This seed is intended for the temporary or permanent treatment of localized brain tumors. These include small circumscribed glial tumors of WHO graded I-IV as well as in brain metastases. The sterile and loose IsoSeeds are implanted using closed double catheters with an inner diameter of ≥ 1 mm. IsoSeed® I25.S17plus for Brain Tumor Treatment can be fixed inside the catheter with spacers, filaments or clips.