An X-ray tube for generating periodic modulation of X-ray intensity, comprising: - a cathode; - an anode disk which provides a rotating anode in the X-ray tube and which is configured for modulating an X-ray beam generated by the X-ray tube; - a tube housing with an X-ray window; wherein the cathode is configured to emit electrons as an electron beam with a focal spot towards a focal track; wherein a centre of the focal spot is located on a focal track centre line on the anode disk; and wherein the anode disk comprises a circumferential target area, which represents the focal track, the target area having: - a target surface area; - the focal track centre line; and - a beam-dump surface area; wherein the target surface area is provided such that, when being hit by an electron beam, X-rays for X-ray imaging can be generated; wherein the target surface area comprises a plurality of target portions; wherein the beam-dump surface area is provided such that, when being hit by an electron beam, no useful X-rays for X-ray imaging can be generated; wherein the beam-dump surface area comprises a plurality of beam-dump portions; wherein for each of the beam-dump portions a bottom surface of the respective beam-dump portion, when being hit by the electron beam, has no line-of-sight to the X-ray window, so that the anode disk is provided with a structure on the circumferential target area, which effects the generation of the X-ray beam in form of a modulation by providing portions from which no useful X-rays are radiated in combination with portions used for the generation of X-ray radiation; wherein the target portions and the beam-dump portions are arranged along the focal track centre line; and wherein structures on both sides of the focal track centre line are arranged such that same radiation intensities are provided on the both sides when being hit by a homogenous electron beam; and wherein at least a part of the target surface area comprises target portions and beam-dump portions in an alternating manner in the direction of the focal track centre line; wherein the target surface area and the beam-dump surface area are arranged along the focal track centre line symmetrically with respect to the focal track centre line; characterized in that the circumferential target area comprises a continuous target centre portion, wherein the beam-dump surface area comprises a first plurality of grooves which form a first groove pattern and which are arranged opposed to a second plurality of grooves which form a second groove pattern, as seen relative to the target centre portion so that the first and the second plurality of grooves (52, 54) are arranged on opposing sides of the target centre portion; wherein the X-ray tube is configured to provide a plurality of different focal spots having different sizes in a radial direction of the anode disk; wherein each of the different focal spots of different sizes extends at least over a portion of each of the groove patterns so that the different focal spots provide different magnitudes of the periodic beam modulation. - a cathode; - an anode disk which provides a rotating anode in the X-ray tube and which is configured for modulating an X-ray beam generated by the X-ray tube; - a tube housing with an X-ray window; - a target surface area; - the focal track centre line; and - a beam-dump surface area;