The present invention relates to collimation of X-ray radiation. In order to provide an X-ray collimation suitable for focal spots spaced apart from each other with improved use of the provided radiation beam, an X-ray source arrangement (10) for medical imaging is provided. The X-ray source arrangement comprises an X-ray source (12), and an X-ray beam shutter device (14). The X-ray source is configured to generate X-ray radiation (18) at least at a first (20) and second focal spot position (22) distanced apart from each other in a direction (D) transverse to a main radiation direction (R). The X-ray beam shutter device comprises at least a first pair of shutters (28) defining a first diaphragm (30) for a first X-ray beam generated at the first focal spot position, and at least a second pair of shutters (34) defining a second diaphragm (36) for a second X-ray beam generated at the second focal spot position. The first pair of shutters is configured for alignment with a first line-of-sight (39) between the first focal spot position and a center of a detector, and the second pair of shutters is configured for alignment with a second line-of-sight (42) between the second focal spot position and a center of a detector. The first and the second diaphragm partly overlap.
