| 摘要 |
An X-ray emitting device (200) with an attenuating element (1) for an X-ray imaging device (100) is proposed. The attenuating element comprises a perforated sheet (3) of strongly X-ray absorbing material such as e.g. tungsten or molybdenum with a sheet thickness of e.g. less than 1 mm. The sheet (3) comprises multiple pinhole openings (5). Therein, a density of pinhole openings is higher at a center region of the sheet than at border regions of the sheet. Accordingly, a transparency to X-rays is higher at the center region than at the border regions. The pinhole openings (5) have geometries such that most parts of contours of the pinhole openings are non-parallel to edges of a focal spot (15) of an X-ray source (101) comprised in the X-ray emitting device. For example, the pinhole openings may have a circular, oval or any other cross-sectional geometry with non- linear edges. In an X-ray imaging device, such attenuating element may avoid beam hardening, needs less space than a conventional bow tie filter and is relatively insensitive to focal spot shifts. |
