Abstract: Arrangement for defining a location within an organism, said arrangement comprising: a hollow needle (2), comprising a longitudinal channel (5) and a distal end (4); a mandrin (1), accommodated in the longitudinal channel (5) in mobile manner in relation to it and removable from said channel (5) and having a distal and (3) of closed design, comprising an electrode pattern including at least two electrodes (7a, 7b, 7c, 7d); as well as a processing unit, configured to monitor the advancement of the distal end (4) only on the basis of a measurement signal of bio impedance received from the electrodes (7a, 7b, 7c, 7d) of the electrode pattern. The application includes also an independent claim for a method for manufacturing a mandrin to be accommodated in a needle.

Abstract: An arrangement for determining the position of a needle in an organ system and a method utilizing the arrangement in cosmetic treatment or cosmetic surgery. The arrangement (1) comprises a needle (2) with a distal tip (3), a measurement circuit (4) measuring the bioimpedance of tissues, a detection means (10) connected to the measurement circuit measuring bioimpedance and arranged to detect the progress of the distal tip (3) of the needle at a real-time basis from the bioimpedance measured from tissues. The arrangement (1) comprises at least two electrodes (16, 18, 21, 22) arranged at the distal tip (3) of the needle and connected to the measurement circuit (4). All the electrodes (16, 18, 21, 22) measuring impedance and needed for monitoring the progress of the distal tip (3) of the needle are arranged to the distal tip (3) of the needle.