Model body for radiotherapy image deformation registration verification and verification method

Abstract

The invention relates to the technical field of radiotherapy, and discloses a mold body for radiotherapy image deformation registration verification and a verification method.The mold body comprises a base, a water mold is placed at the top of the base, an observation assembly is installed at the top of the base, a deformation assembly is installed in the water mold, and an extrusion assembly is installed in the base; a rotating assembly is installed at the bottom of the base, the deformation assembly comprises a supporting column, the supporting column is fixedly connected to the interior of the water mold, connecting pieces are fixedly connected to the sides, opposite to the supporting column, of the water mold, deformation blocks are fixedly connected to one ends of the multiple adjacent connecting pieces, and the deformation blocks are fixedly connected to the other ends of the multiple adjacent connecting pieces. A plurality of second metal beads are fixedly connected to the outer surface of the water mold. High-contrast metal mark points are arranged inside and outside the die body, the actual space positions before and after deformation of the die body are accurately obtained by using an image processing technology, and a physical true value independent of a software algorithm is provided.

Description

Technical Field

[0001] This invention relates to the field of radiotherapy technology, specifically to a phantom and verification method for verifying image deformation registration in radiotherapy. Background Technology

[0002] In the field of modern radiotherapy, especially with the development of advanced technologies such as image-guided radiotherapy and adaptive radiotherapy, accurately tracking and correcting changes in the shape and position of tumors and organs at risk caused by the patient's physiological movements (such as breathing, organ peristalsis or filling) or changes in body position during treatment has become the key to ensuring accurate dose delivery and improving treatment efficacy.

[0003] Deformation image registration algorithms are the core technology for achieving this goal. They establish spatial correspondences between images from different time phases by calculating a complex deformation vector field. However, the accuracy of deformation registration algorithms directly affects the precision of target delineation and the final dose calculation results. Therefore, their performance must be comprehensively and reliably validated before they can be applied clinically.

[0004] Currently, the validation of deformation registration algorithms mainly relies on digital phantoms or limited clinical case data. Digital phantoms are generated by computer software simulations, and their deformation patterns are based on pre-set mathematical models. They cannot fully reproduce the complex tissue mechanics and imaging artifacts in the real physical world, posing a risk of circular reasoning in validation. When using clinical images for validation, since the true, point-to-point gold standard of displacement between organs cannot be predicted, a rough assessment can usually only be made based on the degree of conformity of a few anatomical landmarks, lacking precise quantitative indicators for both global and local data.

[0005] Existing physical phantom verification methods also have significant shortcomings. Many physical phantoms have simple structures, and their deformation is usually applied manually or in a simplified manner, resulting in uncontrollable, unquantifiable, and difficult-to-reproduce deformations. This uncertainty makes it impossible to establish a clear relationship between known deformation inputs and algorithm registration outputs, thus hindering a systematic evaluation of algorithm accuracy and a fair comparison between different algorithms.

[0006] Furthermore, existing technologies generally lack a standardized, integrated physical verification platform capable of simulating the relative motion of multiple internal tissue structures and incorporating functions such as precise actuation, stable locking, and high-quality imaging assurance. This deficiency limits in-depth research and verification of the robustness and reliability of deformation registration algorithms in complex clinical scenarios. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a phantom and verification method for deformation registration verification of radiotherapy images. This solves the problem that the lack of independent, objective, and repeatable deformation registration physical verification tools in existing technologies makes it impossible to accurately and quantitatively evaluate the true accuracy of the algorithm.

[0008] To achieve the above objectives, the first aspect of the present invention provides a phantom for verification of deformation registration in radiotherapy images, comprising a base, a water phantom placed on the top of the base, an observation component installed on the top of the base, a deformation component installed inside the water phantom, a compression component installed inside the base, and a rotation component installed at the bottom of the base. The deformable component includes a support column and multiple deformable blocks. The support column is fixedly connected inside the water mold. Multiple connectors are fixedly connected to both the inner surface of the water mold and the outer surface of the support column. Multiple deformable blocks are fixedly connected to one end of multiple adjacent connectors. Multiple metal beads are fixedly connected to the outer surface of the water mold, and multiple metal beads are fixedly connected to the outer surface of the deformable blocks.

