An applicator for electron beam

Abstract

The present invention belongs to the field of radiotherapy devices and discloses an applicator for electron beams, an applicator structure, and a method for determining electron beam energy. The applicator structure includes a scattering head, a scattering component, a beam-limiting component, and a sealing component. The scattering head is provided with an upwardly opening internal cavity, the opening of the cavity being tangent to the scattering component. The scattering component is arranged between the lower end face of the beam channel and the cavity to scatter electrons and expand the beam, while simultaneously reducing the X-rays incidentally generated due to bremsstrahlung and protecting surrounding normal tissues. The beam-limiting component is provided with a beam channel. The sealing component is located on the upper portion of the beam-limiting component and encapsulates the entrance of the beam channel. The applicator of the present invention can form a spherical dose distribution that is more conformal to the radiotherapy target area, complete a single high-dose radiotherapy during surgery, effectively improve the local control rate of tumors, effectively reduce the side effects caused by X-rays, protect surrounding normal tissues, shorten the treatment time, and is safe, effective, and reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of radiotherapy, and in particular to an applicator for electron beams, an applicator structure, and a method for determining electron beam energy. Background Art

[0002] Medical electron accelerators are usually used in radiotherapy, which can use X-rays or electron beams. X-rays have strong penetrating power and are suitable for radiotherapy of deep tumors. Electron beams have weak penetrating power and are suitable for radiotherapy of surface tumors. In intraoperative radiotherapy, since the radiotherapy area needs to be superficial to the tumor bed, electron beams are usually used for intraoperative radiotherapy. On the one hand, it can increase the radiation dose of the tumor bed area, and at the same time, compared with external irradiation using X-rays, it can reduce the radiation dose of surrounding normal tissues and protect surrounding normal tissues. Therefore, the use of electron beams for intraoperative radiotherapy can improve the local control rate of tumor treatment and reduce the occurrence of toxic and side effects of radiotherapy.

[0003] Existing intraoperative radiotherapy technologies include the use of low-energy X-rays and the use of high-energy electron beams. Among them, the use of low-energy X-rays can form a spherical or quasi-spherical dose distribution, which is suitable for radiotherapy of quasi-spherical target areas such as breast-conserving radiotherapy for breast cancer, brain tumors, etc. However, due to the low energy and weak penetration of the X-rays used, it has defects such as low dose rate, long irradiation time, and shallow treatment depth. The existing technologies for intraoperative radiotherapy using high-energy electron beams are all limited light tube modes, which can form circular, rectangular and other planar irradiation fields, and cannot produce a dose distribution that conforms to the spherical tumor bed. In order to make the tumor bed adapt to the two-dimensional planar irradiation field of the limited light tube, it is usually necessary to enlarge the wound. This method has poor conformity, and the enlargement of the wound causes certain damage to the patient. For electron beams, there is currently a lack of mature and feasible solutions for intraoperative radiotherapy of spherical tumors and tumors in natural human cavities. Summary of the Invention

[0004] To address at least one of the aforementioned deficiencies or shortcomings of the prior art, the present invention provides an electron beam applicator, an applicator structure, and a method for determining electron beam energy. The applicator of the present invention can produce a quasi-spherical dose distribution that is more conformal to the radiotherapy target, enabling single, high-dose radiotherapy during surgery. This effectively improves local tumor control, reduces X-ray side effects, protects surrounding normal tissue, shortens treatment time, and exhibits excellent safety, effectiveness, and reliability. Both the electron beam energy determination method and the applicator structure determination method of the present invention are novel, rational, and highly practical.

[0005] To achieve the above object, the first aspect of the present invention provides an applicator for electron beams, the applicator comprising:

[0006] A scattering head is used to adjust the distribution of the electron beam so that the electron beam forms a uniform dose distribution similar to the shape of the scattering head on the outer surface of the scattering head and the surrounding area. The scattering head is provided with an upwardly open cavity, and the opening of the cavity is tangent to the scattering component;

[0007] The scattering component is placed between the exit of the beam channel and the cavity to scatter electrons and expand the beam. At the same time, it needs to reduce the X-rays generated by Bremsstrahlung and protect the surrounding normal tissues.

