频率可调型磁颗粒靶向热疗实验平台的研制

针对磁颗粒靶向热疗研究,本文设计了一种频率可调型磁颗粒靶向热疗实验平台.首先分析了磁颗粒靶向热疗系统的总体结构,提出了通过串联不同补偿电容来实现频率可调的方案,搭建了频率和幅值可调的高频电源.通过自制探头测量各工作点的磁场强度及其分布情况,表明该实验平台的磁场强度最大可达16 kA/m,磁场分布较为均匀,输出频率可在30~80kHz之间自由调节,基本满足磁颗粒靶向热疗的要求,为进一步的实验研究打下了基础.     

胶囊状全消化道介入诊查装置的三维磁定位

为了对微型诊查胶囊进入人体消化道后的三维位置进行测量,提出了不可见状态下的非接触式永磁定位新方法.具体做法是:根据等效磁荷的原理,建立永磁体空间磁场与空间方位的简化定位模型;根据定位模型确定具体的定位方案;并对磁传感器的输出数据进行差分处理,消除了静态和准静态环境磁场干扰.实验证明定位模型能满足精度要求,定位方案正确可行,此定位法可投入实际应用.     

基于磁定位的消化道微型药物释放装置动态跟踪技术研究

对消化道微型药物释放装置在体内的运动进行无创动态跟踪更具有特别重要的意义.本文在分析永磁体空间磁场分布规律的基础上,提出了利用磁定位原理实现动态跟踪微型药物释放装置在消化道运动状态的方法.其基本过程是在微型药物释放装置上固定永磁体,当其通过消化道时在体外检测磁场变化,进而实时计算出微型药物释放装置的空间位置,并描记出运动轨迹,实现动态跟踪.通过在模拟肠道中的实际测试,该技术可较好地跟踪永磁体的运动轨迹.     

消化道微型诊疗装置磁定位系统的软件设计

为实现对消化道微型诊疗装置在人体内的实时定位与跟踪,使用可视化工具包(VTK)在VC++.Net平台下设计了可应用于消化道微型诊疗装置的定位跟踪软件.该软件采用多线程处理技术,在实时检测电子胶囊内磁标记物的空间磁场信息基础上,利用非线性最优化算法求解出电子胶囊位置和姿态信息,最后将定位结果以二维和三维的形式实时显示并存档.实验结果表明:该程序在基于磁通传感器阵列的硬件平台下,能够稳定的实现磁传感器阵列的数据采集,对非线性最优化磁定位算法进行实时处理,以及空间定位结果的二维、三维显示和数据保存三项任务的流水线并行处理和数据回放等功能,每次传感器阵列数据采集时间小于2 s,定位算法时间小于600 ms.该软件可实时处理定位信息的采集、处理运算及结果显示,能满足消化道内微型装置实时跟踪定位的需要.     

基于连续波的频域磁声耦合成像方法正问题研究

磁声耦合成像常用的时域信号检测方法易受到电磁干扰,限制成像质量。提出频域磁声成像方法,通过锁相放大实现微弱声信号的检测,提高信号检测精度。本研究建立了频域磁声耦合正问题数学模型,基于正弦波激励,对简单电导率边界模型进行了仿真研究和实验验证。仿真研究表明信号频域幅值相位反映了介质声源分布。实验验证了仿真结果,实现了声源幅值锁相检测和空间定位,检测精度达到10-7Pa,实现了激励电流低于1m A下的声检测。本研究提出的频域磁声耦合成像方法,有利于提高微弱磁声信号检测精度,在低频激励下实现高分辨率成像,对实现磁声耦合成像的介质内部电导率研究具有积极意义。     

无创式消化道出血灶的检测与定位方法

消化道出血灶的检测和定位是消化道出血症诊断与治疗的关键.提出了一种无创式出血灶检测与定位的电子微系统方案,研制了一种血红蛋白传感器,并在离体状态下对这种传感器进行了原理性实验.结果表明这种传感器对血红蛋白具有很高的灵敏度,并且输出信号与血红蛋白的浓度有线性关系.     