[0009] Preferably, the extrusion assembly includes a lead screw rotatably connected to the middle of the base, a knob fixedly connected to the end of the lead screw away from the base, an inner cavity formed inside the base, a sliding groove formed at the top of the base communicating with the inner cavity, a movable plate threadedly connected to the outer circumference of the lead screw, the movable plate slidably connected to the middle of the sliding groove, a connecting rod fixedly connected to the middle of the movable plate, a push plate fixedly connected to the end of the connecting rod away from the movable plate, and a locking assembly installed on the outer side of the base.

[0010] Preferably, the engaging assembly includes a round rod, which is fixedly connected to the outside of the base. A pawl is rotatably connected to the outer periphery of the round rod. A ratchet is fixedly connected to the outer periphery of the lead screw. One end of the pawl is engaged in the middle of the tooth groove of the ratchet. A spring plate is fixedly connected to the outside of the base, and the spring plate is in contact with the pawl.

[0011] Preferably, the rotating assembly includes an upper toothed plate, which is fixedly connected to the bottom of the base. A through hole is provided in the middle of the upper toothed plate. A slide rod is slidably connected to the middle of the base. A stop block is fixedly connected to the top of the slide rod. The other end of the slide rod passes through the through hole and is fixedly connected to a lower toothed plate. A compression spring is sleeved on the outer periphery of the slide rod.

[0012] Preferably, the observation component includes a protrusion, which is fixedly connected to the top of the base, and a slot is formed in the middle of the protrusion, with a transparent cover slidably connected to the middle of the slot.

[0013] Preferably, the bottom of the lower toothed plate is provided with anti-slip texture.

[0014] A second aspect of the present invention provides a verification method for a radiation therapy image deformation registration verification phantom, comprising the following steps: S1. Place the model in the initial state, and use an image acquisition device to scan the water model, deformable block, metal bead one and metal bead two to obtain the first image data under the reference state. S2. Activate the extrusion assembly and rotation assembly to cause the water mold and deformable block to produce a preset, quantifiable deformation or displacement; S3. While the mold body is in a deformed or displaced state, use the same image acquisition device and parameters as in step S1 to perform a second scan to obtain second image data in the deformed state. S4. Input the first image data and the second image data into the deformation registration algorithm to be verified for registration. By comparing the deviation between the theoretical positions of the first metal bead and the second metal bead after registration and their actual positions in the second image data, the accuracy of the deformation registration algorithm is evaluated.

[0015] Preferably, in step S2, by rotating the knob to drive the push plate to move on the lead screw, a squeezing force is applied to the water model, and the base is rotated to make the upper toothed plate mesh with the lower toothed plate for angular positioning, which is used to control the linear and rotational composite deformation of the water model.

[0016] Preferably, the deviation assessment in step S4 specifically includes: The initial positions of metal bead one and metal bead two in the first image data and their actual final positions in the second image data are determined by image processing technology. The deformation registration algorithm to be verified is used to transform the first image data, and the theoretical final position obtained from the transformation of the initial position is calculated. Calculate and statistically analyze the spatial distance error between the actual final position and the theoretical final position.

[0017] Preferably, the statistical analysis of the spatial distance error between the actual final position and the theoretical final position includes calculating the average deviation, standard deviation, and maximum deviation of the spatial distance error of all metal beads.

[0018] This invention provides a phantom and verification method for image deformation registration verification in radiotherapy. It has the following beneficial effects: 1. This invention provides a physical truth value independent of the software algorithm itself by setting high-contrast metal markers inside and outside the mold body and using image processing technology to accurately obtain its actual spatial position before and after deformation. By objectively comparing the prediction results of the registration algorithm with this physical truth value, this invention can achieve high-accuracy quantitative verification of the deformation registration algorithm's precision.

[0019] 2. This invention achieves precise control over the degree and direction of mold deformation through integrated extrusion and rotation components. The lead screw and knob transmission mechanism ensures the quantification and repeatability of linear displacement; the ratchet and pawl engagement mechanism immediately locks the mold position after deformation; and the toothed plate and compression spring engagement mechanism ensures discrete positioning and stability of the rotation angle. These structures collectively guarantee the high repeatability of the verification process, ensuring stable and reliable experimental results.

