4DCT图像二维配准与三维配准的区别

从4DCT图像中提取吸气末和呼气末两个相位的断层图像,首先应用Elastix工具包对两个相位的图像逐层进行二维B样条弹性配准,然后结合VTK和Elastix工具包对它们进行三维B样条弹性配准,配准算法与二维相同,只是维数不同,比较二维和三维配准的差异。研究表明,4DCT图像配准宜采用三维弹性配准,其结果更符合呼吸变化规律。     

4D-CT呼吸信号采集方式对运动肿瘤靶区勾画的影响

目的 比较2种呼吸信号采集方式对运动靶区勾画的影响。方法 正方体模体（内含球体）置于运动平台上,设置运动周期、频率和方向,模拟呼吸运动。分别利用RPM法和GE法进行呼吸信号采集,在最大密度投影（MIP）序列进行靶区勾画。比较正方体和球体不同呼吸信号采集方式下各自重建体积与理论运动体积差异。结果 同一种呼吸信号采集方式下,相同呼吸幅度、不同呼吸频率的重建体积变化较小。对于球体靶区,RPM法重建体积与理论运动体积偏差在-1.5%～5.7%(P <0.05);GE法偏差在-1.3%～-13.8%(P <0.05)。对于正方体靶区,RPM法重建体积与理论运动体积偏差在0.2%～0.9%;GE法偏差在-2.6%～0.9%,2种方法与理论体积差异均无统计学意义（P> 0.05）。结论 对于小体积球体靶区,2种方法得到的MIP图像勾画得到的靶区体积均小于实际肿瘤运动体积;对于大体积正方体靶区,2种方法重建结果与理论结果相比差异均无统计学意义。对于小体积靶区而言,RPM法重建偏差更小且重建图像质量更高。     

一种消除脉搏波信号中呼吸基线漂移的方法

该文提出一种在经验模式分解的过程中结合小波变换的方法，来消除呼吸基线漂移的影响。首先通过经验模态分解将脉搏波信号分解为若干内在模式分量，并判断出含有呼吸基线漂移信息的分量，再利用小波变换将这些分量分解，将代表呼吸基线漂移的小波细节置零，信号重构后就达到了消除呼吸基线的目的。利用自行研制的测量装置采集的脉搏波信号进行实验验证，并采用信号交直流比进行效果评价。结果表明该方法有效地消除了呼吸基线漂移，这将有利于血氧饱和度等人体生理参数无创检测精度的提高。     

经相位纠正的稳态自由进动相位敏感压脂技术的研究

目的稳态自由进动序列(SSFP)可在非常短的时间内获得高对比度和高信噪比效率的图像。但是由于其亮的脂肪信号,SSFP成像的临床应用价值受到严重影响。本文目的在于消除SSFP图象亮的脂肪信号。方法单采集相位敏感SSFP通过适当选择重复时间(TR)来获得相位差180°的水脂信号,利用此相位信息,可以快速而有效的获得压脂图像。结果人体和体模试验得出了很好的水脂分离图像,证明了采用此相位纠正算法的单采集相位敏感SSFP成像技术可以获得非常好的压脂图像。结论经相位纠正的稳态自由进动相位敏感压脂技术,可以在非常短的时间内获得压脂图象,避免了运动伪影,具有一定的临床应用价值。     

基于互信息和薄板样条的医学图像弹性配准方法研究

该文介绍了一种基于互信息和薄板样条变换的医学图像弹性自动配准方法。该方法首先利用互信息将图像进行全局配准,然后将图像分块进行配准,选取子块配准前后的中心点作为薄板样条变换的标记点．实现图像弹性自动配准。实验结果表明．该方法与单纯利用互信息进行刚体配准相比,能够明显提高图像配准精度,并在薄板样条变换中实现了标记点自动选取．降低了标记点选取的难度,能更好地满足临床需求。     

基于Cine扫描的4D—CT图像重建系统设计研究

为了在普通多螺旋CT上实现4D—CT重建,研究中采用VC＋＋程序设计语言和模块化的程序设计方法,开发了基于Cine扫描的4D—CT图像重建系统。利用本系统,根据体表轮廓和肺组织的体积变化确定CT图像在呼吸周期中的相位,按相位分组排序后,实现4D—CT重建,其重建过程不依赖于外在的呼吸监测装置、不受Ct机本身的软硬件限制,具有普遍适用性。     

颅内电极定位中的多模图像配准研究

目的：探讨不同配准方法在颅内电极定位中的表现,寻找适合于颅内电极定位的方法。方法：分别利用均方测量和Mattes互信息方法作为代价函数,将患者植入电极后的CT图像与植入电极前的MRI图像进行配准,对比两种方法的表现。结果：两种方法均能较为准确地定位旋转中心的位置。在同一CT和MRI体数据对中,不同断层图像对进行配准时旋转角度的波动较大;而不同断层配准图像的平均旋转角度与人工配准的结果大致接近。结论：不同断层图像对配准结果的平均值可作为整个CT和MRI体数据的配准参数使用,并得到相对良好的匹配结果。     

