胸椎转移癌调强放疗布野方案及脊髓保护边界不同勾画临床研究

Clinical Study of Different Layout of Spinal Cord and Protective Margin of Thoracic Spinal Cord for Metastatic Carcinoma of Thoracic Spine

目的研究胸椎转移癌调强放疗布野方案及脊髓保护边界不同勾画情况。方法选取行调强放疗的胸椎转移患者120例,使用6MV-X射线进行照射,处方剂量是50 Gy,每次2 Gy,每例患者做六个治疗计划,都使用5、7、9野等分布野,脊髓的保护区边界是椎管内壁(f2)与脊髓硬脊膜(f1);对比不同计划靶区的剂量分布情况,PTV适形度的指数(CI),脊髓0%体积的平均及最大剂量情况。结果脊髓保护区两个边界的不同画法PTV剂量对比差异无统计学意义(P> 0. 05),不同布野方式内PTV剂量对比差异无统计学意义(P> 0. 05);脊髓保护区两个边界不同画法PTV适形度的指数对比差异无统计学意义(P> 0. 05),不同布野方式内PTV适形度的指数对比差异有统计学意义(P <0. 05);脊髓保护区两个边界的不同画法脊髓0%体积的平均剂量对比差异无统计学意义(P> 0. 05),不同布野方式内脊髓0%体积的平均剂量对比差异无统计学意义(P> 0. 05);脊髓保护区两个边界不同画法脊髓0%体积的最大剂量对比差异无统计学意义(P> 0. 05),不同布野方式内脊髓0%体积的最大剂量对比差异有统计学意义(P <0. 05)。结论 7及9野方案优于5野方案,可使脊髓的最大受量下降,脊髓安全性更高;调强放疗脊髓保护区边界的不同勾画可统一,使主观差异性降低。

Objective To study the field arrangement of intensity-modulated radiotherapy(IMRT)for thoracic metastatic carcinoma and the different delineation of spinal cord protection boundaries.Methods From March 2015 to March 2017 in our hospital for intensity-modulated radiotherapy of thoracic metastasis in patients with 120 cases,were irradiated by 6MV-X rays,the prescription dose is 50Gy,2Gy each time,each patient of six treatment programs,5,7,9 are wild and so wild,border protection zone of the spinal cord is the spinal canal(F2)and spinal dural(F1);dose distribution comparison of different plan target,PTV conformal index(CI),the average and maximum dose of spinal cord volume 0%.Results Different drawing two boundary protection zones without spinal cord were significant differences in PTV dose contrast(P>0.05),no statistically significant differences in PTV dose comparison of different cloth in the wild(P>0.05);two border protection zone drawing on the different spinal cord PTV conformal index on the ratio of the difference was not statistically significant(P>0.05),different ways of PTV conformal dose distribution index difference degree was statistically significant(P<0.05);no significant different representations of two boundary protection area of the average dose of spinal cord compared to spinal cord volume 0%(P>0.05),there was no significant difference compared to the average dose of spinal cord 0%the volume of different cloth within the field mode(P>0.05);there was no significant difference between the different representations of the maximum dose of 0%volume of spinal cord two boundary spinal cord protection area(P>0.05),different ways of spinal cord irradiation The maximum dose contrast of the 0%volume difference was statistically significant(P<0.05).Conclusion The 7 and 9 field scheme is superior to the 5 field scheme,which can decrease the maximal quantity of spinal cord and make the spinal cord safer.The different delineation of the boundary of the spinal cord protected by IMRT can be unified,and the subjective difference is reduced.