[0020] 3. The phantom material and internal structure design used in this invention can simulate the physical deformation of tissues and organs during radiotherapy. This phantom and verification method provide a reliable and standardized physical tool for evaluating and optimizing deformation registration technology. The verification results can directly guide the selection of clinical deformation registration algorithms and parameter adjustments, which has important clinical application value for improving the accuracy of radiotherapy and ensuring the accurate implementation of treatment plans. Attached Figure Description

[0021] Figure 1 This is a perspective view of an embodiment of the present invention; Figure 2 This is a schematic diagram of the bump structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the cross-sectional structure of the water model according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the extrusion assembly structure according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the cross-sectional structure of the base according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the rotating component structure according to an embodiment of the present invention.

[0022] Explanation of icon numbers: 1. Base; 2. Transparent cover; 3. Protrusion; 4. Knob; 5. Pawl; 6. Spring plate; 7. Water mold; 8. Slide groove; 9. Movable plate; 10. Connecting rod; 11. Push plate; 12. Slot; 13. Round rod; 14. Connector; 15. Deformation block; 16. Support column; 17. Metal bead one; 18. Metal bead two; 19. Inner cavity; 20. Lead screw; 21. Anti-slip texture; 22. Through hole; 23. Compression spring; 24. Stop block; 25. Lower toothed plate; 26. Upper toothed plate; 27. Slide rod; 28. Ratchet. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figures 1-6 This invention provides a phantom for verifying deformation registration of radiotherapy images, including a base 1, a water phantom 7 placed on top of the base 1, an observation component installed on top of the base 1, a deformation component installed inside the water phantom 7, a compression component installed inside the base 1, and a rotation component installed at the bottom of the base 1. In one specific embodiment, the deformation phantom, deformation drive, and rotation positioning functions are integrated into one through the deformation component, compression component, and rotation component, so as to facilitate image observation and error verification, and provide a physical verification platform for radiotherapy image registration.

[0025] See Figure 2 and Figure 3 The deformable component includes a support column 16 and multiple deformable blocks 15. The support column 16 is fixedly connected inside the water mold 7. Multiple connectors 14 are fixedly connected to both the inner surface of the water mold 7 and the outer surface of the support column 16. Multiple deformable blocks 15 are fixedly connected to the opposite ends of multiple adjacent connectors 14. Multiple metal beads 18 are fixedly connected to the outer surface of the water mold 7, and multiple metal beads 17 are fixedly connected to the outer surface of the deformable blocks 15.

[0026] In one specific embodiment, the support column 16 at the center of the polystyrene foam water model 7 first remains stable during deformation. Between the inner wall of the water model 7 and the support column 16, several deformable blocks 15 made of highly elastic material are connected and suspended by multiple flexible connectors 14. The shapes, sizes, and elastic moduli of the multiple deformable blocks 15 can be different to simulate the heterogeneity of different organs or tissues. When external pressure is applied, the force is transmitted to the deformable blocks 15 through the main body of the water model 7 and the connectors 14, causing them to produce complex non-rigid displacements and deformations relative to the support column 16 and to each other, thereby simulating the deformation of organs and tissues under external pressure. To ensure the display effect of the water model 7 and each deformable block 15 in the standard state and the deformed state, multiple metal beads 18 are implanted on the outer surface of the water model 7, and multiple metal beads 17 are firmly implanted on the outer surface of the deformable blocks 15. The metal beads, which are combined inside and outside, serve as markers to improve the clear display effect in radiotherapy images, so as to compare the position changes of the markers based on multiple scanned images, thereby objectively and accurately verifying the accuracy of radiotherapy image deformation registration.

[0027] See Figure 4 and Figure 5 The extrusion assembly includes a lead screw 20, which is rotatably connected to the middle of the base 1. A knob 4 is fixedly connected to the end of the lead screw 20 away from the base 1. An inner cavity 19 is opened inside the base 1, and a sliding groove 8 is opened on the top of the base 1. The sliding groove 8 communicates with the inner cavity 19. A movable plate 9 is threadedly connected to the outer periphery of the lead screw 20. The movable plate 9 is slidably connected to the middle of the sliding groove 8. A connecting rod 10 is fixedly connected to the middle of the movable plate 9. A push plate 11 is fixedly connected to the end of the connecting rod 10 away from the movable plate 9. A locking assembly is installed on the outer side of the base 1.