顺磁纳米铁核素的研制及性能分析

目的 :本研究制备了一种新型的、可定位治疗肿瘤的药物—顺磁放射性纳米铁核素。方法 :采用羰基法制备纳米铁 ,然后通过脉冲中子反应堆辐照纳米铁获得顺磁纳米铁核素。结果 :放射性核素———纳米铁的平均粒径<10 0nm ,具有超顺磁性、放射性活度和较好的磁导向功能 ,可有效定位于靶区。结论 :该研究为肿瘤的治疗提供了一种新型的方法和材料 ,即顺磁纳米铁核素定位治疗肿瘤的方法。     

消化道生理参数检测电子胶囊的温度补偿与试验

介绍了可以在无创条件下检测消化道压力和温度参数的电子胶囊的标定与检测结果.采用硬件补偿解决了扩散硅压力传感器的温漂问题;通过标定实验得到了此装置关于压力和温度的标定曲线以及压力输出值和温度的相关性;临床试验证明了这种电子胶囊优良的工作性能和在消化道功能性疾病的诊断、治疗和预防方面的深远意义.     

磁靶向定位灌注化疗膀胱癌磁性吡柔比星纳米粒的制备与评价

目的构建一种新型的磁靶向定位灌注化疗膀胱癌的吡柔比星纳米制剂,并探讨其磁靶向定位及抗膀胱癌细胞特性,为定位灌注化疗膀胱癌的临床应用提供帮助。方法通过N-N'-羰基二咪唑(CDI)交联剂将治疗膀胱癌的临床药物吡柔比星(pirarubicin,THP)连接在表面氨基化的四氧化三铁(Fe3O4)磁性纳米粒上,制备具有磁性的THP纳米制剂,并在体外考察其磁定位性能和对膀胱癌细胞的抑制作用。结果 THP成功地连接到了粒径40 nm左右的Fe3O4磁性纳米粒上,磁性药物制剂在不同p H值的缓冲液中药物在90%以上,并可在外界磁场作用下定位于靶向部位。对膀胱癌细胞可造成THP和Fe3O4双重抑制效果,抑制率高达58.44%。结论该纳米制剂可通过外界磁场定位于靶向部位,膀胱癌细胞抑制效果明显,为临床定位灌注化疗的应用奠定了基础。     

生物靶向冲击昆虫卵孵化率的实验研究

目的:通过实验研究在生物靶向磁爆冲击干扰下昆虫卵的孵化率。方法:采用桑蚕[秋丰B]3、4、6品系为试验标本组成干扰组和对照组,进行生物靶向磁爆冲击干扰试验,观察分析虫卵动态孵化过程。结果:实验结果表明,在虫卵自然孵化过程中对其进行靶向磁场冲击干扰,不同序列的生物靶标干扰参数,对孵化率有这不同的影响。结论:研究探讨生物电磁干扰参数B/F/N为"窗口"值,受干扰的虫卵胚胎在自然孵化过程中出现非正常发育甚至死亡,B/F/N值越精确,对其孵化率的影响越大。在电磁场频谱中B/F/N"窗口"值的确定和其生物效应的作用机理仍有待进一步研究。     

Effect of geomagnetic storms on the erythrocyte sedimentation rate in ischemic patients

The dynamics of the erythrocyte sedimentation rate (ESR) in patients with ischemic disease shows a significantly different pattern in the days of raised geomagnetic activity as compared to quiet days. This is revealed by a greater intensity of ESR variations during geomagnetic storms as compared to the days of when there was little or no sun activity (quiet sun). Such behavior of red blood cells reflects the patient's individual sensitivity to geomagnetic field fluctuations. This article discusses a possible mechanism of ESR variations.     

Spatial localisation of NMR signals and electrical scanning of sensitive regions by the magnetic focusing method

The spatial localisation of NMR signals by the magnetic focusing method is examined and a method for electrical scanning of a spatially localised region is proposed. The small amount of signal from points of the star taper in static field focusing can almost be neglected, and the spatial localisation of the signal corresponds to the shape of a prolate spheroid in the centre region of the star-shaped focusing field. Electrical scanning of the focused region can be achieved at any position in the magnet system by superimposing linear field gradients on the focused field in the scanning direction. These are the inherent limitations of the static magnetic field focusing method. The embodiment of the scanning movement of the focused field is also confirmed.     

