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

Abstract

The application 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, n strip ionization chambers, a collection unit and a test unit. The m dose ionization chambers and the n strip ionization chambers are sequentially arranged on the mounting rack. The collection unit is used for collecting dose information and position information of the m dose ionization chambers to obtain a measured three-dimensional dose distribution. The position information of the m dose ionization chambers is obtained from the position information of the n strip ionization chambers. The test unit is used for obtaining a verification pass rate according to a comparison result of the measured three-dimensional dose distribution and a planned three-dimensional dose distribution. The m is an integer greater than 1, the n is an integer greater than or equal to 1, and the n is less than or equal to the m. The three-dimensional dose verification device can obtain the position information and the dose information of the multiple dose ionization chambers in a single measurement, obtain the measured three-dimensional dose distribution, and effectively improve the verification efficiency and the accuracy of the verification result.

Description

Technical Field

[0001] This invention relates to the field of radiotherapy technology, and in particular to a three-dimensional dose verification device and method for ion therapy. Background Technology

[0002] The depth-dose distribution of ion beams when penetrating biological tissue is well-suited for tumor treatment. As an ion beam traverses matter, its kinetic energy is primarily lost at the end of its range, exhibiting a sharply enhanced Bragg peak. This means that energy loss during ion-matter interaction occurs primarily within a millimeter-scale range at the end of the beam's range, and the position of the Bragg peak is highly controllable. Utilizing these characteristics, energy can be deposited to the patient's tumor target area to the maximum extent, resulting in enhanced local tumor control and a reduced risk of complications in normal tissues. Ion beam radiotherapy offers unique depth-dose distribution and a high relative biological effect, advantages that conventional radiotherapy methods cannot match.

[0003] In related technologies, amorphous silicon electron beam imaging devices are installed on particle therapy equipment to perform pre-treatment gamma-ray throughput tests or to collect the remaining photon flux after photons penetrate the human body during treatment, thereby reconstructing the dose distribution within the body and achieving dose reconstruction. Electron beam imaging technology can be well applied in photon therapy, but it cannot be used in proton or heavy ion therapy because photons still have a significant flux that can be detected after penetrating human tissue, while protons and heavy ions can hardly penetrate the human body.

[0004] In related technologies, ion therapy uses a matrix ionization chamber in conjunction with an equivalent water material to collect absorbed dose within a fixed depth plane. The collected data is compared with the TPS calculation results to obtain the 2D dose-gamma transmission rate. Some ion centers also use multi-channel ionization chambers to measure point dose in a water tank. This method is cumbersome, requiring multiple measurements to obtain a three-dimensional dose distribution including lateral and depth directions, resulting in large measurement errors and long measurement times. Summary of the Invention

[0005] In view of this, embodiments of the present invention provide a three-dimensional dose verification device and method for ion therapy, which solves the problems of existing three-dimensional dose testing equipment requiring multiple measurements, long measurement time, and poor accuracy of measurement results.

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

[0007] Mounting rack;

[0008] m dose ionization chambers;

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

[0010] The acquisition unit is used to acquire dose information and position information of m dose ionization chambers to obtain a measured three-dimensional metrological distribution. The position information of the m dose ionization chambers is obtained from the position information of n segmented ionization chambers.

[0011] The testing unit is used to obtain the verification pass rate based on the comparison between the measured three-dimensional dose distribution and the planned three-dimensional dose distribution.

[0012] Where 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] The first bracket is connected to the mounting bracket;

[0015] Two first high-voltage plates are mounted on the first bracket;

[0016] The collecting electrode plate is sandwiched between the two first high-voltage electrodes; and

[0017] A first equivalent plate is disposed on the side of the first high-voltage plate opposite to the collecting plate.

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

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

[0020] The second bracket is connected to the mounting bracket;

[0021] Multiple second high-voltage plates are disposed on the second bracket;

[0022] The first electrode is sandwiched between two adjacent second high-voltage plates;

[0023] The second electrode is sandwiched between two adjacent second high-voltage plates; and

[0024] A second equivalent plate is disposed on one side of a second high-voltage plate;

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

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

[0027] Secondly, embodiments of the present invention provide a verification method for a three-dimensional dose verification device for ion therapy, the verification method comprising:

[0028] Obtain dose and location information for any dose ionization chamber;

[0029] Based on the dose information and location information of the multiple dose ionization chambers, the measured three-dimensional dose distribution is obtained;

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

[0031] The location information of the dose ionization chamber is obtained from the location information of the segmented ionization chamber.

