An image-guided therapeutic apparatus (1) comprises a treatment device (2), preferably a HIFU transducer, for treating tissue, at least one imaging device (3) for guidance of a treatment, a mechanism for providing an image (4), a display (5) for displaying an image and planning mechanism (6) for planning a treatment. The planning mechanism (6) is adapted to create a lesion representation (9) of a lesion that will be created in tissue on the image (7) and to overlay the lesion representation (9) over the image (7). The size and/or shape and/or position of the lesion representation (9) is changeable, in particular, depending on the characteristics of the tissue.
