For detecting the relative location of a laser or laser fan beam relative to the x-ray geometry of an x-ray device, a method for calibrating the position of the laser fan beam generated by a laser in relation to the projection geometry of the x-ray device is proposed. The x-ray device comprises an x-ray imaging system featuring an x-ray source and an x-ray detector. The x-ray source, the x-ray detector, the laser, and an imaging facility are arranged on a support. An optical x-ray calibration phantom is used for the calibration. The position of the imaging facility relative to the projection geometry is determined. The position of the laser fan beam relative to the imaging facility is determined. The position of the laser fan beam relative to the projection geometry is reconstructed.