BOLD-fMRI用于邻近大脑初级运动皮层脑胶质瘤术后调强放疗的可行性

目的初步探讨BOLD-fMRI指导邻近大脑初级运动皮层(PMC)脑胶质瘤术后调强放疗(IMRT)的可行性。方法收集30例邻近PMC脑胶质瘤术后拟行放疗患者,行常规MR平扫+增强及BOLD-fMRI检查。获取PMC相关数据并与相应的MRI、CT图像融合,导入放疗计划系统并依此勾画靶区、危及器官及PMC,采用IMRT技术分别制定考虑(IMRT-PMC)与不考虑PMC(IMRT-noPMC)剂量保护的两种放疗计划并进行比较。结果IMRT-PMC与IMRTnoPMC相比较,计划靶区(PTV)的所受最大辐射剂量(Dmax)、平均辐射剂量(Dmean)及适形指数(CI)、剂量均匀性指数(HI)差异均无统计学意义(P均>0.05),常规危及器官的Dmax及Dmean差异均无统计学意义(P均>0.05)。IMRT-PMC计划中患侧、健侧PMC的Dmax及Dmean均明显低于IMRT-noPMC计划(P均<0.05)。结论 BOLD-fMRI能够明确PMC的位置及与脑胶质瘤术后放疗靶区的关系,有助于制定保护性放疗方案,最大程度减低PMC所受辐射剂量,从而降低放疗后发生放射性损伤的可能。

Feasibility of BOLD-fMRI used in postoperative intensity modulated radiotherapy for gliomas adjacent to primary motor cortex

Objective To explore the feasibility of blood oxygenation level dependent functional MRI (BOLD-fMRI) used in postoperative intensity modulated radiotherapy (IMRT) for gliomas adjacent to primary motor cortex (PMC). Methods Totally 30 patients with gliomas adjacent to PMC underwent routine MRI, contrast-enhanced scanning and BOLD-fMRI before postoperative radiotherapy. PMC data sets were acquired and fused with corresponding anatomical MRI and CT images. The aquired data sets were imported radiotherapy planning system to aid the delineation of target volume, organs at risk and PMC. With and without the incorporation of the PMC into the IMRT treatment planning (IMRT-PMC plans vs IMRT-noPMC plans) were developed and compared. Results The maximum dose (D_max), mean dose (D_mean), conformity index (CI) and homogeneity index (HI) of planning target volumes (PTV) had no significant difference between IMRT-PMC plans and IMRT-noPMC plans (all P>0.05). There was no statistically significant difference among the D_max, D_mean to the conventional organs at risk (all P>0.05). In the IMRT-PMC plans, the D_max and the D_mean to the ipsilateral, contralateral PMC were lower than that of IMRT-noPMC plans (all P<0.05). Conclusion BOLD-fMRI can provide the additional information about the location of PMC and the relationship with postoperative radiotherapy target of glioma, contribute to the development of protective radiation programs to reduce the PMC suffered radiation dose furthest, thereby decreasing the possible of damage after radiotherapy.