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

[0033] Obtain the coordinate information of the segmented ionization chamber;

[0034] Obtain the distance information between the segmented ionization chamber and any one of the dose ionization chambers;

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

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

[0037] Obtain the first coordinate information of the first segmented ionization chamber and the second coordinate information of the second segmented ionization chamber;

[0038] Obtain the distance information between the first segmented ionization chamber and any one of the dose ionization chambers;

[0039] Based on the first coordinate information, the second coordinate information, and the spacing information, the location information of any one of the dose ionization chambers is obtained.

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

[0041] Adjust the position error value and / or dose error value 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 range is 2% to 6%.

[0044] The three-dimensional dose verification device and method for ion therapy provided by the embodiments of the present invention can achieve at least the following technical effects: multiple dose ionization chambers and multiple strip ionization chambers are arranged sequentially on the 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, which effectively improves the verification efficiency. The amount of data obtained in the space is large and the sample size is large, which effectively improves the accuracy of the verification results. Attached Figure Description

[0045] The above and other objects, features and advantages of the present invention will become more apparent from the following description of embodiments of the 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 A schematic diagram illustrating an explosion of a dose ionization chamber according to an embodiment of the present invention is shown.

[0048] Figure 3 An explosion diagram of a strip ionization chamber according to an embodiment of the present invention is shown schematically;

[0049] Figure 4 A schematic diagram illustrating the lateral principal axis relative dose curves at different depths according to an embodiment of the present invention;

[0050] Figure 5 This schematic diagram illustrates a depth-dose curve obtained by a three-dimensional dose verification device according to an embodiment of the present invention.

[0051] Figure 6(a) schematically illustrates a cross-sectional view of the planned three-dimensional dose distribution according to an embodiment of the present invention;

[0052] Figure 6(b) schematically illustrates a sagittal view of the planned three-dimensional dose distribution according to an embodiment of the present invention;

[0053] Figure 6(c) schematically illustrates a coronal plot of the planned three-dimensional dose distribution according to an embodiment of the present invention;

[0054] Figure 7(a) schematically shows a cross-sectional view of the measured three-dimensional dose distribution according to an embodiment of the present invention;

[0055] Figure 7(b) schematically illustrates a sagittal plot of the measured three-dimensional dose distribution according to an embodiment of the present invention;

[0056] Figure 7(c) schematically illustrates a coronal plot of a measured three-dimensional dose distribution according to an embodiment of the present invention;

[0057] Figure 8The diagram illustrates the results of gamma analysis of measured three-dimensional dose distribution and planned three-dimensional dose distribution according to an embodiment of the present invention.

[0058] Figure 9 A flowchart illustrating a verification method of a three-dimensional dose verification apparatus according to an embodiment of the present invention is shown schematically.

[0059] Figure label:

[0060] 10: Mounting bracket; 20: Dosage ionization chamber; 21: First support; 211: First connector; 22: First high-voltage electrode; 23: Collecting electrode; 24: First equivalent plate; 30: Segmented ionization chamber; 31: Second support; 311: Second connector; 32: Second high-voltage electrode; 33: First strip electrode; 34: Second strip electrode; 35: Second equivalent plate. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0062] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0063] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0064] Radiation therapy works by directly targeting DNA molecules, disrupting DNA chains, or indirectly ionizing water in human tissues to generate free radicals. These free radicals then interact 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. Radiation therapy utilizes this difference to treat tumors while protecting normal human cells to the greatest extent possible.

