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1.
高强度聚焦超声(HIFU)作为一种具有巨大潜力的、无损的、有效的肿瘤治疗手段,已得到普遍认同。本文介绍了所研制的HIFU治疗系统,对其关键部分高强度聚焦超声换能器的温度场特性,从理论上和实验上进行了深入的研究,并提出了超声声场的理论算法.  相似文献   

2.
姜立新  胡兵  郭倩 《声学技术》2010,29(5):503-506
目的:观察高强度聚焦超声(HIFU)治疗裸鼠胰腺癌皮下移植瘤后的超声回声及病理变化。方法:36只裸鼠在皮下接种SW1990人胰腺癌细胞,随机分成三组,HIFU组18只,假照组9只,对照组9只。治疗中记录肿瘤的回声变化,治疗后每隔四天采用超声观察肿瘤的大小及回声变化,共随访4周。HIFU治疗后于靶区取样进行光镜和电镜检查。结果:HIFU治疗2周后,HIFU组肿瘤体积都有缩小,而假照组和对照组肿瘤继续生长。镜下可见HIFU组靶区内肿瘤组织完全凝固性坏死。结论:HIFU能够有效治疗裸鼠胰腺癌皮下移植瘤,可望成为治疗晚期胰腺癌的有效方法。  相似文献   

3.
吴蓉  胡兵  姜立新 《声学技术》2004,23(Z4):79-81
目的初步探讨高强度聚焦超声对裸鼠卵巢癌皮下移植瘤治疗前后的超声和磁共振变化.方法HIFU治疗裸鼠卵巢癌模型12例,高强度聚焦超声治疗肿瘤外侧1/2,治疗前后进行超声和磁共振检查.结果(1)治疗前肿瘤组织超声表现为低回声,彩色和能量多普勒检测肿瘤内部及周边均有少许血流信号;治疗后肿瘤组织回声增强,彩色和能量多普勒检测肿瘤治疗区域内部及周边均无血流信号.(2)磁共振检查治疗区域肿瘤组织增强后未见明显强化.结论HIFU能准确破坏卵巢肿瘤,治疗过程中超声定位准确、方便,治疗后磁共振有助于评价其疗效,为临床应用提供实验依据.  相似文献   

4.
运用有限元仿真分析了生物组织声学特性对高强度聚焦超声(HIFU)焦域的影响,为HIFU治疗安全性和可靠性提供理论依据。应用超声传播方程以及频域有限元算法(FEM)仿真HIFU治疗过程中因组织特性和厚度引起的焦域变化,并制作仿生物组织模型,进行实验验证焦域变化,分析讨论组织特性和厚度对聚焦区域、位置的影响。结果表明:随着声速增大,焦域尺寸不变,焦域向换能器一侧靠近;随着厚度增大,焦域尺寸基本不变,如果组织声速大于水的声速,则焦域向换能器一侧靠近;如果组织声速小于水的声速,则焦域向远离换能器一侧移动。  相似文献   

5.
腔内高强度聚焦超声肿瘤治疗的实验研究   总被引:3,自引:2,他引:1  
本文作者对于利用高强度聚焦超声(HIFU)进行肿瘤腔内治疗作了许多理论计算和试验工作,比较了两种换能器的聚焦特性并研制了一种既能监视又能治疗的高强度聚焦超声换能器,利用此换能器对人工模及活体肿瘤进行了一系列加热实验,验证了高强度聚焦超声治疗肿瘤的可行性。为加热治疗机的开发提供了依据。  相似文献   

6.
目的:探讨高强度聚焦超声消融滋养动脉治疗子宫肌瘤的可行性及有效性。方法:47例直径4~10cm肌壁间肌瘤,高强度聚焦超声治疗前通过彩色多普勒及超声造影确定肌瘤滋养动脉的蒂,对该区域进行消融,观察治疗前后肌瘤内部彩色多普勒及超声造影等影像学变化、随访临床症状及并发症。结果:治疗后肌瘤体积有不同程度的缩小,瘤体假包膜环状血流信号消失,肌瘤内部处于持续无灌注状态,部分患者临床症状消失或明显改善。结论:HIFU消融滋养动脉治疗子宫肌瘤能够缩短治疗时间,减少并发症,是一种微创和有效的方法。  相似文献   

7.
开口凹球面聚焦声场分析   总被引:2,自引:1,他引:1       下载免费PDF全文
高强度聚焦超声(HIFU)治疗局部肿瘤存在聚焦换能器和定位探头同时旋转的问题,考虑到实际工程中必须考虑B超探头的放置对聚焦声场的影响。文章就此进行了研究。结果表明:开口的凹球面会降低焦区声压幅度。随着开孔半径的变大。焦区声压呈下降的趋势,焦区越长,越不利于聚焦;随着开孔位置距轴线的距离变大。焦区声压呈下降的趋势,而焦区的位置变化不大,文章同时对相应的温度场也进行了相关的分析。  相似文献   

