The present invention relates to a method and an apparatus for guiding an irradiation equipment (2) located outside a human body (1) or an animal body. The method comprises the steps of identifying, in an image (4), a three-dimensional element (7) visible in the image (4), said three-dimensional element (7) has been in position in, or being inserted into, a cavity of the human body (1) or the animal body, establishing, in the image (4), a preliminary position of the three-dimensional element (7) visible in the image (4) in relation to a reference, establishing a preliminary position of the irradiation equipment (2) in relation to the reference, and adjusting the irradiation equipment (2) in response to the position the three-dimensional element (7).