[0065] The depth-dose distribution of ion beams during penetration into biological tissues is ideally suited for tumor treatment. As an ion beam penetrates matter, its kinetic energy is primarily lost towards the end of its range, exhibiting a sharply enhanced Bragg peak. This means that energy loss during ion-matter interaction occurs primarily within a millimeter-scale range at the end of the beam's range, and the position of this Bragg peak is highly controllable. Utilizing these characteristics, energy can be deposited to the patient's tumor target area to the maximum extent, resulting in enhanced local tumor control and a reduced risk of complications in normal tissues. Ion beam radiotherapy offers unique depth-dose distribution and a high relative biological effect, advantages that conventional radiotherapy methods cannot match.

[0066] Point scanning and grid scanning techniques are representative technologies of active beam delivery systems. Unlike passive beam delivery systems, active beam delivery systems generally do not heavily modulate the pencil beam provided by the accelerator. This technique divides the irradiation target area into several isoenergetic sections along the beam injection direction. Each isoenergetic section is further divided into several scanning points, where an isoenergetic section means that all scanning points in that section have the same energy. By adjusting the ion beam energy and scanning magnet parameters to control the pencil beam irradiation position, layered point-by-point irradiation of the tumor target area is achieved. The scanning points are accumulated laterally and longitudinally to achieve a planned uniform dose distribution, greatly improving the conformity of the target area.

[0067] Radiation therapy mainly includes the patient localization phase, the treatment planning phase, and the treatment execution phase. The accuracy of radiation therapy includes both location accuracy and dosage accuracy.

[0068] In existing technologies, amorphous silicon electron field imaging devices are installed on particle therapy equipment to perform pre-treatment gamma-ray throughput tests or to collect the remaining photon flux after photons penetrate the human body during treatment, thereby reconstructing the dose distribution within the body and achieving dose reconstruction. Electron field imaging technology is well-suited for photon therapy, but it cannot be used in proton and heavy ion therapy. This is because photons still have a significant flux that can be detected after penetrating human tissue, while protons and heavy ions can hardly penetrate the human body, making the detector unable to detect the dose. Therefore, electron field imaging technology is meaningless in proton and heavy ion therapy.

[0069] In existing technologies, ion therapy also uses a matrix ionization chamber in conjunction with an equivalent water material to collect absorbed dose within a fixed depth plane. The collected data is compared with the TPS calculation results to obtain the 2D dose-gamma transmission rate. Some ion centers also use a multi-channel ionization chamber to measure point dose in a water tank. This method is cumbersome, requiring multiple measurements to obtain a three-dimensional dose distribution including lateral and depth directions. It suffers from large human error, long measurement time, and is not suitable for large-scale patient validation.

[0070] The following is combined with Figures 1 to 8This invention describes a three-dimensional dose verification device for ion therapy, according to an embodiment of the present invention.

[0071] like Figure 1 As shown, the three-dimensional dose verification device provided in the embodiment of the present invention includes a mounting frame 10, m dose ionization chambers 20, n strip ionization chambers 30, a data acquisition unit, and a testing unit. The n strip ionization chambers 30 and the m dose ionization chambers 20 are sequentially arranged on the mounting frame 10. The data acquisition unit is used to acquire the dose information and position information of the m dose ionization chambers 20 to obtain the measured three-dimensional dose distribution. The position information of the m dose ionization chambers 20 is obtained from the position information of the n strip ionization chambers 30. The testing unit is used to obtain the verification pass rate based on the comparison between the measured three-dimensional dose distribution and the planned three-dimensional dose distribution.

[0072] For example, m dose ionization chambers 20 and n strip ionization chambers 30 are sequentially arranged on the frame along the length of the mounting bracket 10. The number of dose ionization chambers 20 and strip ionization chambers 30 is not specifically limited. The active beam delivery system emits a beam to the three-dimensional dose verification device. The strip ionization chambers 30 are used to record beam projection information, including the lateral beam spot position distribution and beam profile. The dose ionization chambers 20 can reflect dose information, and the position information of each dose ionization chamber 20 is obtained from the beam projection information recorded by the strip ionization chambers 30. The position information includes X-axis coordinate information, Y-axis coordinate information, and Z-axis 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 accommodate multiple dose ionization chambers 20 and multiple strip ionization chambers 30 simultaneously. The number of strip ionization chambers 30, n, is greater than or equal to 1, where n is an integer. The number of dose ionization chambers 20, m, is greater than 1, where m is an integer. At the same time, the number of strip ionization chambers 30 is less than or equal to the number of 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. Dose information is obtained through the dose ionization chamber 20. The strip ionization chamber 30 includes a high-voltage electrode, a strip electrode, and an equivalent plate of a second preset thickness. Position information is obtained through the strip 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 amplifies and processes the ionization signal from the ionization chamber. The acquisition unit acquires the amplified data from the electronics system and processes it. The acquisition unit simultaneously acquires the position information of the strip 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 strip ionization chamber 30.

