呼吸运动对靶区三维重建的影响

目的：自制运动体模，探讨呼吸运动对靶区三维重建的影响。方法：用VEXTA步进电机、YT-H200B型步进电机驱动器、导轮、有机玻璃球、低密度度泡沫等设计能模拟肿瘤随呼吸运动的体模；取不同螺距、层厚和运动周期组成10个不同的扫描序列在GE LightSpeed^16 CT上扫描，然后在GE Advantage Sim6．0上采用体绘制技术（volume rendering）对所获得CT图像进行三维重建．用三维工具软件测量不同扫描条件下各靶体积大小，计算动态与静态扫描靶区重建体积的相对偏差。结果：静态体模同一靶区在层厚与螺距小同时．扫描后三维重建的靶区外观无明显可见变化，重建靶区的体积差异可忽略；在不同运动状态下扫描，同一靶区重建图像的外形差异明显．重建靶体积的相对偏差最大近90％；同一运动状态下，各靶区重建体积变化随靶而异；外形较小的靶区重建体积相对偏差变化范围为-39.8％-89、5％，外形较大的靶区重建体积相对偏差变化范围是-18．4％-20．5％。结论：呼吸运动对靶区重建的响影极大，三维放疗计划设计所依赖的CT图像．必须足肿瘤靶区处于相对静止状态下扫描的图像，否则，适形射野和剂量体积直方图将严重失真。     

呼吸运动对4DCT扫描下靶区体积及位移的影响

【摘要】目的:探讨基于4DCT扫描图像勾画的靶区体积和位移与呼吸运动状态下肿瘤运动频率及幅度的关系。方法:使用自制的人体胸部模体及呼吸运动平台驱动直径为2 cm的小球做正弦运动（周期分别为3.0、3.8、6.0 s,幅度分别为1、2 cm）以模拟肺部肿瘤运动,再进行4DCT扫描。对每组4DCT图像中的10个时相进行大体肿瘤体积（GTV）靶区勾画并对每组4DCT图像中10个时相的GTV进行融合得到内靶区（ITV）。基于平均密度投影（AIP）和最大密度投影（MIP）进行自动靶区勾画,分别获得ITVAIP及ITVMIP。分析GTV体积与小球实际体积的关系,GTV体积和GTV中心位移与小球运动频率和幅度的关系,以及ITVP、ITVMIP及ITVAIP与小球运动范围的体积VP（理论ITV体积）的关系。结果:GTV体积与对应时相小球运动速度无相关性,但GTV中心偏差与小球运动速度呈弱相关性,小球运动速度越快,GTV中心位移的偏差越大。ITV和PTV体积与肿瘤运动周期无关,仅与运动幅度有关。ITVMIP和ITVP的体积与ITVAIP相比更接近理论ITV体积,而ITVAIP体积比理论ITV体积小。结论:对于胸腹部放疗的患者使用适当的呼吸管理手段控制患者呼吸或引导患者平稳呼吸有利于提高放疗精准度;基于MIP勾画的ITV靶区能够更好地反映肿瘤的运动。     

肺癌放疗中活动靶区常规CT定位和PET/CT定位的模体研究比较

目的:肺癌靶区运动是影响放射治疗效果的重要因素之一,目前有很多方法试图解决这一问题,如4D-CT,呼吸门控,慢CT,等,但各有缺陷,都不理想。本文使用模体研究常规CT定位和PET/CT定位并比较。材料和方法:将不同形状CT模体/灌注F18-FDG模体,固定于呼吸运动平台上,使用Simens Biograph64同机PET-CT不同条件扫描(64排CT和39环PET),瓦里安Eclipse治疗计划系统三维重建,勾画并比较体积差异。结果:快速CT扫描运动模体,最大丢失体积达-50.8%(36.2 cm3);PET图像同物体运动轨迹体积比较最大差异-16.3%,且没有出现变形现象。PET图像所有体积小于真实运动轨迹体积,这同显示条件有关系。结论:快速CT只能随机捕捉运动物体部分体积并存在变形情况,不适合应用于活动肿瘤(肺癌)放射治疗计划定位;PET-CT能够较稳定地反映运动物体运动轨迹,且没有图像变形,能较好代表内靶区,并且操作相对简单,病人容易耐受。     

