Scattered radiation grid of a CT detector
A scattered radiation grid of a CT detector is disclosed and includes a plurality of detector elements arranged in multiple cells in the phi direction and in the z direction of a CT system, having a plurality of free passage channels arranged to correspond to the detector elements, and walls fully enclosing the free passage channels at the longitudinal sides thereof. According to an embodiment of the invention, the walls of the scattered radiation grid are produced using a 3D screen-printing method.
1. A scattered radiation grid of a CT detector, comprising:
a plurality of detector elements arranged in multiple rows in a phi direction and z direction of a CT system, including walls, enclosing a plurality of free passage channels, arranged to correspond to the detector elements, at their longitudinal sides,
wherein the scattered radiation grid is made up of a number of individually produced grid modules; and
wherein the walls of the grid modules forming an outer face of the grid modules are configured thinner than the remaining walls of the grid modules.
2. The scattered radiation grid of claim 1 , wherein the walls of the grid modules forming an outer face of the grid modules, and not the outer face of the detector, are thinner than the remaining walls of the grid modules.
3. The scattered radiation grid of claim 1 , wherein the outer walls of the grid modules are embodied in such a manner that the grid modules engage in one another with a form fit.
4. The scattered radiation grid of claim 1 , wherein some of the walls of the grid modules have elongations on the beam exit side, serving for alignment at the detector.
5. The scattered radiation grid of claim 1 , wherein the walls of the grid or the grid modules are configured to be tapered in steps.
6. The scattered radiation grid of claim 1 , wherein the walls of the grid modules forming an outer face of the grid modules are configured half as thin as the remaining walls of the grid modules.
7. The scattered radiation grid of claim 3 , wherein the walls of the grid modules forming an outer face of the grid modules, and not the outer face of the detector, are half as thin as the remaining walls of the grid modules.
8. The scattered radiation grid of claim 2 , wherein the outer walls of the grid modules are embodied in such a manner that the grid modules engage in one another with a form fit.
9. The scattered radiation grid of claim 2 , wherein some of the walls of the grid modules have elongations on the beam exit side, serving for alignment at the detector.
10. A method of manufacturing a scattered radiation grid comprising:
printing a first layer of the radiation grid using a three-dimensional (3D) screen;
adjusting the 3D screen to provide narrower or wider openings in the 3D screen; and
printing a second layer of the radiation grid using the adjusted 3D screen.
11. The method of manufacturing a scattered radiation grid of claim 10 , wherein a suspension of material with an atomic number greater than 19 and binder is used to structure the walls during the course of the 3D screen-printing.
12. The method of manufacturing a scattered radiation grid of claim 10 , wherein a suspension of powdered metal and binder is used to structure the walls during the course of the 3D screen-printing.
13. The method of manufacturing a scattered radiation grid of claim 10 , wherein, during the course of the 3D screen-printing, passage channels with a cross section that varies with height are produced by replacing the screen used at least once with a successively changing covered region in the screen.
14. The method of manufacturing scattered radiation grid of claim 10 , wherein during the course of the 3D screen-printing, passage channels in the shape of truncated pyramids are produced by replacing the screen used a number of times with a successively narrowing covered region in the screen.
15. The scattered radiation grid of claim 10 , wherein during the course of the 3D screen-printing, passage channels in the shape of truncated pyramids, the longitudinal axes of which are respectively aligned with a common focus, are shaped by replacing the screen used at least once.
16. The method of manufacturing a scattered radiation grid of claim 10 , wherein, in a first production phase, passage channels and walls are aligned parallel to one another and a mechanical shaping process is applied before a final hardening, bringing about an alignment of the passage channels with a common focus.
17. The method of manufacturing a scattered radiation grid of claim 16 , wherein, to shape it mechanically, the scattered radiation grid is pressed into the shape of a truncated cone from a cuboid.
18. The method of manufacturing a scattered radiation grid of claim 16 , wherein, to shape it mechanically, at least one of the radiation entry side and radiation exit side is pressed onto a cylindrical or spherical surface.
19. The method of manufacturing a scattered radiation grid of claim 10 , wherein passage channels are embodied as narrowed in the region of the beam exit side of the scattered radiation grid.
20. The method of manufacturing a scattered radiation grid of claim 10 , wherein a longitudinal axes of passage channels are aligned with the focus.
21. The method of manufacturing a scattered radiation grid of claim 10 , wherein outer walls of the grid are configured to engage a second grid with a form fit.
22. The method of manufacturing a scattered radiation grid of claim 10 , wherein a plurality of walls of the grid has elongations on the beam exit side, serving for alignment at the detector.
23. The method of manufacturing a scattered radiation grid of claim 11 , wherein, during the course of the 3D screen-printing, passage channels with a cross section that varies with height are produced by replacing the screen used at least once with a successively changing covered region in the screen.
24. The method of manufacturing a scattered radiation grid of claim 11 , wherein during the course of the 3D screen-printing, passage channels in the shape of truncated pyramids are produced by replacing the screen used a number of times with a successively narrowing covered region in the screen.
25. The method of manufacturing a scattered radiation grid of claim 12 , wherein, during the course of the 3D screen-printing, passage channels with a cross section that varies with height are produced by replacing the screen used at least once with a successively changing covered region in the screen.
26. The method of manufacturing a scattered radiation grid of claim 12 , wherein during the course of the 3D screen-printing, passage channels in the shape of truncated pyramids are produced by replacing the screen used a number of times with a successively narrowing covered region in the screen.