Agility光栅系统在眼眶淋巴瘤放疗剂量学研究

Dosimetric study of Agility system of elekta in radiotherapy of orbital lymphoma

目的眼眶淋巴瘤靶区空间位置比较特殊,提高眼眶淋巴瘤计划的质量,保护眼睛是医生和物理师关注的焦点。本研究旨在探讨Agility光栅系统在眼眶淋巴瘤中的剂量学特点。方法选取2016-05-01-2018-05-30上海交通大学医学院附属第九人民医院放疗的10例眼眶淋巴瘤患者,选用monaco计划系统进行计算,光栅数据分别选择Mlci2和Agility,照射方式采用动态调强。计算时,固定其他组织的限量,仅改变患者患侧晶体的限量,限量范围从4～20Gy进行变化,函数采用Serial,每次变化为2Gy,根据计算结果,分别对眼睛整体、晶体、视神经、靶区的适形性指数(conformal index,CI)、均匀性指数(homogeneity idex,HI)以及计划跳数进行统计分析。结果随着患侧晶体限量增加,在CI、HI、患侧视神经、患侧晶体平均量、患侧眼睛平均量、计划跳数参数上,Agility更具优势,CI差别率从27.12%降到5.11%,HI差别率从11.52%降到1.57%,下降趋势逐渐变缓,差异有统计学意义,P<0.01;患侧视神经差别率从11.99%下降到1.53%,差异有统计学意义,P<0.01;患侧晶体平均值差别率从20.59%下降到3.55%,差异有统计学意义,P<0.01;患侧眼睛平均值在晶体限量低于10Gy时,差异有统计学意义,P<0.05;高于14Gy,差异无统计学意义。对侧晶体的计算结果,Mlci2更具优势。结论眼眶淋巴瘤放疗时,Agility光栅的计算结果比Mlci2光栅更具有剂量学优势,眼眶淋巴瘤的放疗应采用Agility光栅。

OBJECTIVE The space location of the target area of orbital lymphoma is relatively special.To improve the quality of orbital lymphoma planning and protect eye is the focus of attention of doctors and medical physicists.This study aimed at exploring the dosimetric characteristics of orbital lymphoma with Agility grating system.METHODS From January 2016 to May 302018,10 patients with orbital lymphoma received radiotherapy in Ninth People's Hospital Affiliated to Medical College of Shanghai Jiaotong University were selected and calculated by Monaco planning system.Mlci2 and Agility were selected for raster data.Dynamic intensity modulation was used for irradiation.During the calculation,the limits of other tissues were fixed,and only the limit of the patient's affected side len was changed.The limit range was 4-20Gy.Serial was used as the function and the change was 2Gy each time.According to the calculation results,the CI,HI and planned hops of the whole eye,lens,optic nerve,target area were statistically analyzed.RESULTS With the increase of the limitation of the affected side len,Agility had more advantages in CI,HI,optic nerve,lens average,eye average and MU.The difference rate of CI decreased from 27.12% to 5.11%, and the difference rate of HI decreased from 11.52%to1.57%.The trend of decline gradually slowed down,P<0.01.The difference rate of optic nerve decreased from 11.99%to 1.53%,P<0.01;the average difference rate of affected side lens decreased from 20.59%to 3.55%,P<0.01.When the average value of affected side eye lens was lower than 14Gy,there was statistical difference(P<0.05),when it was higher than 14Gy,there was no statistical difference.The results of contralateral crystal calculation showed that Mlci2 had more advantages.CONCLUSIONS Agility grating has more dosimetric advantages than Mlci2 grating in orbital lymphoma radiotherapy.Agility grating should be used in orbital lymphoma radiotherapy.