To compare the dosiology of three-dimensional cnformal radiotherapy (3D-CRT) with that of conventional radiotherapy in lung cancer

Objective:To compare the dosiology of three-dimensional conformal radiotherapy (3D-CRT)and conventional radiotherapy (RT) in the patients with lung cancer.Methods:Ten patients with lung cancer given radical treatment by 3D-CRT were entered into the study.Before CT-simulate scan,conventional irradiation fields were carried on simulator with immobilization device.3D-CRT plans and conventional radiotherapy plans were performed for each patient.Doses distributions and DVH for tumors (CTV) and normal tissue in both plans were compared.Results:Comparing 3D-CRT and conventional RT,the volume of the prescription doses of 3D-CRT was 38% higher than conventional RT(10%～59%), the doses in 95% CTV of 3D-CRT were 11.5Gy more than in conventional RT(5～20Gy). The spinal cord doses,the volume of heart V35,the volume of lung V20 and V30 of 3D-CRT were 4Gy,24.3%,7% and 7.4%,respectively, including that the volume of sick lung V20 and V30 of 3D-CRT were 13% and 15%. The volume of non-affected lung of 3D-CRT was 1.1%～1.7% higher than that with conventional RT.Conclusion:Three-dimensional conformal radiotherapy could reduce the volume of nomal tissue irradiated comparing with conventional radiotherapy.So 3D-CRT could protect normal tissue better.