The present invention is related to a radiofrequency electrode (RF electrode) for the use in hyperthermia that can be fitted to the shape of a target to be treated (e.g. a patient) and that is also able to reversibly retain the shape it has been fitted to. Thereby, a reliable and close contact between the target to be treated (e.g. a patient) and the inventive RF electrode is established that enables an efficient and safe energy transfer to the target to be treated during a hyperthermia treatment of various medical conditions or for cosmetic purposes. The RF electrode has a target-averted side and a mouldable target-facing side and an inner cavity in between, wherein the inner cavity is fillable and emptiable and perfusable with a liquid and/or a liquid substitute and the inner cavity contains solid particles arrangeable in the presence of a liquid and/or a liquid substitute within the inner cavity and at least a part of the surface of the target-facing side is electrically conductive and is connectable to a RF energy source, wherein the target-facing side is fittable to any shape of a target by arranging the solid particles within the inner cavity.