LMS算法在非接触生命参数信号检测中的消噪应用

利用雷达式非接触检测系统可检测到生命参数信号（呼吸，心动等信号），针对呼吸，心动信号频谱有重叠的特征。采用自适应LMS算法对信号进行相关噪声抵消处理，从而获取较为理想的心动信号，实验研究分析及实测结果表明该算法简易，实用。     

基于不同呼吸方式对左侧乳腺癌放疗摆位误差分析

目的：比较分析光学体表监测系统（OSMS）引导下的深度吸气屏气（DIBH）技术与常规自由呼吸（FB）技术在左侧乳腺癌放疗中的摆位误差。方法：选择2019年8月～2021年8月在复旦大学附属肿瘤医院放射治疗中心治疗的40例左侧乳腺癌患者并分为两组：对照组采用FB技术；观察组采用结合光学体表图像引导放疗（SGRT）的DIBH技术，采集并统计各病例前五次锥形束CT(CBCT)扫描图像配准误差。结果：对40例患者200套CBCT图像分析，对照组患者在左右方向（LAT）、头脚方向（LNG）与腹背方向（VRT）的平均误差分布为>7mm:5%、5%和5%;5～7mm:15%、20%和10%;<5mm:80%、75%和85%；观察组患者各方向的平均误差分布均<5mm。首次验证时，观察组LAT误差小于对照组（P<0.05）,LNG与VRT无差异（P>0.05）；第二次验证时，观察组LAT与LNG误差均小于对照组（P<0.05）,VRT无差异（P>0.05）；观察组后三次影像验证时，各方向误差均小于对照组（P<0.05）；平均误差比较时，观察组各方向误差均小...     

放疗中基于灰度的图像配准算法性能研究

目的：阐述图像配准在放疗中应用的关键问题,对基于灰度的3种配准方法的性能做深入研究,包括均方测度、归一化相关测度以及互信息测度。方法：分析各配准要素的算法原理后,基于C＋＋加以实现,提出使用综合配准误差来评价不同配准算法的性能,并与传统目标配准误差的评价结果作对比。结果：3种测度都能对近模态的图像实施准确的配准,其中互信息测度驱动的配准在配准精度和速度上表现更为稳定,综合配准误差仅为另外两个测度的一半左右。结论：利用综合配准误差得到的评价结果更为客观,互信息测度是放疗中实施配准的较理想测度。     

Calcium intake in the elderly: validation of a dietary questionnaire

Epidemiological studies of calcium and osteoporosis have been hampered by the lack of a suitable tool for assessing calcium intake. This report describes a new frequency and amount questionnaire for measuring present and past calcium intake in the elderly. The validity of the questionnaire was tested against two commonly used standards of dietary assessment, five-day duplicate diets and seven-day weighed dietary inventories. The resulting correlation coefficients were, respectively, r = 0.76 and r = 0.69, while that for repeatability was r = 0.84. Furthermore, the questionnaire categorized subjects into thirds of the distribution of intake with almost no gross misclassification. It is suggested that the present findings may be extended to the majority of normal, healthy elderly subjects, implying wide application for the questionnaire in the assessment of calcium intake in the elderly.     

Self-reported health problems among Swedish miners one year after unemployment

Unemployment is considered to be a public health concern sincedeterioration in the health of the unemployed is often anticipated.However, for some groups, such as miners, unemployment mightimprove health due to a cessation of potentially harmful occupationalexposures. This study evaluates the health of 79 miners in oneSwedish iron-ore mine, and 226 age-matched controls from thegeneral population, during one year after the closure of themine. The participants received a questionnaire regarding medicalhistory and subjective symptoms at the beginning of the studyperiod, and after one year. Statistically significant negativeeffects on self-reported health attributable to unemploymentwere not found, although neuropsychiatric symptoms were morecommon among the unemployed miners. The miners reported a statisticallysignificant improvement in grip force (p=0.031). They had asignificantly higher prevalence of symptoms associated withmining related exposures when compared with the population controls;pain in the upper extremities [relative risk (RR)=2.27, 95%confidence interval (Cl)=1.44–3.59), back pain (RR=1.84;Cl=1.237–2.75), vasospastic disease of the fingers (RR=2.05;Cl=1.18–3.57) and obstructive respiratory symptoms (attacksof dyspnea and wheezing: RR=3.67; Cl=1.167–11.6).     

Excès de cas humains et animaux de tularémie en France au cours de l’hiver 2007–2008 : émergence ou phénomène isolé ?

Context

Tularemia is a zoonosis affecting humans and hares in France. We describe the results of surveillance in both species, in 2007 and 2008.

