正电子发射计算机信息处理断层显像在探测甲状腺癌转移灶中的临床应用

探讨18 F-FDG正电子发射计算机断层显像(Positron emission computed tomography imaging,PET/CT)在血清甲状腺球蛋白(hyroglobulin,Tg)阳性,131I全身扫描(131I-whole body scan,131I-WBS)阴性的分化型甲状腺癌131I清除残余甲状腺后随访中的临床意义.选取我院2010年1月至2014年12月核医学科已经接受甲状腺近全或全切除术并用131I清除残余甲状腺的分化型甲状腺癌患者,并在随访中测定血清Tg水平增高,而131I-WBS显像阴性的患者33例,随后进行18F-FDG PET/CT全身显像.利用SPSS13.0分析软件进行数据分析,评估18F-FDG PET/CT在血清TG测定阳性,而131I-WBS显像阴性的分化型甲状腺癌131I清除残余甲状腺后随访中的临床意义.在33例血清Tg阳性,131I-WBS阴性患者中,21例患者18F-FDG PET/CT显像阳性,12例患者18F-FDG PET/CT显像阴性.18F-FDG PET/CT显像的敏感度87.0％(20/23),特异性90％(9/10),准确性87.9％ (29/33),阴性预测值75％(9/12),阳性预测值为95.2％ (20/21).当Tg＞18ng/ml时,随着血清Tg水平的增高,18F-FDG PET/CT对分化型甲状腺癌转移灶的检出率随之升高.18F-FDG PET/CT对于血清Tg测定阳性,而131I-WBS显像阴性的分化型甲状腺癌131I清除残余甲状腺后复发转移的探测具有临床价值.随着血清Tg水平的增高,PET对分化型甲状腺癌转移灶的检出率随之升高.     

床旁高频超声在局限性气胸诊治中的临床应用

探讨床旁高频超声在局限性气胸诊治中的临床应用价值。方法对我院收治的116例临床怀疑局限性气胸患者,分别行床旁胸部高频超声、床旁X线胸部摄片,并以胸部CT检查作为诊断局限性气胸的标准。评判高频超声、X线胸部摄片、CT对局限性气胸诊断的敏感性、特异性、阳性和阴性预测值及准确性,并比较床旁高频超声、床旁X线胸部摄片、CT检查对需要引流的局限性气胸患者穿刺定位所需要的时间。结果116例患者中57例患者,CT确诊为局限性气胸,且均为单发局限性气胸。高频超声诊断55例,漏诊2例;胸部X线摄片诊断12例漏诊45例。高频超声、X线摄片对局限性气胸的特异性和阳性预测值均为100%;阴性预测值分别是98.9%、79.5%;准确性分别是99.1%、80.6%;敏感性分别是96.5%、21.1%。高频超声、床旁X线摄片和胸部CT检查对需要引流的局限性气胸患者穿刺定位所需要的时间分别是。35.6±13.2min,15.2±5.4min,9.8±3.6min结论床旁高频超声在诊断局限性气胸中的准确性、敏感性均明显高于床旁。X线摄片,与胸部CT检查相当对局限性气胸诊治的及时性好于床旁X线摄片和胸部CT检查,且避免了搬运患者过程中发生意外的情况。     

胃非霍奇金淋巴瘤患者幽门螺杆菌检测方法比较

目的比较尿素氮呼气试验和粪便抗原检测胃非霍奇金淋巴瘤患者幽门螺杆菌感染的准确性。方法以病理检测结果为对照,对25例确诊胃非霍奇金淋巴瘤患者分别进行尿素氮呼气试验和粪便抗原检测幽门螺杆菌,比较两者检出的准确度。结果粪便抗原检测敏感性81．3％,特异性88．9％,阳性预测值92．9％,阴性预测值72．7％,准确度84％。尿素氮呼气试验敏感度93．8％,特异度100％,阳性预测值100％,阴性预测值90％,准确度：96％。结论尿素氮呼气试验对幽门螺杆菌检测的准确性高于粪便抗原检测。     

