超声场中振荡微泡对血管壁的生物力学效应
作者:
刘文一;胡继文;刘亚涛;雷卫瑞;陈学坤
期刊:
井冈山大学学报(自然科学版) ,2021年42(01):14-19 ISSN:1674-8085
作者机构:
南华大学数理学院,湖南,衡阳 421001;[胡继文; 陈学坤; 刘文一; 刘亚涛; 雷卫瑞] 南华大学
关键词:
超声;微泡;微血管;应力;有限元法质
摘要:
血管内受束微泡振荡所产生的生物力学效应在靶向药物传递、开放血脑屏障等具有重要的医学应用。本文从生物力学角度,创建了一个气泡-流体-固体耦合动力学模型,利用有限元法,研究超声场中振荡微泡与血管壁的相互作用,得到不同超声频率、血管尺度及不同初始半径微泡对血管壁的应力及应变分布。结果表明:频率1.0~1.5MHz时,血管壁应力随频率增大而降低;1.5~2.0MHz时,应力随频率经历半个正弦波形的变化,2.0 MHz之后不同初始半径微泡对血管壁的应力趋向一个相等的稳定值;当频率和初始微泡确定时,血管壁应力随血管半径先增大后变小,血管越厚,其应力和振动幅值都相应变小。三种不同初始半径微泡在不同血管半径中能产生有相应的应力极大值,其中较小初始半径微泡应力最大。本模型可用于计算不同声参数、血管尺度及不同初始微泡半径时的生物力学效应,为血管损伤评估提供参考。
语种:
中文
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Numerical evaluation of high-intensity focused ultrasound- induced thermal lesions in atherosclerotic plaques
作者:
Lei, Weirui;Hu, Jiwen* ;Liu, Yatao;Liu, Wenyi;Chen, Xuekun
期刊:
MATHEMATICAL BIOSCIENCES AND ENGINEERING ,2021年18(2):1154-1168 ISSN:1547-1063
通讯作者:
Hu, Jiwen
作者机构:
[Chen, Xuekun; Liu, Yatao; Hu, Jiwen; Liu, Wenyi; Lei, Weirui] Univ South China, Coll Math & Phys, Hengyang 421001, Peoples R China.
通讯机构:
[Hu, Jiwen] U;Univ South China, Coll Math & Phys, Hengyang 421001, Peoples R China.
关键词:
Ablation;Noninvasive medical procedures;Ultrasonics;Acoustic parameters;Atherosclerotic plaque;Computational model;Cylindrical coordinates;Finite-element approach;High intensity focused ultrasound;Non-invasive treatment;Temperature elevation;Integral equations;acoustics;atherosclerotic plaque;diagnostic imaging;high intensity focused ultrasound;human;Acoustics;High-Intensity Focused Ultrasound Ablation;Humans;Plaque, Atherosclerotic
摘要:
The aim of this study is to estimate the effects of some acoustic parameters on thermal lesions of atherosclerotic plaques in high-intensity focused ultrasound (HIFU) fields. A fluid-solid thermal coupling model is presented for describing the temperature elevation and thermal ablation of atherosclerotic plaque. A finite element approach is used to solve the coupling equations in cylindrical coordinates. The model considers the effect of the wall thickness of large arteries. The extent of the tissue lesion is determined by the accumulated thermal lesion with Arrhenius integral equation at each location. The results show the lesion size of atherosclerotic plaque is positively correlated to the excited frequency and acoustic output power with heating time. The computational model indicates HIFU may present a novel option for thermal ablation of atherosclerotic plaques with a completely non-invasive treatment paradigm. © 2021 the Author(s), licensee AIMS Press. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0)
语种:
英文
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动脉粥样硬化斑块在血流作用下的应力分析
作者:
王练妹;胡继文;雷卫瑞;陈学坤
期刊:
井冈山大学学报(自然科学版) ,2020年41(1):16-20 ISSN:1674-8085
作者机构:
南华大学数理学院,湖南,衡阳 421001;[胡继文; 陈学坤; 王练妹; 雷卫瑞] 南华大学
关键词:
动脉粥样硬化斑块;应力;失稳破裂;有限元法
摘要:
分析血流作用下动脉硬化斑块的应力分布,对动脉粥样硬化斑块失稳破裂的风险评估有重要理论和实际意义。本文基于有限元法,从生物力学角度,对几种常见的动脉粥样硬化斑块模型在血流作用下的应力分布进行数值计算。结果表明:斑块肩部所受应力最大,相应的应力矩最大,其次是沿斑块两肩部连线方向具有较大的应力分布;在大小不同的连带体斑块中,前部小斑块所受应力相对较大。本文模型能较好地解析血管内因动脉粥样硬化斑块的大破裂、形成继发性血栓、爆发急性心肌梗死和脑卒中等心脑血管疾病现象,可为动脉硬化斑块的不稳定性及可能的破裂提供预测。
