RADIATION THERAPY REFERENCE POSITIONING MARKER

The present invention relates to a radiation therapy or microwave therapy or cryosurgery or ultrasound therapy reference positioning marker (5) adapted to be implanted in tissue using a hollow injection needle (4), wherein the marker comprises an elongated object with a longitudinal axis (CL) and have cross-sections (A-A, B-B, C-C, D-D, E-E, F-F) of the object, perpendicular to said longitudinal axis (CL), being adapted to fit within an inner diameter (DI) of the needle (4), wherein the marker (5) comprises a plurality of first segments (1) having a first cross-section and one or more second segments (2) having a second set of cross- sections, wherein an area of the first cross-section is selected relatively larger than area/s of the second set of cross-sections, and wherein the first segments (1) and second segments (2) are arranged alternately after each other along the longitudinal axis (CL), wherein the one or more of second segments (2) are provided with one or more deformation segments (22) adapted to ensure that any deformation of the plurality of second segments, when positioned inside the needle, occurs in a predetermined location/s between adjoining first segments, such that the plurality of first segments remain linearly aligned in the injection needle when it encounters resistance during implantation into the tissue.