Three-dimensional dose verification device for ion therapy and verification method thereof

Abstract

The invention provides a three-dimensional dose verification device for ion therapy and a verification method thereof. The three-dimensional dose verification device comprises a mounting rack; m dose ionization chambers; the n striping ionization chambers and the m dose ionization chambers are sequentially arranged on the mounting rack; the acquisition unit is used for acquiring dose information and position information of the m dose ionization chambers so as to obtain actually-measured three-dimensional metering distribution, and the position information of the m dose ionization chambers is obtained by the position information of the n split ionization chambers; and the test unit is used for obtaining a verification passing rate according to a comparison result of the actually measured three-dimensional dose distribution and the planned three-dimensional dose distribution, m is an integer greater than 1, n is an integer greater than or equal to 1, and n is less than or equal to m. According to the three-dimensional dose verification device, position information and dose information of a plurality of dose ionization chambers can be obtained in single measurement, actually-measured three-dimensional dose distribution is obtained, and verification efficiency and accuracy of verification results are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of radiotherapy, and in particular to a three-dimensional dose verification device and a verification method thereof for ion therapy. Background Art

[0002] The deep dose distribution of ion beams when penetrating organisms is suitable for treating tumors. When an ion beam passes through matter, its kinetic energy is mainly lost at the end of the range, and a sharply enhanced Bragg peak will appear. That is, when ions interact with matter, the energy is mainly lost within the millimeter range at the end of the range, and the position of the Bragg peak of the ion beam is highly precise and controllable. By utilizing these characteristics, energy can be deposited in the patient's tumor target area to the greatest extent, thereby enhancing the local control rate of the tumor and reducing the risk of complications in normal tissues. Ion beam radiotherapy has advantages that are difficult to match with conventional radiotherapy methods, such as unique deep dose distribution and higher relative biological effect.

[0003] In related technologies, an amorphous silicon electronic portal imaging device is installed on the particle therapy equipment to perform a gamma pass rate test before treatment, or to collect the remaining photon flux after the photons penetrate the human body during treatment, and to infer the dose distribution in the human body to achieve the purpose of dose reconstruction. Electronic portal imaging technology can be well applied in photon therapy, but cannot be used in proton and heavy ion technology, because photons can still have a large flux that can be detected after penetrating human tissue, while protons and heavy ions can hardly penetrate the human body.

[0004] In related technologies, matrix ionization chambers are used in ion therapy in combination with equivalent water materials to collect absorbed doses in a fixed depth plane. The collected data are compared with the TPS calculation results to obtain the 2D dose gamma pass rate. Some ion centers also use multi-channel ionization chambers to measure point doses in water tanks. This method is cumbersome to operate and requires multiple measurements to obtain three-dimensional dose distribution including lateral and depth directions. The measurement error is large and the measurement time is long. Summary of the invention

[0005] In view of this, an embodiment of the present invention provides a three-dimensional dose verification device and a verification method for ion therapy, which are used to solve the problems of existing three-dimensional dose testing equipment that require multiple measurements, long measurement time and poor measurement result accuracy.

[0006] In a first aspect, an embodiment of the present invention provides a three-dimensional dose verification device for ion therapy, comprising:

[0007] Mounting frame;

[0008] m dose ionization chambers;

[0009] n stripe ionization chambers, wherein the n stripe ionization chambers and the m dose ionization chambers are sequentially arranged on the mounting frame;

[0010] A collection unit, used for collecting the dose information and position information of the m dose ionization chambers to obtain the measured three-dimensional metrological distribution, wherein the position information of the m dose ionization chambers is obtained from the position information of the n stripe ionization chambers; and

[0011] A testing unit is used to obtain a verification pass rate according to a comparison result between the measured three-dimensional dose distribution and the planned three-dimensional dose distribution,

[0012] Wherein, m is an integer greater than 1, n is an integer greater than or equal to 1, and n is less than or equal to m.

[0013] According to an embodiment of the present invention, the dose ionization chamber comprises:

[0014] A first bracket connected to the mounting frame;

[0015] Two first high-voltage plates, arranged on the first bracket;

[0016] A collecting plate, sandwiched between the two first high-voltage plates; and

[0017] The first equivalent plate is arranged on a side of the first high-voltage electrode plate away from the collecting electrode plate.

[0018] According to an embodiment of the present invention, the first bracket is detachably connected to the mounting frame.

[0019] According to an embodiment of the present invention, the stripe ionization chamber comprises:

[0020] A second bracket connected to the mounting frame;

[0021] A plurality of second high-voltage plates, arranged on the second bracket;

[0022] A first strip electrode, sandwiched between two adjacent second high-voltage plates;

[0023] A second strip electrode, sandwiched between two adjacent second high-voltage plates; and

[0024] A second equivalent plate, provided on one side of the second high voltage plate;

[0025] The strip structure direction of the first strip electrode intersects with the strip structure direction of the second strip electrode.

[0026] According to an embodiment of the present invention, the second bracket is detachably connected to the mounting frame.

[0027] In a second aspect, an embodiment of the present invention provides a verification method for a three-dimensional dose verification device for ion therapy, the verification method comprising:

[0028] Obtain the dose information and position information of any dose ionization chamber;

[0029] Based on the dose information and position information of the plurality of dose ionization chambers, obtaining a measured three-dimensional dose distribution;

[0030] Based on the comparison results of the measured three-dimensional dose distribution and the planned three-dimensional dose distribution, the verification pass rate is obtained.

