An apparatus and method for shielding non-target tissues and organs during thermotherapy, brachytherapy or other treatment of a diseased target tissue. The system includes a chemical injection unit and a controller positioned at a remote subsea location. The carriage arrangement includes a sidecar or nut arrangement for engagement with a screw of the drive mechanism. The control unit is configured to trigger the setting mechanism to set the at least two cylinders against each other. When changing the migration destination, a previously selected alternate storage apparatus is selected as the new migration-destination storage apparatus. The two holders on one side and the alignment means and preferably the electrodes on the other side can move relative to one another between a splicing position and a release position such that the splice connection is released in the release position.