语种:
中文
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Dynamics of an ultrasound contrast agent microbubble near spherical boundary in ultrasound field
作者:
Hu, Ji-Wen;Wang, Lian-Mei;Qian, Sheng-You* ;Liu, Wen-Yi;Liu, Ya-Tao;...
期刊:
中国物理B ,2019年28(11):114301 ISSN:1674-1056
通讯作者:
Qian, Sheng-You
作者机构:
[Liu, Wen-Yi; Lei, Wei-Rui; Wang, Lian-Mei; Liu, Ya-Tao; Hu, Ji-Wen] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;[Qian, Sheng-You; Hu, Ji-Wen] Hunan Normal Univ, Sch Phys & Elect, Changsha 410081, Hunan, Peoples R China.
通讯机构:
[Qian, Sheng-You] H;Hunan Normal Univ, Sch Phys & Elect, Changsha 410081, Hunan, Peoples R China.
关键词:
ultrasound contrast agent (UCA) microbubble;spherical boundary;ultrasound;natural frequency
摘要:
The goal of this article is to establish the conditions of excitation where one has to deal with ultrasound contrast agent (UCA) microbubbles pulsating near biological tissues with spherical boundary in ultrasound field for targeted drug delivery and cavitation-enhanced thrombolysis, etc., and contributes to understanding of mechanisms at play in such an interaction. A modified model is presented for describing microbubble dynamics near a spherical boundary (including convex boundary and concave boundary) with an arbitrary-sized aperture angle. The novelty of the model is such that an oscillating microbubble is influenced by an additional pressure produced by the sound reflection from the boundary wall. It is found that the amplitude of microbubble oscillation is positively correlated to the curve radius of the wall and negatively correlated to the aperture angle of the wall and the sound reflection coefficient. Moreover, the natural frequency of the microbubble oscillation for such a compliable wall increases with the wall compliance, but decreases with the reduction of the wall size, indicating distinct increase of the natural frequency compared to a common rigid wall. The proposed model may allow obtaining accurate information on the radiation force and signals that may be used to advantage in related as drug delivery and contrast agent imaging. © 2019 Chinese Physical Society and IOP Publishing Ltd.
语种:
英文
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超声场中凹球面内受束微泡的动力学行为研究
作者:
胡继文;孙佳娜
期刊:
系统仿真学报 ,2018年30(3):880-885 ISSN:1004-731X
作者机构:
[胡继文; 孙佳娜] 南华大学数理学院, 湖南, 衡阳, 421001
关键词:
超声造影剂微泡;超声;凹球面;动力学响应
摘要:
超声场中利用超声造影剂微泡UCA(ultrasound contrast agent)与凹球面间的相互作用来了解微泡在血管壁附近的声响应。基于“虚像法”及壁面的声反射效应,建立了一个UCA微泡在凹球形面内的动力学模型,通过数值计算分析了受束微泡的动力学行为。结果表明:在壁面附近时微泡振动受到压制,且刚性壁面对微泡振动的抑制比柔性壁面强;凹球面半径越小,或凹球面中心角越大,微泡振动越易受到抑制;在完全封闭球面内,球面半径越大,对微泡振动影响越弱。该模型为理解超声微泡在血管内的动力学响应及其在超声影像和药物传递中的应用提供理论参考。
语种:
中文
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Tunable thermal rectification in graphene/hexagonal boron nitride hybrid structures
作者:
Chen, Xue-Kun* ;Hu, Ji-Wen;Wu, Xi-Jun;Jia, Peng;Peng, Zhi-Hua;...