低剂量迭代重建技术在放疗定位图像中的应用

目的:探讨新型低剂量迭代重建技术应用于放疗定位图像的可行性。方法:基于体模的实验数据,对CT辐射剂量进行分析。对CT值、低对比度分辨率、噪声、均匀性以及几何畸变各项质量评价参数进行定量的分析。对仿真体模进行迭代重建技术扫描重建,并在放射治疗计划系统中对仿真体模进行模拟剂量计算,分析感兴趣体积的绝对剂量和平面内剂量的Gamma通过率。结果:低剂量迭代重建技术能够在保证图像质量的同时减少约60%的CT扫描辐射剂量。当管电压保持不变时,低剂量迭代重建技术对TPS剂量计算的准确性的影响可以忽略不计,感兴趣体积剂量最大差异0.6%,面剂量的Gamma通过率优于99.82%。低剂量迭代重建技术对图像低对比度分辨率有一定影响,需要进一步结合临床影像进行分析。结论:低剂量迭代重建技术可以应用于放疗定位图像中,但是需要注意图像特性和某些图像质量的改变,建议与PET-CT、超声、核磁等检查手段结合综合考虑确定靶区范围。 【关键词】低剂量迭代重建;放射治疗;定位图像     

3DCT联合4DCBCT在中下叶肺癌SABR放疗靶区外放边界中的应用研究

目的:利用四维锥形束CT（4DCBCT）扫描获取放疗靶区摆位误差和呼吸运动误差,计算肿瘤立体定向消融放射治疗（SABR）中计划靶区体积（PTV）外放边界大小。方法:回顾性分析19例中下叶肺癌SABR治疗患者,治疗前4DCBCT扫描,共72次扫描图像。根据4DCBCT与定位CT的配准结果,评估放疗靶区分次间摆位和呼吸运动误差,确定PTV外放边界大小。结果:放疗靶区摆位误差在左右、上下、前后3个方向上分别为（0.11±0.29）、（0.02±0.58）、（0.05±0.26） cm,放疗靶区呼吸运动误差在3个方向上分别为（-0.06±0.34）、（0.09±0.68）、（0.06±0.23） cm,利用ICRU83#报告公式计算PTV外放边界,在3个方向上分别为1.13、2.15、0.90 cm。结论:4DCBCT可有效评估放疗靶区摆位和呼吸运动误差,并确定中下叶肺癌SABR治疗中PTV外放边界大小。利用本方法计算的外放边界比原来RTOG提出的外放标准更加精确,可个体化评估放疗靶区外放边界。     

呼吸运动对锥形束CT确定靶区的影响

肺部肿瘤会随着人的呼吸运动而运动,为研究肿瘤运动周期内运动时段的不同对锥形束CT(CBCT)确定肿瘤靶区的影响,应用CIRS008胸部运动模体,取直径分别为1cm和3cm的球形靶模拟肺部肿瘤的正弦运动,然后在振幅不变的情况下改变靶运动在近呼气端与近吸气端时间的比值(E/I)进行CBCT扫描。提取靶运动方向中心线上每个像素的CT值分析图像中靶区对比度的变化,应用区域生长的方法自动勾画靶区,并与根据小球运动轨迹计算的运动体积进行比较。结果显示随着E/I的增大,近呼气端对比度升高而近吸气端对比度降低。勾画的靶区体积随着E/I的增大而减小,当E/I=4,振幅A=1cm时,直径分别为1cm和3cm的小球,体积分别减小了48.2%和22.7%;研究表明E/I增大时CBCT不能完整的反映靶的运动范围,CBCT可能会低估肺部肿瘤的内靶区。     

一种用于全身照射技术的全身模拟定位CT扫描与图像重建方法

目的：探索一种适用于全身照射（TBI）的CT重建方法,可同体位连续扫描后获得一套完整的全身模拟定位CT。方法：使用TBI CT重建方法对患者进行CT模拟定位,完成后于Eclipse v15.5计划系统中生成一套全身模拟定位CT,将其运用到TBI计划设计与评估。在应用过程中,基于Python系统开发出相应的图像重建软件,与手动图像重建结果进行对比。结果：该全身模拟定位扫描方案可在Eclipse v15.5中实现两套CT的重建。在工作效率上,手工重建方法生成全身模拟定位CT平均需要10 min,软件重建方法只需要5 s。两种CT重建方法在图像质量上无差异,重建CT与真实值相比误差小于1 mm。使用重建的全身模拟定位进行TBI计划设计与评估,靶区适形度指数（CI）=0.854,剂量均匀性指数（HI）=0.199。结论：本文介绍的TBI全身模拟定位CT扫描与图像重建的方法可以简单、快速地获得完整的全身模拟定位CT图像,适用于后期的TBI计划设计、优化和评估过程。     

