm to 20m. A light source is provided for emitting a light signal toward the detection area, the light signal being configured such that at least a portion of it can be absorbed by the ionization products, and the unabsorbed light signal is emitted from the detection area. An image acquisition module is used to acquire a two-dimensional image of the light intensity distribution formed by the light signal emitted from the detection area.

12. The radiation dosimeter as claimed in claim 11, characterized in that: The inner cavity of the water tank includes an input light side and an output light side, and the distance between the input light side and the output light side is 3cm to 40cm.

13. The radiation dosimeter as described in claim 11, characterized in that: The water tank is made of quartz glass, crystal glass, or acrylic.

14. The radiation dosimeter as claimed in claim 11, characterized in that: The radiation dosimeter also includes an image processing module, which is used to reconstruct a three-dimensional image based on the two-dimensional image of the light intensity distribution.

15. The radiation dosimeter as claimed in claim 11, characterized in that: The radiation dosimeter also includes a rotation drive device configured to rotate the light source and the image acquisition module.

Images