arXiv: Medical Physics最新文献_第7页

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

arXiv: Medical Physics Pub Date : 2011-05-24 DOI: 10.21236/ada554690

A. Courtney, M. Courtney

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

arXiv: Medical Physics Pub Date : 2011-02-16 DOI: 10.4236/IJMPCERO.2013.24020

W. Ulmer

{"title":"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","authors":"W. Ulmer","doi":"10.4236/IJMPCERO.2013.24020","DOIUrl":"https://doi.org/10.4236/IJMPCERO.2013.24020","url":null,"abstract":"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.","PeriodicalId":8462,"journal":{"name":"arXiv: Medical Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83004084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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

arXiv: Medical Physics Pub Date : 2011-02-09 DOI: 10.1063/1.4740222

K. Ocegueda, S. Hidalgo, S. Solis, A. Rodriguez

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

arXiv: Medical Physics 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

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

arXiv: Medical Physics Pub Date : 2010-01-06 DOI: 10.1142/9789814307529_0103

S. Braccini, A. Ereditato, I. Kreslo, U. Moser, C. Pistillo, P. Scampoli, S. Studer

{"title":"Nuclear Emulsion Film Detectors for Proton Radiography: Design and Test of the First Prototype","authors":"S. Braccini, A. Ereditato, I. Kreslo, U. Moser, C. Pistillo, P. Scampoli, S. Studer","doi":"10.1142/9789814307529_0103","DOIUrl":"https://doi.org/10.1142/9789814307529_0103","url":null,"abstract":"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.","PeriodicalId":8462,"journal":{"name":"arXiv: Medical Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80999831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Scientific and Technological Development of Hadrontherapy 强龙疗法的科技发展

arXiv: Medical Physics Pub Date : 2010-01-06 DOI: 10.1142/9789814307529_0099

S. Braccini

{"title":"Scientific and Technological Development of Hadrontherapy","authors":"S. Braccini","doi":"10.1142/9789814307529_0099","DOIUrl":"https://doi.org/10.1142/9789814307529_0099","url":null,"abstract":"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.","PeriodicalId":8462,"journal":{"name":"arXiv: Medical Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72676589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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

arXiv: Medical Physics Pub Date : 2009-09-07 DOI: 10.1051/DYMAT/2009125

S. Laporte, F. David, V. Bousson, S. Pattofatto

{"title":"Dynamic behavior and microstructural properties of cancellous bone","authors":"S. Laporte, F. David, V. Bousson, S. Pattofatto","doi":"10.1051/DYMAT/2009125","DOIUrl":"https://doi.org/10.1051/DYMAT/2009125","url":null,"abstract":"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.","PeriodicalId":8462,"journal":{"name":"arXiv: Medical Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74583458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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

arXiv: Medical Physics 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

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

arXiv: Medical Physics Pub Date : 2008-10-09 DOI: 10.1063/1.3043725

M. Freire, R. Marqués, L. Jelínek

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

arXiv: Medical Physics 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

{"title":"Radiotherapy using a laser proton accelerator","authors":"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","doi":"10.1063/1.2958203","DOIUrl":"https://doi.org/10.1063/1.2958203","url":null,"abstract":"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.","PeriodicalId":8462,"journal":{"name":"arXiv: Medical Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88811626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 33