[0028] In one specific embodiment, rotating the knob 4 drives the lead screw 20 to rotate in the inner cavity 19, causing the movable plate 9 to move under the rotation of the lead screw 20 and the limiting action of the slide groove 8. While moving, the movable plate 9 drives the push plate 11 to make linear displacement through the connecting rod 10. Under the action of multiple push plates 11 that can move independently, the applied deformation is controllable and repeatable, which can accurately simulate the displacement and deformation of the tissue, providing a basis for quantitative verification.

[0029] See Figure 2 , Figure 4 and Figure 5 The engaging assembly includes a round rod 13, which is fixedly connected to the outside of the base 1. A pawl 5 is rotatably connected to the outer periphery of the round rod 13. A ratchet 28 is fixedly connected to the outer periphery of the lead screw 20. One end of the pawl 5 is engaged in the middle of the tooth groove of the ratchet 28. A spring plate 6 is fixedly connected to the outside of the base 1, and the spring plate 6 is in contact with the pawl 5.

[0030] In one specific embodiment, when the operator rotates the lead screw 20 via the knob 4, the ratchet 28 on the outer periphery of the lead screw 20 will rotate along with it. The helical tooth surface of the ratchet 28 will push open the pawl 5, allowing it to rotate smoothly. When rotation stops, the pawl 5 will engage with the nearest tooth groove under the action of the spring plate 6, and the straight tooth surface of the ratchet 28 will prevent it from rotating back. Thus, after deformation is applied to the mold body, it can instantly lock the lead screw 20, preventing the push plate 11 from retracting due to the elastic restoring force of the water mold 7 and the deformation block 15. This ensures that the mold body can accurately maintain its deformation state throughout the entire process of the second image scan, thereby ensuring the validity of the acquired image data and the accuracy of the verification results. When reset is required, pressing the pawl 5 will lift it, allowing the lead screw 20 to rotate in the opposite direction, thereby allowing the push plate 11 to reset.

[0031] See Figure 5 and Figure 6The rotating assembly includes an upper toothed plate 26, which is fixedly connected to the bottom of the base 1. A through hole 22 is provided in the middle of the upper toothed plate 26. A slide rod 27 is slidably connected to the middle of the base 1. A stop block 24 is fixedly connected to the top of the slide rod 27. The other end of the slide rod 27 passes through the through hole 22 and is fixedly connected to a lower toothed plate 25. A compression spring 23 is sleeved on the outer periphery of the slide rod 27.

[0032] In one specific embodiment, a pressure is constantly applied to the upper toothed plate 26 and the lower toothed plate 25 under the action of the compression spring 23 fitted on the slide rod 27, so that they mesh with each other. In the static state, the teeth of the two toothed plates are engaged with each other, and the base 1 cannot rotate. When rotation is required, the operator needs to forcefully rotate the base 1, so that the two teeth slide and lift up under the action of the inclined plane. The lifting force will overcome the elastic force of the compression spring 23, so that the base 1 can freely rotate to a new angle. After rotating to the position, the base 1 is released, and the restoring force of the compression spring 23 will immediately push the spring back, so that the lower toothed plate 25 and the upper toothed plate 26 re-engage and lock at the new angle position. The number and distribution of the teeth on the toothed plates determine the step accuracy of rotation, ensuring that the rotation angle is discrete, known and highly repeatable, thereby simulating rotation and other scenarios and providing a reliable physical realization.

[0033] See Figure 1 and Figure 2 The observation component includes a protrusion 3, which is fixedly connected to the top of the base 1. A slot 12 is provided in the middle of the protrusion 3, and a transparent cover 2 is slidably connected to the middle of the slot 12.

[0034] In one specific embodiment, a transparent cover 2 is first slidably installed through a slot 12 on the protrusion 3 at the top of the base 1. The transparent cover 2 covers the top of the water model 7 and serves as the X-ray incident window of the image acquisition device. The transparent cover 2 is made of a material with extremely low attenuation characteristics for high-energy rays such as X-rays, such as polymethyl methacrylate, which can minimize interference with imaging rays and ensure that the acquired image is clear, has few artifacts, and has a high signal-to-noise ratio. This provides high-quality raw data for subsequent high-precision image processing and marker positioning. At the same time, the transparent cover 2 can provide protection for the water model 7.

[0035] See Figure 5 and Figure 6 The bottom of the lower toothed plate 25 is provided with anti-slip texture 21; in a specific embodiment, the bottom of the lower toothed plate 25 is provided with anti-slip texture 21, thereby increasing the static friction coefficient between the entire mold device and the placement plane, thereby preventing the mold device from undergoing slight translation or sliding on the smooth scanning bed, and ensuring the accuracy of measurement.