期刊:
Journal of Physics D: Applied Physics ,2018年51(8):085103 ISSN:0022-3727
通讯作者:
Chen, Xue-Kun
作者机构:
[Wu, Xi-Jun; Peng, Zhi-Hua; Chen, Xue-Kun; Jia, Peng; Hu, Ji-Wen] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;[Chen, Ke-Qiu] Hunan Univ, Sch Phys & Elect, Dept Appl Phys, Changsha 410082, Hunan, Peoples R China.;[Chen, Ke-Qiu] Synerget Innovat Ctr Quantum Effects & Applicat H, Changsha 410081, Hunan, Peoples R China.
通讯机构:
[Chen, Xue-Kun] U;Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.
关键词:
Graphene;Hybrid materials;Molecular dynamics;Nitrides;Phonons;Temperature;Hybrid nanostructures;Low frequency regions;Negative temperatures;Non equilibrium molecular dynamic (NEMD);Phonon resonance;Structural diversity;Substrate interaction;thermal rectification;Boron nitride
摘要:
Using non-equilibrium molecular dynamics simulations, we investigate thermal rectification (TR) in graphene/hexagonal boron nitride (h-BN) hybrid structures. Two different structural models, partially substituting graphene into h-BN (CBN) and partially substituting h-BN into graphene (BNC), are considered. It is found that CBN has a significant TR effect while that of BNC is very weak. The observed TR phenomenon can be attributed to the resonance effect between out-of-plane phonons of graphene and h-BN domains in the low-frequency region under negative temperature bias. In addition, the influences of ambient temperature, system size, defect number and substrate interaction are also studied to obtain the optimum conditions for TR. More importantly, the TR ratio could be effectively tuned through chemical and structural diversity. A moderate C/BN ratio and parallel arrangement are found to enhance the TR ratio. Detailed phonon spectra analyses are conducted to understand the thermal transport behavior. This work extends hybrid engineering to 2D materials for achieving TR. © 2018 IOP Publishing Ltd.
语种:
英文
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超声造影剂对生物壁面的声孔效应研究
作者:
孙佳娜;胡继文
期刊:
黑龙江科学 ,2016年7(24):18-21,56 ISSN:1674-8646
作者机构:
南华大学数理学院,湖南 衡阳,421001;[胡继文; 孙佳娜] 南华大学
关键词:
超声造影剂;生物壁面;声孔效应概率
摘要:
超声协同微泡对生物壁面的声孔效应在靶向药物治疗等医疗领域受到普遍关注。通过超声造影剂与生物壁面间的相互作用了解声孔效应发生的概率。为此构建了单个造影剂微泡对生物壁面产生声孔效应的概率模型,并利用微泡振荡时在生物壁面的声反射效应,分析壁面的声反射系数及其激励频率等对于声孔效应的影响。数值模拟表明:造影剂微泡振荡时的声孔效应在弹性壁面发生的概率大于刚性壁面;声孔效应发生概率随超声频率在经历两个峰值后而逐渐趋向于零。该模型在评估生物壁面细胞的损伤及利用超声微泡在药物/基因传输的应用可提供理论参考。
语种:
中文
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Pt/TiO2/Nb:SrTiO3/Pt器件的记忆效应
作者:
胡苹;彭志华;胡继文
期刊:
天津理工大学学报 ,2016年32(1):44-48 ISSN:1673-095X
作者机构:
南华大学数理学院,湖南衡阳,421001;[胡继文; 彭志华; 胡苹] 南华大学
关键词:
阻变存储;负电容;双极性;氧空位
摘要:
本文以Pt/TiO2/Nb:SrTiO3/Pt为研究对象,研究了此种器件的阻变存储效应和容变存储效应.所研究的器件表现出明显的双极多态存储性能,同时也具备负电容的特性.在正、反向偏压的作用下,器件能够实现从导通状态到绝缘态或者其他程度的导通态的转变.不仅如此,该器件还表现出与初始状态关联的负电容特性.产生这些现象的原因可认为是氧空位在外加电场的驱动下移动造成的,从而使得器件的导电状态发生变化,同时也使得电荷变化滞后于电压的变化,产生了负电容现象.