[0076] The method for the acquisition unit to acquire dose information from the dose ionization chamber 20 is as follows.

[0077] Ion therapy uses an active beam delivery system to deliver the beam, meaning the beam is stratified by energy. Assuming the total number of strata is N, there will be N dose sets collected at the same location, denoted as N0. The coordinates of a point within the dose ionization chamber 20 are: The dose obtained at each layer at this point is denoted as Therefore, the total dose at that point It can be obtained through formula (1):

[0078] (1)

[0079] Assuming the total beam delivery time is t, and the number of dose ionization chambers 20 is m, the dose value of the k-th (k=1,…,m) dose ionization chamber 20 at time p (p=0,…,t) is denoted as The total dose of the dose ionization chamber 20 is denoted as Total dose It can be obtained through formula (2):

[0080] (2)

[0081] The depth dose curve is an ordered arrangement of the total dose values ​​of all dose ionization chambers (20). , ..., A schematic diagram of the dose-depth curve is shown below. Figure 5 As shown.

[0082] The method for acquiring the location information of the dose ionization chamber 20 by the acquisition unit is as follows. Depending on the number of segmented ionization chambers 30, the methods for acquiring the location information of the dose ionization chamber 20 include the following three methods. It is understood that the methods for acquiring the location information of the dose ionization chamber 20 are not limited to these three methods.

[0083] For example, the number of strip ionization chambers 30 is equal to the number of dose ionization chambers 20. Multiple strip ionization chambers 30 and multiple dose ionization chambers 20 are staggered along the length of the mounting frame 10. The position information of each dose ionization chamber 20 is obtained from the adjacent strip ionization chambers 30. Multiple strip ionization chambers 30 make the lateral point position distribution on each dose ionization chamber 20 more precise.

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

[0085] When there are two striped ionization chambers 30, the two striped ionization chambers 30 are defined as the first striped ionization chamber 30 and the second striped ionization chamber 30, respectively. The first striped ionization chamber 30 and the second striped ionization chamber 30 are not adjacent. When there are more than two dose ionization chambers 20, according to the arrangement order of the multiple ionization chambers, 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 m-th dose ionization chamber 20. The first dose ionization chamber 20 is adjacent to the first striped ionization chamber 30, and the second dose ionization chamber 20 is adjacent to the second striped ionization chamber 30. The position information of the first dose ionization chamber 20 is directly obtained from the first striped ionization chamber 30, and the position information of the second dose ionization chamber 20 is directly obtained from the second striped ionization chamber 30. The position information of other dose ionization chambers 20 can be calculated according to the principle of similar triangles. The specific calculation method is as follows.

[0086] The coordinates of the first segmented ionization chamber 30 are ( , , The coordinate information of the second segmented ionization chamber 30 is ( , , The Z value can be read based on the installation position of the strip ionization chamber 30 on the mounting bracket 10. The position information of the first dose ionization chamber 20 is obtained from the coordinate information of the first strip ionization chamber 30, and the position information of the second dose ionization chamber 20 is obtained from the coordinate information of the second strip ionization chamber 30. The position information of the kth dose ionization chamber 20 is calculated as shown in formulas (3), (4) and (5):

[0087] (3)

[0088] (4)

[0089] (5)

[0090] Where d is the distance from the first segmented ionization chamber 30 to the k-th dose ionization chamber 20. The location information of the other dose ionization chambers 20 can be obtained from the above formula.

[0091] For example, there is one strip ionization chamber 30, which is installed at the end of the mounting frame 10 and 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 strip ionization chamber 30, and the specific calculation method is as follows.