[0008] A beam limiting component, used for guiding and confining the electron beam and provided with a beam channel;

[0009] The sealing component is located on the upper part of the beam limiting component and encapsulates the entrance of the beam channel. The electron beam can pass through the sealing component and enter the beam channel.

[0010] In some embodiments, the scattering head can be spherical, hemispherical, ellipsoidal or other spherical shapes. The scattering head is made of metal or polymer material.

[0011] Furthermore, the radial size of the scattering head ranges from 1 cm to 8 cm.

[0012] Optionally, the cavity is an arc-shaped groove or an arc-shaped groove that matches the shape of the scattering head.

[0013] Optionally, the scattering component is made of metal or polymer material.

[0014] Furthermore, the applicator may include scattering components made of different materials, and the scattering components made of different materials have different and fixed thicknesses.

[0015] Furthermore, the thickness of the scattering component may be 0.1 mm-5 mm.

[0016] In some embodiments, the scattering head and the beam limiting component may be integrally formed.

[0017] Optionally, the sealing component is made of polymer material.

[0018] The second aspect of the present invention provides a method for determining the electron beam energy of the above-mentioned applicator, the method comprising:

[0019] S11. Provide an applicator;

[0020] S12, selecting incident electron beams of different energies for irradiation, and correspondingly obtaining electron beam distribution and electron beam intensity on the outer surface of the scattering head and the surrounding area after the electron beams are scattered by the scattering component;

[0021] S13. Determine an electron beam energy that meets a preset electron beam distribution and a preset electron beam intensity.

[0022] Furthermore, the preset electron beam distribution and the preset electron beam intensity are electron distributions with relatively high beam intensity on the outer surface of the scattering head, and the electron beam can expand to cover the expected irradiation range after scattering.

[0023] The third aspect of the present invention also provides a method for determining the structure of an electron beam applicator. The applicator includes a scattering head, a scattering component, and a beam limiting component. The beam limiting component is provided with a beam channel. The scattering component is disposed between the lower end surface of the beam channel and the cavity to scatter electrons and expand the beam while simultaneously reducing incidental X-rays generated by bremsstrahlung radiation and protecting surrounding normal tissue. The method includes:

[0024] S21. providing an applicator;

[0025] S22, digging cavities of different sizes from the upper end plane of the scattering head toward the center of the scattering head, and selecting an electron beam of preset energy for irradiation, to determine the relationship between the size of the cavity and the dose distribution on the outer surface of the scattering head;

[0026] S23. Adjust the size parameters of the cavity so that when the scattering head is irradiated by an electron beam of preset energy, the dose distribution formed on the outer surface of the scattering head conforms to the preset outer surface dose distribution, forming an equal dose distribution similar to the shape of the outer surface of the scattering head.

[0027] S24. Determine the diameter of the scattering component and the diameter of the beam channel according to the size of the cavity opening.

[0028] Optionally, the isodose distribution formed on the outer surface of the scattering head and the surrounding area is similar to the shape of the outer surface of the scattering head, and can better conform to the radiotherapy target area.

[0029] In some embodiments, an isodose line where the preset outer surface dose distribution intersects the outer surface of the scattering head coincides with a contour line of the outer surface of the scattering head.

[0030] Compared to existing technologies, the applicator of the present invention utilizes scattering components designed to expand the electron beam while simultaneously reducing incidental X-rays generated by bremsstrahlung radiation and protecting surrounding normal tissue. This allows the electron beam to form a uniform dose irradiation pattern similar to the outer surface of the applicator's scattering tip. This allows for radiotherapy of spherical tumors and tumors within natural cavities, producing a high-dose distribution that conforms to the lesion. Furthermore, the applicator utilizes the dose distribution characteristics of the electron beam to effectively protect normal tissue surrounding the target area. Furthermore, due to the electron beam's high dose rate, treatment time can be reduced, reducing the risk of intraoperative infection and the difficulty of anesthesia.