[0031] Wherein, the position information of the dose ionization chamber is obtained from the position information of the stripe ionization chamber.

[0032] According to an embodiment of the present invention, when the number of the stripe ionization chambers is equal to 1, obtaining the position information of any dose ionization chamber includes:

[0033] Acquiring coordinate information of the stripe ionization chamber;

[0034] Acquiring the spacing information between the stripe ionization chamber and any of the dose ionization chambers;

[0035] Based on the coordinate information and the spacing information of the stripe ionization chambers, the position information of any one of the dose ionization chambers is acquired.

[0036] According to an embodiment of the present invention, when the number of the stripe ionization chambers is less than the number of the dose ionization chambers, and the number of the stripe ionization chambers is greater than 1, the acquiring the position information of any dose ionization chamber includes:

[0037] Obtaining first coordinate information of a first stripe ionization chamber and second coordinate information of a second stripe ionization chamber;

[0038] Acquire the spacing information between the first stripe ionization chamber and any of the dose ionization chambers;

[0039] Based on the first coordinate information, the second coordinate information and the distance information, the position information of any one of the dose ionization chambers is acquired.

[0040] According to an embodiment of the present invention, obtaining the verification pass rate based on the comparison result between the measured three-dimensional dose distribution and the planned three-dimensional dose distribution includes:

[0041] The position error value and / or the dosage error value are adjusted to obtain the verification pass rate.

[0042] According to an embodiment of the present invention, the position error value ranges from 2 to 4 mm; and / or

[0043] The dosage error value ranges from 2% to 6%.

[0044] The three-dimensional dose verification device and verification method for ion therapy provided by the embodiments of the present invention can at least achieve the following technical effects: multiple dose ionization chambers and multiple stripe ionization chambers are arranged in sequence on a mounting frame, and the position information and dose information of multiple dose ionization chambers can be obtained in a single measurement to obtain the measured three-dimensional dose distribution, thereby effectively improving the verification efficiency. A large amount of data and a large sample size are obtained in the space, thereby effectively improving the accuracy of the verification results. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0046] Figure 1 A schematic diagram of the structure of a three-dimensional dose verification device according to an embodiment of the present invention is shown;

[0047] Figure 2 Schematically shows an exploded schematic diagram of a dose ionization chamber according to an embodiment of the present invention;

[0048] Figure 3 Schematically shows an exploded schematic diagram of a striped ionization chamber according to an embodiment of the present invention;

[0049] Figure 4 Schematically showing a schematic diagram of relative dose curves of transverse main axes at different depths according to an embodiment of the present invention;

[0050] Figure 5 A schematic diagram of a depth dose curve obtained by a three-dimensional dose verification device according to an embodiment of the present invention is schematically shown;

[0051] FIG6( a ) schematically shows a cross-sectional view of a planned three-dimensional dose distribution according to an embodiment of the present invention;

[0052] FIG6( b ) schematically shows a sagittal view of a planned three-dimensional dose distribution according to an embodiment of the present invention;

[0053] FIG6( c ) schematically shows a coronal view of a planned three-dimensional dose distribution according to an embodiment of the present invention;

[0054] FIG7( a ) schematically shows a cross-sectional view of a measured three-dimensional dose distribution according to an embodiment of the present invention;

[0055] FIG7( b ) schematically shows a sagittal view of a measured three-dimensional dose distribution according to an embodiment of the present invention;

[0056] FIG7( c ) schematically shows a coronal view of a measured three-dimensional dose distribution according to an embodiment of the present invention;

[0057] Figure 8A schematic diagram schematically shows a gamma analysis result of a measured three-dimensional dose distribution and a planned three-dimensional dose distribution according to an embodiment of the present invention;

[0058] Fig. 9 A flowchart schematically shows a verification method of a three-dimensional dose verification device according to an embodiment of the present invention;

[0059] Reference numerals:

[0060] 10: mounting frame; 20: dose ionization chamber; 21: first bracket; 211: first plug-in portion; 22: first high-voltage electrode plate; 23: collecting electrode plate; 24: first equivalent plate; 30: stripe ionization chamber; 31: second bracket; 311: second plug-in portion; 32: second high-voltage electrode plate; 33: first strip electrode; 34: second strip electrode; 35: second equivalent plate. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0062] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0063] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0064] Radiotherapy directly acts on DNA molecules to destroy DNA chains or indirectly ionizes water in human tissues to generate free radicals, which then react with biological macromolecules to kill cells. Within the therapeutic dose range, normal human cells have a much stronger ability to repair radiation damage than tumor cells. Radiotherapy uses this difference to treat tumors while protecting normal human cells to the greatest extent.

[0065] The deep dose distribution of ion beams when penetrating organisms is very suitable for treating tumors. When an ion beam passes through matter, its kinetic energy is mainly lost at the end of the range, and a sharply enhanced Bragg peak will appear. That is, when ions interact with matter, the energy is mainly lost within the millimeter range at the end of the range, and the position of the Bragg peak of the ion beam is highly precise and controllable. By utilizing these characteristics, energy can be deposited in the patient's tumor target area to the greatest extent, thereby enhancing the local control rate of the tumor and reducing the risk of complications in normal tissues. Ion beam radiotherapy has advantages that are difficult to match with conventional radiotherapy methods, such as unique deep dose distribution and higher relative biological effect.

