Method and system for checking consistency between radiotherapy equipment isocenter and treatment isocenter

1. A method for checking a consistency between a radiotherapy equipment isocenter and a treatment isocenter, the method comprising:

acquiring projection data from a detector and generating image data based on the projection data, wherein the image data comprises a light spot and a shading located in the light spot, and the light spot and the shading are formed by a radiation beam generated by a treatment head of the radiotherapy equipment and then being blocked by a radiation blocking body; and

determining an offset between the radiotherapy equipment isocenter and the treatment isocenter based on the image data.

2. The method according to claim 1 , wherein said determining the offset between the radiotherapy equipment isocenter and the treatment isocenter based on the image data comprises:

determining the offset between the radiotherapy equipment isocenter and the treatment isocenter based on an offset between the light spot and the shading in the image data.

3. The method according to claim 2 , wherein said acquiring the projection data from the detector and generating the image data based on the projection data comprises:

acquiring, in response to a gantry of the radiotherapy equipment being rotated by a first preset angle, projection data corresponding to the first preset angle from the detector and generating first image data; and

acquiring, in response to the gantry of the radiotherapy equipment being rotated by a second preset angle, projection data corresponding to the second preset angle from the detector and generating second image data, and

wherein said determining the offset between the radiotherapy equipment isocenter and the treatment isocenter based on the offset between the light spot and the shading in the image data comprises:

determining a three-dimensional offset between the light spot and the shading based on a two-dimensional offset between the light spot and the shading in the first image data and a two-dimensional offset between the light spot and the shading in the second image data; and

determining the offset between the radiotherapy equipment isocenter and the treatment isocenter based on the three-dimensional offset between the light spot and the shading.

4. The method according to claim 3 , wherein the image data comprises a plurality of light spots and a plurality of shadings in one-to-one correspondence with the plurality of light spots, and

wherein said determining the offset between the radiotherapy equipment isocenter and the treatment isocenter based on the three-dimensional offset between the light spot and the shading comprises:

determining an average offset based on three-dimensional offset between each of the plurality of light spots and a shading corresponding to the light spot in the image data; and

determining the offset between the radiotherapy equipment isocenter and the treatment isocenter based on the average offset.

5. The method according to claim 3 , wherein the first preset angle differs from the second preset angle by 90 degrees.

6. The method according to claim 1 , wherein said determining the offset between the radiotherapy equipment isocenter and the treatment isocenter based on the image data comprises:

determining the offset between the radiotherapy equipment isocenter and the treatment isocenter based on an offset between a center point of the light spot and a center point of the shading in the image data.

7. The method according to claim 1 , wherein said acquiring the projection data from the detector and generating the image data based on the projection data comprises:

acquiring, in response to a gantry of the radiotherapy equipment being rotated by a different angle relative to an initial position, projection data corresponding to each of respective angles from the detector and generating image data corresponding to each of the respective angles, and

wherein said determining the offset between the radiotherapy equipment isocenter and the treatment isocenter based on the image data comprises:

determining the offset between the radiotherapy equipment isocenter and the treatment isocenter based on the image data corresponding to each of the respective angles.

8. The method according to claim 7 , wherein said determining the offset between the radiotherapy equipment isocenter and the treatment isocenter based on the image data corresponding to each of the respective angles comprises:

determining the offset between the radiotherapy equipment isocenter and the treatment isocenter by back-projecting the image data corresponding to each of the respective angles to the radiotherapy equipment isocenter.

9. The method according to claim 8 , wherein said determining the offset between the radiotherapy equipment isocenter and the treatment isocenter by back-projecting the image data corresponding to each of the respective angles to the radiotherapy equipment isocenter comprises:

back-projecting the light spot in the image data corresponding to each of the respective angles to the radiotherapy equipment isocenter, and constructing a light spot body according to a three-dimensional reconstruction algorithm; and

determining the offset between the radiotherapy equipment isocenter and the treatment isocenter based on an offset between a center of the light spot body and the radiotherapy equipment isocenter.

10. The method according to claim 8 , wherein said determining the offset between the radiotherapy equipment isocenter and the treatment isocenter by back-projecting the image data corresponding to each of the respective angles to the radiotherapy equipment isocenter comprises:

back-projecting the light spot and the shading in the image data corresponding to each of the respective angles to the radiotherapy equipment isocenter, and constructing a light spot body and a shading body according to a three-dimensional reconstruction algorithm; and

determining the offset between the radiotherapy equipment isocenter and the treatment isocenter based on an offset between a center of the light spot body and a center of the shading body.

11. The method according to claim 7 , wherein the gantry of the radiotherapy equipment is rotated by an angle of 0.5 degree each time.

12. The method according to claim 1 , wherein the shading formed by the radiation blocking body is a centrosymmetric pattern.

13. The method according to claim 1 , wherein the shading is in a circular shape, the light spot is in a circular shape, and a diameter of the light spot is greater than or equal to twice of a diameter of the shading.

14. A non-transitory computer readable storage medium storing at least one instruction therein, wherein the at least one instruction is loaded and executed by a processor to implement the method for checking the consistency between the radiotherapy equipment isocenter and the treatment isocenter according to claim 1 .

15. A device for checking a consistency between a radiotherapy equipment isocenter and a treatment isocenter, the device comprising:

a processor and a memory storing at least one instruction thereon,

wherein the at least one instruction is loaded and executed by the processor to implement a method for checking the consistency between the radiotherapy equipment isocenter and the treatment isocenter,

wherein the method comprises:

acquiring projection data from a detector and generating image data based on the projection data, wherein the image data comprises a light spot and a shading located in the light spot, and the light spot and the shading are formed by a radiation beam generated by a treatment head of the radiotherapy equipment and then being blocked by a radiation blocking body; and

determining an offset between the radiotherapy equipment isocenter and the treatment isocenter based on the image data.

16. A system for checking a consistency between a radiotherapy equipment isocenter and a treatment isocenter, the system comprising:

radiotherapy equipment, a radiation blocking body, and a processing device, wherein:

the radiotherapy equipment comprises a gantry, the gantry comprises a treatment head and a detector mounted on a position opposite to the treatment head, and the detector is configured to receive a radiation beam generated by the treatment head and convert the radiation beam into projection data;

the radiation blocking body is detachably mounted at the radiotherapy equipment isocenter, and a center of the radiation blocking body coincides with the radiotherapy equipment isocenter; and

the processing device is electrically connected to the detector, and the processing device is configured to execute a method for checking the consistency between the radiotherapy equipment isocenter and the treatment isocenter, wherein the method comprises:

acquiring projection data from the detector and generating image data based on the projection data, wherein the image data comprises a light spot and a shading located in the light spot, and the light spot and the shading are formed by a radiation beam generated by the treatment head of the radiotherapy equipment and then being blocked by the radiation blocking body; and

determining an offset between the radiotherapy equipment isocenter and the treatment isocenter based on the image data.

17. The system according to claim 16 , wherein the radiation blocking body is a radiation blocking ball.

18. The system according to claim 17 , wherein the radiation blocking ball is a metal ball.

19. The system according to claim 16 , further comprising a checking phantom, the radiation blocking body being mounted at a central position of the checking phantom, and the radiation blocking body is detachably mounted at the radiotherapy equipment isocenter by means of the checking phantom.

20. The system according to claim 19 , wherein the radiotherapy equipment further comprises a treatment couch, and the checking phantom is detachably mounted at a preset position on the treatment couch and is located at the radiotherapy equipment isocenter.