RATIONALE: Radiation therapy uses high energy x-rays to kill tumor cells. Drugs used in chemotherapy, such as carboplatin, paclitaxel, cisplatin, and etoposide, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Radiolabeled monoclonal antibodies can find tumor cells and carry tumor-killing substances to them without harming normal cells. Giving radiation therapy and combination chemotherapy together before radiolabeled monoclonal antibody therapy may kill more tumor cells.