[0031] Furthermore, the applicator of the present invention utilizes a sealing member that encapsulates the entrance to the beam channel, allowing the electron beam to pass through the sealing member and enter the beam channel. This seal does not affect the normal passage of the electron beam, but also seals the beam channel, preventing the external environment from affecting the transmission and scattering of the electron beam, thereby forming a stable dose distribution. The methods for determining the electron beam energy and the structure of the applicator of the present invention are both novel, reasonable, and highly practical.

[0032] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0034] Figure 1 It shows a structural schematic diagram of a treatment device according to a specific embodiment of the present invention;

[0035] Figure 2 A flowchart showing a method for determining electron beam energy of an applicator according to a specific embodiment of the present invention; and

[0036] Figure 3 A flow chart of a method for determining an applicator structure for an electron beam according to a specific embodiment of the present invention is shown.

[0037] Description of reference numerals:

[0038] 1 Scattering head 11 Cavity

[0039] 12 Scattering head outer surface 2 Scattering component

[0040] 3 Beam limiting components 31 Beam channel

[0041] 4 Sealing components DETAILED DESCRIPTION

[0042] The following describes the specific implementation of the embodiment of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the embodiment of the present invention and is not used to limit the embodiment of the present invention.

[0043] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0044] In the embodiments of the present invention, unless otherwise specified, directional words such as "up, down, top, bottom" are usually used to describe the relative positional relationships of components in the directions shown in the drawings or in the vertical, perpendicular or gravity directions.

[0045] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with exemplary embodiments.

[0046] Existing intraoperative radiotherapy technologies include the use of low-energy X-rays and the use of high-energy electron beams. Among them, the use of low-energy X-rays can form a spherical or quasi-spherical dose distribution, which is suitable for radiotherapy of quasi-spherical target areas such as breast-conserving radiotherapy for breast cancer, brain tumors, etc. However, due to the low energy and weak penetration of the X-rays used, it has defects such as low dose rate, long irradiation time, and shallow treatment depth. The existing technologies for intraoperative radiotherapy using high-energy electron beams are all limited light tube modes, which can form circular, rectangular and other planar irradiation fields, and cannot produce a dose distribution that conforms to the spherical tumor bed. In order to make the tumor bed adapt to the two-dimensional planar irradiation field of the limited light tube, it is usually necessary to enlarge the wound. This method has poor conformity, and the enlargement of the wound causes certain damage to the patient. At present, there is still a lack of mature and feasible solutions for the use of electron beams in intraoperative radiotherapy of spherical tumors and tumors in natural human cavities.

[0047] In view of this, the first part of the present invention provides an electron beam applicator, which includes a scattering head 1, a scattering component 2, a beam limiting component 3, and a sealing component 4. The scattering head 1 is used to adjust the distribution of the electron beam so that the electron beam forms a uniform, isodose distribution similar to the shape of the scattering head on the outer surface 12 of the scattering head and the surrounding area. The scattering head 1 is provided with an upwardly open cavity 11 inside, and the opening of the cavity 11 is tangent to the scattering component 2. The scattering component 2 is arranged between the lower end surface of the beam channel 31 and the cavity 11. The electrons expand the beam while reducing the X-rays generated by Bremsstrahlung to protect the surrounding normal tissues. The beam limiting component 3 is used to guide and constrain the electron beam and is provided with a beam channel 31.

[0048] To prevent external influences on the transmission and scattering of the electron beam, a sealing plate 4 is placed above the beam-limiting component 3 and encapsulates the entrance of the beam channel 31. The electron beam can pass through the sealing plate 4 and enter the beam channel 31. This seal does not affect the normal passage of the electron beam, but also seals the beam channel, preventing external influences on the transmission and scattering of the electron beam, thereby forming a stable dose distribution.