[0066] Point scanning and raster scanning technology are representative technologies of active beam delivery systems. Unlike passive beam delivery systems, active beam delivery systems generally do not make too much modulation on the pencil beam provided by the accelerator. This technology divides the irradiated target area into several equal energy slices along the incident direction of the beam, and each equal energy slice is further divided into several scanning points, where an equal energy slice means that all scanning points on the slice have the same energy. By adjusting the ion beam energy and scanning magnet parameters to control the pencil beam irradiation position, layered and point-by-point irradiation of the tumor target area is achieved, and the scanning points are mutually added in the horizontal and vertical directions to achieve the planned uniform dose distribution, which greatly improves the conformity of the target area.

[0067] Radiotherapy mainly includes the stages of patient positioning, plan design and plan execution. The treatment accuracy of radiotherapy includes position accuracy and dose accuracy.

[0068] In the prior art, an amorphous silicon electronic portal imaging device is installed on the particle therapy equipment to perform a pre-treatment plan gamma pass rate test, or collect the remaining photon flux after the photons penetrate the human body during treatment, and infer the dose distribution in the human body to achieve the purpose of dose reconstruction. Electronic portal imaging technology can be well applied in photon therapy, but cannot be used in proton and heavy ion technology, because photons still have a large flux that can be detected after penetrating human tissue, while protons and heavy ions can hardly penetrate the human body, and the detector cannot detect the dose, so electronic portal imaging technology loses its meaning in proton and heavy ion technology.

[0069] In the prior art, matrix ionization chambers are used in ion therapy in conjunction with equivalent water materials to collect absorbed doses in a fixed depth plane. The collected data are compared with the TPS calculation results to obtain the 2D dose gamma pass rate. Some ion centers also use multi-channel ionization chambers to measure point doses in a water tank. This method is cumbersome to operate and requires multiple measurements to obtain a three-dimensional dose distribution including the lateral and depth directions. It has large human errors and long measurement time, and is not suitable for large-scale patient plan verification.

[0070] Combine the following Figures 1 to 8A three-dimensional dose verification apparatus for ion therapy according to an embodiment of the present invention is described.

[0071] like Figure 1 As shown, the three-dimensional dose verification device provided by the embodiment of the present invention includes a mounting frame 10, m dose ionization chambers 20, n stripe ionization chambers 30, a collection unit and a test unit. The n stripe ionization chambers 30 and the m dose ionization chambers 20 are arranged in sequence on the mounting frame 10. The collection unit is used to collect the dose information and position information of the m dose ionization chambers 20 to obtain the measured three-dimensional metering distribution, and the position information of the m dose ionization chambers 20 is obtained from the position information of the n stripe ionization chambers 30. The test unit is used to obtain the verification pass rate according to the comparison result between the measured three-dimensional dose distribution and the planned three-dimensional dose distribution.

[0072] Exemplarily, m dose ionization chambers 20 and n stripe ionization chambers 30 are sequentially arranged on the frame along the length direction of the mounting frame 10, and the number of dose ionization chambers 20 and the number of stripe ionization chambers 30 are not specifically limited. The active beam delivery system emits a beam to the three-dimensional dose verification device, and the stripe ionization chamber 30 is used to record beam projection information, which includes the lateral beam spot position distribution and the beam profile. The dose ionization chamber 20 can reflect the dose information, and the position information of each dose ionization chamber 20 is obtained from the beam projection information recorded by the stripe ionization chamber 30. The position information includes X-direction coordinate information, Y-direction coordinate information, and Z-direction coordinate information.

[0073] The structure of the mounting frame 10 is not specifically limited. The mounting frame 10 can be a square frame structure. The length of the mounting frame 10 is set according to actual needs to meet the requirement of being able to simultaneously install multiple dose ionization chambers 20 and multiple stripe ionization chambers 30. The number n of the stripe ionization chambers 30 is greater than or equal to 1, and n is an integer. The number m of the dose ionization chambers 20 is greater than 1, and m is an integer, and the number of the stripe ionization chambers 30 is less than or equal to the number of the dose ionization chambers 20.

[0074] The dose ionization chamber 20 includes a high voltage electrode, a collecting electrode and an equivalent plate of a first preset thickness, and the dose information is obtained through the dose ionization chamber 20. The stripe ionization chamber 30 includes a high voltage electrode, a stripe electrode and an equivalent plate of a second preset thickness, and the position information is obtained through the stripe ionization chamber 30.

[0075] The three-dimensional dose verification device also includes an electronics system, which can be integrated into the rear end of the mounting frame 10 to avoid direct beam irradiation. The electronics system is used to amplify and process the ionization signal of the ionization chamber. The acquisition unit collects the data amplified by the electronics system and performs data processing. The acquisition unit synchronously collects the position information of the stripe ionization chamber 30 and the dose information of the dose ionization chamber 20. The position information of the dose ionization chamber 20 is obtained from the position information of the stripe ionization chamber 30.

[0076] The method in which the collecting unit collects the dose information of the dose ionization chamber 20 is as follows.

[0077] In ion therapy, an active beam delivery system is used to emit beams, that is, the beams are irradiated in layers according to energy. Assuming that the total number of layers is N, there are N groups of doses collected at the same position, recorded as The coordinates of a point in the dose ionization chamber 20 are The dose obtained by each layer at this point is recorded as , so the total dose at this point It can be obtained by formula (1):

[0078] (1)

[0079] Assuming that the total time of beam delivery is t, the number of dose ionization chambers 20 is m, the dose value of the kth (k=1,…,m) dose ionization chamber 20 at time p (p=0,…,t) is recorded as The total dose of the dose ionization chamber 20 is recorded as , total dose It can be obtained by formula (2):

[0080] (2)

[0081] The depth dose curve is an ordered arrangement of the total dose values ​​of all dose ionization chambers 20 ( , …, ). The dose depth curve diagram is as follows Figure 5 shown.