[0092] When there is only one strip ionization chamber 30, the distance from the ion source to the reference point of the three-dimensional dose verification device needs to be known. Typically, the source axis distance of the accelerator is a constant. When the reference point for 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. Adding or subtracting this movement distance from the source axis distance gives the distance from the ion source to the reference point of the three-dimensional dose verification device, denoted as L. The coordinate information of the strip ionization chamber 30 is ( , , The calculation method for the position information of the k-th dose ionization chamber 20 is shown in formulas (6), (7) and (8):

[0093] (6)

[0094] (7)

[0095] (8)

[0096] Where d is the distance from the segmented ionization chamber 30 to the k-th 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 at all points within the detection range. These point doses are then spatially arranged and saved as a DICOM file (Digital Image and Communication File System). From this, the depth dose curve and the surface dose distribution perpendicular to the beam can be obtained within the test range. The surface dose distribution is the lateral dose distribution. A schematic diagram of the lateral principal axis dose curves at different depths is shown below. Figure 4 As shown, the multiple points acquired 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.

[0098] The test unit processes the position 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 Figure 7(a), Figure 7(b) and Figure 7(c).

[0099] Taking a carbon ion therapy system as an example, a uniform water phantom measuring 30cm*30cm*30cm was scanned using CT. The acquired CT images were then imported into a treatment planning system. The target area, approximately 30mm*30mm*15mm in size, was delineated within the phantom using this system. An active beam delivery method was used to formulate the treatment plan. The beam consisted of three layers, with energies of 291.14 MeV / u, 295.33 MeV / u, and 299.5 MeV / u. The planning system file was imported into the test unit to obtain the planned three-dimensional dose distribution, as shown in Figures 6(a), 6(b), and 6(c).

[0100] The testing unit compares the measured three-dimensional dose distribution with the planned three-dimensional dose distribution. This comparison includes differential comparison to obtain the validation pass rate. Based on the comparison between the validation pass rate and the preset pass rate, the unit determines whether the dose validation has passed. For example, if the preset pass rate is 90%, a validation pass rate less than or equal to 90% indicates that the metrological validation has failed; a validation pass rate greater than 90% indicates that the dose validation has passed.

[0101] In an embodiment of the present invention, multiple dose ionization chambers 20 and multiple strip ionization chambers 30 are sequentially arranged on the mounting frame 10. In a single measurement, the position information and dose information of multiple dose ionization chambers 20 can be obtained to obtain the measured three-dimensional dose distribution, which effectively improves the verification efficiency. The amount of data obtained in the space is large and the sample size is large, which effectively improves the accuracy of the verification results.

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

[0103] For example, the dose ionization chamber 20 uses an air ionization chamber. The first support 21 can be a square frame structure, and the first high-voltage electrode 22, the collecting electrode 23, and the first equivalent plate 24 can be screwed onto the first support 21. There are two first high-voltage electrodes 22, and the first equivalent plate 24, the first high-voltage electrode 22, the collecting electrode 23, and the first high-voltage electrode 22 are stacked sequentially.

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

[0105] In some embodiments, a plurality of slots are spaced apart along the length of the mounting frame 10, and a first insertion part 211 is provided at the bottom of the first bracket 21. The first insertion part 211 matches the slot, and the first bracket 21 can be installed in the slot of the mounting frame 10 by insertion, thereby detachably connecting the dose ionization chamber 20 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), 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 support 21, and the first equivalent plate 24 can be connected to the first support 21 by screwing. For example, the first equivalent plate 24, the first high-voltage electrode plate 22, the collecting electrode plate 23, and the first support 21 are all provided with through holes. Bolts pass through multiple through holes, and nuts are tightened to connect the first equivalent plate 24, the first high-voltage electrode plate 22, the collecting electrode plate 23, and the first support 21.

[0108] The first equivalent plate 24 is replaceable. The first equivalent plate 24 on each dose ionization chamber 20 can be replaced. By replacing the first equivalent plate 24 with one of different thicknesses, the patient tissue can be better restored, and various measurement needs can be met.

