Patent Number: 
Section: claims

1. A process for producing a detected X-ray image of a breast, the process comprising the steps of: a) directing an X-ray beam produced by an X-ray tube, characterized by an output function comprising an X-ray tube current function and an X-ray tube voltage function, from a focus of the X-ray tube through the breast so that the beam impacts an image receptor to produce the detected X-ray image, where the intensity of primary X-ray radiation at a given point on the image receptor is characterized as a function of time by an image intensity function;  b) placing an anti-scatter grid between the breast and the image receptor, the anti-scatter grid characterized by a grid transmission function that is a periodic function of position characterized by a grid pitch;  c) producing a grid motion by moving the grid at a velocity during an X-ray exposure, the velocity characterized as a velocity function; and  d) modulating the output function such that for some thickness and composition of breast tissue, the image intensity function is substantially equal to the function i(t) defined by the equation  where x c (t) is the position of the center of the anti-scatter grid at time t, the velocity function v(x) is the velocity of the grid when the center of the anti-scatter grid is at position x, g(x) is an arbitrary function with a finite integral over x and has zero value outside a finite domain of x, h(x) is non-negative for every value of x, R(x) is the rect function, n is a positive integer, and P is the grid pitch. 2. The process of  claim 1  where the velocity function is substantially constant during the X-ray exposure, the tube voltage function is substantially constant during the X-ray exposure, the tube current function is modulated by varying a tube current, and the grid motion is characterized by a grid repeat time, where the grid repeat time is equal to the grid pitch divided by the grid velocity. claim 1 3. The process of  claim 2  where the tube current function is modulated by varying a filament current of the X-ray tube. claim 2 4. The process of  claim 2  where the tube current function is modulated by varying a voltage of a part of the X-ray tube selected from the group consisting of: a control grid and a bias cup. claim 2 5. The process of  claim 2  where the tube current function has a Fourier transform that has a negligible amplitude at all frequencies equal to positive multiples of the reciprocal of the grid repeat time. claim 2 6. The process of  claim 2  where the tube current function is substantially equal to a convolution of an arbitrary function with a rect function having a width substantially equal to an integer multiple of the grid repeat time. claim 2 7. The process of  claim 2  where the tube current function is a symmetric trapezoidal function having a ramp time substantially equal to a positive integer multiple of the grid repeat time. claim 2 8. The process of  claim 2  where the tube current function is a convolved dual symmetric trapezoidal function. claim 2 9. The process of  claim 1  where the output function is modulated by using a dynamic tube current function and a pseudo-rect tube voltage function. claim 1 10. The process of  claim 1  where the output function is modulated by using a dynamic tube current function and a dynamic tube voltage function. claim 1 11. The process of  claim 1  where the output function is modulated by using a pseudo-rect tube current function and a dynamic voltage function. claim 1 12. The process of  claim 1  where the velocity function is substantially constant during the X-ray exposure. claim 1 13. The process of  claim 1  where the velocity function varies during the X-ray exposure. claim 1 14. The process of  claim 1  where the anti-scatter grid comprises claim 1 a) a plurality of radio-opaque septa, interspersed with a radiolucent interspace material; and  b) a means to move the grid during the X-ray exposure to produce the grid motion at the velocity. 15. The process of  claim 14  where the width of the interspace material is greater than 8 times the width of the septa. claim 14 16. The process of  claim 14  wherein the grid motion is linear. claim 14 17. The process of  claim 14  wherein the anti-scatter grid further comprises a focusing means to keep the grid aligned on the focus during the grid motion. claim 14 18. The process of  claim 14  wherein the anti-scatter grid comprises one set of radio-opaque septa, where the septa are substantially parallel to each other and are substantially aligned with the focus. claim 14 19. The process of  claim 14  where the focusing means comprises a mechanism that moves the grid in an arc whose center is substantially coincident with a grid focal axis, the grid is periodic in an angular distance relative to the grid focal axis, and the velocity function describes an angular velocity of the grid about the grid focal axis. claim 14 20. The process of  claim 19  wherein the focusing means comprises a plurality of bearings mated to the grid and a plurality of curved guide tracks, the bearings configured to engage the plurality of curved guide tracks, where the focus and a center of curvature of each curved guide track are substantially coincident with the grid focal axis. claim 19 21. The process of  claim 19  wherein the focusing means comprises a plurality of bearings mated to the grid and at least two straight guide tracks, the bearings configured to engage the at least two straight guide tracks, the at least two straight guide tracks positioned such that a line normal to each track at a point where the bearings contact the track at a center of motion of the grid passes substantially close to the focus. claim 19 22. The process of  claim 14  where the focusing means comprises an articulating mechanism which articulates the septa individually to keep the septa focused on the focus, the motion of the grid is linear in a plane substantially parallel to the image receptor, the grid transmission function is periodic in linear distance in the direction of motion, and the velocity function describes a linear velocity of the grid. claim 14 23. The process of  claim 22  where the articulating mechanism comprises an upper support, a lower support, a first hinge means to moveably attach the septa to the upper support and a second hinge means to moveably attach the septa to the lower support and the articulating mechanism moves the upper support a first distance and the lower support a second distance. claim 22 24. The process of  claim 23  where the first distance and the second distance are not the same. claim 23 25. The process of  claim 23  where the ratio of the first distance to the second distance is equal to a distance from the focus to the upper support divided by a distance from the focus to the lower support. claim 23 26. The process of  claim 14  where the interspace material is air, polymer foam or aerogel. claim 14 27. The process of  claim 14  wherein the anti-scatter grid comprises two sets of radio-opaque septa, where the septa within each set are substantially parallel to each other and oriented to align with the focus, and the septa and a focal axis of the first set of septa are substantially perpendicular to the septa and a focal axis of the second set of septa. claim 14 28. The process of  claim 14  wherein the anti-scatter grid comprises a plurality of radio-opaque sheets having a plurality of holes perforating the sheets, the sheets stacked so the holes are aligned with each other and with the focus. claim 14 29. The process of  claim 28  wherein the focusing mechanism consists of a mechanism that moves the radiopaque sheets individually to keep them oriented on the focus. claim 28 30. The process of  claim 28  wherein the pattern of holes in the plurality of sheets is periodic in the direction of the grid motion, and is periodic either in a linear position or in an angular position on the sheet. claim 28 31. The process of  claim 28  wherein the shape of the holes in the plurality of sheets is selected from the group consisting of: hexagonal, square and triangular. claim 28 32. The process of  claim 14  where the spacing between the septa is maintained by a thin radiolucent sheet fixedly attached to the edges of the septa. claim 14 33. The process of  claim 14  where the spacing between the septa is maintained by a thin radiolucent sheet pivotally attached to the edges of the septa. claim 14