Dosimetric Verification And Clinical Efficacy Of Intensity Modulated Radiotherapy In Soft Tissue Sarcomas Of The Lower Extremity

Objective: To analysis the dosimetric characteristic and observeefficiency and toxicities in intensity modulated radiation therapy (IMRT)for soft tissue sarcomas of the thigh.Method:28patients undergoing post-operative radiotherapy of STS wereenrolled for this research. Clinical tumor volume (CTVtb) was definedusing pre-operative imaging. CTV1consisted of the tumour bed with a1cm margin in all directions. CTV2was formed by adding a2cm marginaxially to the tumour bed and4-6cm superior/inferior margins. CTV3included CTV1, CTV2and the whole muscular compartment. Treatmentplanning of IMRT and conformal radiotherapy was done for each patient.The prescribed doses of PTV1were70Gy, with95%of PTV1receivingthe prescribed dose.The therapeutic effect as well as the late toxicities ofnormal tissues were observed.Results: IMRT achieved better dose distribution than conventional radiotherapy.2-year-local control rate was92.6%,2-year-survival ratewas96.3%，the incidence rate of the femur and skin’s late side effectswas lower.Conclusion: IMRT could achieve significantly better dose distribution inpatients with resected soft tissue sarcomas. IMRT reduces dose to theOAR structures without compromising target coverage.