[0109] By equipping dose ionization chambers 20 with varying water equivalent thicknesses, measurements with different accuracy combinations can be achieved. For example, a dose ionization chamber 20 with a small water equivalent thickness can be installed at locations with large dose gradients, while a dose ionization chamber 20 with a large water equivalent thickness can be installed at locations with small dose gradients. Locations with large dose gradients experience rapid dose changes, requiring higher accuracy measurements.

[0110] like Figure 3 As shown, in an optional embodiment, the strip ionization chamber 30 includes a second support 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 disposed on the second support 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 disposed on one side of one of the second high-voltage plates 32. The strip structure direction of the first strip electrode 33 intersects with the strip structure direction of the second strip electrode 34.

[0111] For example, the second support 31 can be a frame structure, and the second high-voltage electrode 32, the first strip electrode 33, the second strip electrode 34, and the second equivalent plate 35 can be screwed onto the second support 31. In some embodiments, the number of second high-voltage electrode 32 is three, and the second equivalent plate 35, the second high-voltage electrode 32, the second strip electrode 34, the second high-voltage electrode 32, the first strip electrode 33, and the second high-voltage electrode 32 are stacked sequentially.

[0112] Understandably, the strip ionization chamber 30 is perpendicular to the beam injection direction. The direction of the strip structure on the first strip electrode 33 intersects the direction of the strip structure on the second strip electrode 34; for example, they are perpendicular to each other, allowing for the acquisition of horizontal and vertical beam projection information, respectively. They 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 and position of the slit ionization chambers 30 mounted on the mounting frame 10 can be adjusted according to measurement requirements.

[0114] In some embodiments, the bottom of the second bracket 31 is provided with a second insertion part 311, which matches the slot. The second bracket 31 can be installed in the slot of the mounting frame 10 by insertion, thereby detachably connecting the slit ionization chamber 30 to the mounting frame 10. The slit 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), 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 support 31, and the second equivalent plate 35 can be connected to the second support 31 by screwing. For example, the second equivalent plate 35, the second high-voltage electrode 32, the first strip electrode 33, the second strip electrode 34, and the second support 31 are all provided with through holes. Bolts pass through multiple through holes, and nuts are tightened to achieve the connection of the second equivalent plate 35, the second high-voltage electrode 32, the second strip electrode 34, the first strip electrode 33, and the second support 31.

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

[0118] The first bracket 21 and the second bracket 31 are detachably connected to the mounting frame 10. Multiple dose ionization chambers 20 and multiple segmented ionization chambers 30 can be installed on the mounting frame 10 in the target sequence according to measurement requirements. For example, the mounting frame 10 has p slots, each corresponding to a depth. Installing a dose ionization chamber 20 at the first slot allows the acquisition unit to collect the position and dose information of the corresponding chamber, thus obtaining the lateral dose distribution at the first depth. Installing a dose ionization chamber 20 at the q-th slot (q < p) allows the acquisition unit to collect the position and dose information of the corresponding chamber, thus obtaining the lateral dose distribution at the q-th depth. This flexibly meets more measurement needs and allows for the acquisition of the lateral dose distribution at depths of interest.

[0119] The first support 21 and the second support 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 sampling density can be set as needed. For example, installing the dose ionization chamber 20 in the first slot can obtain the lateral dose distribution at the first depth; installing the dose ionization chamber 20 in the second slot can obtain the lateral dose distribution at the second depth; installing the dose ionization chamber 20 in the third slot can obtain the lateral dose distribution at the third depth; installing the dose ionization chamber 20 in the fourth slot can obtain the lateral dose distribution at the fourth depth; and installing the dose ionization chamber 20 in the p-th slot can obtain the lateral dose distribution at the p-th depth. By adjusting the installation positions of the multiple strip ionization chambers 30 and the multiple dose ionization chambers 20 on the mounting frame 10, the lateral dose distribution at the target depth of interest can be obtained.

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

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

[0122] like Figure 9 As shown, embodiments of the present invention also provide a verification method for a three-dimensional dose verification device for ion therapy, the verification method comprising:

[0123] Step 110: Obtain the dose information and location information of any dose ionization chamber 20;

[0124] Step 120: Based on the dose information and location information of multiple dose ionization chambers 20, obtain the measured three-dimensional dose distribution;

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

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

[0127] The structure of the three-dimensional dose verification device is as described above. m dose ionization chambers 20 and n strip ionization chambers 30 are sequentially arranged on the mounting frame 10 along its length. An active beam delivery system emits a beam into the three-dimensional dose verification device.