运动模体中靶区长度与锥形束CT扫描速度的相关性

目的:研究锥形束CT扫描速度与动态模体中靶区长度的相关性。方法 :选用QUASAR(Modus,Germany)呼吸运动模体,模体内含运动插件,插件中心内嵌入一边长3 cm的立方体,用其来模拟运动靶区。设置模体振幅为0.5、1、2 cm,每一振幅分别设20、15、10次/min三种频率,在每振幅下分别行300°、180°、90°/min运动速度的CBCT扫描。计算CBCT图像靶区长度及靶区长度覆盖率与理论结果比较。结果:振幅为5 mm时,300、180、90°/min扫描时所得不同频率下靶区长度分别为(30.17,30.33,30.5)mm;(31.17,31.83,32)mm;(32.5,33.67,33.67)mm;振幅为10 mm时,300°、180°、90°/min扫描时所得靶区长度分别为(32.67,33.67,35.67)mm;(36,37.5,37.65)mm;(40.17,40.5,41.17)mm;振幅为15 mm时,300°、180°、90°/min扫描时所得靶区长度分别为(39.33,41,41.83)mm;(43,46,46.5)mm;(47.83,48.83,49.17)mm。结论 :CBCT扫描速度、模体振幅以及模体运动频率对靶区长度均有影响。扫描速度越慢,图像所得靶区长度越接近靶区长度真实值,但是各种速度下均小于理论靶区长度。振幅越小时所得靶区长度越接近于靶区理论值,靶区覆盖率越高。临床实践中使用CBCT对动态肿瘤监控时应使用患者平静呼吸的慢速扫描。     

肿瘤靶区呼吸运动位移误差补偿系统模型的研究

在肿瘤精确放射治疗过程中,减少照射靶区呼吸运动造成相对于静止照射野的照射位移误差量. 我们采用步进电机驱动的机电一体化系统,以控制一块叠放在原加速器治疗床上的可移动平台,在治疗过程中的每一时刻,使之能够在二维冠状平面带动患者的体位,实现对肿瘤靶区实施呼吸运动造成位移的实时反向跟踪运动.通过CT扫描和图像重建的算法,可以检测出在使用运动补偿系统前后,患者肿瘤靶区在冠状平面上呼吸运动位移量的大小,经过对比后发现,后者的位移误差量确实小于前者.使用肿瘤靶区呼吸位移误差补偿系统,能够比较有效地缩减靶区的呼吸运动范围,在肿瘤精确放疗计划的设计过程中,对缩小计划靶区(PTV)范围以提高肿瘤治疗增益比(TCP)发挥了重要的作用.     

CT模拟软件的质量保证

目的:CT-SIM模拟软件作为几何模拟的重要工具,其精确度和完整性应是目前三维立体放射治疗中首要考虑的问题之一.本文旨在研究和探讨CT模拟软件的质量保证和质量控制(quality assurance and quality control,QA&QC)的检测方法.材料与方法:利用飞利浦BrillianceTMCT模拟机对QUASTM蹦模体和QUASAR多叶准直器束流几何模体分别实施扫描,通过在ACQSim工作站软件中来实现以下几项质控检测:(1)等中心计算和空间/几何精度检测;(2)图像重建精度测试;(3)DRR几何精确度的评估;(4)射野几何学和MLC精度的测量.结果:(1)用QUASAR模体检测模拟软件等中心计算及空间/几何计算精度,偏差均小于1 mm.(2)所测量的模体插件体积与标称值相比较:大正方体为1.24%.小正方体为1.76%,楔形空腔体积为2.1%,大球体相差-0.44%,中球体为0.56%,小球体为13.68%.(3)在DRR图像中测量出最里面的丙烯酸材料的矩形面积为0.9 cm×1.9 cm,中间空气腔矩形面积为10 cm×9.9 cm,外面丙烯酸材料的矩形面积为14.7 cm×14.8 cm.(4)照射野的MLC与模体的几何精度误差基本保持在±1 mm精度.结论:CT模拟软件的QA在CT模拟定位系统质量保证中应占有十分重要地位,其直接影响到放疗定位的精确度和治疗的准确性.     

Renal dysplasia and asplenia in two sibs

A family is reported in which two sibs, one male and the other female, both died within 24 hours of birth with enlarged polycystic kidneys. Postmortem histology in the second child showed gross renal dysplasia. In both children the pancreas was enlarged, nodular and cystic but the liver appeared macroscopically normal. In the second child, histological examination confirmed pancreatic fibrosis with cystic dilation of ducts, but showed portal fibrosis with bile duct proliferation in the liver.
This combination of findings is very reminiscent of those in a girl and her brother reported by Ivemark et al. (1959). The children reported here also showed absence or hypoplasia of the spleen, cardiac anomalies and other features of the Ivemark syndrome (Ivemark 1955), a quite different, usually sporadic, congenital disorder. It is suggested that the children described here have a distinct lethal congenital disorder, probably inherited in an autosomal recessive manner.     

