The invention relates to an interface unit (10) for positioning an irradiation object relative to a radiation source, comprising at least one first positioning surface (32) for positioning the interface unit relative to the radiation source and a second positioning surface (22) for contacting the irradiation object. The interface unit provides a path extending through the second positioning surface for the radiation of the radiation source. According to the invention, the interface unit comprises an interface body that is produced as one piece and that forms the at least one first positioning surface (32) and the second positioning surface (22). The interface body is preferably made from a plastic material in an injection compression method in order to achieve the desired high production accuracy.