共查询到20条相似文献,搜索用时 62 毫秒
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西方国家的临床试验表明:高强度聚焦超声(HIFU)能够杀死癌细胞,但很少有HIFU被应用于临床。在澳大利亚、日本和法国,临床应用也只局限于前列腺癌。然而,从1998~2002年,中国应用HIFU技术已经成功地治疗了10000多个癌症患者。这些患者有骨癌、肝癌、胰腺癌、皮肤癌等。目前,至少有三家厂商生产HIFU设备(有些已出口)。2002年8月,西雅图时报以“中国在HIFU方面的医疗优势”为题,介绍了第二届国际医疗超声研讨会(ISTU2),从中得出的结论是:“不要害怕气泡”。 相似文献
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高强度聚焦超声(High Intensity Focused Ultrasound,HIFU)消融实体肿瘤已在临床治疗中展示出良好的应用前景。HIFU消融肿瘤技术由于其使靶区肿瘤组织瞬时升温至60℃以上,产生不可逆性凝固性坏死,同时不影响靶区外正常组织而被广泛应用。目前治疗用超声主要使用单频率高强度聚焦超声,但其临床应用的主要限制是靶区组织消融时间较长,靶区外正常组织损伤风险较大。缩短靶区组织消融时间,对于提高HIFU治疗效率,更好地应用于临床较为关键。在总结HIFU换能器的特性和影响HIFU治疗因素的基础上,综述了应用不同类型的双频HIFU换能器强空化和缩短靶区组织消融时间等方面的研究进展。 相似文献
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目的:探讨高强度聚焦超声(High-Intensity Focused Ultrasound,HIFU)联合全氟戊烷液滴(Perfluoropentane droplets,PFP),对小鼠乳腺癌4T1细胞治疗的增效作用。方法:制备PFP,检测其平均粒径及形态结构。试验设立三组:HIFU假照组,单纯HIFU治疗组,HIFU联合PFP治疗组。流式细胞仪检测HIFU分组治疗乳腺癌细胞后细胞存活率及死亡率;体内动物试验分组处理后,二维超声观察HIFU辐照前后肿瘤回声灰度变化情况,超声造影剂灌注缺损面积占总面积百分比评价不同治疗方式对裸鼠皮下移植瘤的消融能力。结果:所制备的PFP平均粒径为1.2μm,形态呈规则球形。细胞试验显示,HIFU联合PFP治疗组乳腺癌细胞死亡率(23.50±1.34)%显著高于单纯HIFU治疗组(14.34±0.55)%和HIFU假照组(11.76±0.62)%(P<0.05);动物试验显示HIFU联合PFP治疗组肿瘤消融面积占总面积百分比(84.03±4.47)%显著高于单纯HIFU治疗组(41.23±4.24)%(P<0.05),HIFU假照组无明显灌注缺损区域。结论:HIFU联合PFP可显著增强对乳腺癌细胞及组织的消融能力。 相似文献
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A cylindrical-section ultrasound phased-array applicator for hyperthermia cancer therapy 总被引:2,自引:0,他引:2
Ebbini ES Umemura SI Ibbini M Cain CA 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1988,35(5):561-572
A phased-array applicator geometry for deep localized hyperthermia is presented. The array consists of rectangular transducer elements forming a section of a cylinder that conforms to the body portals in the abdominal and pelvic regions. Focusing and scanning properties of the cylindrical-section array are investigated in homogeneous lossy media using appropriate computer simulations. The characteristic focus of this array is shown to be spatially limited in both transverse and longitudinal directions with intensity gain values suitable for deep hyperthermia applications. The ability of the cylindrical-section phased array to generate multiple foci using the field conjugation method is examined. The effect of the grating lobes on the power deposition pattern of the scanned field is shown to be minimal. Steady-state temperature distributions are simulated using a three-dimensional thermal model of the normal tissue layers surrounding a tumor of typical volume. The advantages and the limitations of this array configuration are discussed. 相似文献
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Xu Z Raghavan M Hall TL Mycek MA Fowlkes JB 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2008,55(5):1122-1132
Mechanical tissue fractionation can be achieved using successive, high-intensity ultrasound pulses in a process termed histotripsy. Histotripsy has many potential clinical applications where noninvasive tissue removal is desired. The primary mechanism for histotripsy is believed to be cavitation. Using fast-gated imaging, this paper studies the evolution of a cavitating bubble cloud induced by a histotripsy pulse (10 and 14 cycles) at peak negative pressures exceeding 21MPa. Bubble clouds are generated inside a gelatin phantom and at a tissue-water interface, representing two situations encountered clinically. In both environments, the imaging results show that the bubble clouds share the same evolutionary trend. The bubble cloud and individual bubbles in the cloud were generated by the first cycle of the pulse, grew with each cycle during the pulse, and continued to grow and collapsed several hundred microseconds after the pulse. For example, the bubbles started under 10 microm, grew to 50 microm during the pulse, and continued to grow 100 microm after the pulse. The results also suggest that the bubble clouds generated in the two environments differ in growth and collapse duration, void fraction, shape, and size. This study furthers our understanding of the dynamics of bubble clouds induced by histotripsy. 相似文献