Schizophrenia in a North Swedish geographical isolate, 1900–1977. Epidemiology, genetics and biochemistry

Over 200 schizophrenic patients belonging to three major and interrelated pedigree complexes have been investigated over the past 30 years in a North Swedish geographically isolated population, presently numbering about 6,000. An intensive investigation of a number of biochemical correlates and genetic markers in a few selected families belonging to one of the major pedigrees has indicated new strategies for the current research program.
Schizophrenia, as defined operationally, is significantly associated with decreased activities of two enzymes (1) blood platelet monoamine oxidase, (2) plasma dopamine-β-hydroxylase, and (3) with the genetic marker Gc² (group specific antigen). Both enzymes are subject to genetic variation. A positive score for linkage between schizophrenia and low plasma DBH activity has been calculated, but, so far, available data are insufficient for discrimination between linkage and partial contribution of genetically controlled low plasma DBH to the pathogenesis of the disease. Alternatively, both mechanisms could be involved.
As a model for continued research, schizophrenia is explained as based on a double dominant-recessive genotype (Aabb), representing a vulnerability which in about 50 % of cases develops into clinical schizophrenia. It is suggested that the dominant mutation (A) operates on or affects MAO activity, and that the recessive genotype (bb) is instrumental in low variates of DBH activity and very likely such variates within the normal range of physiological variation. Moreover, it is suggested that the combined effects of MAO- and DBH-reduced efficiency on the metabolism of e.g. dopamine could be an essential pathogenic mechanism for the schizophrenic illness which is segregating in this population.     

What will studies of Fulani individuals naturally exposed to malaria teach us about protective immunity to malaria?

There are an estimated over 200 million yearly cases of malaria worldwide. Despite concerted international effort to combat the disease, it still causes approximately half a million deaths every year, the majority of which are young children with Plasmodium falciparum infection in sub-Saharan Africa. Successes are largely attributed to malaria prevention strategies, such as insecticide-treated mosquito nets and indoor spraying, as well as improved access to existing treatments. One important hurdle to new approaches for the treatment and prevention of malaria is our limited understanding of the biology of Plasmodium infection and its complex interaction with the immune system of its human host. Therefore, the elimination of malaria in Africa not only relies on existing tools to reduce malaria burden, but also requires fundamental research to develop innovative approaches. Here, we summarize our discoveries from investigations of ethnic groups of West Africa who have different susceptibility to malaria.     

The dominant diseases of modernized societies as omega-3 essential fatty acid deficiency syndrome: Substrate beriberi

About 1900, modern food selection and processing caused widespread $\text{epidemics}$ of the B vitamin deficiency diseases of beriberi and pellagra which, for genetic reasons, often expressed as different diseases ranging from bowel and heart disease to dermatoses and psychoses. But the B vitamins merely help convert essential fatty acids (EFA) into the prostaglandin (PG) tissue regulators and it now turns out that, through hydrogenation, milling and selection of w3-poor southern foods, we have also been systematically depleting, by as much as 90%, a newly discovered trace Nordic EFA (w3) of special importance to primates and sole precursor of the PG3(4) series, even as a concurrent fiber deficiency increases body demand for EFA. Since substrate EFA is processed by many B vitamin catalysts, an EFA deficiency will mimic a $\text{panh}$ypovitaminosis B, i.e., a mixture of $\text{substrate}$ beriberi and $\text{substrate}$ pellagra resembling vitamin beriberi and pellagra but exhibiting as even more diverse $\text{endemic}$ disease. This would consitute a second stage of the Modern Malnutrition and explain why some workers now hold the dominant diseases of modermized societies to be new, nutritionally based, pellagraform yet lipid-related and to range, once again, from heart disease to psychosis. It is an assumption that our dominant diseases are unrelated to each other or are merely revealed by our diagnostic acumen and therapeutic success; and that hydrogenating millions of tons of food oils annually, to destroy the rancidity producing w3-EFA, is safe for $\text{primates}$. Extensive beriberiform disease is reported here in 32 typical cases taken from medical practice which responds strikingly to linseed oil supplements (60% w3-EFA) in confirmation of identical results in Capuchins.     

