Radiotherapy reference positioning mark

The invention relates to a reference positioning marker (5) suitable for radiotherapy or microwave therapy or cryosurgery or ultrasound therapy implanted in tissue using a hollow injection needle (4), the marker comprising an elongated object, the elongated object has a longitudinal axis (CL) and has a cross-section (A-A, B-B, C-C, D-D, E-E, F-F) perpendicular to said longitudinal axis (CL) adapted to fit within the inner diameter (DI) of the needle (4), in which the marker (5) comprises a plurality of first sections (1) having a first cross-section and one or more second sections (2) having a second set of cross-sections, in which the first sections (1) and the one or more second sections (2) each have a second set of cross-sections, the area of the first cross-section is selected to be relatively larger than the area of the second group of cross-sections, and wherein the first sections (1) and the second sections (2) are arranged alternately with one another along the longitudinal axis (CL), and wherein one