1. A marking apparatus for marking a location in a medical image, comprising: a providing unit for providing a first marker within a first medical image, which shows an object, at a first location, a location determination unit for determining a second location, which corresponds to the first location, within a second medical image showing the same object, an uncertainty determining unit for determining an uncertainty of the correspondence of the first location and the second location, a marking unit for marking the second location with a second marker, which is different in appearance to the first marker, wherein the marking unit is adapted for providing the appearance of the second marker in dependence on the determined uncertainty, a presenting unit for presenting the first medical image, the first marker, the second medical image and the second marker.