利用3D打印颅脑辐射等效体模进行个性化适形放疗的剂量验证

目的 建立利用3D打印颅脑辐射等效体模对患者进行个性化放疗剂量验证的方法，为三维适形放射治疗安全提供一种可靠的剂量保证手段。方法 采集两例患者（患者1和患者2）的CT图像数据，基于患者1的图像数据，重建其颅骨与脑组织，制作颅脑体模，验证颅骨与脑组织的等效材料。基于患者2的图像数据，根据3D图像重建并选用组织等效材料重建完全的头颅结构，采用3D打印技术制作全头颅体模。通过对目标区域插入电离室剂量仪并行放射治疗方案，获得头颅体模病灶部的剂量，验证和校准实际放疗计划的安全性。结果 对所获两个体模分别进行DR、CT成像，颅脑体模的等效骨骼与患者1骨骼的X射线灰度值差异为13 721，颅脑体模的等效脑组织与患者1的脑组织的CT值差异为35~40 HU，全头颅体模等效颞肌与患者2的颞肌组织的CT值差异为18~28 HU，影像数据表明体模材质的辐射等效性与人体组织近似，并且等效剂量分布符合常规治疗范围，体模的剂量验证可以有效验证放疗计划系统的准确性。结论 基于3D打印和组织等效技术所设计的个性化放疗体模，可应用于个性化放射治疗验证。体模制作方法简单快速，个性化程度高，为三维适形放射治疗安全提供一种可靠的剂量保证手段。     

人脑血氧水平依赖信号有源仿真和成像

目的 对人脑血氧水平依赖（BOLD）信号进行仿真并成像，以之作为金标准和标准信号，基于信号成像灰度幅值变化评价脑功能磁共振成像（fMRI）质量和检出率。方法 设计一种能有源模拟人脑BOLD的激发电路，实现不同电流幅值、不同频率、不同占空比的稳定矩形波输出，在时间域内仿真人脑BOLD信号。结果 3台不同型号、不同场强MR皆有稳定的矩形波输入，且检出率一致。结论 同一设备对同一刺激模式检出率相近，可作为已知且确定信号的参考标准，定量分析MR系统对BOLD信号的检出率和一致性。     

磁共振综合测试体模的设计

目的设计并测试自制MR综合测试体模。方法按照国家卫生行业标准,采用机械加工聚甲基丙烯酸甲酯组件并组合装配,制作MR体模。体模具有三向定位、满周星(楔)形测试调制传递函数(MTF)、正交双测试等独有设计,并与美国Magphan SMR170柱形综合测试体模进行实验比较。结果对自制体模与美国Magphan体模分别在场强0.36T(1个)和1.5T(2个)的临床医学MR系统上进行综合检测试验。自制体模能正常测试12项测试参数(空间定位、弛豫值、高对比度分辨率、低对比度分辨率、几何畸变、线性度、均匀度、SNR、流体测试、层厚、层偏差、MTF),结果均准确,其中低对比度分辨率、MTF、弛豫值优于美国Magphan体模。结论自制MR综合测试体模性能良好,可有效替代国外同类产品,成本较低,能满足常规MR质量控制与保障工作。     

数字化X线胸部摄影管电压选择对影像质量影响的研究

Objective To study the relationship between the selection of tube tension in digitalchest radiograph and image quality.Methods When tube current was fixed at 4 mAs, the choice of X-ray tube voltage changed from 60 to 120 kV.CDRAD2.0 contrast details phantom and normal human chest were exposed by X-ray system with 7 kinds of tube voltage (the difference between tube voltage was 10 kV) ,and the X-ray incidental dose of phantom surface was measured.Five radiologists with 3 years working experience evaluated the image quality on monitor and calculated the image quality factor (IQF) and image reading score.Statistics analysis was then performed by using ANOVA test and t test.According to the results, the optimum tube voltage range was determined.Results (1) The incidental dose of phantom surface increased with the higher tube voltage.(2)When the tube voltage was changed from 60 kV to 120 kV, the IQF value observed in CDRAD2.0 phantom image on monitor was 75.0±10.4,57.1±6.4,52.7±2.5,47.9±4.5, 46.0±3.8,46.0±2.8,45.2±3.5 ,there was significant statistical differences between groups(F=19.10, P<0.01).(3)The integrated score of the chest image quality in the tube voltage 90 kV and 120 kV were 12.4±0.9 and 13.0±0.7, respectively, and there was no statistical difference between two groups(t= 1.500,P>0.05).Conclusions (1)With the increase of tube tension,the display capacity of display device gradually strengthened.When the tube tension exceeded 90 kV, the increase of image quality on monitor was not evident.(2) With proper radiation dose, the value of tube tension in digital X-ray chest photograph was about 90 kV.     

