摘要
目的:比较左乳癌根治术后胸壁电子线照射与X线调强放疗计划的靶区和危及器官剂量学差异,为临床选择放疗计划提供参考依据。方法:16例左乳腺癌改良根治术后患者胸壁表面垫5 mm填充物,并用热塑体膜固定CT扫描定位,利用TPS计划系统设计胸壁9MeV电子线照射和6MeV-X线IMRT两种放疗计划,处方剂量均为50 Gy/25次,比较两种计划的剂量学差异。结果:调强放疗计划PTV的D_(mean)、D_(min)、V_(95)和D_(95)明显高于电子线放疗计划,两者比较差异有统计学意义(P<0.05);D_(max)、V_(105)、V_(110)和D_5明显低于电子线放疗计划,两者比较差异有统计学意义(P<0.05);CI两者比较差异无统计学意义(P>0.05),HI调强放疗计划明显优于电子线放疗计划,两者比较差异有统计学意义(P<0.05),MU调强放疗计划明显增多,两者比较差异有统计学意义(P<0.05);左肺V_5、V_(10)、D_(mean)、全肺V_(20)、D_(mean)和脊髓D_(max)两者比较差异无统计学意义(P>0.05);左肺V_(20)、右肺D_(mean)心脏V_(10)、V_(30)、D_(mean)和右乳D_(mean)两者比较差异有统计学意义(P<0.05)。结论:X线调强放疗计划在靶区剂量分布上比电子线放疗放疗有明显优势,X线调强放疗计划能明显降低患侧肺高剂量受照体积,但也不可避免地在一定程度上增加患侧肺低剂量照射体积及心脏的照射剂量,在表面垫适当厚度的填充物可使靶区剂量分布更均匀和进一步降低心肺的受照剂量并同时提高皮肤剂量。
Objective To compare the dosimetric differences of target volumes and organs at risk （OAR） between the elec-tron beam irradiation and intensity modulated radiotherapy （IMRT） on the chest wall for patients receiving left - sided modified radical mastectomy, with an aim to provide reference for selecting radiotherapy plans in clinical practice. Method 16 patients who had received left - sided modified radical mastectomy were enrolled. Those patients, who used the 5 mm - in - thickness e-quivalent filler upon the chest wall, received position fixed by the thermoplastic sheet, as well as CT scanning and positioning. The TPS system was adopted to design two radiotherapy plans on the chest wall,which were the 9 Mev electron beam irradiation plan and the 6 MV - X ray IMRT plan;the prescribed dose of both plans was set at 50 Gy/25 times;and the dosimetric parameters of the two radiotherapy plans were compared. Results The mean dose （ Dmean ）,minimal dose （ Dmin ）, the Dmean and percentage of volume receiving more than 95 Gy （ V95） and the dose of 95% CTV （ D95） were higher in the IMRT plan than in the electron beam irradiation plan, the differences were statistically significant （P 〈0. 05） ;the maximal dose （ Dmax） ,as well as the Dmean and percentage of volume receiving more than 105 Gy （ V105） and 110 Gy （V110） irradiation, and the dose of 5% CTV （ D5） were lower in the former than in the latter,with the differences being of statistical significance （P 〈0. 05） ;the differences in the conformity index （Cl） was of no statistical significance （P 〉0. 05） ,the homogeneity index （HI） in the IMRT plan was superiorto that in the electron beam irradiation plan, and the difference was statistically significant （P 〈 0. 05 ） ; the monitor unit （ MU） was remarkably higher in the IMRT plan than in the electron beam irradiation plan,with statistically significant difference （P 〈 0.05）. With regard to the organs at risk, the differences in the V5, V10, and Dmean of the left lung,V2〇 and Dmean of whole lungs,and Dmax of spine were of no statistical significance （P 〉0. 05） ;the differences in the V2〇 of the left lung,Dmean of the right lung,as well as V10 ,V30 and Dmean of the heart,and Dmean of the right breast were of statistical significance （P 〈0. 05）. Conclusion The IMRT plan has more significant advantages over the electron beam irradiation plan in terms of dose distribution in the target volumes,and markedly reduces the high - dose irradiation volume of the left lung. However,it inevitably increases the low - dose irradiation volume in the left lung and the of heart to some extent. Applying the filler with appropriate thickness upon the chest wall renders more uniform dose distribution of target volume,which can further reduce the exposure dose of heart and lung,and meanwhile improves that of skin.
出处
《吉林医学》
CAS
2017年第7期1230-1233,共4页
Jilin Medical Journal
关键词
乳腺癌
改良根治术
胸壁
电子线放疗计划
调强放疗计划
Breast cancer
Modified radical mastectomy
Chest wall
Electron beam radiotherapy
IMRT
