DOSIMETRIC COMPARISON OF FIXED FIELD STATIC INTENSITY-MODULATED RADIOTHERAPY WITH DYNAMIC INTENSITY-MODULATED RADIOTHERAPY AND VOLUMETRIC MODULATED ARC THERAPY IN POSTOPERATIVE RADIOTHERAPY FOR CERVICAL CANCER
Objective To investigate the dosimetric differences and applicability of volume modulated arc therapy (VMAT),dynamic intensity-modulated radiotherapy (Dmlc-IMRT) and static intensity modulated radiotherapy (Step&shoot-IMRT) in postoperative radiotherapy for cervical cancer.Methods Twenty patients with cervical cancer after operation were selected.Plans of VMAT,Dmlc-IMRT and Step&shoot IMRT were designed,respectively,for the 20 patients.Applying dose volume histogram (DVH),target dose distribution,conformal and uniformity,low dose irradiation volume and organ threatening dose distribution among three plans were compared,and the machine hops and treatment time were recorded and compared as well.Results On the shape and uniformity of target area,VMAT and Dmlc IMRT plans were better than that of Step&shoot IMRT,the difference being statistically significant (F =12.34,31.64;P ＜ 0.05).The low dose irradiation volume of the VMAT plan was slightly higher than that of Dmlc-IMRT and Step％shoot-IMRT,but the difference in that was not significant.As for the dose distribution of organs at risk-such as small bowel and bladder-the Dmlc-IMRT was overall lower than VMAT and Step&shootIMRT,the Dmlc-IMRT plan quality being the best.The treatment time of VMAT was 49％ lower than that of Step&shoot IMRT and 35％ lower than that of Dmlc-IMRT.Conclusion VMAT plan quality can meet or exceed Step&shoot-IMRT plan quality,and the time of treatment is greatly shortened as compared with the other two schemes,which is suitable for patients with poor control of long term radiotherapy and in some busy radiotherapy centers.When Step&shoot IMRT technology is difficult to ensure the quality of the plan,replacing Dmle IMRT technology,all dose evaluation parameters can basically be optimized.
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NSTL
万方数据
维普