[0036] This invention also provides a verification method for a radiation therapy image deformation registration verification phantom, specifically including the following steps: S1. Place the model in the initial state and use an image acquisition device to scan the water model 7, the deformable block 15, the metal bead 17 and the metal bead 2 18 to obtain the first image data under the reference state. S2. Activate the extrusion and rotation components to cause the water mold 7 and the deformation block 15 to produce a preset, quantifiable deformation or displacement. S3. While the model remains deformed or displaced, scan it again using the same image acquisition device and parameters as in step S1 to obtain the second image data under the deformed state. S4. Input the first image data and the second image data into the deformation registration algorithm to be verified for registration. By comparing the deviation between the theoretical positions of metal bead 17 and metal bead 28 after registration and their actual positions in the second image data, the accuracy of the deformation registration algorithm is evaluated.

[0037] In step S2, the push plate 11 is driven to move on the lead screw 20 by rotating the knob 4, which applies a squeezing force to the water model 7. The base 1 is rotated so that the upper toothed plate 26 and the lower toothed plate 25 are engaged for angular positioning, which is used to control the linear and rotational composite deformation of the water model 7.

[0038] The deviation assessment in step S4 specifically includes: The initial positions of metal bead 17 and metal bead 28 in the first image data and their actual final positions in the second image data are determined by image processing technology. The deformation registration algorithm to be verified is used to transform the first image data, and the theoretical final position obtained from the transformation of the initial position is calculated. Calculate and statistically analyze the spatial distance error between the actual final position and the theoretical final position.

[0039] The statistical analysis of the spatial distance error between the actual final position and the theoretical final position includes calculating the average deviation, standard deviation, and maximum deviation of the spatial distance error of all metal beads.

[0040] The working principle is as follows: First, a polystyrene foam water mold 7 with good elasticity and plasticity and a silicone deformable block 15 are used as the substrate. Then, the water mold 7 is placed on an image acquisition device commonly used in radiotherapy. The device performs a first scan to obtain an image set of the mold in a reference state. Under the action of metal beads 18 and 17 on the surface of the water mold 7 and the deformable block 15, they are clearly displayed as marker points in the radiotherapy image. Thus, when the water mold 7 and multiple deformable blocks 15 undergo displacement and deformation for a second scan, the image acquisition device can objectively and accurately verify the accuracy of the deformation registration of the radiotherapy image based on the positional changes of the marker points.

[0041] By rotating the knob 4, the lead screw 20 is rotated, allowing the movable plate 9 on the outer periphery of the lead screw 20 to slide in the middle of the slide groove 8, thereby moving the connecting rod 10. The connecting rod 10 then deforms the water model 7 by pressing it against the push plate 11. Under the action of the movable plates 9, which can move independently in four directions, the operator can adjust the degree and direction of deformation of the water model 7 and the deformable block 15 as needed. At the same time, by rotating the base 1, the upper toothed plate 26 at the bottom of the base 1 can rotate on the lower toothed plate 25. When the base 1 is lifted during rotation, it will cause the upper toothed plate 26 to slide on the outer periphery of the slide rod 27, thereby compressing the compression spring 23 under the action of the stop block 24. After the rotation is completed, the upper toothed plate 26 and the lower toothed plate 25 abut against each other under the push of the compression spring 23. Thus, under the compression action of the compression spring 23, the operator does not need to rotate the base 1 with force, so that the base 1 will not shake, ensuring the repeatability of the verification process.

[0042] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A phantom for verifying image deformation registration in radiotherapy, characterized in that, Includes a base (1), a water model (7) is placed on the top of the base (1), an observation component is installed on the top of the base (1), a deformation component is installed inside the water model (7), an extrusion component is installed inside the base (1), and a rotation component is installed at the bottom of the base (1). The deformable component includes a support column (16) and multiple deformable blocks (15). The support column (16) is fixedly connected to the inside of the water mold (7). Multiple connectors (14) are fixedly connected to the inner surface of the water mold (7) and the outer surface of the support column (16). Multiple deformable blocks (15) are fixedly connected to one end of multiple adjacent connectors (14). Multiple metal beads (2) are fixedly connected to the outer surface of the water mold (7), and multiple metal beads (17) are fixedly connected to the outer surface of the deformable blocks (15).