8.
陈莉  姜立新  胡兵 《声学技术》2016,35(5):430-434
目的:观察兔VX2移植性骨肿瘤经高强度聚焦超声(High Intensity Focused Ultrasound,HIFU)治疗前后超声造影的图像变化,以评价高强度聚焦超声治疗骨肿瘤的疗效。方法:将VX2瘤块植入20只兔的右侧胫骨髓腔内,三周后进行HIFU治疗。治疗前后均推注超声微泡造影剂,对肿瘤治疗前后的超声造影图像进行比较。结果:治疗前超声造影显示,右侧胫骨髓内肿瘤快速、明显强化,与周边组织分界清楚,测得病灶平均大小为,上下径(17.614±0.955)mm,前后径(10.414±1.142)mm。治疗后造影,治疗区域显示为造影剂灌注缺损区,平均范围为上下径(8.010±0.584)mm,前后径(7.540±0.499)mm,未经治疗的肿瘤组织仍有超声造影剂灌注。结论:超声造影成像清楚地显示肿瘤范围以及治疗后灌注缺损区的大小,通过反映治疗后肿瘤的血供改变来评价HIFU治疗肿瘤的疗效。  相似文献   

9.
本文通过对高强度聚焦超声治疗基本原理介绍,对HY2900聚焦超声肿瘤治疗系统实际工作几项特色专项技术HIFU声场分布参数测量、HIFU温度场测量、三维重建技术中任意方位切面图像浏览及边界轮廓的实现方法等进行讨论,介绍相关技术及方法.  相似文献   

10.
高强度聚焦超声换能器的新型设计   总被引:4,自引:1,他引:3       下载免费PDF全文
采用高强度聚焦超声(HIFU)治疗局部肿瘤,如何增强对病变区域的辐照效果,而尽量减少对健康区域的辐照损伤是一个很重要的问题。文章基于目前常用的凹球面自聚焦换能器,提出了解决上述问题的方案,设计了新型的换能器,对其工作方式及声场特性进行了研究。结果表明:采用多换能器轮流发射的方式进行治疗是一种行之有效的解决方案。  相似文献   

11.
In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.  相似文献   

12.
13.
A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.  相似文献   

14.
On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……  相似文献   

15.
Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……  相似文献   

16.
A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.  相似文献   

17.
In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M2(B,C), (W,Mo)2(B,C), M3(B,C), M23(B,C)6 type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm2. The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K1 mill housing of bar mill.  相似文献   

18.
The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...  相似文献   

19.
Several researches have been reported about the characteristic of β-Ga2O3 nanowires which was synthesized on nickel oxide particle. But indeed, recent researches about synthesis of β-Ga2O3 nanowires on oxide-assisted transition metal are limited to nickel or cobalt oxide catalyst. In this work, Gallium oxide (β-Ga2O3 ) nanowires were synthesized by a simple thermal evaporation method from gallium powder in the range of 700 - 1000℃ using the iron, nickel, copper, cobalt and zinc oxide as a catalyst, respectively. The β-Ga2O3 nanowires with single crystalline without defects were successfully synthesized at the reaction temperature of 850, 900 and 950℃ in all the catalysts. But optimum experimental condition in synthesis of nanowires varied with the kind of catalyst. As increasing synthesis temperature,the morphology of gallium oxide nanowires changed from nanowires to nanorods, and its diameter increased. From these results, we could be proposed that the growth mechanism of β-Ga2O3 nanowires was changed with synthesis temperature of nanowires. Microstructure and morphology of Synthesized nanowire was characterized by HR-TEM, FE-SEM, EDX and XRD.  相似文献   

20.
Cubic boron nitride(c-BN) film was deposited on a Si (100) substrate by the RF-magnetron sputtering.The mainly problems for fabrication of c-BN films are the low purity and high intrinsic compressive stress. In order to solve the two problems, the c-BN film with the buffer interlayer was deposited on the substrate which had been implanted with nitrogen and/or boron ions. The results show: the implantation of nitrogen ions can obviously increase c-BN content and reduce the internal stress slightly; while the implantation of boron shows no obvious improvement to the content of c-BN, which can reduce the internal stress in the film obviously. In addition, it is suggested that the implantation of nitrogen and boron shows the best result, which not only can increase the content of c-BN, but also reduce the internal stress in the c-BN film obviously.  相似文献   

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