口服ALA脑肿瘤光敏诊断的实验研究

目的:探求ALA口服在脑肿瘤光敏诊断中的最佳剂量、口服后最佳诊断时间、效果、阳性率、假阳性率、假阴性率及光谱分析的方法。方法:口服不同剂量的ALA(20mg/kg、40mg/kg、60mg/kg),不同时间(3小时、4小时、5小时、6小时)以激光诱导荧光OMA检测系统测定无脑瘤正常鼠二侧大脑半球,及G422脑胶质母细胞瘤模型的脑肿瘤、正常脑组织的荧光,并经各种方法进行数据处理,寻求脑肿瘤、正常脑组织相对值相差最大的合适的ALA口服剂量及诊断时间。诊断的阳性率、假阳性率、假阴性率。并将标本作病理检查。结果:脑肿瘤、正常脑组织相对值相差最小剂量及时间是在ALA40mg/kg,服ALA后4小时时比值最大。将标本作病理检查,诊断的阳性率为84%、假阳性率10%、假阴性率16%。结论:从实验数据分析口服ALA经OMA荧光光谱分析能作脑肿瘤荧光诊断,剂量以40mg/kg,服ALA后4小时左右作荧光光谱分析较合适。     

CT图像中肿大淋巴结肺癌转移分类方法

为解决肺癌N分期中胸部CT难于对肿大淋巴结是否癌转移进行评价的问题,寻求能够有效表示淋巴结病理特性的图像特征,实现对肿大淋巴结癌转移快速准确地判别。该文采取交互式分割从CT图像中提取出肿大淋巴结;直接计算淋巴结的多分辨率直方图得到200维空间信息特征样本集;利用具有处理高维数据集优势的支持向量机(SVM)构造分类器;用测试集对经训练的SVM分类器进行测试以评价分类性能。经96例病例实验结果表明:100个淋巴结图像的200维特征计算用时1.91 s,SVM分类器训练测试用时1.36 s,敏感性76%,特异性64%,准确度70%,接受者操作特性曲线(ROC)下面积(AUC)0.6525。高维图像空间信息特征能够有效表示淋巴结特性;没有考虑医学征象进行肿大淋巴结癌转移定性诊断的准确度就达到了70%,同时分类速度比传统纹理算法提高了约10倍。     

980nm高功率垂直腔面发射激光器的理论分析

理论分析了980nm高功率垂直腔面发射激光器(VCSEL)的器件特性与其分布布拉格反射镜(DBR)反射率的依赖关系,并计算了具有不同有源区直径的VCSEL的输出特性.分析了具有不同有源区直径的VCSEL在不同DBR反射率条件下的连续输出特性曲线,发现DBR反射率的改变会对有源区直径不同的VCSEL产生不同程度的影响.为了验证理论分析的结果,进行了器件测试实验.实验结果表明,有源区直径为500μm的VCSEL,当其N-DBR反射率分别为99.7%及99.2%时,在连续注入电流为6A时,其输出功率分别为2.01W和2.09W;而有源区直径为200μm的VCSEL,当N-DBR反射率为99.7%及99.2%时,连续注入电流为3A时,其输出功率分别为0.64W及1.12W.器件测试结果有效验证了理论分析的结论.     

高能铒离子注入硅单晶的辐射损伤及其退火行为

利用卢瑟福背散射及沟道技术研究了2MeV Er+以不同剂量注入硅(100)所引起的辐射损伤及其退火行为.采用多重散射模型计算了2MeV 1×1014/cm2注入硅(100)引起的损伤分布,并与TRIM96模拟得到的结果进行了比较.结果表明计算得到的损伤分布与TRIM96模拟的损伤分布完全符合;实验结果表明MeV Er+注入后硅样品的退火行为与注入剂量及退火温度紧密相关.随着退火温度的变化,注入剂量为5×1014/cm2及其以上的样品存在反常退火行为.     

钝化材料对深紫外LED器件性能的影响

对比研究了SiO2、聚酰亚胺薄膜、SiNx/旋涂玻璃(SOG)复合材料等钝化材料对倒装焊深紫外LED器件抑制漏电流恶化、改善器件可靠性的作用。实际测试结果表明,未钝化和采用SiO2、聚酰亚胺、SiNx/SOG复合钝化膜后,倒装焊紫外LED短路漏电比例分别为100%、100%、55%和18%,采用聚酰亚胺和SiNx/SOG复合钝化膜的器件点亮1 000h后光衰分别为67%和20%。分析表明,SiNx与SOG结合使用有效降低了表面电荷复合几率并改善了倒装焊短路问题;SOG还进一步降低了表面的粗糙度,改善了由于AlGaN外延表面上的深凹槽结构引起的器件漏电及倒装焊金属溢流的短路,从而大大提高了可靠性。     

