A phasing radiotherapy spacer and methods of making and using the same

Abstract

This invention provides a PHA radiotherapy isolator, its preparation method, and its usage method. The PHA radiotherapy isolator is made of PHA material, and the weight-average molecular weight of the PHA material ranges from 500 to 800 kDa. The preparation method of the PHA radiotherapy isolator includes: dissolving the PHA material in an organic solvent to obtain a PHA solution; pre-freezing the PHA solution to form a solidified body; and vacuum drying the solidified body to obtain the PHA radiotherapy isolator. The PHA radiotherapy isolator provided by this invention is absorbable by the human body, has good mechanical properties, and good fixation; it uses a single-component raw material, i.e., it is made only from PHA material, and the preparation process is simple; the PHA radiotherapy isolator contains only PHA material, and its degradation products have the effect of reducing radiation-induced inflammation, and tissue fluid does not easily penetrate into the PHA radiotherapy isolator during use.

Description

Technical Field

[0001] This invention relates to a PHA radiotherapy isolator, its preparation method, and its application method, belonging to the field of biomedical engineering technology. Background Technology

[0002] Radiation therapy is a local treatment method that uses radiation (such as alpha, beta, and gamma rays) to treat tumors. During radiation therapy, while the radiation produced by radioactive elements (such as alpha, beta, and gamma rays) kills cancer cells, it also causes some damage to the normal tissue adjacent to the tumor. To reduce the exposure of normal tissue to radiation and the occurrence of complications, a certain distance needs to be created between the normal tissue and the radiation zone to improve the patient's postoperative quality of life.

[0003] Among the commonly used adjuvant radiotherapy methods, an inflatable balloon is first implanted around the radiotherapy target area during tumor resection. The balloon is then inflated to isolate the tumor from normal tissue at a certain distance, thereby reducing the radiation dose to normal tissue and reducing radiotherapy complications. However, the implanted balloon restricts the patient's movement and has poor fixation. After radiotherapy, a second surgery is required to remove the balloon, which increases the damage to the body and causes secondary injury.

[0004] Currently, the main material for absorbable radiotherapy isolation bodies on the market is polyethylene glycol hydrogel, such as SpaceOAR. TM The system, used as adjuvant therapy for prostate cancer, primarily consists of Trilysine and polyethylene glycol powder as a precursor solution and an accelerator solution, mixed using a static "Y" device to form a soft gel. This device requires premixing of the two components and use within a specified time. If unforeseen circumstances arise during surgery leading to interruption of the solution injection, it may cause device blockage, necessitating replacement. Furthermore, the production of this product requires multiple components and the preparation process is complex. The product mainly reduces the risk of radiation damage to surrounding healthy tissues and organs during radiotherapy by "spacing" adjacent organs from the tumor site. However, the degradation products of polyvinyl alcohol are carbon dioxide and water, which do not alleviate radiation-induced inflammation.

[0005] Synthetic biology has become a hot research field in recent years, with the most rapid development being in biopolymer materials obtained through microbial fermentation. Polyhydroxyalkanoate (PHA), due to its unique properties, is one of the most ideal biomedical materials currently available. PHA is a natural high-molecular-weight biomaterial, an intracellular polyester synthesized by microorganisms. Due to its excellent biocompatibility and biodegradability, it is one of the most ideal biomedical materials. It has been widely used in the medical device industry, such as in the manufacture of absorbable surgical sutures, medical aesthetic microspheres, and hernia patches. This type of material is biodegradable, and its degradation product is trihydroxybutyric acid (THB), a normal component of human blood, non-toxic and causing no rejection reaction in the human body, and can be gradually degraded and excreted through human metabolism. Furthermore, studies have shown that THB has significant anti-fibrotic effects, reduces inflammatory cell infiltration, and promotes intestinal repair, effectively treating radiation-induced intestinal injury.

[0006] In the process of realizing the concept of this invention, the inventors discovered that the related technologies have at least the following problems: the airbags implanted in the commonly used radiotherapy adjuvant therapy have problems such as poor fixation and non-degradability; while the raw materials of the existing absorbable radiotherapy isolation body contain multiple components, the preparation process is complicated, and the degraded components have no therapeutic effect.