[0049] This applicator enables the electron beam to form a uniform dose irradiation on a non-planar surface, thereby achieving the purpose of radiotherapy for spherical tumors and tumors within natural cavities in the human body. Furthermore, this applicator effectively utilizes the dose distribution characteristics of the electron beam, which has a high surface dose, enters a dose plateau after reaching the depth of the maximum dose point, and then drops sharply at the end of the range. Therefore, the electron beam is more suitable for radiotherapy of spherical tumor beds and tumors within natural cavities in the human body, and can effectively protect normal tissue around the target area. Furthermore, due to the high dose rate of the electron beam, the applicator of this application can effectively reduce treatment time, the risk of intraoperative infection, and the difficulty of anesthesia.

[0050] Specifically, if Figure 1 As shown, the scattering head 1 is located below the beam-limiting component 3, is in the shape of a spherical segment and has an upwardly open cavity 11 therein, and the opening of the cavity 11 is tangent to the scattering component 2. In addition to being in the shape of a spherical segment, the outer wall shape of the scattering head 1 can also be hemispherical, ellipsoidal, or irregular. The material of the scattering head 1 can be a polymer material. The radial dimension range of the scattering head 2 is 1 cm to 8 cm. The cavity 11 can be an arc-shaped groove or an arc-shaped groove that matches the shape of the scattering head. The size parameters of the cavity 11 are adjusted according to the shape and size of the scattering head, so that after the electron beam is scattered by the applicator, an equal dose distribution similar to the shape of the outer surface of the applicator is formed on the outer surface of the scattering head and the surrounding area.

[0051] In addition, if Figure 1 As shown, when the scattering head is in a spherical segment shape, the size parameters of the cavity 11 are the height H and the opening diameter R. Optionally, when the scattering head is in other shapes such as an ellipsoid or a special shape, the size parameters of the cavity 11 can be set and adjusted according to the shape of the scattering head.

[0052] In addition, if Figure 1 As shown, the scattering component 2 is located below the beam limiting component 3 and is disposed between the lower end surface of the beam channel 31 and the cavity 11. The electron beam can elastically or inelasticly collide with the scattering component 2, thereby causing the electron beam to disperse at an angle.

[0053] The main factors that determine the electron beam scattering angle are the energy of the electron beam and the material of the scattering component 2. Under the premise of the same scattering material, the higher the electron beam energy, the smaller the scattering angle, and the higher the beam intensity after scattering; the lower the electron beam energy, the larger the scattering angle, and the lower the beam intensity after scattering. The interaction between electrons and matter mainly includes elastic scattering and inelastic scattering. Inelastic scattering includes ionization, excitation and bremsstrahlung, and bremsstrahlung will produce X-rays. X-rays have strong penetrating power and can cause radiation damage to normal tissues outside the target area of ​​intraoperative radiotherapy, increasing the toxic and side effects of radiotherapy. Therefore, when selecting scattering components for intraoperative radiotherapy, it is necessary to consider reducing the generation of X-rays. The material of the scattering component 2 is metal or polymer material, such as titanium, copper, aluminum, tungsten and other metals.

[0054] Optionally, the scattering component 2 may have a fixed thickness determined based on the penetration thickness of the material corresponding to the target energy of the electron beam required clinically. The thickness of the scattering component 2 may be 0.1 mm to 5 mm.

[0055] In some specific embodiments, the applicator may include scattering components 2 made of different materials, and the scattering components 2 made of different materials have different and fixed thicknesses.

[0056] Specifically, the applicator includes a scattering head 1, a scattering component 2, a beam limiting component 3 and a sealing component 4 arranged in sequence from bottom to top. Figure 1 As shown, the beam-limiting component 3 is cylindrical and includes a first, second, and third segment connected sequentially from top to bottom. The outer diameters of the first, second, and third segments decrease in order. The large outer radius of the first and second segments provides superior structural strength, while the smaller outer radius of the third segment facilitates insertion of the treatment portion 1 into the treatment area. Furthermore, the outer wall of the second and third segments has a smooth transition.