基于注意力机制和Inf-Net的新冠肺炎图像分割方法

新型冠状病毒肺炎肆虐全球,严重影响了人类社会的生活和健康。CT影像技术是检测新冠肺炎的重要诊断方式,从CT图像中自动准确分割出新冠肺炎病灶区域,对于诊断、治疗和预后都有重要意义。针对新冠肺炎病灶的自动分割,文中提出基于Inf-Net算法改进的自动分割方法,通过引入通道注意力机制加强特征表示,并运用注意力门模块来更好地融合边缘信息。在COVID-19 CT分割数据集上的实验结果表明,文中所提出新冠肺炎图像分割方法的Dice系数、灵敏度、特异率分别为75.1%、75.4%和95.4%,算法性能也优于部分主流方法。     

多算法融合的眼底图像渗出液分割

利用眼底图像中渗出液的亮度与边缘特征,文中采用一种多算法融合的渗出液自动检测分割方法来解决目前传统算法灵敏度低以及检测中存在视盘和其它微血管瘤等暗病灶的干扰等问题。为了提高分割效率和准确率,文中对原始图像进行顶帽底帽变换来增强图像对比度,采用GA与KSW熵法相结合的双阈值分割法对眼底图像进行渗出液分割。实验在Kaggle数据库上进行测试,结果显示该算法在像素层统计的SE和阳性预测值PPV分别为83.6%和93.2%,在图像层统计的SE、SP与AC分别为95.2%、86.2%和90.8%。在另一个独立的DIARETDB1数据库上进行测试,获得的结果分别为82.4%、93.3%、93.6%、96.2%和89.9%。与其它算法对比,文中方法可以很好地区分开渗出液与暗病灶,且检测时间短,具有准确性和高效性。     

A computational neural approach to support the discovery of gene function and classes of cancer

Advances in molecular classification of tumours may play a central role in cancer treatment. Here, a novel approach to genome expression pattern interpretation is described and applied to the recognition of B-cell malignancies as a test set. Using cDNA microarrays data generated by a previous study, a neural network model known as simplified fuzzy ARTMAP is able to identify normal and diffuse large B-cell lymphoma (DLBCL) patients. Furthermore, it discovers the distinction between patients with molecularly distinct forms of DLBCL without previous knowledge of those subtypes.     

面向乳腺肿瘤诊断的时域扩散荧光―光学层析成像系统

为了解决传统乳腺扩散光学层析成像可靠性低的问题,设计了一套基于多通道时间相关单光子计数的时域扩散荧光—光学层析成像系统.该系统采用32根同轴光纤均匀分布于组织体表面,作类似X射线层析工作方式的同层扫描,由此获得多角度下的时间分辨投影.通过测量不同仿体,应用相应的迭代图像重建算法,获得了可靠的重建结果.研究表明,该系统工作可靠,是进行乳腺肿瘤早期诊断研究的理想模式之一.     

3例急性冠脉综合征患者CTA、冠脉造影及OCT对比

目的了解急性冠脉综合征患者冠脉CTA、冠脉造影、OCT的表现。方法急性冠脉综合征患者3例,在行冠脉造影前均行64排CT(Somatom Definition)冠脉CTA检查,明确罪犯病变;常规冠状动脉造影后行OCT检查(Lightlab),分别分析冠脉CT、冠脉造影和OCT影像学结果。结果冠脉CTA均提示为软斑块,斑块最低CT值均小于100Hu,1例伴有轻度钙化,斑块负荷较重,均呈正性重构;OCT示2例有极薄的纤维帽(分别为50μm和40μm),纤维帽后有大的脂核。结论冠脉CTA对于血管壁较宏观的观察较有优势,冠脉造影可以动态观察血管的情况,OCT可细致观察血管壁、斑块和血栓。     

Experimental fluorescence tomography of tissues with noncontact measurements

Noncontact optical measurements from diffuse media could facilitate the use of large detector arrays at multiple angles that are well suited for diffuse optical tomography applications. Such imaging strategy could eliminate the need for individual fibers in contact with tissue, restricted geometries, and matching fluids. Thus, it could significantly improve experimental procedures and enhance our ability to visualize functional and molecular processes in vivo. In this paper, we describe the experimental implementation of this novel concept and demonstrate capacity to perform small animal imaging.     

