[en] Full text: Radioisotopes with medium-energy beta emission and half life of a few days are attractive option for systemic delivery of targeted irradiation. Samarium-153 ethylene diamine tetra-ethylene phosphonale (153Sm-EDTMP), a bone-seeking radiopharmaceutical, provides therapeutic irradiation to osteoblastic osseous lesion. The usual dose of Sm-153 in metastatic disease is 1mCi/Kg (37MBq/Kg) and the dose limiting toxicity is thrombocytopenia. As local radiotherapy has only a limited therapeutic role in the treatment of osteosarcoma, and some types of the tumour portray an unpredictable response to chemotherapy. High dose Sm-153 (30mCi/Kg) was proposed for the target management of recurrent osteosarcoma, this was followed by stem cell transplant (peripheral-blood progenitor, PBPCs). A female child, 10 years old, with polyostotic osteosarcoma with local recurrence in the right hipbone was chosen for therapy. She had left knee prosthesis, right lower limb dis-articulation, and was given chemotherapy in multiple regions. She was subjected to MDP bone scan showing active uptake in an expanding bone lesion in the right hip bone, and was also subjected to MIBI scan, which showed negative uptake. She received 30mCi/Kg Sm-153 (660mCi in total dose), with no major events occurring in the post-injection period. After 10 days the patient went into pancytopenia, which necessitated haematological support. By day 14, there was minimal radiation in the whole body image and the child received her bone marrow transplant. There was marked improvement in the tumour size after 6 weeks of therapy, with improvement in the alkaline phosphatase level (from 1350Iu, before treatment to 350 post treatment). This was confirmed by serial MDP bone scan. High dose Sm-153 with stem cell transplant is considered view a promising method in the management of osteosarcoma. (author)