[0082] The method for collecting the position information of the dose ionization chamber 20 by the collection unit is as follows: According to the number of the stripe ionization chambers 30, the method for collecting the position information of the dose ionization chamber 20 includes the following three methods. It is understandable that the method for collecting the position information of the dose ionization chamber 20 is not limited to the following three methods.

[0083] For example, the number of stripe ionization chambers 30 is equal to the number of dose ionization chambers 20, and a plurality of stripe ionization chambers 30 and a plurality of dose ionization chambers 20 are staggered along the length direction of the mounting frame 10, and the position information of each dose ionization chamber 20 is obtained from the adjacent stripe ionization chambers 30. The plurality of stripe ionization chambers 30 makes the horizontal point position distribution on each dose ionization chamber 20 more accurate.

[0084] For example, the number of the stripe ionization chambers 30 is less than the number of the dose ionization chambers 20, and the number of the stripe ionization chambers 30 is greater than 1. The spatial coordinates directly read from the stripe ionization chambers 30 cannot cover all the dose ionization chambers 20, and the position information of other dose ionization chambers 20 can be calculated according to the principle of similar triangles. The number of the stripe ionization chambers 30 is two or more.

[0085] When the number of the stripe ionization chambers 30 is two, the two stripe ionization chambers 30 are defined as the first stripe ionization chamber 30 and the second stripe ionization chamber 30, and the first stripe ionization chamber 30 and the second stripe ionization chamber 30 are not adjacent. When the number of the dose ionization chambers 20 is greater than two, the multiple dose ionization chambers 20 are defined as the first dose ionization chamber 20, the second dose ionization chamber 20, the third dose ionization chamber 20 ... the mth dose ionization chamber 20 according to the arrangement order of the multiple ionization chambers. The first dose ionization chamber 20 is adjacent to the first stripe ionization chamber 30, the second dose ionization chamber 20 is adjacent to the second stripe ionization chamber 30, the position information of the first dose ionization chamber 20 is directly obtained from the first stripe ionization chamber 30, the position information of the second dose ionization chamber 20 is directly obtained from the second stripe ionization chamber 30, and the position information of other dose ionization chambers 20 can be calculated according to the principle of similar triangles, and the specific calculation method is as follows.

[0086] The coordinate information of the first stripe ionization chamber 30 is ( , , ), the coordinate information of the second stripe ionization chamber 30 is ( , , ), wherein the Z value can be read according to the installation position of the stripe ionization chamber 30 on the mounting frame 10. The position information of the first dose ionization chamber 20 is obtained from the coordinate information of the first stripe ionization chamber 30, and the position information of the second dose ionization chamber 20 is obtained from the coordinate information of the second stripe ionization chamber 30. The calculation method of the position information of the kth dose ionization chamber 20 is shown in formula (3), formula (4) and formula (5):

[0087] (3)

[0088] (4)

[0089] (5)

[0090] Wherein, d is the distance from the first stripe ionization chamber 30 to the kth dose ionization chamber 20. The position information of other dose ionization chambers 20 can be obtained from the above formula.

[0091] For example, the number of the stripe ionization chamber 30 is 1, the stripe ionization chamber 30 is installed at the end of the mounting frame 10, and the stripe ionization chamber 30 is opposite to the incident end of the active beam delivery system. The position information of multiple dose ionization chambers 20 can be collected through one stripe ionization chamber 30, and the specific calculation method is as follows.

[0092] When the number of stripe ionization chambers 30 is 1, the distance from the ion source to the reference point of the three-dimensional dose verification device needs to be known. Usually, the source axis distance of the accelerator is a fixed value. When the reference point of the three-dimensional dose verification device is placed at the isocenter, the distance from the ion source to the three-dimensional dose verification device is equal to the source axis distance. In actual use, it may be moved back and forth near the isocenter. The distance from the ion source to the reference point of the three-dimensional dose verification device is obtained by adding or subtracting the moving distance based on the source axis distance, which is recorded as L. The coordinate information of the stripe ionization chamber 30 is ( , , ), the calculation method of the position information of the kth dose ionization chamber 20 is shown in formula (6), formula (7) and formula (8):

[0093] (6)

[0094] (7)

[0095] (8)

[0096] Wherein, d is the distance from the stripe ionization chamber 30 to the kth dose ionization chamber 20. The position information of any dose ionization chamber 20 can be obtained from the above formula.

[0097] The above formula can be used to obtain the dose of all points within the detection range. After spatially arranging these point doses, they are saved as DICOM files, which are medical digital imaging and communication files. From this, the depth dose curve within the test range and the surface dose distribution perpendicular to the beam can be obtained. The surface dose distribution is the transverse dose distribution. The schematic diagram of the transverse main axis dose curve at different depths is shown in Figure 4 The multiple points collected by the depth dose curve correspond to the dose at each dose ionization chamber 20 , and the lateral dose distribution at each dose ionization chamber 20 can also be directly obtained.

[0098] The test unit processes the position information and dose information of the multiple dose ionization chambers 20 obtained above to obtain a measured three-dimensional dose distribution. The measured three-dimensional dose distribution diagrams are shown in FIG. 7( a ), FIG. 7( b ) and FIG. 7( c ).

