A digital X-ray tomosynthesis mammography imaging system for forming a three dimensional image of an object, comprising: an X-ray source adapted to irradiate the object with a beam of X-rays from a plurality of positions along a path in a sector; an X-ray detector positioned relative to the X-ray source to detect X-rays transmitted through the object; and a processor which is adapted to generate a three dimensional image of the object based on X-rays detected by the X-ray detector; wherein: the X-ray detector is adapted to move relative to the object; the X-ray source is adapted to move relative to the object and the X-ray detector; characterized in that: the X-ray source is adapted to irradiate the object with the beam of X-rays, wherein the X-ray source is adapted to emit the beam of X-rays while rotating in a first direction in an arc shaped path in a rotation plane; and the X-ray detector is positioned relative to the X-ray source to detect X-rays transmitted through the object, wherein the X-ray detector is adapted to move in a second direction opposite to the first direction while the X-ray source moves in the first direction and the X-ray source emits the beam of X-rays; such that X-rays passing through a mid-point of the object are incident on the same spot on the moving detector and such that a focal spot of the beam of X-rays follows a non arc shaped path relative to the X-ray detector. an X-ray source adapted to irradiate the object with a beam of X-rays from a plurality of positions along a path in a sector; an X-ray detector positioned relative to the X-ray source to detect X-rays transmitted through the object; and a processor which is adapted to generate a three dimensional image of the object based on X-rays detected by the X-ray detector; wherein: the X-ray detector is adapted to move relative to the object; the X-ray source is adapted to move relative to the object and the X-ray detector; characterized in that: the X-ray source is adapted to irradiate the object with the beam of X-rays, wherein the X-ray source is adapted to emit the beam of X-rays while rotating in a first direction in an arc shaped path in a rotation plane; and the X-ray detector is positioned relative to the X-ray source to detect X-rays transmitted through the object, wherein the X-ray detector is adapted to move in a second direction opposite to the first direction while the X-ray source moves in the first direction and the X-ray source emits the beam of X-rays; such that X-rays passing through a mid-point of the object are incident on the same spot on the moving detector and such that a focal spot of the beam of X-rays follows a non arc shaped path relative to the X-ray detector. the X-ray detector is adapted to move relative to the object; the X-ray source is adapted to move relative to the object and the X-ray detector; characterized in that: the X-ray source is adapted to irradiate the object with the beam of X-rays, wherein the X-ray source is adapted to emit the beam of X-rays while rotating in a first direction in an arc shaped path in a rotation plane; and the X-ray detector is positioned relative to the X-ray source to detect X-rays transmitted through the object, wherein the X-ray detector is adapted to move in a second direction opposite to the first direction while the X-ray source moves in the first direction and the X-ray source emits the beam of X-rays; the X-ray source is adapted to irradiate the object with the beam of X-rays, wherein the X-ray source is adapted to emit the beam of X-rays while rotating in a first direction in an arc shaped path in a rotation plane; and the X-ray detector is positioned relative to the X-ray source to detect X-rays transmitted through the object, wherein the X-ray detector is adapted to move in a second direction opposite to the first direction while the X-ray source moves in the first direction and the X-ray source emits the beam of X-rays; such that X-rays passing through a mid-point of the object are incident on the same spot on the moving detector and such that a focal spot of the beam of X-rays follows a non arc shaped path relative to the X-ray detector.