基于ROC分析和ALVIM体模的乳腺CAD分割方法评测

目的：使用基于ROC分析和ALVIM体模的方法，对不同的乳腺CAD分割算法进行比较，获得方法的准确性和信号检出率方面的比较结果，总结出一种适于进行分割算法横向比较的方法。方法：编制出完整的乳腺CAD常用分割算法四种，进行实际影像分割和ALVIM影像分割，计算与金标准的重叠率、分割真阳性率、假阳性率等信号检出能力参数，并进行四种分割轮廓帮助的体模影像识读ROC分析，获得不同算法对识读结果的帮助程度。结果：获得了不同分割算法与实际病灶面积重叠率，不同算法的信号检出能力，算法分割对诊断医师读片的帮助程度。结论：基于ROC分析和分割ALVIM体模的方法可以全面的获得不同分割算法的分割效果和信号检出能力，可对不同分割算法进行横向比较，测试算法准确性和鲁棒性。ALVIM体模在采用五值判断法时的计算方法简便宜行，方便进行大数据量和多种方法之间的ROC比较分析。     

1992年广东省食品中有机氯污染物现状调查

１９９２年广东省食品中有机氯污染物现状调查黄伟雄，高燕红，邱建峰，邓峰作者单位：广东省食品卫生监督检验所５１０３００有机氯农药污染物监测是ＵＮＥＰ／ＦＡＯ／ＷＨＯ的联合食品污染监测规划（ＧＥＭＳ／ＦＯＯＤ）的一部分。在我国，有机氯农药虽已禁用十几年，...     

基于数字乳腺图像分割算法的比较研究

乳腺疾病的发病率近年来不断增高,为增加诊断乳腺疾病的正确率和减轻医生的诊断负担,计算机辅助诊断技术应运而生。本文主要介绍运用阈值法和边缘检测法分割数字乳腺图像,实现对乳腺钙化点边缘的检测。     

数字化X线胸部摄影管电压选择对影像质量影响的研究

Objective To study the relationship between the selection of tube tension in digitalchest radiograph and image quality.Methods When tube current was fixed at 4 mAs, the choice of X-ray tube voltage changed from 60 to 120 kV.CDRAD2.0 contrast details phantom and normal human chest were exposed by X-ray system with 7 kinds of tube voltage (the difference between tube voltage was 10 kV) ,and the X-ray incidental dose of phantom surface was measured.Five radiologists with 3 years working experience evaluated the image quality on monitor and calculated the image quality factor (IQF) and image reading score.Statistics analysis was then performed by using ANOVA test and t test.According to the results, the optimum tube voltage range was determined.Results (1) The incidental dose of phantom surface increased with the higher tube voltage.(2)When the tube voltage was changed from 60 kV to 120 kV, the IQF value observed in CDRAD2.0 phantom image on monitor was 75.0±10.4,57.1±6.4,52.7±2.5,47.9±4.5, 46.0±3.8,46.0±2.8,45.2±3.5 ,there was significant statistical differences between groups(F=19.10, P<0.01).(3)The integrated score of the chest image quality in the tube voltage 90 kV and 120 kV were 12.4±0.9 and 13.0±0.7, respectively, and there was no statistical difference between two groups(t= 1.500,P>0.05).Conclusions (1)With the increase of tube tension,the display capacity of display device gradually strengthened.When the tube tension exceeded 90 kV, the increase of image quality on monitor was not evident.(2) With proper radiation dose, the value of tube tension in digital X-ray chest photograph was about 90 kV.     

右冠状动脉起源于左冠状窦的血流动力学分析

目的通过计算流体动力学(computational fluid dynamics,CFD)分析右冠状动脉起源于左冠状窦(anomalous origin of the right coronary artery from the left coronary artery sinus,AORL)的血流动力学参数,从而有效评估疾病。方法选取正常右冠状动脉(right coronary artery,RCA)和AORL两例个体病例,在Mimics软件中重建两个病例的血管模型,并将模型导入ANSYS CFX软件中进行血流动力学模拟计算,比较正常和AORL两种模型的血流动力学情况。结果 AORL模型右冠状动脉入口截面具有较小的血流量(9. 35 cm~3/s),有可能会导致右冠状动脉下游供血不足; AORL模型右冠状动脉急性拐角处的压力(13. 78 kPa)相比于正常模型右冠状动脉(14. 9 kPa)较低; AORL模型壁面剪切力(12. 83 Pa)大于正常模型(9. 74 Pa); AORL模型血管壁变形量较大。结论 AORL入口流速及拐角处压力均比正常RCA小,从而可能导致缺血症状发生。研究结果对临床上有效评估缺血等疾病具有理论指导意义。     

数字化X线胸部摄影管电压选择对影像质量影响的研究

Objective To study the relationship between the selection of tube tension in digitalchest radiograph and image quality.Methods When tube current was fixed at 4 mAs, the choice of X-ray tube voltage changed from 60 to 120 kV.CDRAD2.0 contrast details phantom and normal human chest were exposed by X-ray system with 7 kinds of tube voltage (the difference between tube voltage was 10 kV) ,and the X-ray incidental dose of phantom surface was measured.Five radiologists with 3 years working experience evaluated the image quality on monitor and calculated the image quality factor (IQF) and image reading score.Statistics analysis was then performed by using ANOVA test and t test.According to the results, the optimum tube voltage range was determined.Results (1) The incidental dose of phantom surface increased with the higher tube voltage.(2)When the tube voltage was changed from 60 kV to 120 kV, the IQF value observed in CDRAD2.0 phantom image on monitor was 75.0±10.4,57.1±6.4,52.7±2.5,47.9±4.5, 46.0±3.8,46.0±2.8,45.2±3.5 ,there was significant statistical differences between groups(F=19.10, P<0.01).(3)The integrated score of the chest image quality in the tube voltage 90 kV and 120 kV were 12.4±0.9 and 13.0±0.7, respectively, and there was no statistical difference between two groups(t= 1.500,P>0.05).Conclusions (1)With the increase of tube tension,the display capacity of display device gradually strengthened.When the tube tension exceeded 90 kV, the increase of image quality on monitor was not evident.(2) With proper radiation dose, the value of tube tension in digital X-ray chest photograph was about 90 kV.