[0099] Taking the carbon ion therapy system as an example, a 30cm*30cm*30cm uniform water phantom is scanned by CT. After the CT image is obtained, it is imported into the treatment planning system. The treatment planning system is used to outline the target area in the phantom. The target area size is about 30mm*30 mm*15mm. The treatment plan is formulated using an active beam delivery method. There are three layers of beams, including three energies of 291.14MeV / u, 295.33 MeV / u and 299.5 MeV / u. The planning system file is imported into the test unit to obtain the planned three-dimensional dose distribution. The planned three-dimensional dose distribution diagrams are shown in Figures 6 (a), 6 (b) and 6 (c).

[0100] The test unit compares the measured three-dimensional dose distribution with the planned three-dimensional dose distribution. The comparison includes difference comparison, obtaining the verification pass rate, and judging whether the dose verification has passed based on the comparison result between the verification pass rate and the preset pass rate. For example, if the preset pass rate is 90%, and the verification pass rate is less than or equal to 90%, it indicates that the measurement verification has not passed; if the verification pass rate is greater than 90%, it indicates that the dose verification has passed.

[0101] In an embodiment of the present invention, a plurality of dose ionization chambers 20 and a plurality of stripe ionization chambers 30 are sequentially arranged on a mounting frame 10. Position information and dose information of a plurality of dose ionization chambers 20 can be obtained in a single measurement, and a measured three-dimensional dose distribution can be obtained, thereby effectively improving the verification efficiency. A large amount of data and a large sample size are obtained in the space, thereby effectively improving the accuracy of the verification result.

[0102] like Figure 2 As shown, in an optional embodiment, the dose ionization chamber 20 includes a first bracket 21, two first high-voltage plates 22, a collecting plate 23 and a first equivalent plate 24. The two first high-voltage plates 22 are arranged on the first bracket 21; the collecting plate 23 is sandwiched between the two first high-voltage plates 22; and the first equivalent plate 24 is arranged on a side of one of the first high-voltage plates 22 away from the collecting plate 23.

[0103] Exemplarily, the dose ionization chamber 20 uses an air ionization chamber. The first bracket 21 can be a square frame structure, and the first high-voltage plate 22, the collecting plate 23 and the first equivalent plate 24 can be installed on the first bracket 21 by screwing. The number of the first high-voltage plate 22 is two, and the first equivalent plate 24, the first high-voltage plate 22, the collecting plate 23 and the first high-voltage plate 22 are stacked in sequence.

[0104] Optionally, the first bracket 21 is detachably connected to the mounting frame 10. The number of dose ionization chambers 20 installed on the mounting frame 10 and the positions of the dose ionization chambers 20 can be adjusted according to measurement requirements.

[0105] In some embodiments, a plurality of slots are arranged at intervals along the length direction of the mounting frame 10, a first plug-in portion 211 is arranged at the bottom of the first bracket 21, the first plug-in portion 211 matches the slot, and the first bracket 21 can be installed at the slot of the mounting frame 10 by plugging, so that the dose ionization chamber 20 is detachably connected to the mounting frame 10. The dose ionization chamber 20 can be installed at any position of the mounting frame 10 according to measurement requirements.

[0106] The material of the first equivalent plate 24 includes PMMA (polymethyl methacrylate) material, and the thickness of the first equivalent plate 24 is set according to actual needs.

[0107] Optionally, the first equivalent plate 24 is detachably connected to the first bracket 21, and the first equivalent plate 24 can be connected to the first bracket 21 by screwing. For example, through holes are provided on the first equivalent plate 24, the first high-voltage electrode plate 22, the collecting electrode plate 23 and the first bracket 21, and bolts pass through the multiple through holes and nuts are screwed on to achieve the connection between the first equivalent plate 24, the first high-voltage electrode plate 22, the collecting electrode plate 23 and the first bracket 21.

[0108] The first equivalent plate 24 is replaceable. The first equivalent plate 24 on each dose ionization chamber 20 is replaceable. By replacing the first equivalent plates 24 of different thicknesses, the patient's tissue can be better restored to meet various measurement requirements.

[0109] By equipping dose ionization chambers 20 with various water equivalent thicknesses, it is possible to achieve measurements with various precision combinations. For example, dose ionization chambers 20 with small water equivalent thickness are installed at locations with large dose gradients, and dose ionization chambers 20 with large water equivalent thickness are installed at locations with small dose gradients. At locations with large dose gradients, the dose changes quickly, and higher precision tests are required.

[0110] like Figure 3 As shown, in an optional embodiment, the stripe ionization chamber 30 includes a second bracket 31, a plurality of second high-voltage plates 32, a first strip electrode 33, a second strip electrode 34, and a second equivalent plate 35. The plurality of second high-voltage plates 32 are arranged on the second bracket 31; the first strip electrode 33 is sandwiched between two adjacent second high-voltage plates 32; the second strip electrode 34 is sandwiched between two adjacent second high-voltage plates 32; and the second equivalent plate 35 is arranged on one side of a second high-voltage plate 32. The strip structure direction of the first strip electrode 33 intersects with the strip structure direction of the second strip electrode 34.

[0111] Exemplarily, the second bracket 31 may be a frame structure, and the second high-voltage plate 32, the first strip electrode 33, the second strip electrode 34, and the second equivalent plate 35 may be screwed to the second bracket 31. In some embodiments, the number of the second high-voltage plates 32 is three, and the second equivalent plate 35, the second high-voltage plate 32, the second strip electrode 34, the second high-voltage plate 32, the first strip electrode 33, and the second high-voltage plate 32 are stacked in sequence.