语种:
中文
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留学生课堂教学改革探究——以《医用物理》为例
作者:
胡苹;彭志华;郭萍;胡继文
期刊:
学周刊 ,2015年(33):4-4 ISSN:1673-9132
作者机构:
南华大学数理学院 421001;[胡继文; 彭志华; 胡苹; 郭萍] 南华大学
关键词:
留学生;临床医学;教学质量改革
摘要:
本文以本校临床医学专业的留学生《医用物理》课堂教学为对象,分析目前国内外留学生教育的现状,对比本校的留学生教育实际情况,论述如何进行留学生教学与管理,探讨专业基础课程的教学改革方式,以提高留学生教育教学质量,这有利于推动我校教育国际化的进程。
语种:
中文
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声压加权法在平面相控阵声聚焦控制中的应用
作者:
胡继文;孙佳娜;张亚楠;贾鹏;吕云宾
期刊:
南华大学学报(自然科学版) ,2015年(3):60-63 ISSN:1673-0062
作者机构:
南华大学 数理学院,湖南 衡阳,421001;[胡继文; 张亚楠; 孙佳娜; 吕云宾; 贾鹏] 南华大学
关键词:
声压加权法;平面相控阵;声聚焦
摘要:
通过对被控点声压进行幅值和相位补偿,得到了一个简化的声压加权公式。应用该公式预设被控点声压值,结合改进的伪逆矩阵算法得到振源的振幅和相位。基于该合成模式,设计了一个由10×10个小正方形阵元构成的平面相控阵,并对多焦点声场的合成进行了数值仿真。结果表明,该方法可提高声能在目标点的沉积能力,具有较高的声场合成效率,为超声热疗中声聚焦控制提供了一条有效的途径。
语种:
中文
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研究生教育课程高等量子力学教学改革
作者:
胡苹;彭志华;郭萍;胡继文
期刊:
科教导刊 ,2015年(07):34,47 ISSN:1674-6813
作者机构:
南华大学数理学院 湖南·衡阳 421001;[胡继文; 彭志华; 胡苹; 郭萍] 南华大学
关键词:
量子力学;教学改革;创新能力;研究性教学
摘要:
研究生阶段既是知识深化的学习过程,也是科研能力培养的过程,学习知识为科学研究打下基础。本文从现阶段研究生授课模式存在的问题出发,探讨了高校研究生高等量子力学教学的必要性,在教学过程中引入研究性教学模式,提高教学质量,使学生在掌握量子力学基本原理的基础上,综合素质能力、科研创新能力得到极大的提高。
语种:
中文
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“卓越医生教育培养计划”背景下医用物理学的教学改革
作者:
吴喜军;彭志华;胡继文;贾鹏;杜丹;...