Human secretory component. II. Easy detection of abnormal amounts of combined secretory component in human sera.

A simple method, allowing easy detection of abnormally increased sIgA levels is described. It consists in quantitation of combined SC by gel double diffusion, using appropriate anti-SC immune sera. The technical conditions, locating the threshold of sensitivity of precipitation at about 25 microgram/ml, a value higher than that found in normal sera, were established. Comparison with other classical methods (SRID, ELISA and IHA) emphasizes the validity and simplicity of the technique which has shown convenient whenever a large number of sera have to be tested.     

Effects of the local and geocosmic environment on the efficacy of Energy Medicine treatments: An exploratory study

IntroductionOutcomes of medical treatments tend to be highly variable. Some of the underlying variance is due to well-known factors such as age, gender, ethnicity, and effects of local weather. There are also less obvious influences including variations in solar wind, the Earth's geomagnetic field, and the interplanetary magnetic field.This study explored possible effects of these local and solar/geomagnetic variables on the outcomes of energy medicine treatments. The context was a pilot clinical trial involving 17 energy medicine practitioners who treated a total of 190 participants presenting with hand and wrist pain.MethodsEighteen environmental variables were correlated against changes in subjective pain and against changes in objective measures of nerve conduction velocity.ResultsThe results showed that local barometric pressure, interplanetary magnetic field, lunar illumination, proton fluence, electron fluence, and solar radio flux showed statistically significant relationships with these health outcomes (at p < 0.05 or better) before correction for multiple comparison corrections. The variable of barometric pressure had a robust correlation with nerve conduction velocity, surviving adjustment for false discovery rate among the 18 variables at p < 0.05.DiscussionThis study lends support for future research into local weather, and potentially also to fluctuations in the solar/geomagnetic environment environmental measures as potential sources of variation in energy medicine sessions.     

Estimation of Motion in Angiographic Images

The effect of organ and tissue motion on X-ray image quality in angiography is discussed. It is shown that estimation of such motion may benefit the diagnostic value of images in several ways. The block-matching method is described. This method provides information on motion in the form of an offset vector field. The modifications of the block-matching algorithm described in this work include static region segmentation based on noise estimation and application of an additional flicker coefficient that improves the confidence of the method in case of changes in illumination.     

Modality-integrated magnetic catheter tracking for x-ray vascular interventions

A novel setup for the integration of a magnetic tracking system (MTS) into a catheter laboratory environment by attaching the field generator of the MTS to the C-arm of the x-ray system was investigated. The metal interference of the x-ray system with the MTS then becomes static and can be calibrated. The registration of a tracked catheter to 2D live x-ray images with high and well-defined accuracy is thus possible for arbitrary C-arm positions. Interference with imaging by blocking the field of view is avoided. Real-time registration methods to maintain the registration of the catheter also to static 2D or 3D images (roadmaps), regardless of the C-arm rotation during catheter tracking, were investigated. Residual registration errors of the tracked catheter with respect to the static roadmaps (2D and 3D) were reduced by using the vessel geometry and shape information. The algorithms potentially allow for motion correction (e.g. due to respiration). Using the shape-based correction algorithms the average registration accuracies to static roadmaps for different C-arm angulations and catheter positions were determined to be 3.3-4.2 mm. The magnetic registration of the C-arm was furthermore allowed to compute the imaging geometry (position of the C-arm) and to produce virtual angiographic preview images before contrast injection and x-ray dose application. Thus, optimal projection geometries and collimator settings for the target region can be chosen in an 'off line' fashion. The proposed MTS-supported navigation setup on both 3D (static) and 2D (live and static) roadmaps merges the high resolution and real-time feedback of 2D x-ray images with the navigation support from 3D static images.     

