ABSTRACT
Objective To investigate the difference of standard tangential field and multiple fileld radiotherapy in axillary lymph node after conserving surgery,to provide a reference for clinical treatment.Methods 20 cases of left breast cancer patients were selected,all patients underwent breast -conserving surgery,postoperative radiothera-py.All patients used standard radiotherapy wild tangent based and reverse -intensity modulated radiation therapy optimization.Armpit I,Ⅱ lymph nodes were used to calculate the extent of coverage of the original plan,target dose uniformity HI,dose conformal CI,dosimetric parameters were calculated.Results Under standard tangential field irradiation,I stand mean dose was (33.95 ±8.24)Gy,which was significantly higher than Ⅱ station (22.13 ± 6.67)Gy,and V50,V45,V40 were (22.45 ±6.32)%,(39.83 ±7.54)%,(49.65 ±8.31)%,which were higher than Ⅱ stand,I stand irradiation was significantly more,the differences were statistically significant (t =5.632,P =0.009;t =7.214,P =0.000;t =8.954,P =0.000;t =6.121,P =0.002).The whole breast irradiation armpit IMRT plan,19 patients (95.00%)reached 95% by volume APTV≥50Gy,coverage was better;but HI,CI were (1.11 ± 0.03),(1.36 ±0.07)respectively,which were significantly worse than the standard wild tangent,the differences were statistically significant (t =6.584,P =0.001;t =9.144,P =0.000).Under Hatano IMRT irradiation ipsilateral lung,heart suffered an average dose of (1 694.58 ±102.31)cGy,(645.54 ±74.44)cGy,which were significantly more than the standard tangential field irradiation,the differences were statistically significant (t =7.654,P =0.000;t =6.654,P =0.001).Conclusion Standard tangential field irradiation has poor coverage in Ⅱ axillary lymph node station,irradiation intensity modulated radiation has better coverage,but significantly increased the dose to normal tissues.