TTF电极阵列及头皮保护技术对放疗剂量分布影响的初步研究

目的:研究肿瘤治疗电场（TTF）电极阵列及头皮保护技术对放疗剂量分布的影响。方法:实测TTF电极对于剂量分布的影响；在没有TTF电极阵列的CT上设计容积旋转调强计划，在有TTF电极阵列的CT上重新计算，比较TTF电极阵列对于剂量分布的影响；比较TTF电极阵列不同位置对计划剂量分布的影响；设计头皮保护计划，探讨保护前后靶区和头皮剂量的差异。结果:TTF电极阵列使靶区Dmean降低约0.55%，头皮的D20 cc、D30 cc、Dmean和Dmax升高8.8%、8.9%、8.1%和4.0%，TTF电极阵列位置改变对剂量分布影响不大。头皮保护计划可明显降低头皮剂量，D20 cc、D30 cc、Dmean和Dmax下降8.4%、7.0%、4.2%和19.7%。结论:TTF电极阵列对靶区剂量分布的影响是可接受的，但会使头皮剂量明显增加，采用头皮保护计划，能明显降低头皮剂量，值得进一步研究。

Preliminary study on the effects of electrodes array for tumor treating fields and scalp sparing technology on the dose distribution in radiotherapy

Objective To study the effects of electrodes array for tumor treating fields(TTF)and scalp sparing technology on the radiation dose distribution.Methods The variations of dose distribution due to TTF electrodes array were measured in the study.Volumetric modulated arc therapy plans were designed on CT without TTF electrodes array and recalculated on CT with TTF electrodes array to investigate the effects of TTF electrodes array on dose distribution.The effect of different TTF electrodes array positions on the dose distribution was also analyzed.Moreover,scalp sparing plan was designed to compare the dose to the target areas and the scalp before and after scalp sparing.Results TTF electrodes array reduced the average dose to the target areas by about 0.55%,and increased the D_(20 cc),D_(30 cc),D_mean and Dmax to the scalp by 8.8%,8.9%,8.1%and 4.0%,respectively.The change of TTF electrode array position had little effect on the dose distribution.The comparison between scalp sparing or not showed that the D_(20 cc),D_(30 cc),D_mean and Dmax to the scalp in scalp sparing plan were decreased by 8.4%,7.0%,4.2%and 19.7%,respectively.Conclusion The effect of TTF electrodes array on the dose distribution in the target areas is acceptable,but it will make the scalp dose increase significantly.Scalp sparing plan can significantly reduce the scalp dose.It is worthy of a further study.