We report the case of a 48-year-old woman affected by inoperable primary angiosarcoma of the right atrium who was treated with 4 cycles of induction chemotherapy and radical radiotherapy. We present the application and the result of helical tomotherapy for this patient. We also describe the technical aspects of the simulation, planning, setup and delivery of radiotherapy. At 16 months after the diagnosis the patient is still in good condition without any symptoms and with a partial response of the lesion. This case shows the feasibility of treatment with high doses of radiation for a primary unresectable cardiac sarcoma