[0007] Therefore, there is a need for a novel absorbable radiotherapy isolator that is absorbable by the human body, has good fixation, is simple to operate as a single component, and whose degradation products have the effect of reducing radiation-induced inflammation. Summary of the Invention

[0008] In view of this, the technical problem to be solved by the present invention is to provide a PHA radiotherapy isolator and its preparation and use methods, which solves the problems of poor fixation and non-degradability of the airbags implanted in commonly used radiotherapy adjuvant therapy methods; as well as the problems of existing absorbable radiotherapy isolators containing multiple components in their raw materials, complicated preparation processes, and the lack of therapeutic effect of degraded components.

[0009] To address the aforementioned technical problems, a specific embodiment of the present invention provides a PHA radiotherapy isolator, wherein the PHA radiotherapy isolator is made of PHA material, and the weight-average molecular weight of the PHA material ranges from 500 to 800 kDa.

[0010] In one embodiment of the present invention, the weight-average molecular weight of the PHA material is in the range of 600 to 700 kDa.

[0011] In this invention, the weight-average molecular weight of the PHA material affects the surface smoothness, elasticity, and shapeability of the resulting PHA radiotherapy isolator. This invention controls the weight-average molecular weight of the PHA material to a range of 500–800 kDa, preferably 600–700 kDa, which results in a PHA radiotherapy isolator with a smooth surface, no obvious cracks, and good elasticity and shapeability.

[0012] In one embodiment of the present invention, the PHA material is a natural or non-natural polyhydroxy fatty acid ester, including one or a combination of several of PHB, PHBV, PHBHHx, P34HB, PHBVHHx and PHHx.

[0013] Among them, PHB is poly(3-hydroxybutyrate), PHBV is a copolymer of hydroxybutyrate and hydroxyvalerate, PHBHHx is a copolymer of 3-hydroxybutyric acid (3HB) and 3-hydroxyhexanoic acid (3HHx), P34HB is a copolymer of 3-hydroxybutyric acid (3HB) and 4-hydroxybutyric acid (4HB), PHBVHHx is a copolymer of 3-hydroxybutyric acid (3HB), 3-hydroxyhexanoic acid (3HHx) and 3-hydroxyvalerate (3HV), and PHHx is poly(hydroxyhexanoate).

[0014] In this invention, the structural shape and size of the PHA radiotherapy isolator are determined based on the radiotherapy time, the shape of the radiation target area, and the isolation distance requirements between the radiation target area and normal tissue.

[0015] In one embodiment of the present invention, the shape of the PHA radiotherapy isolator includes block, sheet, or irregular shape, etc.

[0016] The present invention also provides a method for preparing the above-described PHA radiotherapy isolator, wherein the preparation method includes:

[0017] Step (1): Dissolve the PHA material in an organic solvent to obtain a PHA solution;

[0018] Step (2): Pre-freeze the PHA solution to form a solidified body;

[0019] Step (3): Vacuum dry the solidified body to obtain the PHA radiotherapy isolator.

[0020] In one embodiment of the present invention, in step (1), the mass percentage concentration of the PHA material is 2-20%, preferably 5-10%, based on the total weight of the PHA solution as 100%.

[0021] In one embodiment of the present invention, in step (1), the PHA material is a high-purity PHA material, and the specific purity can be reasonably selected as needed.

[0022] In one embodiment of the present invention, in step (1), the organic solvent includes one or a combination of several organic solvents such as 1,4-dioxane, dichloromethane, chloroform, methyl formate, ethyl acetate, methyl acetate, acetone, dichloroethane and pentane, preferably 1,4-dioxane.

[0023] In one embodiment of the present invention, the pre-freezing temperature in step (2) is -16 to -20°C. The present invention does not specify a particular pre-freezing time in step (2) of the preparation method of the PHA radiotherapy isolator described above; it can be reasonably adjusted as needed, as long as the purpose of pre-freezing is achieved. For example, in some specific embodiments of the present invention, the pre-freezing time can be 2 hours, etc.