期刊:
科教文汇(下旬刊) ,2015年(24):38-39 ISSN:1672-7894
作者机构:
南华大学数理学院 湖南·衡阳 421001;[胡继文; 彭志华; 胡苹; 吴喜军; 杜丹; 吕云宾; 贾鹏] 南华大学
关键词:
医用物理学;教学改革;临床应用
摘要:
本文总结了南华大学医用物理学课程教学中存在的问题,并从教学目标、教学内容的选择、教学模式的改革、教学手段的整合、教学团队的建设、评价体系的建立等六个方面进行了探索。希望通过对"卓越医生班"与"卓越免费全科医生班"的医用物理学课程的教学改革,以点带面真正实现"老师好教、学生好学"的双赢局面,以适应学校施行"卓越医生教育培养计划"的新形势。
语种:
中文
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Microflow-induced shear stress on biomaterial wall by ultrasound-induced encapsulated microbubble oscillation
作者:
Hu Ji-Wen;Qian Sheng-You* ;Sun Jia-Na;Lu Yun-Bin;Hu Ping
期刊:
中国物理B ,2015年24(9):094301 ISSN:1674-1056
通讯作者:
Qian Sheng-You
作者机构:
[Hu Ji-Wen; Hu Ping; Sun Jia-Na; Lu Yun-Bin] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;[Hu Ji-Wen; Qian Sheng-You] Hunan Normal Univ, Sch Phys & Informat Sci, Changsha 410081, Hunan, Peoples R China.
通讯机构:
[Qian Sheng-You] H;Hunan Normal Univ, Sch Phys & Informat Sci, Changsha 410081, Hunan, Peoples R China.
关键词:
encapsulated microbubble;shear stress;sonoporation
摘要:
A model of an ultrasound-driven encapsulated microbubble (EMB) oscillation near biomaterial wall is presented and used for describing the microflow-induced shear stress on the wall by means of a numerical method. The characteristic of the model lies in the explicit treatment of different types of wall for the EMB responses. The simulation results show that the radius-time change trends obtained by our model are consistent with the existing models and experimental results. In addition, the effect of the elastic wall on the acoustic EMB response is stronger than that of the rigid wall, and the shear stress on the elastic wall is larger than that of the rigid wall. The closer the EMB to the wall, the greater the shear stress on the wall. The substantial shear stress on the wall surface occurs inside a circular zone with a radius about two-thirds of the bubble radius. This paper may be of interest in the study of potential damage mechanisms to the microvessel for drug and gene delivery due to sonoporation.
语种:
英文
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《麻醉设备学》教学中多媒体技术作用浅析
作者:
吴喜军;彭志华;贾鹏;胡继文;吕云宾
期刊:
中国科教创新导刊 ,2014年(02):177 ISSN:1673-9795
作者机构:
南华大学数理学院 湖南衡阳 421001;[胡继文; 彭志华; 吴喜军; 吕云宾; 贾鹏] 南华大学
关键词:
多媒体技术;《麻醉设备学》;临床实践
摘要:
南华大学物理教研室在充分调研麻醉专生学生培养方案与培养目标的基础上,结合《麻醉设备学》课程的教学特点,探讨了多媒体技术在《麻醉设备学》教学中的地位、作用及注意事项.以实现多媒体技术更好地藏务于教与学的过程.
语种:
中文
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Simulations of adaptive temperature control with self-focused hyperthermia system for tumor treatment
作者:
Hu, Jiwen;Ding, Yajun;Qian, Shengyou* ;Tang, Xiangde
期刊:
Ultrasonics ,2013年53(1):171-177 ISSN:0041-624X
通讯作者:
Qian, Shengyou
作者机构:
[Qian, Shengyou; Ding, Yajun; Hu, Jiwen] Hunan Normal Univ, Coll Phys & Informat Sci, Changsha 410081, Hunan, Peoples R China.;[Hu, Jiwen] Univ S China, Coll Math & Phys, Hengyang 421001, Peoples R China.;[Tang, Xiangde] Hengyang Normal Coll, Dept Math, Hengyang 421008, Peoples R China.
通讯机构:
[Qian, Shengyou] H;Hunan Normal Univ, Coll Phys & Informat Sci, Changsha 410081, Hunan, Peoples R China.
