胃癌术后调强和三维适形计划的剂量学比较

Comparison of The Dosimetry of Intensity-modulated Radiotherapy and 3 Dimensional ConFormal Radiotherapy for Postoperation Patients on Gastric Cancer

目的:研究比较胃癌术后放疗中三维适形和调强两种不同方法产生的计划在靶区剂量分布,正常组织受量等方面的区别,比较两种计划的优缺点,以期指导临床应用。方法:选取5个胃癌术后放疗病人,勾画完靶区后,分别运用三维适形和调强制作计划,比较靶区适形度,均匀性,正常肝组织(Liver-PTV)的(V30,Mean),双肾(V5,V15,V20,Mean),脊髓的受量。结果:三维适形计划与调强计划相比,适形度,均匀性较差;正常肝组织的V30和平均剂量调强计划略优于三维适形;双肾的V15,平均剂量两者没有明显差异,V20调强略优于适形计划,小于V5的低剂量体积调强计划要小于三维适形;脊髓受量两者没有明显差异。结论:总体来说,胃癌术后的调强计划靶区适形度,均匀性优于三维适形计划,正常组织受量与三维适形相当或者略优于三维适形,所以调强计划可以替代三维适形计划作为胃癌术后放疗的主要计划设计方法。

Objective： To compare the dosimetry of planing target volume and normal tissues of intensity-modulater radiotherapy （IMRT） and 3 dimensional conformal radiotherapy（3DCRT） for postoperation patients on gastric cancer ,in order to guide clinical application. Methods： Five postoperation patients of gastric cancer were chosen, IMRT and 3DCRT plans were made. The Comformal Index and uniformity of PTV, the dose volume V30 and the mean dose of normal liver tissue （Liver-PTV）, kidney dose （V5, V15, V20, Mean） were compared. Results： The conformal index and uniformity of IMRT are better than that of 3DCRT. The dose volume （V30,Mean） of liver tissue of IMRT is slihtly better than that of 3DCRT. The dose volume （V155,Mean） of kidney of IMRT and 3DCRT do not differ significantly. The V20 of kidney of IMRT is better than it of 3DCRT.The low dose volume （less than Vs） of kidney of IMRT is less than it of 3DCRT. The both plans of spinal cord do not differ significantly. Conclusions： The conformal Index and uniformity of IMRT are better than that of 3DCRT. The dose volume of normal tissue of IMRT plan is equal or slightly better than that of 3DCRT. So the IMRT plan is better than 3DCRT plan in gastric cancer.