[0024] In one embodiment of the present invention, step (2) specifically includes: transferring the PHA solution into a fixed mold and pre-freezing it to form a solidified body. In the present invention, the fixed mold is selected based on information such as the structural shape and size of the PHA radiotherapy isolator.

[0025] This invention does not specify the exact operation of vacuum drying in step (3) of the preparation method described above, nor does it specify the temperature and time conditions for vacuum drying. These conditions can be adjusted as needed, as long as the purpose of removing organic solvents is achieved. In some specific embodiments of this invention, the vacuum drying is carried out in a vacuum dryer.

[0026] The specific embodiments of the present invention also provide a method of using the above-described PHA radiotherapy isolator, wherein the method of use includes:

[0027] The PHA radiotherapy isolator is implanted between normal tissue and the radiation target area;

[0028] The PHA radiotherapy isolator is fixed between normal tissue and the radiation target area.

[0029] In one embodiment of the present invention, the method of use further includes:

[0030] The PHA radiotherapy isolator was sterilized before implantation.

[0031] In the above-described method of use of the present invention, the operations such as implantation, fixation and aseptic treatment can all be performed in accordance with the conventional operations in the art, as long as the purpose of the present invention can be achieved.

[0032] Compared with the prior art, the beneficial technical effects that the technical solution of the present invention can achieve include at least the following:

[0033] The PHA radiotherapy isolator provided by this invention has a smooth surface, no obvious cracks, and good elasticity; it is absorbable by the human body, has good mechanical properties, and good fixation; it is made from a single-component raw material, that is, only PHA material, and the preparation process is simple; the PHA radiotherapy isolator contains only PHA material, and its degradation products have the effect of reducing radiation-induced inflammation, and tissue fluid does not easily penetrate into the PHA radiotherapy isolator during use; it can solve the problems existing in existing traditional non-absorbable radiotherapy isolators and absorbable radiotherapy isolators, that is, it can solve the problems of poor fixation and non-degradability of the balloons implanted in commonly used radiotherapy adjuvant therapy methods, and the problems of existing absorbable radiotherapy isolators being made from multiple components, with complex preparation methods and no therapeutic effect of degradation components.

[0034] It should be understood that the above general description and the following specific embodiments are merely exemplary and illustrative, and do not limit the scope of the invention. Attached Figure Description

[0035] The accompanying drawings, which are part of the specification of this invention, illustrate exemplary embodiments of the invention. The drawings, together with the description in the specification, serve to illustrate the principles of the invention.

[0036] Figure 1 This is a partial electron microscope image of the PHA radiotherapy isolator provided in Embodiment 1 of the present invention.

[0037] Figure 2 This is a partial electron microscope image of the PHA radiotherapy isolator provided in Embodiment 2 of the present invention.

[0038] Figure 3 This is a partial electron microscope image of the PHA radiotherapy isolator provided in Embodiment 3 of the present invention.

[0039] Figure 4 A local electron microscope image of the PHA radiotherapy isolator provided for Comparative Example 1.

[0040] Figure 5 A local electron microscope image of the PHA radiotherapy isolator provided for Comparative Example 2.

[0041] Figure 6 A local electron microscope image of the PHA radiotherapy isolator provided for Comparative Example 3. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the spirit of the contents disclosed in the present invention will be clearly explained below with reference to the accompanying drawings and detailed description. After understanding the embodiments of the present invention, any person skilled in the art can make changes and modifications based on the technology taught in the present invention without departing from the spirit and scope of the present invention.

[0043] The illustrative embodiments and descriptions of the present invention are used to explain the invention, but are not intended to limit the invention. Furthermore, elements / components using the same or similar reference numerals in the drawings and embodiments are used to represent the same or similar parts.

[0044] The terms "first," "second," etc., used in this document are not intended to specifically refer to order or sequence, nor are they intended to limit the invention. They are merely used to distinguish elements or operations described using the same technical terms.

[0045] The directional terms used in this article, such as up, down, left, right, front, or back, are for reference only when referring to the accompanying drawings. Therefore, the use of directional terms is for illustrative purposes and not to limit this work.