扩散光层析成像系统研究现状及发展

对国内外有关扩散光成像系统进行总结分析,将成像系统分为三大部分,对每部分进行分类并分析了各自的优缺点。分析介绍了国内外具有代表性的扩散光层析成像系统,总结了成像系统存在的问题。     

Towards cardiac C-arm computed tomography

Cardiac interventional procedures would benefit tremendously from sophisticated three-dimensional image guidance. Such procedures are typically performed with C-arm angiography systems, and tomographic imaging is currently available only by using preprocedural computed tomography (CT) or magnetic resonance imaging (MRI) scans. Recent developments in C-arm CT (Angiographic CT) allow three-dimensional (3-D) imaging of low contrast details with angiography imaging systems for noncardiac applications. We propose a new approach for cardiac imaging that takes advantage of this improved contrast resolution and is based on intravenous contrast injection. The method is an analogue to multisegment reconstruction in cardiac CT adapted to the much slower rotational speed of C-arm CT. Motion of the heart is considered in the reconstruction process by retrospective electrocardiogram (ECG)-gating, using only projections acquired at a similar heart phase. A series of N almost identical rotational acquisitions is performed at different heart phases to obtain a complete data set at a minimum temporal resolution of 1/N of the heart cycle time. First results in simulation, using an experimental phantom, and in preclinical in vivo studies showed that excellent image quality can be achieved.     

Overcoming ill-posedness of diffuse optical tomography in steady-state domain

In recent decades, diffuse optical tomography (DOT) has drawn more and more interest in molecular imaging because of its advantage of large penetration depth in optical image technology. However, ill-posedness problems have dramatically limited this application technique. In this paper, a new method to remove the ill-posedness of DOT is introduced. With a rotating steady-state domain experiment system, by increasing experimental data that could be obtained from any visual angle, four contrast experiments were simulated. It was proved that when the sum of the experiment data is larger than that of the unknown optical coefficient of phantom,ill-posedness would be reduced and the quality of the reconstructed image could be improved.     

Application of computerized tomography to radiation therapy and surgical planning

Computerized tomography (CT) which permits imaging the internal anatomy in axial cross section, has had a major impact in medicine, primarily in the diagnostic area. The CT scans are also useful in determining the extent of disease which is important in selecting the appropriate therapy. For therapy, the CT scan is becoming important in planning a course of radiation therapy for a cancer patient and to a lesser extent, in planning a surgical reconstruction for some patients. For both of these treatment modalities it would be desirable to have a three-dimensional reconstruction of the internal anatomy. This paper discusses the use of a three-dimensional perspective of the internal anatomy, obtained from multiple CT scans, as a guide to these two therapeutic modalities.     

磁共振辅助的近红外扩散光学断层成像

将大脑磁共振T1加权像分割为头皮、头骨、脑脊液、灰质和白质,并生成分层体网格.利用具有大脑解剖结构信息的分层体网格建立近红外扩散光学断层成像前向光学模型和实现功能重建,可以避免目前所使用的半球头模或图谱头模空间定位不准的问题,解决图像重建过程中所解方程的欠定性和病态性.在棋盘格旋转视觉刺激及扩张视觉刺激实验中,基于磁共振图像的扩散光学断层成像重建的含氧血红蛋白图像具有更高的空间分辨率及定位精度.     

The visualization of hepatic vasculature by X-ray micro-computed tomography

In this study, X-ray micro-computed tomography (CT) was used to reconstruct the fine structure macro- and microvasculature in three dimensions in contrast-enhanced rat liver samples. The subsequent application in the experimental CC531s colorectal cancer model was concurrent with results obtained from confocal microscopy in earlier studies. The en bloc stains osmium tetroxide in combination with uranyl acetate provided an excellent contrasting result for hepatic tissue after a trial of several contrasting agents. X-ray micro-CT allowed us to image the large blood vessels together with the branching sinusoids of hepatic tissue in three dimensions. Furthermore, interruption of the microvasculature was noted when rats were injected with CC531s colorectal cancer cells indicating the presence of hepatic metastases.