Methods

Human tularemia cases are mandatorily notifiable in France since 2003. In hares, surveillance relies on volunteer hunter associations in all districts of the country. Data from mandatory reports and volunteer surveillance in 2007/2008 were analyzed and compared with previous results.

Results

In 2007/2008, 144 cases were reported in humans and 117 cases in hares. This was a 100% increase compared to previous years. Human cases differed from those of previous years only by the frequency of contact with breeding animals. Human cases without any documented risk exposure were also more frequent.

Conclusion

An increase of tularemia cases occurred in 2007/2008 in both species. Complementary studies are needed to identify the species reservoir in France to understand the causes of this peak of cases.     

Occupational health hazards in mining: an overview

This review article outlines the physical, chemical, biological, ergonomic and psychosocial occupational health hazards of mining and associated metallurgical processes. Mining remains an important industrial sector in many parts of the world and although substantial progress has been made in the control of occupational health hazards, there remains room for further risk reduction. This applies particularly to traumatic injury hazards, ergonomic hazards and noise. Vigilance is also required to ensure exposures to coal dust and crystalline silica remain effectively controlled.     

Manufacture and use of nanomaterials: current status in the UK and global trends

This paper provides an overview of the production and use of nanomaterials (NMs), particularly in the UK. Currently, relatively few companies in the UK are identifiable as NM manufacturers, the main emphasis being the bulk markets in metals and metal oxides, and some niche markets such as carbon nanotubes and quantum dots. NM manufacturing in the UK does not reflect the global emphasis on fullerenes, nanotubes and fibres. Some assumptions have been made about the types of NM that are likely to be imported into the UK, which currently include fullerenes, modified fullerenes and other carbon-based NMs including nanotubes. Many university departments, spin-offs and private companies have developed processes for the manufacture of NMs but may only be producing small quantities for research and development (R&D) purposes. However, some have the potential to scale up to produce large quantities. The nanotechnology industry in the UK has strong R&D backup from universities and related institutions. This review has covered R&D trends at such institutions, and appropriate information has been added to a searchable database. While several companies are including NMs in their products, only a few (e.g. manufacturers of paints, coatings, cosmetics, catalysts, polymer composites) are using nanoparticles (NPs) in any significant quantities. However, this situation is likely to change rapidly. There is a need to collect more information about exposure to NPs in both manufacturing and user scenarios. As the market grows, and as manufacturers switch from the micro- to the nanoscale, the potential for exposure will increase. More research is required to quantify any risks to workers and consumers.     

深圳公立医院管理体制改革制度设计

深圳公立医院管理体制改革实行政事分开、管办分开,在理事会架构下按法定机构模式组建市医管中心,落实公立医院运营管理自主权.作者从当前公立医院管理体制的弊端入手,介绍了深圳市进行公立医院管理体制改革的基本思路及改革方案设计的主要举措,深入剖析了的改革方案的特点,并对改革效果进行了预测.     

Effects of nitrogen dioxide on red blood cells of rats: Changes in components of red cell membranes during in vivo exposure to NO2

Red cell membranes, prepared from red blood cells of rats exposed to 4, 10, or 20 ppm nitrogen dioxide (NO₂) for 1 to 10 days, were examined for evidence of changes in membrane components. Appreciable changes were not found in contents of phospholipid and cholesterol during exposure to 10 ppm NO₂. By contrast, protein content altered with the time of exposure. Moreover, changes in protein composition were observed by employing sodium dodecyl sulfate — polyacrylamide gel electrophoresis. Twenty-four-hour exposure to NO₂ at the concentration above 10 ppm resulted in a marked increase in the percentage of lysophosphatidylethanolamine (LysoPE) to the total phospholipids. The prolonged exposure to 10 ppm NO₂ gave rise to a further increase in LysoPE, whereas the percentage of phosphatidylethanolamine (PE) showed a gradual decrease. A 1-day exposure to 4.0 ppm NO₂ also caused an increase in sialic acid content and decreases in those of PE and hexose. In addition to contents of these components the percentage of LysoPE increased 5 days after exposure and the elevated values were maintained up to the end of exposure period. These results demonstrate that red blood cells in circulation exhibit different membrane properties in terms of lipid and carbohydrate composition during 10 days of exposure to 4.0 ppm NO₂.     

Investigating clusters in the workplace and beyond

Clusters of disease are common and occur in the workplace and in the general community. They often arouse considerable concern among the population. Investigations have sometimes lead to exciting new knowledge, but in general the investigation of clusters is difficult and often unrewarding, especially for community clusters. In the workplace, investigations are more likely to find associations and even new causes, but still many clusters remain enigmatic. Despite this, there are many reasons for investigating clusters, including allaying community concern and identifying uncontrolled exposures. A structure for investigating clusters in the workplace is suggested.