关键词:
Simulation;Temperature control;Tumor treatment;Ultrasound hyperthermia
摘要:
The control problem in ultrasound therapy is to destroy the tumor tissue while not harming the intervening healthy tissue with a desired temperature elevation. The objective of this research is to present a robust and feasible method to control the temperature distribution and the temperature elevation in treatment region within the prescribed time, which can improve the curative effect and decrease the treatment time for heating large tumor (>= 2.0 cm in diameter). An adaptive self-tuning-regulator (STR) controller has been introduced into this control method by adding a time factor with a recursive algorithm, and the speed of sound and absorption coefficient of the medium is considered as a function of temperature during heating. The presented control method is tested for a self-focused concave spherical transducer (0.5 MHz, 9 cm aperture, 8.0 cm focal length) through numerical simulations with three control temperatures of 43 degrees C, 50 degrees C and 55 degrees C. The results suggest that this control system has adaptive ability for variable parameters and has a rapid response to the temperature and acoustic power output in the prescribed time for the hyperthermia interest. There is no overshoot during temperature elevation and no oscillation after reaching the desired temperatures. It is found that the same results can be obtained for different frequencies and temperature elevations. This method can obtain an ellipsoid-shaped ablation region, which is meaningful for the treatment of large tumor. (C) 2012 Elsevier B.V. All rights reserved.
语种:
英文
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非线性超声场中医用微泡的空化预测研究
作者:
胡继文;唐祥德;陈铀;郭萍
期刊:
河南大学学报(自然科学版) ,2012年42(2):134-138+143 ISSN:1003-4978
作者机构:
南华大学数理学院,湖南衡阳,421001;衡阳师范学院数学系,湖南衡阳,421008;[胡继文; 陈铀; 郭萍] 南华大学;[唐祥德] 衡阳师范学院
关键词:
医用微泡;非线性超声场;空化预测
摘要:
以两种常见医用微泡的实验材料为计算参数,利用修正的Rayleigh-Plesset方程,对粘滞流体中不同半径的医用微泡在非线性超声波驱动下的空化行为进行了数值仿真.结果表明:一定驱动声频下,声压越大,医用微泡的空化概率越大,且向半径减小的方向移动,其空化概率受微泡材料参数影响也较大;同时,声作用周期个数越多,空化概率越大.当声作用周期个数增到一定数量时,其空化概率达到饱和.
语种:
中文
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“科学探究”与“知识建构”在有意义学习理论上的统一
作者:
吕云宾;胡继文
期刊:
大学教育 ,2012年(8):57+61 ISSN:2095-3437
作者机构:
南华大学数理学院,湖南衡阳421001
关键词:
科学探究;知识建构;教学改革
摘要:
针对探究式教学在实践中存在的不足和激进建构主义对科学教育的不良影响,提出了将两者的积极因素统一于有意义学习理论。在有意义学习过程中,通过激发学习者有意义学习心向,在科学探究中获取有潜在意义的学习材料;有潜在意义的学习材料与学习者的认知结构相互作用而实现知识的建构,科学探究与知识建构在有意义学习理论中得到了统一。
语种:
中文
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被控点声压直接加权的相控声场合成模式
作者:
胡继文;钱盛友;丁亚军
期刊:
声学学报 ,2011年36(6):626-630 ISSN:0371-0025
通讯作者:
Qian, S.(syqian@foxmail.com)
作者机构:
[钱盛友; 丁亚军; 胡继文] College of Physics and Information Science, Hunan Normal University, Changsha 410081, China;[胡继文] College of Mathematics and Physics, University of South China, Hengyang 421001, China
通讯机构:
College of Physics and Information Science, Hunan Normal University, China
关键词:
平面相控阵;合成模式;声场;声压;加权;相位补偿;矩阵算法;模式设计
摘要:
为快速高效地对相控阵声场进行优化,对伪逆算法进行了简化.通过对被控点声压进行幅值和相位补偿,得到了一个 近似的声压加权公式.应用该公式预设被控点声压值,然后运用改进的伪逆矩阵算法确定相控阵各阵元的振幅和相位,从而 得到一个直接的多焦点声场合成模式.基于该合成模式设计了一 16x16个正方形阵元构成的平面相控阵,并对多焦点声场 的合成进行了数值仿真.结果表明,该方法可提高声能在目标点的沉积能力,具有较高的声场合成效率,为超声热疗中声聚 焦控制提供了一条有效的途径. PACS 数
