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Cerebrovascular injury caused by a high strain rate insult in the thorax 胸部高应变率损伤引起的脑血管损伤
Pub Date : 2011-05-24 DOI: 10.21236/ada554690
A. Courtney, M. Courtney
Abstract : Primary blast-induced traumatic brain injury (TBI) has increased in documented incidence and public prominence in recent conflicts. Evidence for a thoracic mechanism of blast-induced TBI was recently reviewed and, while the totality is compelling, data from experiments isolating this mechanism is sparse. Notably, one recent study showed pericapillar haemorrhage in brain tissue from victims of single, fatal gunshot wounds to the chest. Here, qualitative results are reported for a small field study that isolated a thoracic mechanism for TBI caused by a high strain rate insult in white-tailed deer (Odocoileus virginianus, mass 49-80 kg) in a natural environment. In each of three cases, petechiae were present on the surface of the frontal, occipital and/or left parietal lobes, along with capillary damage in the choroid plexus. The location of the projectile impact to the thorax seemed to affect the degree of damage. This may be due to the proximity to the great vessels. The data reported here provides direct evidence of a thoracic mechanism resulting in gross injury to the cerebral vasculature.
摘要:在最近的冲突中,原发性爆炸引起的创伤性脑损伤(TBI)的发生率和公众关注度都有所增加。最近回顾了爆炸引起的TBI的胸部机制的证据,虽然总体上令人信服,但从实验中分离出这种机制的数据很少。值得注意的是,最近的一项研究表明,胸部单一致命枪伤的受害者脑组织中存在毛细血管周围出血。本文报道了一项小型野外研究的定性结果,该研究分离了自然环境中白尾鹿(Odocoileus virginianus,体重49- 80kg)高应变率损伤引起的创伤性脑损伤的胸部机制。3例患者均在额叶、枕叶和/或左顶叶表面出现瘀点,并伴脉络膜丛毛细血管损伤。弹丸击中胸部的位置似乎影响了损伤程度。这可能是由于靠近大血管。本文报道的数据提供了导致脑血管系统严重损伤的胸部机制的直接证据。
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引用次数: 1
Creation of high energy/intensity bremsstrahlung by a multitarget and focusing of the scattered electrons by small-angle backscatter at a cone wall and a magnetic field II - Enhancement of the outcome of linear accelerators in radiotherapy 通过多目标产生高能量/强度轫致辐射,并通过锥形壁和磁场的小角度后向散射使散射电子聚焦II——线性加速器在放射治疗中的效果增强
Pub Date : 2011-02-16 DOI: 10.4236/IJMPCERO.2013.24020
W. Ulmer
The yield of bremsstrahlung from collisions of fast electrons (energy at least 6 MeV) with a Tungsten target can be significantly improved by exploitation of Tungsten wall scatter in a multi-layered target. A simplified version of a previously developed principle is also able to focus small angle scattered electrons by a Tungsten wall. It is necessary that the thickness of each Tungsten layer does not exceed 0.04 mm - a thickness of 0.03 mm is suitable for accelerators in medical physics. Further focusing of electrons results from suitable magnetic fields with field strength between 0.5 Tesla and 1.2 Tesla (if the cone with multi-layered targets is rather narrow). Linear accelerators in radiation therapy only need focusing by wall scatter without further magnetic fields (standard case: 31 plates with 0.03 mm thickness and 1 mm distance between the plates). We considered three cases with importance in medical physics: A very small cone with additional magnetic field for focusing (field diameter at 90 cm depth: 6cm), a medium cone with optional magnetic field (field diameter at 90 cm depth: 13 cm) and broad cone without magnetic field (field diameter at 90 cm depth: 30 cm). All these cases can be positioned in a carousel. Measurements have been performed in the existing carousel positioned in the plane of the flattening filter and scatter foils for electrons.