The universal muscular chain reaction,muscle spasm,Torsions, ruptures and extravasations. Chameleons of pathology and some manifestations of simple muscular disorders

Most bodily functions require the coordinated actions of complementary and supplementary paired muscle groups. Where this essential muscular cooperation is lacking, hollow organs may burst and others become literally screwed up, giving rise to many similar spastic diseases such as Torticollis, Twisted ovarian cyst, Torsion of the Testis, Volvulus of the intestines, Varicose Veins, Megacolon, Aortamegaly, Scoliosis, Erb's Palsy, Peyronie's Disease, Main-en-Griffe, Undescended Foot (Pes Cavus), Talipes, Strabismus. Spasm is “panenepidemic” and unclassified examples of Torsion Dystonia and Dyskinesia really are as common as debt and taxes.     

Class II HLA in Georgia Caucasus Tbilisi Georgians and their Mediterranean ancestry: The Usko Mediterranean languages

Georgia (or Sakartvelo in its own language) is a South Caucasus Mts. country with its easternmost part is enigmatically named Iberia, like the Iberian Peninsula, which may refer to rivers “Kura” and “Ebro” or their valleys respectively. Most of their inhabitants speak Georgian which is included within Dene-Caucasian group and Usko-Mediterranean subgroup of languages. The latter includes Basque, Berber, ancient Iberian-Tartessian, Etruscan, Hittite, Minoan Lineal A and others. In the present paper, HLA class II -DRB1 and -DQB1 alleles has been studied and extended haplotypes calculated. Most frequent haplotypes are also of Mediterranean origin (i. e.: (A*02-B*51)-DRB1*11:01-DQB1*03:01, (A*02-B*51)-DRB1*13:01-DQB1*06:03, or (A*24-B*35)-DRB1*01:01-DQB1*05:01) and DA genetic distances show that closest world populations to Georgians are Mediterraneans. Georgians also show common extended haplotypes ((A*02-B*51)-DRB1*11:01-DQB1*03:01, (A*02-B*13)-DRB1*07:01-DQB1*02:01 and (A*03-B*35)-DRB1*11:01-DQB1*03:01) with Svan people, a secluded population in North Georgia mountains. We can conclude that Georgians belong to a very old Mediterranean substratum according to both linguistics (Usko Mediterranean languages) and HLA genetics.     

'Very sore nights and days': the child's experience of illness in early modern England, c.1580-1720

Sick children were ubiquitous in early modern England, and yet they have received very little attention from historians. Taking the elusive perspective of the child, this article explores the physical, emotional, and spiritual experience of illness in England between approximately 1580 and 1720. What was it like being ill and suffering pain? How did the young respond emotionally to the anticipation of death? It is argued that children’s experiences were characterised by profound ambivalence: illness could be terrifying and distressing, but also a source of emotional and spiritual fulfilment and joy. This interpretation challenges the common assumption amongst medical historians that the experiences of early modern patients were utterly miserable. It also sheds light on children’s emotional feelings for their parents, a subject often overlooked in the historiography of childhood. The primary sources used in this article include diaries, autobiographies, letters, the biographies of pious children, printed possession cases, doctors’ casebooks, and theological treatises concerning the afterlife.     

Guidelines for the Validation and Use of Immunoassays for Determination of Introduced Proteins in Biotechnology Enhanced Crops and Derived Food Ingredients

Recent advancements in agricultural biotechnology have created a need for analytical techniques to determine introduced proteins in crops enhanced through modern biotechnology techniques. These proteins are expressed in plant tissues and may be present in food ingredients. Immunoassays are ideally suited for protein detection and may be used as both quantitative and threshold methods. Microplate ELISA and lateral flow devices are two of the most commonly used immunoassay formats for agricultural biotechnology applications. This paper provides general background information and a discussion of criteria for the validation and application of immunochemical methods to the analysis of proteins introduced into plants and food ingredients using biotechnology methods. It is the result of a collaborative effort of members of the Analytical Environmental Immunochemical Consortium. This collaborative effort represents the combined expertise of several organizations to reach consensus on establishing guidelines for the validation and use of immunoassays. Further, the paper offers developers and users a consistent approach to adopting the technology as well as aid in producing accurate and meaningful results.     

Ultracryotomy: development and application (with examples from the yeast cytology) (author's transl)

The preparation steps usually necessary for obtaining ultrathin frozen sections of biological material (chemical prefixation, enclosing, cryoprotective treatment, freezing, sectioning, and post-staining the sections for transmission electron microscopy) are submitted to a critical analysis. The application of cryo-ultramicrotomy, in particularly for cytochemical purposes, is reviewed. Fundamental considerations of chemical prefixation and poststaining are supported by examples from yeast cytology. Furthermore, the efficiency of the cryo-ultramicrotomy (electron optical resolution of ultrastructural details) is demonstrated on yeast cells and protoplasts.