语种:
中文
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伪逆算法的改进及其用于相控阵激发声场的控制
作者:
胡继文;钱盛友;丁亚军
期刊:
系统仿真学报 ,2010年22(5):1111-1113+1116 ISSN:1004-731X
作者机构:
[胡继文; 钱盛友; 丁亚军] 湖南师范大学物理与信息科学学院;南华大学数理学院
关键词:
平面相控阵;伪逆算法;焦点控制;声场仿真
摘要:
相控阵作为高强度聚焦超声肿瘤治疗中备受关注的一种换能器, 运用伪逆算法可使其在媒质中产生的声场进行准确的声聚焦控制. 但目前伪逆算法中的位置控制函数表述过于复杂, 程序编译及计算时间过长. 对原伪逆算法进行了改进, 并将其用于一10×10个正方形阵元的平面相控阵在多层媒质中当肿瘤位于不同深度处时激发的声场进行了仿真. 结果表明: 利用改进的伪逆算法可对不同深度不同尺寸的肿瘤进行准确的声聚焦控制, 并使程序设计及计算时间都大为减少. 该算法为高强度聚焦超声肿瘤治疗提供了理论参考
语种:
中文
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Research on adaptive temperature control in sound field induced by self-focused concave spherical transducer
作者:
Hu, Jiwen;Qian, Shengyou* ;Ding, Yajun
期刊:
Ultrasonics ,2010年50(6):628-633 ISSN:0041-624X
通讯作者:
Qian, Shengyou
作者机构:
[Qian, Shengyou; Ding, Yajun; Hu, Jiwen] Hunan Normal Univ, Coll Phys & Informat Sci, Changsha 410081, Hunan, Peoples R China.;[Hu, Jiwen] Univ S China, Coll Math & Phys, Hengyang 421001, Peoples R China.
通讯机构:
[Qian, Shengyou] H;Hunan Normal Univ, Coll Phys & Informat Sci, Changsha 410081, Hunan, Peoples R China.
关键词:
Self-focused concave source;Temperature control;Tumor therapy
摘要:
Temperature control of hyperthermia treatments is generally implemented with multipoint feedback system comprised of phased-array transducer, which is complicated and high cost. Our simulations to the acoustic field induced by a self-focused concave spherical transducer (0.5 MHz, 9 cm aperture width, 8.0 cm focal length) show that the distribution of temperature can keep the same "cigar shape" in the focal region during ultrasound insonation. Based on the characteristic of the temperature change, a two-dimensional model of a "cigar shape" tumor is designed and tested through numerical simulation. One single-point on the border of the "cigar shape" tumor is selected as the control target and is controlled at the temperature of 43 °C by using a self-tuning regulator (STR). Considering the nonlinear effects of biological medium, an accurate state-space model obtained via the finite Fourier integral transformation to the bioheat equation is presented and used for calculating temperature. Computer simulations were performed with the perfusion rates of 2.0 kg/(m<sup>3</sup> s) and 4.5 kg/(m<sup>3</sup> s) to the different targets, it was found that the temperatures on the border of the "cigar shape" tumor can achieve the desired temperature of 43 °C by control of one single-point. A larger perfusion rate requires a higher power output to obtain the same temperature elevation under the same insonation time and needs a higher cost for compensating the energy loss carried away by blood flow after steady state. The power output increases with the controlled region while achieving the same temperature at the same time. Especially, there is no overshoot during temperature elevation and no oscillation after steady state. The simulation results demonstrate that the proposed approach may offers a way for obtaining a single-point, low-cost hyperthermia system. ©2010 Elsevier B.V. All rights reserved.
语种:
英文
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