利用多层靶中的钨壁散射,可以显著提高快电子(能量至少6 MeV)与钨靶碰撞的轫致辐射产率。先前开发的原理的简化版本也能够通过钨壁聚焦小角度的散射电子。每层钨的厚度必须不超过0.04毫米——0.03毫米的厚度适用于医学物理学中的加速器。适当的磁场强度在0.5 - 1.2特斯拉之间(如果多层靶区的锥体很窄),可以使电子进一步聚焦。放射治疗中的直线加速器只需要通过壁散射聚焦,不需要进一步的磁场(标准情况:31块板,厚度0.03 mm,板间距离1mm)。我们考虑了在医学物理学中具有重要意义的三种情况:具有额外磁场用于聚焦的非常小的锥体(在90厘米深的场直径:6厘米),具有可选磁场的中等锥体(在90厘米深的场直径:13厘米)和没有磁场的宽锥体(在90厘米深的场直径:30厘米)。所有这些箱子都可以放在旋转木马上。测量是在现有的旋转木马上进行的,旋转木马位于电子的平坦滤波器和散射箔的平面上。
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引用次数: 1
Theoretical signal-to-noise ratio of a slotted surface coil for magnetic resonance imaging 用于磁共振成像的开槽表面线圈的理论信噪比
Pub Date : 2011-02-09 DOI: 10.1063/1.4740222
K. Ocegueda, S. Hidalgo, S. Solis, A. Rodriguez
The analytical expression for the signal-to-noise ratio of a slotted surface coil with an arbitrary number of slots was derived using the quasi-static approach. This surface coil based on the vane-type magnetron tube. To study the coil perfomance, the theoretical signal-to-noise ratio predictions of this coil design were computed using a different number of slots. Results were also compared with theoretical results obtained for a circular coil with similar dimensions. It can be appreciated that slotted surface coil performance improves as the number of coils increases and, outperformed the circular-shaped coil. This makes it a good candidate for other MRI applications involving coil array techniques.
利用准静态方法,推导了具有任意槽数的槽形表面线圈的信噪比解析表达式。这种表面线圈基于叶片式磁控管。为了研究线圈的性能,使用不同的槽数计算了该线圈设计的理论信噪比预测。结果还与相似尺寸的圆线圈的理论结果进行了比较。可以理解的是,开槽表面线圈的性能随着线圈数量的增加而提高,并且优于圆形线圈。这使其成为涉及线圈阵列技术的其他MRI应用的良好候选者。
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引用次数: 3
A method for the determination of nuclear cross sections of proton beams by the collective model and extended nuclear-shell theory 用集体模型和扩展核壳理论确定质子束核截面的方法
Pub Date : 2010-09-04 DOI: 10.1007/978-3-642-03474-9_51
W. Ulmer, E. Inc., Baden, Switzerland., M.Marsman Institute for Physical Chemistry, Gottingen, H Germany
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引用次数: 1
Nuclear Emulsion Film Detectors for Proton Radiography: Design and Test of the First Prototype 质子放射照相用核乳剂膜探测器:第一个原型的设计和测试
Pub Date : 2010-01-06 DOI: 10.1142/9789814307529_0103
S. Braccini, A. Ereditato, I. Kreslo, U. Moser, C. Pistillo, P. Scampoli, S. Studer
Proton therapy is nowadays becoming a wide spread clinical practice in cancer therapy and sophisticated treatment planning systems are routinely used to exploit at best the ballistic properties of charged particles. The information on the quality of the beams and the range of the protons is a key issue for the optimization of the treatment. For this purpose, proton radiography can be used in proton therapy to obtain direct information on the range of the protons, on the average density of the tissues for treatment planning optimization and to perform imaging with negligible dose to the patient. We propose an innovative method based on nuclear emulsion film detectors for proton radiography, a technique in which images are obtained by measuring the position and the residual range of protons passing through the patient's body. Nuclear emulsion films interleaved with tissue equivalent absorbers can be fruitfully used to reconstruct proton tracks with very high precision. The first prototype of a nuclear emulsion based detector has been conceived, constructed and tested with a therapeutic proton beam at PSI. The scanning of the emulsions has been performed at LHEP in Bern, where a fully automated microscopic scanning technology has been developed for the OPERA experiment on neutrino oscillations. After track reconstruction, the first promising experimental results have been obtained by imaging a simple phantom made of PMMA with a step of 1 cm. A second phantom with five 5 x 5 mm^2 section aluminum rods located at different distances and embedded in a PMMA structure has been also imaged. Further investigations are in progress to improve the resolution and to image more sophisticated phantoms.