[0046] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0047] The term "and / or" as used herein includes any or all of the things mentioned.

[0048] The term "multiple" in this article includes "two" and "more than two"; the term "multiple groups" in this article includes "two groups" and "more than two groups".

[0049] The terms "approximately," "about," etc., used herein are intended to modify any quantity or error that may vary slightly, but these slight variations or errors do not change the essence of the quantity or error. Generally, the range of slight variations or errors modified by such terms may be 20% in some embodiments, 10% in others, 5% in still others, or other values. Those skilled in the art should understand that the aforementioned values ​​can be adjusted according to actual needs and are not limited thereto.

[0050] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0051] When expressions such as "at least one of A, B, and C" are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (e.g., "a system having at least one of A, B, and C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.). When expressions such as "at least one of A, B, or C" are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (e.g., "a system having at least one of A, B, or C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.). Those skilled in the art should also understand that any conjunction and / or phrase that substantially arbitrarily indicates two or more optional items, whether in the specification, claims, or drawings, should be understood to indicate the possibility of including one of these items, either of these items, or both items. For example, the phrase “A or B” should be understood as including the possibility of “A” or “B”, or “A and B”.

[0052] The "range" disclosed in this invention is given in the form of a lower limit and an upper limit. It can be one or more lower limits and one or more upper limits, respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower and upper limits define the boundaries of the particular range. All ranges defined in this way are composable, meaning that any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for specific parameters, it is also expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if the listed minimum range values ​​are 1 and 2, and the listed maximum range values ​​are 3, 4, and 5, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0053] In this invention, unless otherwise specified, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this invention, and "0-5" is simply a shortened representation of these numerical combinations.

[0054] In this invention, unless otherwise specified, all steps mentioned herein may be performed sequentially or randomly, but are preferably performed sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0055] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0056] Example 1

[0057] This embodiment provides a PHA radiotherapy isolator made of polyhydroxyalkanoate, specifically P34HB, with a weight-average molecular weight of 600-700 kDa.

[0058] The PHA radiotherapy isolator is prepared using a method comprising the following specific steps:

[0059] Step (1): Using 1,4-dioxane as an organic solvent, a polyhydroxy fatty acid ester (specifically P34HB) with a weight-average molecular weight of 600-700 kDa is dissolved in 1,4-dioxane to obtain a PHA solution with a mass percentage concentration of 10%.

[0060] Step (2): Carefully transfer the above PHA solution into a cube-shaped mold (1cm*1cm*1cm in size), and ensure that the PHA solution is evenly distributed. Place the mold containing the PHA solution in a -20℃ freezer and pre-freeze for 2 hours to allow the PHA solution to completely solidify and form a solid body.

[0061] Step (3): Take the pre-frozen solidified body out of the freezing equipment, quickly transfer it to a vacuum dryer, and dry the solidified body under vacuum conditions to remove residual organic solvents, and finally obtain the PHA radiotherapy isolator.

[0062] The surface morphology of the PHA radiotherapy isolator provided in Example 1 was observed using an electron microscope. A partial electron microscope image of the PHA radiotherapy isolator is shown below. Figure 1 As shown, from Figure 1 As can be seen, the surface of the PHA radiotherapy isolator is smooth and without obvious cracks.

[0063] Example 2

[0064] This embodiment provides a PHA radiotherapy isolator made of polyhydroxyalkanoate, specifically P34HB, with a weight-average molecular weight of 600-700 kDa.

[0065] The PHA radiotherapy isolator is prepared using a method comprising the following specific steps:

[0066] Step (1): Using 1,4-dioxane as an organic solvent, a polyhydroxy fatty acid ester (specifically P34HB) with a weight-average molecular weight of 600-700 kDa is dissolved in 1,4-dioxane to obtain a PHA solution with a mass percentage concentration of 8%.

[0067] Step (2): Carefully transfer the above PHA solution into a cube-shaped mold (1cm*1cm*1cm in size), and ensure that the PHA solution is evenly distributed. Place the mold containing the PHA solution in a -20℃ freezer and pre-freeze for 2 hours to allow the PHA solution to completely solidify and form a solid body.