[0112] It can be understood that the stripe ionization chamber 30 is perpendicular to the beam incident direction. The stripe structure direction on the first stripe electrode 33 intersects with the stripe structure direction on the second stripe electrode 34. For example, the two are perpendicular to each other, and horizontal and vertical beam projection information can be obtained respectively. The two can also be at an angle other than 90 degrees.

[0113] Optionally, the second bracket 31 is detachably connected to the mounting frame 10. The number of the striped ionization chambers 30 installed on the mounting frame 10 and the positions of the striped ionization chambers 30 can be adjusted according to measurement requirements.

[0114] In some embodiments, a second plug-in portion 311 is provided at the bottom of the second bracket 31, and the second plug-in portion 311 matches the slot, and the second bracket 31 can be installed in the slot of the mounting frame 10 by plugging, so that the striped ionization chamber 30 is detachably connected to the mounting frame 10. The striped ionization chamber 30 can be installed at any position of the mounting frame 10 according to actual needs.

[0115] The material of the second equivalent plate 35 includes PMMA (polymethyl methacrylate) material, and the thickness of the second equivalent plate 35 is set according to actual needs.

[0116] Optionally, the second equivalent plate 35 is detachably connected to the second bracket 31, and the second equivalent plate 35 can be connected to the second bracket 31 by screwing. For example, the second equivalent plate 35, the second high-voltage plate 32, the first strip electrode 33, the second strip electrode 34 and the second bracket 31 are all provided with through holes, and bolts pass through the multiple through holes and nuts are screwed on to achieve the connection between the second equivalent plate 35, the second high-voltage plate 32, the second strip electrode 34, the first strip electrode 33 and the second bracket 31.

[0117] The second equivalent plate 35 is replaceable. The second equivalent plate 35 on each stripe ionization chamber 30 is replaceable. By replacing the second equivalent plates 35 with different thicknesses, various measurement requirements can be met.

[0118] The first bracket 21 is detachably connected to the mounting frame 10, and the second bracket 31 is detachably connected to the mounting frame 10. A plurality of dose ionization chambers 20 and a plurality of stripe ionization chambers 30 can be installed on the mounting frame 10 in a target order according to measurement requirements. For example, p slots are provided on the mounting frame 10, and the p slots correspond to p depths. The dose ionization chamber 20 is installed at the first slot, and the acquisition unit acquires the position information and dose information of the dose ionization chamber 20 corresponding to the first slot, so as to obtain the transverse surface dose distribution of the first depth. The dose ionization chamber 20 is installed at the qth slot, q is less than p, and the acquisition unit acquires the position information and dose information of the dose ionization chamber 20 corresponding to the qth slot, so as to obtain the transverse surface dose distribution of the qth depth. In this way, more measurement requirements can be flexibly met and the transverse surface dose distribution of the depth of interest can be obtained.

[0119] The first bracket 21 and the second bracket 31 are detachably connected to the mounting frame 10, and the positions of the multiple ionization chambers on the mounting frame 10 can be randomly combined. The acquisition density can be set as needed. For example, by installing the dose ionization chamber 20 in the first slot, the transverse surface dose distribution of the first depth can be obtained; by installing the dose ionization chamber 20 in the second slot, the transverse surface dose distribution of the second depth can be obtained; by installing the dose ionization chamber 20 in the third slot, the transverse surface dose distribution of the third depth can be obtained; by installing the dose ionization chamber 20 in the fourth slot, the transverse surface dose distribution of the fourth depth can be obtained; by installing the dose ionization chamber 20 in the pth slot, the transverse surface dose distribution of the pth depth can be obtained. By adjusting the installation positions of the multiple stripe ionization chambers 30 and the multiple dose ionization chambers 20 on the mounting frame 10, the transverse surface dose distribution of the target depth of interest can be obtained.

[0120] In an optional embodiment, the number of the stripe ionization chambers 30 is equal to the number of the dose ionization chambers 20 , and a plurality of dose ionization chambers 20 and a plurality of stripe ionization chambers 30 are arranged alternately.

[0121] When there are multiple stripe ionization chambers 30, in some embodiments, the number of stripe ionization chambers 30 is equal to the number of dose ionization chambers 20, and multiple stripe ionization chambers 30 and multiple dose ionization chambers 20 are staggered along the length direction of the mounting frame 10. The position information of each dose ionization chamber 20 is obtained through the stripe ionization chamber 30 close to the dose ionization chamber 20. Multiple stripe ionization chambers 30 make the horizontal point position distribution on each dose ionization chamber 20 more accurate, which is conducive to improving the verification accuracy.

[0122] like Fig. 9 As shown, an embodiment of the present invention further provides a verification method for a three-dimensional dose verification device for ion therapy, the verification method comprising:

[0123] Step 110: Obtaining dose information and position information of any dose ionization chamber 20;

[0124] Step 120: obtaining a measured three-dimensional dose distribution based on the dose information and position information of the multiple dose ionization chambers 20;

[0125] Step 130: Based on the comparison results of the measured three-dimensional dose distribution and the planned three-dimensional dose distribution, obtain the verification pass rate.

[0126] The position information of the dose ionization chamber 20 is obtained from the position information of the stripe ionization chamber 30 .

[0127] The structure of the three-dimensional dose verification device is as described above, and m dose ionization chambers 20 and n stripe ionization chambers 30 are sequentially arranged on the mounting frame 10 along the length direction of the mounting frame 10. The active beam delivery system emits beams to the three-dimensional dose verification device.

