FIELD: medicine.SUBSTANCE: group of inventions refers to medical equipment, namely, to means for calibrating a system for introducing an influencing element into an object. Calibration apparatus comprises an image providing unit for providing a first image showing a longish introduction device, and a tracking device, which is adapted to track the introduction device and to be inserted into the introduction device as far as possible, and a second image showing the introduction device and a calibration element, which has the same dimensions as the influencing element and which is to be inserted into the introduction device as far as possible, identification unit for identifying the tip of the introduction device, the tracking device and the calibration element in the first and second images, spatial relation determining unit for determining a spatial relation between the tracking device and the calibration element from the first and second images, in which the tip of the introduction device, the tracking device and the calibration element have been identified. Apparatus for determining an influencing plan for influencing a target region within an object, comprises a unit for providing positions of a tracking device within an introduction device, unit for determining the pose and shape of the introduction device, unit for providing the pose and shape of the target region, unit for determining the influencing plan depending on the pose and shape of the introduction device, the pose and shape of the target region, the furthest position of the tracking device within the introduction device and the spatial relation between the tracking device and the calibration element. Method for calibrating a system for introducing an introduction element into an object is carried out by means of a calibration device using a machine-readable medium for calibrating a system for introducing an introduction element. Method for determining an influencing plan for influencing a target region