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

[0129] The testing unit processes the dose and location information of m dose ionization chambers 20 to obtain the measured three-dimensional dose distribution. The testing unit also processes the planning system file to obtain the planned three-dimensional dose distribution. The testing unit further compares the measured and planned three-dimensional dose distributions, obtaining the verification pass rate from the comparison results. Based on the comparison between the verification pass rate and the preset pass rate, the unit determines whether the dose verification has passed. For example, if the preset pass rate is 90%, a verification pass rate less than or equal to 90% indicates that the dose verification has failed; a verification pass rate greater than 90% indicates that the dose verification has passed.

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

[0131] The method for the acquisition unit to acquire dose information from the dose ionization chamber 20 is as follows.

[0132] Ion therapy uses an active beam delivery system to deliver the beam, meaning the beam is stratified by energy. Assuming the total number of strata is N, there will be N dose sets collected at the same location, denoted as N0. The coordinates of a point within the dose ionization chamber 20 are: The dose obtained at each layer at this point is denoted as Therefore, the total dose at that point It can be obtained through formula (1):

[0133] (1)

[0134] Assuming the total beam delivery time is t, and the number of dose ionization chambers 20 is m, the dose value of the k-th (k=1,…,m) dose ionization chamber 20 at time p (p=0,…,t) is denoted as The total dose of the dose ionization chamber 20 is denoted as Total dose It can be obtained through formula (2):

[0135] (2)

[0136] The depth dose curve is an ordered arrangement of the total dose values ​​of all dose ionization chambers (20). , ..., A schematic diagram of the depth-dose curve is shown below. Figure 5 As shown.

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

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

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

[0140] (3)

[0141] (4)

[0142] (5)

[0143] Where d is the distance from the first segmented ionization chamber 30 to the k-th dose ionization chamber 20. The location information of the other dose ionization chambers 20 can be obtained from the above formula.

[0144] Therefore, by using the principle of similar triangles, the position information of any one of the dose ionization chambers 20 can be obtained by installing two segmented ionization chambers 30 on the mounting frame 10. This effectively improves the efficiency of acquiring the position information of the dose ionization chamber 20, thereby improving the verification efficiency.

[0145] The number of slit circuit chambers is 1. A slit ionization chamber 30 is installed at the end of the mounting bracket 10, and the slit ionization chamber 30 is opposite to the incident end of the active beam delivery system. The coordinate information of the slit ionization chamber 30 is ( , , The calculation method for the position information of the k-th dose ionization chamber 20 is shown in formulas (6), (7) and (8):

[0146] (6)

[0147] (7)

[0148] (8)

[0149] Where d is the distance from the segmented ionization chamber 30 to the k-th 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 segmented ionization chamber 30 at the end of the mounting bracket 10, the position information of any dose ionization chamber 20 can be obtained. This effectively improves the efficiency of acquiring the position information of the dose ionization chamber 20, thereby improving the verification efficiency.

[0151] Understandably, when the number of strip 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 strip ionization chambers 30. The more strip ionization chambers 30 there are, the more accurate the lateral point position distribution on each dose ionization chamber 20 becomes.

[0152] The above formula can be used to obtain the dose at all points within the detection range. After spatially arranging these point doses and saving them as a DICOM file, the depth dose curve and the surface dose distribution perpendicular to the beam within the test range can be obtained. The multiple points acquired in 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 location and dose information of the multiple dose ionization chambers 20 obtained above to obtain the measured three-dimensional dose distribution, as 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, as 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. By adjusting the position error and dose error values, different validation pass rates are obtained. Furthermore, the validation pass rate is compared with the preset pass rate to determine whether the dose validation is successful. The preset pass rate can be 90%. The position error range is 2~4mm. The dose error range is 2%~6%.

[0155] For example, if the position error is set to 3 mm and the dose error is set to 3%, the validation pass rate is 47.2%. A validation pass rate of less than 90% indicates that the dose validation has failed.

