目的:探讨基于CT图像的影像组学特征对辨别上行型与下行型鼻咽癌的应用价值。方法:回顾性分析2015年2月至2017年10月在中南大学湘雅医学院附属肿瘤医院行根治性放射治疗前CT定位扫描并获得CT图像的鼻咽癌患者共217例,其中上行型鼻咽癌48...目的:探讨基于CT图像的影像组学特征对辨别上行型与下行型鼻咽癌的应用价值。方法:回顾性分析2015年2月至2017年10月在中南大学湘雅医学院附属肿瘤医院行根治性放射治疗前CT定位扫描并获得CT图像的鼻咽癌患者共217例,其中上行型鼻咽癌48例,下行型鼻咽癌169例。将217例鼻咽癌患者随机分成训练集153例,验证集64例。获取手动分割的鼻咽部大体肿瘤靶区(gross tumor volume in the nasopharynx,GTVnx)为感兴趣区域(region of interest,ROI)。使用IBEX软件提取影像组学特征1300个,采用最小绝对收缩和选择算子(least absolute shrinkage and selection operator,LASSO)算法进行特征选择,结合所选择的特征和临床资料建立支持向量机、随机森林2种分类器,并对其用受试者工作特征(receiver operating characteristic,ROC)曲线的曲线下面积(area under curve,AUC)进行验证。结果:从1300个鼻咽癌影像组学特征中筛选出6个特征。在得到的分类器中,随机森林分类器表现出更好的分类性能,其AUC、精确度、敏感度及特异度在训练集分别为0.989,0.941,1.000及0.924,在验证集分别为0.994,0.937,1.000及0.924。结论:基于CT的影像组学特征可以作为分辨上行型与下行型鼻咽癌的有效方法,这些结果为鼻咽癌的精准医疗提供了一定的依据,并可能影响未来鼻咽癌的治疗策略。展开更多
A promising sulfated zirconia(SZ) was successfully synthesized to remove olefins from aromatics. The effects of type and quantity of precipitant, the concentration of impregnants and the calcination temperature were s...A promising sulfated zirconia(SZ) was successfully synthesized to remove olefins from aromatics. The effects of type and quantity of precipitant, the concentration of impregnants and the calcination temperature were studied, and the synthesized samples were characterized by XRD, SEM, TG-DTG, FTIR, N_2 adsorption analysis and the FTIR pyridine adsorption(py-IR) techniques. This catalyst was found to be superiorly active as compared with the commercial ROC, which exhibited promising application prospects in industry. The optimum synthesis variables required that SZ was impregnated with 2.0 mol/L sulfuric acid and calcined at 650 ℃, and the precursor was precipitated by ammonium hydroxide to reach eventually a p H value of over 9.46. The addition of SO_4^(2-) species increased the amount of catalytically active t-ZrO_2, which was helpful to an increasing abundance of acid sites for enhancing the activity. Meanwhile, the calcination temperature had a great effect on the structure, composition and properties of sulfated zirconia.展开更多
文摘目的:探讨基于CT图像的影像组学特征对辨别上行型与下行型鼻咽癌的应用价值。方法:回顾性分析2015年2月至2017年10月在中南大学湘雅医学院附属肿瘤医院行根治性放射治疗前CT定位扫描并获得CT图像的鼻咽癌患者共217例,其中上行型鼻咽癌48例,下行型鼻咽癌169例。将217例鼻咽癌患者随机分成训练集153例,验证集64例。获取手动分割的鼻咽部大体肿瘤靶区(gross tumor volume in the nasopharynx,GTVnx)为感兴趣区域(region of interest,ROI)。使用IBEX软件提取影像组学特征1300个,采用最小绝对收缩和选择算子(least absolute shrinkage and selection operator,LASSO)算法进行特征选择,结合所选择的特征和临床资料建立支持向量机、随机森林2种分类器,并对其用受试者工作特征(receiver operating characteristic,ROC)曲线的曲线下面积(area under curve,AUC)进行验证。结果:从1300个鼻咽癌影像组学特征中筛选出6个特征。在得到的分类器中,随机森林分类器表现出更好的分类性能,其AUC、精确度、敏感度及特异度在训练集分别为0.989,0.941,1.000及0.924,在验证集分别为0.994,0.937,1.000及0.924。结论:基于CT的影像组学特征可以作为分辨上行型与下行型鼻咽癌的有效方法,这些结果为鼻咽癌的精准医疗提供了一定的依据,并可能影响未来鼻咽癌的治疗策略。
文摘A promising sulfated zirconia(SZ) was successfully synthesized to remove olefins from aromatics. The effects of type and quantity of precipitant, the concentration of impregnants and the calcination temperature were studied, and the synthesized samples were characterized by XRD, SEM, TG-DTG, FTIR, N_2 adsorption analysis and the FTIR pyridine adsorption(py-IR) techniques. This catalyst was found to be superiorly active as compared with the commercial ROC, which exhibited promising application prospects in industry. The optimum synthesis variables required that SZ was impregnated with 2.0 mol/L sulfuric acid and calcined at 650 ℃, and the precursor was precipitated by ammonium hydroxide to reach eventually a p H value of over 9.46. The addition of SO_4^(2-) species increased the amount of catalytically active t-ZrO_2, which was helpful to an increasing abundance of acid sites for enhancing the activity. Meanwhile, the calcination temperature had a great effect on the structure, composition and properties of sulfated zirconia.