[0057] It should be noted that the beam-limiting component 3 can be cylindrical or rectangular, or other shapes, depending on the beam-limiting requirements. The beam-limiting component 3 can be made of a polymer, metal, alloy, or a combination or composite of these and other materials. The beam-limiting component 3 can provide a certain degree of shielding, shielding against electron leakage and stray radiation generated by the interaction between electrons and matter.

[0058] Optionally, the scattering head 1 and the beam limiting component 3 may be integrally formed, which is easier to process and has better structural strength.

[0059] In addition, the sealing member 4 is provided in the beam channel 31 and seals the upper opening of the beam channel 31, and the electron beam can pass through the sealing member 4 and enter the beam channel 31. Figure 1 As shown, the sealing component 4, the beam limiting component 3, and the scattering head 1 collectively define a sealed chamber that is isolated from the outside world, preventing the external environment from affecting the transmission and scattering of the electron beam, thereby forming a stable dose distribution. The sealing component 4 is made of a material that has low electron beam scattering, such as a polymer material. After the sealing component 4 seals the beam channel 31, the chamber can be filled with a gas, such as air or an inert gas.

[0060] To this end, the second aspect of the present invention further provides a method for determining the electron beam energy of the above-mentioned applicator, the method comprising:

[0061] S11, providing the above-mentioned applicator;

[0062] S12, selecting incident electron beams of different energies for irradiation, and correspondingly obtaining electron beam distribution and electron beam intensity on the outer surface 12 of the scattering head and the surrounding area after the electron beam is scattered by the scattering component 2;

[0063] S13. Determine an electron beam energy that meets a preset electron beam distribution and a preset electron beam intensity.

[0064] The preset electron beam distribution and the preset electron beam intensity are electron distributions with relatively high beam intensity on the outer surface of the scattering head, indicating that the electron beam can expand to cover the expected irradiation range after scattering.

[0065] Among them, in S12, by testing or simulating at certain intervals, the distribution and intensity information of electrons of different energies after transmission can be obtained, thereby obtaining the changing relationship between the electron beam energy change and the electron distribution and intensity, and then the target energy required clinically can be selected.

[0066] The electron beam distribution is the distribution of the electron beam after it passes through the scattering component 2. The preset electron beam distribution is the electron beam distribution that effectively covers the range of the spherical head. The coverage rate can be set according to actual clinical needs. The electron beam intensity must ensure that the electron beam dose rate does not drop significantly and can meet clinical requirements. The preset electron beam intensity can be set according to actual clinical needs.

[0067] Determining the electron beam energy can be done using a variety of methods. For example, electron beams of varying energies can be directly collected to irradiate the applicator, and the distribution of the scattered electron beams can be measured and analyzed. Physical simulation methods can also be used, such as the Monte Carlo method, to calculate the electron beam distribution and intensity for different electron beam energies. Based on the changes in electron distribution and intensity, the appropriate electron beam energy can be selected to ensure that the electron beam spread covers the scattering head while ensuring radiation intensity.

[0068] Alternatively, since the scattering head 1 has a certain radiation blocking effect, in order to obtain the electron distribution of electrons transmitted through the scattering component 2, an applicator without a scattering head can be used to eliminate the influence of the ball head on the distribution. To this end, the applicator in step S11 can be an applicator without a scattering head. Except for the scattering head, the other components of the applicator without a scattering head are the same as those of the applicator with a ball head.

[0069] The above method for determining the electron beam energy of the applicator can provide a more reasonable and reliable applicator with better treatment effect. Moreover, the method is novel and reasonable, highly practical, simple in steps, and easy to operate.