[0156] For example, setting the position error to 3mm and the dose error to 5% yields a validation pass rate of 96.4%. A validation pass rate greater than 90% indicates that the dose validation has 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 the measured three-dimensional dose distribution. The measured three-dimensional dose distribution is compared with the planned three-dimensional dose distribution to obtain the verification pass rate, which effectively improves the verification efficiency and the accuracy of the verification results.

[0158] The above description is merely a specific embodiment of the present invention, but the scope of protection of this application is not limited thereto. Any changes or substitutions made within the spirit and principles of the present invention should be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A three-dimensional dose verification device for ion therapy, characterized in that, include: Mounting rack; m dose ionization chambers; n strip ionization chambers, the n strip ionization chambers and m dose ionization chambers are sequentially arranged on the mounting frame; The acquisition unit is used to acquire dose information and position information of m dose ionization chambers to obtain the measured three-dimensional dose distribution. The position information of the m dose ionization chambers is obtained from the position information of n segmented ionization chambers. as well as The testing unit is used to obtain the verification pass rate based on the comparison between the measured three-dimensional dose distribution and the planned three-dimensional dose distribution. Where 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; The dose ionization chamber includes: The first bracket is connected to the mounting bracket; Two first high-voltage plates are mounted on the first bracket; The collecting electrode plate is sandwiched between the two first high-voltage electrodes; and A first equivalent plate is disposed on the side of the first high-voltage electrode plate away from the collecting electrode plate, and the first equivalent plate is detachably connected to the first bracket. The segmented ionization chamber includes: The second bracket is connected to the mounting bracket; Multiple second high-voltage plates are disposed on the second bracket; The first electrode is sandwiched between two adjacent second high-voltage plates; The second electrode is sandwiched between two adjacent second high-voltage plates; and The second equivalent plate is disposed on one side of a second high voltage plate, and the second equivalent plate is detachably connected to the second bracket. The direction of the strip structure of the first strip electrode intersects with the direction of the strip structure of the second strip electrode.

2. The three-dimensional dose verification device according to claim 1, characterized in that, The first bracket is detachably connected to the mounting bracket.

3. The three-dimensional dose verification device according to claim 1, characterized in that, The second bracket is detachably connected to the mounting bracket.

4. A verification method using a three-dimensional dose verification device for ion therapy as described in any one of claims 1 to 3, characterized in that, The verification method includes: Obtain dose and location information for any dose ionization chamber; Based on the dose information and location information of the multiple dose ionization chambers, the measured three-dimensional dose distribution is obtained; Based on the comparison between the measured three-dimensional dose distribution and the planned three-dimensional dose distribution, the verification pass rate is obtained. The location information of the dose ionization chamber is obtained from the location information of the segmented ionization chamber.

5. The verification method according to claim 4, characterized in that, When the number of segmented ionization chambers is equal to 1, obtaining the location information of any dose ionization chamber includes: Obtain the coordinate information of the segmented ionization chamber; Obtain the distance information between the segmented ionization chamber and any one of the dose ionization chambers; Based on the coordinate information and spacing information of the segmented ionization chambers, the position information of any one of the dose ionization chambers is obtained.

6. The verification method according to claim 4, characterized in that, When the number of segmented ionization chambers is less than the number of dose ionization chambers, and the number of segmented ionization chambers is greater than 1, obtaining the location information of any dose ionization chamber includes: Obtain the first coordinate information of the first segmented ionization chamber and the second coordinate information of the second segmented ionization chamber; Obtain the distance information between the first segmented ionization chamber and any one of the dose ionization chambers; Based on the first coordinate information, the second coordinate information, and the spacing information, the location information of any one of the dose ionization chambers is obtained.

7. The verification method according to claim 4, characterized in that, The verification pass rate is obtained based on the comparison between the measured three-dimensional dose distribution and the planned three-dimensional dose distribution, including: Adjust the position error value and / or dose error value to obtain the verification pass rate.

8. The verification method according to claim 7, characterized in that, The position error value is in the range of 2~4mm; and / or The dosage error range is 2% to 6%.

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