质子治疗如今已成为癌症治疗中广泛应用的临床实践,复杂的治疗计划系统通常用于至多利用带电粒子的弹道特性。关于光束质量和质子范围的信息是优化治疗的关键问题。为此,质子放射照相可用于质子治疗,以获得关于质子范围的直接信息,关于组织的平均密度,以优化治疗计划,并对患者进行可忽略剂量的成像。我们提出了一种基于核乳剂膜探测器的质子放射成像的创新方法,该方法通过测量穿过患者身体的质子的位置和残余范围来获得图像。与组织等效吸收剂交织的核乳剂膜可以有效地用于重建质子轨迹,具有很高的精度。第一个原型的核乳液为基础的探测器已经构思,构造和测试与治疗质子束在PSI。在伯尔尼的LHEP上对乳剂进行了扫描,在那里,为中微子振荡的OPERA实验开发了一种全自动显微扫描技术。在轨迹重建后,通过对一个步长为1cm的简单PMMA模体进行成像,获得了第一个有希望的实验结果。第二个幻影是5个5 × 5 mm^2截面的铝棒,位于不同的距离,并嵌入在PMMA结构中,也被成像。进一步的研究正在进行中,以提高分辨率和成像更复杂的幽灵。
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引用次数: 2
Scientific and Technological Development of Hadrontherapy 强龙疗法的科技发展
Pub Date : 2010-01-06 DOI: 10.1142/9789814307529_0099
S. Braccini
Hadrontherapy is a novel technique of cancer radiation therapy which employs beams of charged hadrons, protons and carbon ions in particular. Due to their physical and radiobiological properties, they allow one to obtain a more conformal treatment with respect to photons used in conventional radiation therapy, sparing better the healthy tissues located in proximity of the tumour and allowing a higher control of the disease. Hadrontherapy is the direct application of research in high energy physics, making use of specifically conceived particle accelerators and detectors. Protons can be considered today a very important tool in clinical practice due to the several hospital-based centres in operation and to the continuously increasing number of facilities proposed worldwide. Very promising results have been obtained with carbon ion beams, especially in the treatment of specific radio resistant tumours. To optimize the use of charged hadron beams in cancer therapy, a continuous technological challenge is leading to the conception and to the development of innovative methods and instruments. The present status of hadrontherapy is reviewed together with the future scientific and technological perspectives of this discipline.
强子疗法是一种利用带电强子、质子和碳离子束进行癌症放射治疗的新技术。由于它们的物理和放射生物学特性,与传统放射治疗中使用的光子相比,它们允许人们获得更适形的治疗,更好地保留位于肿瘤附近的健康组织,并允许更好地控制疾病。强子疗法是高能物理研究的直接应用,利用专门设计的粒子加速器和探测器。如今,质子可以被认为是临床实践中非常重要的工具,因为有几个以医院为基础的中心在运作,而且世界各地拟议的设施数量不断增加。碳离子束已经获得了非常有希望的结果,特别是在治疗特定的放射抗性肿瘤方面。为了优化带电强子束在癌症治疗中的使用,一个持续的技术挑战正在导致创新方法和仪器的概念和发展。综述了强龙疗法的研究现状,并对该学科未来的科学技术前景进行了展望。
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引用次数: 8
Dynamic behavior and microstructural properties of cancellous bone 松质骨的动力学行为和微观结构特性
Pub Date : 2009-09-07 DOI: 10.1051/DYMAT/2009125
S. Laporte, F. David, V. Bousson, S. Pattofatto
The aim of the presented study is to identify some properties of the dynamic behavior of the cancellous bone and to identify the link between this mechanical behavior and the microstructural properties. 7 cylinders of bovine cancellous bone (diameter 41 mm, thickness 14 mm) were tested in quasi static loading (0.001 s-1), 8 in dynamic loading (1000 s-1) and 10 in dynamic loading (1500 s-1) with a confinement system. All the specimens were submitted to imaging before the tests (pQCT) in order to indentify two microstructural properties: Bone Volume / Total Volume ? BV/TV ? and Trabeculae Thickness ? Tb.Th. The behavior of bovine cancellous bone under compression exhibits a foam-type behavior over the whole range of strain rates explored in this study. The results show that for the quasi-static tests only the stresses are correlated with BV/TV. For the unconfined dynamic tests, the yield stress is correlated to BV/TV and the plateau stress to BV/TV and Tb.Th. For the confined tests, only the plateau stress is correlated to BV/TV and Tb.Th. The effect of strain rate is an increase of the yield stress and the plateau stress. The confinement has an effect on the measured values of compression stresses that confirms the importance of marrow flow in the overall behavior.