[0128] The acquisition unit acquires beam projection information of each stripe ionization chamber 30 and dose information of each dose ionization chamber 20 , and obtains position information of m dose ionization chambers 20 from the beam projection information of n stripe ionization chambers 30 .

[0129] The test unit processes the dose information and position information of the m dose ionization chambers 20 to obtain the measured three-dimensional dose distribution. The test unit processes the planning system file to obtain the planned three-dimensional dose distribution. The test unit further compares the measured three-dimensional dose distribution with the planned three-dimensional dose distribution, obtains the verification pass rate from the comparison result, and further determines whether the dose verification is passed based on the comparison result between the verification pass rate and the preset pass rate. For example, if the preset pass rate is 90%, the verification pass rate is less than or equal to 90%, indicating that the dose verification has not passed; if the verification pass rate is greater than 90%, it indicates that the dose verification has passed.

[0130] The verification method of the present invention can obtain the position information and dose information of multiple dose ionization chambers 20 in a single measurement, obtain the measured three-dimensional dose distribution, effectively improve the verification efficiency, obtain more data in space, and have a large sample size, which effectively improves the accuracy of the verification result.

[0131] The method in which the collecting unit collects the dose information of the dose ionization chamber 20 is as follows.

[0132] In ion therapy, an active beam delivery system is used to emit beams, that is, the beams are irradiated in layers according to energy. Assuming that the total number of layers is N, there are N groups of doses collected at the same position, recorded as The coordinates of a point in the dose ionization chamber 20 are The dose obtained by each layer at this point is recorded as , so the total dose at this point It can be obtained by formula (1):

[0133] (1)

[0134] Assuming that the total time of beam delivery is t, the number of dose ionization chambers 20 is m, the dose value of the kth (k=1,…,m) dose ionization chamber 20 at time p (p=0,…,t) is recorded as The total dose of the dose ionization chamber 20 is recorded as , total dose It can be obtained by formula (2):

[0135] (2)

[0136] The depth dose curve is an ordered arrangement of the total dose values ​​of all dose ionization chambers 20 ( , …, ). The depth dose curve diagram is as follows Figure 5 shown.

[0137] The method for the acquisition unit to acquire the position information of the dose ionization chamber 20 is as follows.

[0138] The number of the stripe ionization chambers 30 is less than the number of the dose ionization chambers 20 , and the number of the stripe ionization chambers 30 is greater than 1. When there are two stripe ionization chambers 30 , the two stripe ionization chambers 30 are defined as a first stripe ionization chamber 30 and a second stripe ionization chamber 30 .

[0139] The coordinate information of the first stripe ionization chamber 30 is ( , , ), the coordinate information of the second stripe ionization chamber 30 is ( , , ), if the first dose ionization chamber 20 is adjacent to the first stripe ionization chamber 30, and the second dose ionization chamber 20 is adjacent to the second stripe ionization chamber 30. The position information of the first dose ionization chamber 20 is obtained from the coordinate information of the first stripe ionization chamber 30, and the position information of the second dose ionization chamber 20 is obtained from the coordinate information of the second stripe ionization chamber 30. The calculation method of the position information of the kth dose ionization chamber 20 is shown in formula (3), formula (4) and formula (5):

[0140] (3)

[0141] (4)

[0142] (5)

[0143] Wherein, d is the distance from the first stripe ionization chamber 30 to the kth dose ionization chamber 20. The position information of other dose ionization chambers 20 can be obtained from the above formula.

[0144] Therefore, by using the similar triangle principle calculation method, two stripe ionization chambers 30 are installed on the mounting frame 10 to obtain the position information of any dose ionization chamber 20. This effectively improves the efficiency of collecting the position information of the dose ionization chamber 20, thereby facilitating the improvement of verification efficiency.

[0145] The number of stripe circuit chambers is 1, and the stripe ionization chamber 30 is installed at the end of the mounting frame 10, and the stripe ionization chamber 30 is opposite to the incident end of the active beam delivery system. The coordinate information of the stripe ionization chamber 30 is ( , , ), the calculation method of the position information of the kth dose ionization chamber 20 is shown in formula (6), formula (7) and formula (8):

[0146] (6)

[0147] (7)

[0148] (8)

[0149] Wherein, d is the distance from the stripe ionization chamber 30 to the kth dose ionization chamber 20. The position information of any dose ionization chamber 20 can be obtained from the above formula.

[0150] Therefore, by installing a stripe ionization chamber 30 at the end of the mounting frame 10, the position information of any dose ionization chamber 20 can be obtained, which effectively improves the collection efficiency of the position information of the dose ionization chamber 20, thereby facilitating the improvement of the verification efficiency.

[0151] It is understandable that when the number of stripe ionization chambers 30 is equal to the number of dose ionization chambers 20, the position information of each dose ionization chamber 20 is obtained from the adjacent stripe ionization chambers 30. The more the number of stripe ionization chambers 30, the more accurate the horizontal point position distribution on each dose ionization chamber 20.

[0152] The above formula can be used to obtain the dose of all points within the detection range. After spatially arranging these point doses and saving them as DICOM files, the depth dose curve within the test range and the surface dose distribution perpendicular to the beam can be obtained. The multiple points collected by the depth dose curve correspond to the dose at the location of each dose ionization chamber 20, and the lateral dose distribution at the location of each dose ionization chamber 20 can also be directly obtained.

