A beam collimator arrangement for scanned-slot x-ray imaging having one or several collimators in an x-ray apparatus is disclosed. The beam collimator arrangement includes an x-ray source; an x-ray image receiver positioned to receive x-rays from the x-ray source; a compressor or means for compressing a female breast to be examined where the compressor is positionable between the x-ray source and the x-ray image receiver; and the beam collimator is positioned between the x-ray source and the compressor. The beam collimator arrangement is arranged on a carrying structure to displace the beam collimator arrangement between a first position when no x-ray exposure is conducted and a second position before x-ray exposure is initiated.