[0070] The third aspect of the present invention further provides a method for determining the structure of an electron beam applicator, the applicator comprising a scattering head 1, a scattering component 2, and a beam limiting component 3. The beam limiting component 3 is provided with a beam channel 31. The scattering component 2 is disposed between the lower end surface of the beam channel 31 and the cavity 11 to scatter electrons to expand the beam while reducing X-rays incidentally generated by bremsstrahlung radiation to protect surrounding normal tissue. The method comprises:

[0071] S21, providing the above-mentioned applicator;

[0072] S22, digging cavities 11 of different sizes from the upper end plane of the scattering head 1 toward the center of the scattering head 1, and selecting an electron beam of preset energy for irradiation, to determine the relationship between the size of the cavity 11 and the dose distribution on the outer surface 12 of the scattering head 1;

[0073] S23, adjusting the size parameters of the cavity 11 so that when the scattering head 1 is irradiated with an electron beam of preset energy, a dose distribution formed on the outer surface 12 of the scattering head conforms to a preset outer surface dose distribution, forming an equal dose distribution similar to the shape of the outer surface of the scattering head;

[0074] S24. Determine the diameters of the scattering component and the beam channel according to the size of the cavity opening.

[0075] The effect of the cavity 11 on the dose distribution on the outer surface of the spherical head can be calculated through iteration.

[0076] Furthermore, step S22 excavates cavities 11 of varying sizes and shapes on the upper plane of the scattering head of the applicator. Cavities 11 of varying sizes can be obtained by varying the dimensional parameters of cavity 11. Specifically, step S22 can determine the relationship between the size of cavity 11 and the dose distribution on the outer surface 12 of the scattering head 1 through physical testing or simulation, and further comprehensive analysis can be performed to determine the effect of the dimensional parameters of cavity 31 on the dose distribution on the outer surface of the scattering head.

[0077] Furthermore, step S23 can obtain a preliminary suitable size for cavity 11 based on the change relationship obtained in step S22. The preliminary suitable size for cavity 11 is the size of cavity 11 that conforms to the preliminary preset dose distribution on the outer surface of the spherical head under the conditions of the preset electron beam energy. The preliminary preset dose distribution on the outer surface of the spherical head approximates the contour of the outer surface of the spherical head. To obtain a more optimal dose distribution on the outer surface of the spherical head, when producing a physical object for verification, the dimensional parameters of cavity 11 can be further adjusted based on the preliminary suitable size, so that when the scattering head 1 is irradiated with an electron beam of the preset energy, the dose distribution formed on the outer surface 12 of the spherical head is more uniform and more consistent with the preset outer surface dose distribution.

[0078] Preferably, the isodose line where the preset outer surface dose distribution in step S23 intersects the outer surface 12 of the scattering head may coincide with the contour of the outer surface 12 of the spherical head.

[0079] In some embodiments, the process of determining the size of cavity 11 can employ a combination of direct physical measurement and simulation analysis. Monte Carlo methods can be used to establish a physical model and iteratively calculate the relationship between cavity parameters and the dose distribution on the outer surface of the scattering head to select an appropriate cavity size. Furthermore, through physical measurement, fine-tuning of the energy and cavity size can be performed to correct errors, resulting in a uniform isodose distribution on the outer surface of the applicator scattering head and surrounding areas that resembles the shape of the scattering head.

[0080] In summary, the present invention provides an applicator for electron beams, an applicator structure, and a method for determining electron beam energy. The applicator can form a spherical dose distribution that is more conformal to the radiotherapy target area, complete a single large-dose radiotherapy during surgery, effectively improve the local control rate of tumors, effectively reduce the side effects caused by X-rays, protect surrounding normal tissues, shorten the treatment time, and have good safety, effectiveness, and reliability. The electron beam energy determination method of the applicator and the ball head cavity determination method of the applicator are both novel, reasonable, and highly practical. The optional implementation methods of the embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above implementation methods. Within the technical concept of the embodiments of the present invention, the technical solutions of the embodiments of the present invention can be subjected to a variety of simple modifications, and these simple modifications all fall within the scope of protection of the embodiments of the present invention.