[0153] The test unit processes the position information and dose information of the multiple dose ionization chambers 20 obtained above to obtain the measured three-dimensional dose distribution, and the measured three-dimensional dose distribution diagrams are shown in Figures 7 (a), 7 (b) and 7 (c). The planning system file is imported into the test unit to obtain the planned three-dimensional dose distribution, and the planned three-dimensional dose distribution diagrams are shown in Figures 6 (a), 6 (b) and 6 (c).

[0154] like Figure 8 As shown, the test unit compares the measured three-dimensional dose distribution with the planned three-dimensional dose distribution, and obtains different verification pass rates by adjusting the position error value and the dose error value. Further, the verification pass rate is compared with the preset pass rate to determine whether the dose verification is passed. The preset pass rate value can be 90%. The position error value ranges from 2 to 4 mm. The dose error value ranges from 2% to 6%.

[0155] For example, when the position error is set to 3 mm and the dose error is set to 3%, the obtained verification pass rate is 47.2%. The verification pass rate is less than 90%, indicating that the dose verification has failed.

[0156] For example, the position error is set to 3 mm and the dose error is set to 5%, and the obtained verification pass rate is 96.4%. The verification pass rate is greater than 90%, indicating that the dose verification is passed.

[0157] In an embodiment of the present invention, the position information and dose information of multiple dose ionization chambers 20 can be obtained in a single measurement to obtain a measured three-dimensional dose distribution, which is then compared with the planned three-dimensional dose distribution to obtain a verification pass rate, thereby effectively improving the verification efficiency and the accuracy of the verification results.

[0158] The above is only a specific embodiment of the present invention, but the protection scope of this application is not limited thereto. Any changes or substitutions made within the spirit and principle of the present invention should be included in the protection scope of this application. Therefore, the protection scope of this application should be based on the protection scope of the claims.

Claims

1. A three-dimensional dose verification device for ion therapy, characterized in that: include: Mounting frame; m dose ionization chambers; n stripe ionization chambers, wherein the n stripe ionization chambers and the m dose ionization chambers are sequentially arranged on the mounting frame; A collection unit, used for collecting the dose information and position information of the m dose ionization chambers to obtain the measured three-dimensional metrological distribution, wherein the position information of the m dose ionization chambers is obtained from the position information of the n stripe ionization chambers; as well as A testing unit is used to obtain a verification pass rate according to a comparison result between the measured three-dimensional dose distribution and the planned three-dimensional dose distribution, Wherein, m is an integer greater than 1, n is an integer greater than or equal to 1, and n is less than or equal to m.

2. The three-dimensional dose verification device according to claim 1, characterized in that: The dose ionization chamber comprises: A first bracket connected to the mounting frame; Two first high-voltage plates, arranged on the first bracket; A collecting plate, sandwiched between the two first high-voltage plates; and The first equivalent plate is arranged on a side of the first high-voltage electrode plate away from the collecting electrode plate.

3. The three-dimensional dose verification device according to claim 2, characterized in that: The first bracket is detachably connected to the mounting frame.

4. The three-dimensional dose verification device according to claim 1, characterized in that: The stripe ionization chamber comprises: A second bracket connected to the mounting frame; A plurality of second high-voltage plates, arranged on the second bracket; A first strip electrode, sandwiched between two adjacent second high-voltage plates; A second strip electrode, sandwiched between two adjacent second high-voltage plates; and A second equivalent plate, provided on one side of the second high voltage plate; The strip structure direction of the first strip electrode intersects with the strip structure direction of the second strip electrode.

5. The three-dimensional dose verification device according to claim 4, characterized in that: The second bracket is detachably connected to the mounting frame.

6. A verification method using the three-dimensional dose verification device for ion therapy according to any one of claims 1 to 5, characterized in that: The verification method comprises: Obtain the dose information and position information of any dose ionization chamber; Based on the dose information and position information of the plurality of dose ionization chambers, obtaining a measured three-dimensional dose distribution; Based on the comparison results of the measured three-dimensional dose distribution and the planned three-dimensional dose distribution, the verification pass rate is obtained. Wherein, the position information of the dose ionization chamber is obtained from the position information of the stripe ionization chamber.

7. The verification method according to claim 6, characterized in that: When the number of the stripe ionization chambers is equal to 1, obtaining the position information of any dose ionization chamber includes: Acquiring coordinate information of the stripe ionization chamber; Acquiring the spacing information between the stripe ionization chamber and any of the dose ionization chambers; Based on the coordinate information and the spacing information of the stripe ionization chambers, the position information of any one of the dose ionization chambers is acquired.

8. The verification method according to claim 6, characterized in that: When the number of the stripe ionization chambers is less than the number of the dose ionization chambers, and the number of the stripe ionization chambers is greater than 1, the acquiring the position information of any dose ionization chamber includes: Obtaining first coordinate information of a first stripe ionization chamber and second coordinate information of a second stripe ionization chamber; Acquire the spacing information between the first stripe ionization chamber and any of the dose ionization chambers; Based on the first coordinate information, the second coordinate information and the distance information, the position information of any one of the dose ionization chambers is acquired.

9. The verification method according to claim 6, characterized in that: The obtaining of the verification pass rate based on the comparison result between the measured three-dimensional dose distribution and the planned three-dimensional dose distribution includes: The position error value and / or the dosage error value are adjusted to obtain the verification pass rate.

10. The verification method according to claim 9, characterized in that: The position error value ranges from 2 to 4 mm; and / or The dosage error value ranges from 2% to 6%.

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