[0068] Step (3): Take the pre-frozen solidified body out of the freezing equipment, quickly transfer it to a vacuum dryer, and dry the solidified body under vacuum conditions to remove residual organic solvents, and finally obtain the PHA radiotherapy isolator.

[0069] The surface morphology of the PHA radiotherapy isolator provided in Example 2 was observed using an electron microscope. A partial electron microscope image of the PHA radiotherapy isolator is shown below. Figure 2 As shown, from Figure 2 As can be seen, the surface of the PHA radiotherapy isolator is smooth and without obvious cracks.

[0070] Example 3

[0071] This embodiment provides a PHA radiotherapy isolator made of polyhydroxyalkanoate, specifically P34HB, with a weight-average molecular weight of 600-700 kDa.

[0072] The PHA radiotherapy isolator is prepared using a method comprising the following specific steps:

[0073] Step (1): Using 1,4-dioxane as an organic solvent, a polyhydroxy fatty acid ester (specifically P34HB) with a weight-average molecular weight of 600-700 kDa is dissolved in 1,4-dioxane to obtain a PHA solution with a mass percentage concentration of 5%.

[0074] Step (2): Carefully transfer the above PHA solution into a cube-shaped mold (1cm*1cm*1cm in size), and ensure that the PHA solution is evenly distributed. Place the mold containing the PHA solution in a -20℃ freezer and pre-freeze for 2 hours to allow the PHA solution to completely solidify and form a solid body.

[0075] Step (3): Take the pre-frozen solidified body out of the freezing equipment, quickly transfer it to a vacuum dryer, and dry the solidified body under vacuum conditions to remove residual organic solvents, and finally obtain the PHA radiotherapy isolator.

[0076] The surface morphology of the PHA radiotherapy isolator provided in Example 3 was observed using an electron microscope. A partial electron microscope image of the PHA radiotherapy isolator is shown below. Figure 3 As shown, from Figure 3 As can be seen, the surface of the PHA radiotherapy isolator is smooth and without obvious cracks.

[0077] Comparative Example 1

[0078] This comparative example provides a PHA radiotherapy isolator made of polyhydroxyalkanoate, specifically P34HB, with a weight-average molecular weight of 200–300 kDa.

[0079] The PHA radiotherapy isolator is prepared using a method comprising the following specific steps:

[0080] Step (1): Using 1,4-dioxane as an organic solvent, a polyhydroxy fatty acid ester (specifically P34HB) with a weight-average molecular weight of 200-300 kDa is dissolved in 1,4-dioxane to obtain a PHA solution with a mass percentage concentration of 5%.

[0081] Step (2): Carefully transfer the above PHA solution into a cube-shaped mold (1cm*1cm*1cm in size), and ensure that the PHA solution is evenly distributed. Place the mold containing the PHA solution in a -20℃ freezer and pre-freeze for 2 hours to allow the PHA solution to completely solidify and form a solid body.

[0082] Step (3): Take the pre-frozen solidified body out of the freezing equipment, quickly transfer it to a vacuum dryer, and dry the solidified body under vacuum conditions to remove residual organic solvents, and finally obtain the PHA radiotherapy isolator.

[0083] The surface morphology of the PHA radiotherapy isolator provided in Comparative Example 1 was observed using an electron microscope. A partial electron microscope image of the PHA radiotherapy isolator is shown below. Figure 4 As shown, from Figure 4 As can be seen, the surface of the PHA radiotherapy isolator has obvious cracks and poor elasticity.

[0084] Comparative Example 2

[0085] This comparative example provides a PHA radiotherapy isolator made of polyhydroxyalkanoate, specifically P34HB, with a weight-average molecular weight of 200–300 kDa.

[0086] The PHA radiotherapy isolator is prepared using a method comprising the following specific steps:

[0087] Step (1): Using 1,4-dioxane as an organic solvent, a polyhydroxy fatty acid ester (specifically P34HB) with a weight-average molecular weight of 200-300 kDa is dissolved in 1,4-dioxane to obtain a PHA solution with a mass percentage concentration of 3%.

