Scanning X-ray imaging device comprising: an X-ray source; an X-ray line detector; a field limiter arrangement; an observation volume; wherein the X-ray source is adapted to emit an X-ray beam towards the X-ray line detector; a moving mechanism coupled to at least one of the X-ray source and the X-ray line detector, the moving mechanism adapted to perform a scanning motion such as to scan at least portions of the X-ray beam through a region of interest within the observation volume; wherein the observation volume is arranged between the X-ray source and the X-ray line detector; wherein the field limiter arrangement is arranged between the X-ray source and the observation volume; wherein the field limiter arrangement comprises at least two variable shield plates (174, 175) and a displacing mechanism; wherein the shield plates may be displaced with respect to the center axis of the x-ray beam by means of the displacing mechanism such as to vary a cross section of an opening between the field plates through which at least a part of the X-ray beam is transmitted; and wherein the shield plates may be displaced independently from each other by means of the displacing mechanism; wherein the independent displacing of the shield plates (174, 175) is controlled by the displacing mechanism such that the opening between the shield plates (174, 175) is first successively opened to a larger cross section and then successively closed again to a smaller cross section during the scanning motion, and in such a manner so as to achieve a uniform dose level distribution. an X-ray source; an X-ray line detector; a field limiter arrangement; an observation volume; wherein the X-ray source is adapted to emit an X-ray beam towards the X-ray line detector; wherein the X-ray source is adapted to emit an X-ray beam towards the X-ray line detector; a moving mechanism coupled to at least one of the X-ray source and the X-ray line detector, the moving mechanism adapted to perform a scanning motion such as to scan at least portions of the X-ray beam through a region of interest within the observation volume; wherein the observation volume is arranged between the X-ray source and the X-ray line detector; wherein the field limiter arrangement is arranged between the X-ray source and the observation volume; wherein the field limiter arrangement comprises at least two variable shield plates (174, 175) and a displacing mechanism; wherein the shield plates may be displaced with respect to the center axis of the x-ray beam by means of the displacing mechanism such as to vary a cross section of an opening between the field plates through which at least a part of the X-ray beam is transmitted; and wherein the shield plates may be displaced independently from each other by means of the displacing mechanism; wherein the independent displacing of the shield plates (174, 175) is controlled by the displacing mechanism such that the opening between the shield plates (174, 175) is first successively opened to a larger cross section and then successively closed again to a smaller cross section during the scanning motion, and in such a manner so as to achieve a uniform dose level distribution. wherein the observation volume is arranged between the X-ray source and the X-ray line detector; wherein the field limiter arrangement is arranged between the X-ray source and the observation volume; wherein the field limiter arrangement comprises at least two variable shield plates (174, 175) and a displacing mechanism; wherein the shield plates may be displaced with respect to the center axis of the x-ray beam by means of the displacing mechanism such as to vary a cross section of an opening between the field plates through which at least a part of the X-ray beam is transmitted; and wherein the shield plates may be displaced independently from each other by means of the displacing mechanism; wherein the independent displacing of the shield plates (174, 175) is controlled by the displacing mechanism such that the opening between the shield plates (174, 175) is first successively opened to a larger cross section and then successively closed again to a smaller cross section during the scanning motion, and in such a manner so as to achieve a uniform dose level distribution.