[0081] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0082] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0083] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. Throughout this specification, the schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0084] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the embodiments of the present invention will no longer separately describe various possible combinations.

[0085] In addition, various implementations of the embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed in the embodiments of the present invention.

Claims

1. An applicator for electron beams, characterized in that The applicator comprises: A scattering head (1) is used to adjust the distribution of the electron beam so that the electron beam forms a uniform isodose distribution similar to the shape of the scattering head on the outer surface (12) of the scattering head and the surrounding area, wherein the scattering head (1) is provided with an upwardly opening cavity (11) inside, and the opening of the cavity (11) is tangent to the scattering component (2); A scattering component (2) is arranged between the lower end surface of the beam channel (31) and the cavity (11) to scatter electrons to expand the beam, while reducing X-rays incidentally generated by bremsstrahlung radiation to protect surrounding normal tissues; A beam limiting component (3) is used to guide and constrain the electron beam and is provided with a beam channel (31); a sealing component (4) located on the upper portion of the beam limiting component (3) and encapsulating the entrance of the beam channel (31), wherein the electron beam can pass through the sealing component (4) and enter the beam channel (31); The scattering head (1) is spherical, hemispherical or ellipsoidal, and the material of the scattering head (1) is metal or polymer material; The cavity (11) is an arc-shaped groove or an arc-shaped groove that matches the shape of the scattering head.

2. The applicator according to claim 1, wherein: The radial size range of the scattering head (1) is 1 cm to 8 cm.

3. The applicator according to claim 1, wherein: The scattering component (2) is made of metal or polymer material.

4. The applicator according to claim 3, wherein: The applicator comprises the scattering components (2) made of different materials, and the scattering components (2) made of different materials have different and fixed thicknesses.

5. The applicator according to claim 4, characterized in that The thickness of the scattering component (2) is 0.1 mm to 5 mm.

6. The applicator according to claim 1, wherein: The scattering head (1) and the beam-limiting component (3) are integrally formed.

7. The applicator according to claim 1, wherein: The sealing component (4) is made of polymer material.

8. A method for determining the electron beam energy of the applicator according to any one of claims 1 to 7, characterized in that: The method comprises: S11, providing the applicator; S12, selecting incident electron beams of different energies for irradiation, and correspondingly obtaining the electron beam distribution and electron beam intensity on the outer surface (12) of the scattering head and the surrounding area after the electron beam is scattered by the scattering component (2); S13. Determine the incident electron beam energy that meets the preset electron beam distribution and the preset electron beam intensity.

9. The method according to claim 8, characterized in that The preset electron beam distribution is an electron distribution with a relatively high beam intensity on the outer surface of the scattering head, and the electron beam expands after scattering to cover the expected irradiation range.

10. A method for determining the structure of an applicator according to any one of claims 1 to 7, characterized in that The method comprises: S21, providing the applicator; S22, respectively digging cavities (11) of different sizes from the upper end plane of the scattering head (1) toward the center of the scattering head (1), and selecting an electron beam of preset energy for irradiation, and determining a relationship between the size of the cavity (11) and the dose distribution on the outer surface (12) of the scattering head; S23, adjusting the size parameters of the cavity (11) so that when the scattering head (1) is irradiated by an electron beam of preset energy, an equal dose distribution formed on the outer surface (12) of the scattering head conforms to a preset outer surface dose distribution; S24. Determine the diameter of the scattering component (2) and the diameter of the beam channel (31) based on the size of the cavity opening.

11. The method according to claim 10, characterized in that The isodose distribution formed on the outer surface (12) of the scattering head and the surrounding area is similar to the shape of the outer surface of the scattering head and can better conform to the radiotherapy target area.

12. The method according to claim 11, characterized in that An isodose line where the preset outer surface dose distribution intersects the outer surface (12) of the scattering head coincides with a contour line of the outer surface (12) of the scattering head.

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