摘要
目的通过MRI模拟定位技术与CT模拟定位技术在局部晚期鼻咽癌肿瘤靶区和危及器官(OAR)勾画方面的应用对比,探讨两种定位技术在鼻咽癌放射治疗中的剂量学差异。方法选择蚌埠医学院第一附属医院2022年4月至2023年9月接受鼻咽癌放射治疗的37例患者,其中男性29例,女性8例;年龄29~75岁,平均年龄53.14岁;美国癌症联合委员会(AJCC)分期Ⅱ期24例,Ⅲ期13例。患者在相同体位下行CT模拟定位及MRI模拟定位,在CT定位上通过患者现有影像学资料勾画靶区及OAR,并完成三维适形调强治疗计划;然后进行CT模拟定位及MRI模拟定位融合,再进行靶区勾画及OAR勾画;比较两种计划靶区体积、剂量[近似最大剂量(D_(2%))、近似最小剂量(D_(98%))、中位剂量(D_(50%))和OAR接受的最大点剂量(D_(max))]及适形性指数(CI)和均匀性指数(HI)差异。并比较二者OAR的剂量学差异。结果MRI模拟定位图像上所勾画放疗计划靶区体积小于CT模拟定位(30.54 mm^(3)±18.98 mm^(3)vs 39.56 mm^(3)±19.22 mm^(3)),差异有统计学意义(t=2.004,P=0.049)。CT模拟定位原发病灶放射剂量D_(2%)大于MRI模拟定位[(73.00±1.08)Gy vs(72.23±0.76)Gy],差异有显著统计学意义(t=3.536,P=0.001)。MRI模拟定位在靶区的HI和CI均明显优于CT模拟定位(0.037±0.009 vs 0.049±0.021、0.88±0.02 vs 0.84±0.01。t=3.119、9.951,P<0.01)。OAR,MRI模拟定位的脑干、颞叶、内耳D_(max)明显优于CT定位[脑干:(46.79±5.78)Gy vs(50.87±3.66)Gy;颞叶:(46.39±5.21)Gy vs(49.68±4.72)Gy;内耳:(34.28±5.29)Gy vs(38.71±4.33)Gy。P<0.01]。结论MRI模拟定位下所勾画的鼻咽癌肿瘤靶区体积小于CT定位下的勾画,且MRI定位在剂量的均质性和适形性更好,OAR最高剂量更低。因此在局部晚期鼻咽癌放疗中,MRI模拟定位技术值得更多的关注和应用。
Objective To compare the application of MRI simulation localization technique and CT simulation localization technique in delineation of tumor target area and organ at risk(ORA)of locally advanced nasopharyngeal carcinoma(NPC),and explore dosimetric differences between the two localization techniques in radiotherapy of NPC.Methods From April 2022 to September 2023,a total of 37 NPC patients performed radiotherapy were enrolled,which included 29 males and 8 females,aged 29-75 years old with mean age of 53.14 years old.There were 24 cases of stage II and 13 of stage II according to Ameri can Joint Committee on Cancer(AJCC).All of the patients were given CT simulation localization and MRI simulation localization in the same position.In CT localization,the target area and OAR were delineated by existing imaging data,and threedimensional conformal intensity-modulated treatment plan was completed.Then,CT simulation localization and MRI simulation localization fusion were performed,the target area and ORA delineation were performed.The differences of target volume,dose[approximate maximum dose(D2%),approximate minimum dose(D_(50%),median dose(D_(2%)),maximum dose(D_(98%))],conformity index(CI)and homogeneity index(HI)were compared between 2 plans.The OAR dosimetric differences between 2 groups were compared.Results The volume of the radiotherapy plan target area delineated on the MRI simulated localization image was smaller than that of CT simulation localization(30.54 mm±18.98 mm vs 39.56 mm±19.22 mm^(3)),and the difference was statistically significant(t=2.004,P=0.049).The radiation dose D2%of primary lesion by CT simulation localization was higher than that by MRI simulation localization[(73.00±1.08)Gy vs(72.23±0.76)Gy],and the difference was statistically significant(t=3.536,P=0.001).The HI and CI of MRI simulation localization in target area were significantly better than those of CT simulation localization(0.037±0.009 vs 0.049±0.021,0.88±0.02 s 0.84±0.01.t=3.119,9.951.P<0.01).The D_(mx) of brainstem,temporal lobe and inner ear in MRI simulation localization were significantly better than those of CT simulation localization[brainstem:(46.79±5.78)Gy vs(50.87±3.66)Gy;temporal lobe:(46.39±5.21)Gy vs(49.68±4.72)Gy;inner ear:(34.28±5.29)Gy vs(38.71±4.33)Gy.P<0.01].Conclusion It is demonstrated that the volume of NPC target area delineated by MRI simulation localization is smaller than that of CT localization,and MRI localization showed better dose homogeneity and conformity,and the highest dose of OAR is lower.Therefore,MRI simulation localization technique deserves more attention and application in radiotherapy of locally advanced NPC.
作者
蔡丰
徐露
徐洪波
张雷
汪庚明
CAI Feng;XU Lu;XU Hong-bo;ZHANG Lei;WANG Geng-ming(Departmer of Radiotherapy,The First Afiliated Hospital of Bengbu Medical College,Bengbu 23300,Anhui,China)
出处
《生物医学工程与临床》
CAS
2024年第1期42-45,共4页
Biomedical Engineering and Clinical Medicine
基金
安徽省临床医学优先发展重点专科项目(卫教科2018-291)。
关键词
MRI模拟定位
鼻咽癌
放射治疗
剂量学
MRI simulation localization
nasopharyngeal cancer
radiotherapy
dosimetry