本研究的目的是确定松质骨的动态行为的一些特性,并确定这种力学行为和微观结构特性之间的联系。在准静态加载(0.001 s-1)、动态加载(1000 s-1)和动态加载(1500 s-1)下,采用约束系统对7根牛松质骨(直径41 mm,厚度14 mm)进行了测试。所有的标本在测试前都进行了成像(pQCT),以确定两个微观结构特性:骨体积/总体积?BV /电视吗?和小梁厚度?Tb.Th。牛松质骨在压缩下的行为在本研究中探索的应变率的整个范围内表现出泡沫型行为。结果表明,在准静态试验中,应力只与BV/TV相关。在无侧限动态试验中,屈服应力与BV/TV相关,高原应力与BV/TV和tbh相关。在密闭试验中,只有高原应力与BV/TV和tbth相关。应变速率的影响是屈服应力和平台应力的增加。约束对压缩应力的测量值有影响,证实了骨髓流动在整体行为中的重要性。
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引用次数: 8
A Mathematical Aid Decision Tool for RT Planning RT计划的数学辅助决策工具
Pub Date : 2009-06-06 DOI: 10.1007/978-3-642-03474-9_29
O. Sotolongo-Grau, D. Rodríguez-Pérez, J. Santos-Miranda, M. Desco, O. Sotolongo-Costa, J. Antoranz
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引用次数: 2
Experimental demonstration of a mu=-1 metamaterial lens for magnetic resonance imaging 磁共振成像用mu=-1超材料透镜的实验演示
Pub Date : 2008-10-09 DOI: 10.1063/1.3043725
M. Freire, R. Marqués, L. Jelínek
In this work a mu=-1 metamaterial (MM) lens for magnetic resonance imaging (MRI) is demonstrated. MRI uses surface coils to detect the radiofrequency(RF) energy absorbed and emitted by the nuclear spins in the imaged object. The proposed MM lens manipulates the RF field detected by these surface coils, so that the coil sensitivity and spatial localization is substantially improved. Beyond this specific application, we feel that the reported results are the experimental confirmation of a new concept for the manipulation of RF field in MRI, which paves the way to many other interesting applications.
在这项工作中,展示了用于磁共振成像(MRI)的mu=-1超材料(MM)透镜。MRI使用表面线圈来检测被成像物体中核自旋吸收和发射的射频(RF)能量。所提出的MM透镜对这些表面线圈检测到的射频场进行操纵,从而大大提高了线圈的灵敏度和空间定位。除了这个特定的应用之外,我们认为报告的结果是对MRI中射频场操作新概念的实验证实,这为许多其他有趣的应用铺平了道路。
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引用次数: 149
Radiotherapy using a laser proton accelerator 使用激光质子加速器进行放射治疗
Pub Date : 2008-04-24 DOI: 10.1063/1.2958203
M. Murakami, Y. Hishikawa, S. Miyajima, Y. Okazaki, K. Sutherland, M. Abe, S. V. Bulanov, H. Daido, T. Esirkepov, J. Koga, M. Yamagiwa, T. Tajima
Laser acceleration promises innovation in particle beam therapy of cancer where an ultra-compact accelerator system for cancer beam therapy can become affordable to a broad range of patients. This is not feasible without the introduction of a technology that is radically different from the conventional accelerator-based approach. The laser acceleration method provides many enhanced capabilities for the radiation oncologist. It reduces the overall system size and weight by more than one order of magnitude. The characteristics of the particle beams (protons) make them suitable for a class of therapy that might not be possible with the conventional accelerator, such as the ease for changing pulse intensity, the focus spread, the pinpointedness, and the dose delivery in general. A compact, uncluttered system allows a PET device to be located in the vicinity of the patient in concert with the compact gantry. The radiation oncologist may be able to irradiate a localized tumor by scanning with a pencil-like particle beam while ascertaining the actual dosage in the patient with an improved in-beam PET verification of auto-radioactivation induced by the beam therapy. This should yield an unprecedented flexibility in the feedback radiotherapy by the radiation oncologist. Laser accelerated radiotherapy has a unique niche in a current world of high energy accelerator using synchrotron or cyclotron.
激光加速有望在癌症的粒子束治疗中实现创新,一种用于癌症束治疗的超紧凑加速器系统可以使广大患者负担得起。如果不引入一种与传统的基于加速器的方法截然不同的技术,这是不可行的。激光加速方法为放射肿瘤学家提供了许多增强的能力。它将整个系统的尺寸和重量减少了一个数量级以上。粒子束(质子)的特性使它们适合于传统加速器无法实现的一类治疗,例如易于改变脉冲强度、焦点扩散、精确定位和剂量传递。紧凑,整洁的系统允许PET装置与紧凑的龙门架一起放置在患者附近。放射肿瘤学家可能能够通过铅笔状粒子束扫描照射局部肿瘤,同时通过改进的束内PET验证束治疗诱导的自动放射来确定患者的实际剂量。这将在放射肿瘤学家的反馈放射治疗中产生前所未有的灵活性。激光加速放射治疗在目前使用同步加速器或回旋加速器的高能加速器中具有独特的地位。
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引用次数: 33
期刊
arXiv: Medical Physics
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