[0088] Step (2): Carefully transfer the above PHA solution into a cube-shaped mold (1cm*1cm*1cm in size), and ensure that the PHA solution is evenly distributed. Place the mold containing the PHA solution in a -20℃ freezer and pre-freeze for 2 hours to allow the PHA solution to completely solidify and form a solid body.

[0089] Step (3): Take the pre-frozen solidified body out of the freezing equipment, quickly transfer it to a vacuum dryer, and dry the solidified body under vacuum conditions to remove residual organic solvents, and finally obtain the PHA radiotherapy isolator.

[0090] The surface morphology of the PHA radiotherapy isolator provided in Comparative Example 2 was observed using an electron microscope. A partial electron microscope image of the PHA radiotherapy isolator is shown below. Figure 5 As shown, from Figure 5 As can be seen, the surface of the PHA radiotherapy isolator has obvious cracks and is inelastic and misshapen.

[0091] Compared to Example 3, the weight-average molecular weight of P34HB used in Comparative Example 1 was only 200-300 kDa, while Comparative Example 2, based on the already low weight-average molecular weight of P34HB (200-300 kDa), further reduced its concentration to 3%. Figures 3-5 It can be seen that, compared with Example 3, the PHA radiotherapy isolators made of low molecular weight polyhydroxyalkanoate materials in Comparative Examples 1 and 2 have a more porous texture, resulting in an uneven surface and obvious cracks. Compared with Example 3, the P34HB used in Comparative Example 1 has a lower weight-average molecular weight, as low as 200-300 kDa, and the resulting PHA radiotherapy isolator has poor elasticity. In Comparative Example 2, the weight-average molecular weight of P34HB is only 200-300 kDa, and its concentration is further reduced to 3%, resulting in a PHA radiotherapy isolator that is inelastic, easily loose, and misshapen.

[0092] Comparative Example 3

[0093] This comparative example provides a PHA radiotherapy isolator made of polyhydroxyalkanoate, specifically P34HB, with a weight-average molecular weight of 200–300 kDa.

[0094] The PHA radiotherapy isolator is prepared using a method comprising the following specific steps:

[0095] Step (1): Using 1,4-dioxane as an organic solvent, a polyhydroxy fatty acid ester (specifically P34HB) with a weight-average molecular weight of 200-300 kDa is dissolved in 1,4-dioxane to obtain a PHA solution with a mass percentage concentration of 10%.

[0096] Step (2): Carefully transfer the above PHA solution into a cube-shaped mold (1cm*1cm*1cm in size), and ensure that the PHA solution is evenly distributed. Place the mold containing the PHA solution in a -20℃ freezer and pre-freeze for 2 hours to allow the PHA solution to completely solidify and form a solid body.

[0097] Step (3): Take the pre-frozen solidified body out of the freezing equipment, quickly transfer it to a vacuum dryer, and dry the solidified body under vacuum conditions to remove residual organic solvents, and finally obtain the PHA radiotherapy isolator.

[0098] The surface morphology of the PHA radiotherapy isolator provided in Comparative Example 3 was observed using an electron microscope. A partial electron microscope image of the PHA radiotherapy isolator is shown below. Figure 6 As shown, from Figure 6 As can be seen, the surface of the PHA radiotherapy isolator is uneven with obvious burrs, and although it is formed, its elasticity is poor.

[0099] Compared to Example 1, Comparative Example 3 used only P34HB, which has a lower weight-average molecular weight, as low as 200–300 kDa. Figure 1 and Figure 6 It can be seen that, compared with Example 1, the PHA radiotherapy isolator made of low molecular weight polyhydroxy fatty acid ester material in Comparative Example 3 has a more porous texture, resulting in an uneven surface with obvious burrs. Although it is formed, its elasticity is poor.

[0100] Test Example 1

[0101] This test example focuses on the PHA radiotherapy isolators provided in Examples 1-3 and Comparative Examples 1-3 of the present invention. The in vivo compressive strength was simulated and tested using conventional methods in the art to evaluate their mechanical strength. The results show that the compressive strength of the PHA radiotherapy isolators provided in Examples 1-3 of the present invention all reached 35 MPa, which is significantly better than that of the PHA radiotherapy isolators provided in Comparative Examples 1-3. This indicates that the PHA radiotherapy isolators provided in the embodiments of the present invention all have good mechanical properties and can maintain a stable position during radiotherapy.

