RESUMEN
Objective To introduce a new way to solve the problem of field-field junction in the traditional radiotherapy of the nasopharyngeal carcinoma better.Methods Using the 3-dimentional planning system,the dose distribution of traditional radiotherapy and the electronic beam irradiation technology of L shape field for nasopharyngeal carcinoma in 2D-or 3D-CRT could be gotten.Results The dose coverage of V95 of the gross tumor volume(GTV)satisfied the clinical requirements.The highest dose in the electronic beam irradiation of L shape field was 7200 cGy,while it was 8900 cGy in the traditional way.The volume of dose that over 6500 cGy of throat was 19.64 ％ in the former,the latter was 31.95 ％.Conclusion The electronic beam irradiation technology of L shape field is better than the traditional radiotherapy in field-field junction and in dose distribution.Since that,the electronic beam irradiation technology of L shape field is worth of application for the treatment of nasopharyngeal carcinoma.