2. The phantom for verifying image deformation in radiotherapy according to claim 1, characterized in that, The extrusion assembly includes a lead screw (20), which is rotatably connected to the middle of the base (1). A knob (4) is fixedly connected to one end of the lead screw (20) away from the base (1). An inner cavity (19) is opened inside the base (1). A sliding groove (8) is opened on the top of the base (1). The sliding groove (8) is connected to the inner cavity (19). A movable plate (9) is threadedly connected to the outer periphery of the lead screw (20). The movable plate (9) is slidably connected to the middle of the sliding groove (8). A connecting rod (10) is fixedly connected to the middle of the movable plate (9). A push plate (11) is fixedly connected to one end of the connecting rod (10) away from the movable plate (9). A locking assembly is installed on the outer side of the base (1).

3. The phantom for verifying image deformation in radiotherapy according to claim 2, characterized in that, The engaging assembly includes a round rod (13), which is fixedly connected to the outside of the base (1). A pawl (5) is rotatably connected to the outer periphery of the round rod (13). A ratchet (28) is fixedly connected to the outer periphery of the lead screw (20). One end of the pawl (5) is engaged in the middle of the tooth groove of the ratchet (28). A spring plate (6) is fixedly connected to the outside of the base (1), and the spring plate (6) is in contact with the pawl (5).

4. The phantom for verifying image deformation in radiotherapy according to claim 1, characterized in that, The rotating assembly includes an upper toothed plate (26), which is fixedly connected to the bottom of the base (1). A through hole (22) is provided in the middle of the upper toothed plate (26). A slide rod (27) is slidably connected to the middle of the base (1). A stop block (24) is fixedly connected to the top of the slide rod (27). The other end of the slide rod (27) passes through the through hole (22) and is fixedly connected to a lower toothed plate (25). A compression spring (23) is sleeved on the outer periphery of the slide rod (27).

5. A phantom for verifying image deformation in radiotherapy according to claim 1, characterized in that, The observation component includes a protrusion (3), which is fixedly connected to the top of the base (1). A slot (12) is provided in the middle of the protrusion (3), and a transparent cover (2) is slidably connected to the middle of the slot (12).

6. A phantom for verifying image deformation in radiotherapy according to claim 4, characterized in that, The bottom of the lower toothed plate (25) is provided with anti-slip texture (21).

7. A verification method for a radiation therapy image deformation registration verification phantom according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Place the model in the initial state and use an image acquisition device to scan the water model (7), the deformable block (15), the first metal bead (17) and the second metal bead (18) to obtain the first image data under the reference state. S2. Start the extrusion assembly and the rotation assembly to cause the water mold (7) and the deformation block (15) to produce a preset, quantifiable deformation or displacement; S3. While the mold body is in a deformed or displaced state, use the same image acquisition device and parameters as in step S1 to perform a second scan to obtain second image data in the deformed state. S4. Input the first image data and the second image data into the deformation registration algorithm to be verified for registration. By comparing the deviation between the theoretical position of the first metal bead (17) and the second metal bead (18) after registration and the actual position in the second image data, the accuracy of the deformation registration algorithm is evaluated.

8. The verification method for a radiation therapy image deformation registration verification phantom according to claim 7, characterized in that, In step S2, by rotating the knob (4) to drive the push plate (11) to move on the lead screw (20), a squeezing force is applied to the water mold (7). The base (1) is rotated to make the upper toothed plate (26) mesh with the lower toothed plate (25) for angular positioning, which is used to control the linear and rotational composite deformation of the water mold (7).

9. The verification method for a radiation therapy image deformation registration verification phantom according to claim 7, characterized in that, The deviation assessment in step S4 specifically includes: The initial positions of metal bead one (17) and metal bead two (18) in the first image data and their actual final positions in the second image data are determined by image processing technology. The deformation registration algorithm to be verified is used to transform the first image data, and the theoretical final position obtained from the transformation of the initial position is calculated. Calculate and statistically analyze the spatial distance error between the actual final position and the theoretical final position.

10. The verification method for a radiation therapy image deformation registration verification phantom according to claim 9, characterized in that, The statistical analysis of the spatial distance error between the actual final position and the theoretical final position includes calculating the average deviation, standard deviation, and maximum deviation of the spatial distance error of all metal beads.

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