[0102] Test Example 2

[0103] In this test example, the PHA radiotherapy isolators provided in Examples 1-3 and Comparative Examples 1-3 of the present invention were respectively placed in a colored solution (methyl red indicator with a concentration of 0.5 mg / ml) to simulate the in vivo tissue fluid exudation. The results showed that tissue fluid did not easily penetrate into the PHA radiotherapy isolators provided in Examples 1-3 of the present invention, but easily penetrated into the PHA radiotherapy isolators provided in Comparative Examples 1-3. This indicates that the isolators provided in the embodiments of the present invention are suitable for use as isolators in the radiotherapy process.

[0104] In summary, the PHA radiotherapy isolator provided in this embodiment of the invention is absorbable by the human body, has good mechanical properties and good fixation; it is made from a single-component raw material, i.e., only PHA material, and the preparation process is simple; the PHA radiotherapy isolator contains only PHA material, and its degradation products have the effect of reducing radiation-induced inflammation, and tissue fluid does not easily penetrate into the PHA radiotherapy isolator during use; it can solve the problems existing in existing traditional non-absorbable radiotherapy isolators and absorbable radiotherapy isolators, namely, it can solve the problems of poor fixation and non-degradability of the balloons implanted in commonly used radiotherapy adjuvant therapy methods, and the problems of existing absorbable radiotherapy isolators being prepared from multiple components, with complex preparation methods and no therapeutic effect of degradation components.

[0105] Those skilled in the art will understand that the features described in the various embodiments and / or claims of the present invention can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments and / or claims of the present invention can be combined or combined in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or combinations fall within the scope of the present invention.

[0106] The embodiments of the present invention have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of the invention. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of the invention is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. A PHA radiotherapy isolator, characterized in that, The PHA radiotherapy isolator is made of PHA material, and the weight-average molecular weight of the PHA material ranges from 500 to 800 kDa.

2. The PHA radiotherapy isolator according to claim 1, characterized in that, The weight-average molecular weight of the PHA material is in the range of 600–700 kDa.

3. The PHA radiotherapy isolator according to claim 1 or 2, characterized in that, The PHA material is a natural or non-natural polyhydroxy fatty acid ester, including one or a combination of several of PHB, PHBV, PHBHHx, P34HB, PHBVHHx and PHHx.

4. The PHA radiotherapy isolator according to claim 1 or 2, characterized in that, The shape of the PHA radiotherapy isolator includes block, sheet, or irregular shape.

5. The method for preparing the PHA radiotherapy isolator according to any one of claims 1-4, characterized in that, The preparation method includes: Step (1): Dissolve the PHA material in an organic solvent to obtain a PHA solution; Step (2): Pre-freeze the PHA solution to form a solidified body; Step (3): Vacuum dry the solidified body to obtain the PHA radiotherapy isolator.

6. The preparation method according to claim 5, characterized in that, In step (1), the mass percentage concentration of the PHA material is 2-20%, preferably 5-10%, based on the total weight of the PHA solution as 100%.

7. The preparation method according to claim 5 or 6, characterized in that, In step (1), the organic solvent includes one or a combination of several of 1,4-dioxane, dichloromethane, chloroform, methyl formate, ethyl acetate, methyl acetate, acetone, dichloroethane and pentane, preferably 1,4-dioxane.

8. The preparation method according to claim 5 or 6, characterized in that, In step (2), the pre-freezing temperature is -16 to -20°C.

9. The method of using the PHA radiotherapy isolator according to any one of claims 1-4, characterized in that, The method of use includes: The PHA radiotherapy isolator is implanted between normal tissue and the radiation target area; The PHA radiotherapy isolator is fixed between normal tissue and the radiation target area.

10. The method of use according to claim 9, characterized in that, The method of use also includes: The PHA radiotherapy isolator was sterilized before implantation.

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