以CT和MRI颅底骨成像计算鼻咽癌肿瘤靶体积及邻近危及器官照射剂量的对比研究

目的 比较CT与MRI颅底骨成像差异对鼻咽癌肿瘤靶体积及邻近危及器官照射剂量的影响。方法 从101例鼻咽癌中选出MRI与CT颅底骨成像差异病例26例,分别根据MRI与CT成像信息应用ARTP-TOP 3D-TPS系统制定三维适形计划,比较两计划中GTV_MR和GTV_CT,及邻近危及器官的平均剂量和D₅平均剂量。结果 GTV_MR为(47.0±16.3)cm³,GTV_CT为(31.6±10.0)cm³,差异有统计学意义(Z＝4.462,P＜0.01);MRI计划中的脑干、垂体、左右颞叶和左右眼球的平均剂量大于CT计划中相应器官的平均剂量(P＜0.05);两个计划中脊髓平均剂量比较差异无统计学意义;MRI计划中的脑干、脊髓、垂体、左右颞叶、左右眼球的D₅平均剂量均大于CT计划中相应器官的D₅平均剂量(P＜0.05)。结论 根据MRI制定的三维适形计划,肿瘤靶区的剂量覆盖较CT好,但是邻近危及器官组织的照射剂量相对CT的较高。

Treating dose of target volume of nasopharyngeal carcinoma and contiguous organ at risk influenced by MRI and CT image difference in cranial base

Objective To study the treating dose of target volume of nasopharyngeal carcinoma (NPC) and contiguous organ at risk influenced by magnetic resonance imaging (MRI) and computed tomography(CT) Image difference in cranial base. Methods 26 cases were performed from 101 patients of NPC with MRI and CT image difference in cranial base. We applied ARTP-TOP3D-TPS system to delineate target volume of NPC and contiguous organ at risk and develop the three-dimensional conformal radiotherapy (3-DCRT) plan, and compared the target volume of NPC by MRI (GTVMR) with the target volume of NPC by CT ( GTVCT) . Results There was statistic difference between GTVMT(47.0±16.3) cm3 and GTVCT (31.6±10.0) cm3 ( Z = 4.462, P < 0.01 ). Compared with CT based plan, the mean dose of brainstem, pituitary, temporal lobe and both eyes and the D5 mean dose of brainstem, spinal cord, pituitary, temporal lobe and both eyes in MRI based plan were larger. There was no statistic difference in the mean dose of spinal cord between two plans. Conclusions The dose of target volume in 3D-CRT plan based GTVMR is superior m GTVCT, but the dose of contiguous organ at risk in 3D-CRT plan based GTVMR is higher.