Suppression of Interference and Artifacts by the Signal Space Separation Method

Multichannel measurement with hundreds of channels oversamples a curl-free vector field, like the magnetic field in a volume free of sources. This is based on the constraint caused by the Laplace's equation for the magnetic scalar potential; outside of the source volume the signals are spatially band limited. A functional solution of Laplace's equation enables one to separate the signals arising from the sphere enclosing the interesting sources, e.g. the currents in the brain, from the magnetic interference. Signal space separation (SSS) is accomplished by calculating individual basis vectors for each term of the functional expansion to create a signal basis covering all measurable signal vectors. Because the SSS basis is linearly independent for all practical sensor arrangements, any signal vector has a unique SSS decomposition with separate coefficients for the interesting signals and signals coming from outside the interesting volume. Thus, SSS basis provides an elegant method to remove external disturbances. The device-independent SSS coefficients can be used in transforming the interesting signals to virtual sensor configurations. This can also be used in compensating for distortions caused by movement of the object by modeling it as movement of the sensor array around a static object. The device-independence of the decomposition also enables physiological DC phenomena to be recorded using voluntary head movements. When used with properly designed sensor array, SSS does not affect the morphology or the signal-to-noise ratio of the interesting signals.     

Analysis of the seasonal pattern in suicide

BACKGROUND: Suicide has been attributed to social and psychological factors but also to geophysical effects. Of the latter, changes in solar radiation and geomagnetic activities may contribute to the frequency and the seasonal pattern of suicides. METHODS: We studied with a population-based, nationwide analysis all the individuals who committed suicide (n=27,469) in Finland during the period of 1979 to 1999. The daily data on the number of suicides, and the mean and maximum levels of geomagnetic activity were compiled and modelled with Poisson regression using the number of inhabitants in each province as the denominator. Time series analysis of monthly numbers of suicides was carried out using a seasonal-trend decomposition procedure. RESULTS: There was a strong seasonal effect on suicide occurrence (P<0.00001), the risk of suicide being greatest in spring. The seasonal effect was most pronounced when the number of suicides was relatively low. High levels of solar radiation activity were associated with the increased risk of suicide (P=0.00001), but the effect of geomagnetic activity was weak. LIMITATIONS: No individual data on alcohol consumption or mental disorders were available. CONCLUSIONS: Suicide occurrence varies markedly by season and needs attention where prevention is concerned.     

一种新的检测磁共振设备主磁场均匀性的设计

目的：为了弥补传统检测方法在检测效果上的缺陷，实现连续地从磁场平面获得其均匀度的数据。方法：设计了一个运动探测器来进行磁场的均匀性检测，将摄取的信号经过转换和数据处理，最后通过计算机仿真对基于有限测量点的传统方法进行了比较。结果：传统检测法的结果与检测时的采样方式（采点数和采点位置）密切相关。在仿真环境中同样的磁场在不同的检测方式下很大可能会得到多个不同的且不具有近似性的结果，特别是在不均匀性不规则分布的磁场中：而本设计只得到唯一的检测结果，并且可以看到检测视野内采点数越多其检测结果将越逼近本设计的结果。结论：本设计能有效弥补传统检测方法充分度和精确度不足的缺陷，同时也说明磁场的均匀性检测应该从连续平面获取数据。     

Optimization of intensity modulated radiotherapy under constraints for static and dynamic MLC delivery.

Multi-leaf collimators (MLCs) are emerging as the prevalent modality to apply intensity modulated radiotherapy (IMRT). Both the principle and the particular design of MLCs stipulate complex constraints on the practically applicable intensity modulated radiation fields. Most consequentially, the distribution of exposure times across the maximum field outline is either a piecewise constant function in the static mode or a piecewise linear function in the dynamic mode of driving an MLC. In view of clinical utility, the total leaf movement should be minimized, which requires that MLC-related constraints be considered in the dose optimization process. A method is proposed to achieve this for both static MLC fields and dynamic leaf close-in application. The method is an amendment to a generic gradient-based IMRT dose optimization algorithm and solves numerical problems related to the non-convexity of the MLC constraints, which can cause erratic behaviour of a gradient-based algorithm. It employs bistable penalty functions to select preferrable leaf configurations from the configuration space of the MLC, which is limited by specific design features. Together with an 'annealing' escape mechanism from local minima, the algorithm is capable of finding the optimum of an IMRT problem as leaf sequences with minimized leaf travel. In particular, the efficiency of static IMRT can be raised to the levels of unmodulated fields with very few field segments, thereby increasing the utility of IMRT in clinical practice.