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McGough RJ Cindric D Samulski TV 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2001,48(2):494-505
A conformal ultrasound phased array prototype with 96 elements was previously calibrated for electronic steering and focusing in a water tank. The procedure for calibrating the shape of this 2D therapy array consists of two steps. First, a least squares triangulation algorithm determines the element coordinates from a 21×21 grid of time delays. The triangulation algorithm also requires temperature measurements to compensate for variations in the speed of sound. Second, a Rayleigh-Sommerfeld formulation of the acoustic radiation integral is aligned to a second grid of measured pressure amplitudes in a least squares sense. This shape calibration procedure, which is applicable to a wide variety of ultrasound phased arrays, was tested on a square array panel consisting of 7-×7-mm elements operating at 617 kHz. The simulated fields generated by an array of 96 equivalent elements are consistent with the measured data, even in the fine structure away from the primary focus and sidelobes. These two calibration steps are sufficient for the simulation model to predict successfully the pressure field generated by this conformal ultrasound phased array prototype 相似文献
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Chopra R Luginbuhl C Foster FS Bronskill MJ 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2003,50(7):881-889
Control over the pattern of thermal damage generated by interstitial ultrasound heating applicators can be enhanced by changing the ultrasound frequency during heating. The ability to change transmission frequency from a single transducer through the use of high impedance front layers was investigated in this study. The transmission spectrum of multifrequency transducers was calculated using the KLM equivalent circuit model and verified with experimental measurements on prototype transducers. The addition of a quarter-wavelength thick PZT (unpoled) front layer enabled the transmission of ultrasound at two discrete frequencies, 4.7 and 9.7 MHz, from a transducer with an original resonant frequency of 8.4 MHz. Three frequency transmission at 3.3, 8.4, and 10.8 MHz was possible for a transducer with a half-wavelength thick front layer. Calculations of the predicted thermal lesion size at each transmission frequency indicated that the depth of thermal lesion could be varied by a factor of 1.6 for the quarter-wavelength front layer. Heating experiments performed in excised liver tissue with a dual-frequency applicator confirmed this ability to control the shape of thermal lesions during heating to generate a desired geometry. Practical interstitial Designs that enable the generation of shaped thermal lesions are feasible. 相似文献
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Fudan Dong Qikun Jiang Lingxiao Li Tian Liu Shiyi Zuo Lin Gao Mengna Fang Yanlin Gao Bingjun Sun Cong Luo Zhonggui He Jin Sun 《Nano Research》2022,(4):3422-3433
Mitochondrial bioenergy plays a vital role in the occurrence and development of cancer.Although strategies to impede mitochondrial energy supply have been rapid... 相似文献
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The presence of kidney stone in the kidney causes discomfort to patients. Hence, removal of such stones is important which
is commonly done these days, non-destructively, with lithotripters without surgery. Commercially, lithotripters like extra-corporeal
shock wave lithotripters (ESWL) made by Siemens etc are in routine use. These methods are very cumbersome and expensive. Treatment
of the patients also takes comparatively more time because of more number of sittings. Some delicate nerves and fibres in
the surrounding areas of the stones present in the kidney are also damaged by high ultrasonic intensity used in such systems.
In the present work, enhancement of the kidney stone fragmentation by using ultrasound is studied. The cavitation bubbles
are found to implode faster, with more disintegration efficiency of the lithotripters, which give better treatment to the
patients. 相似文献
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The use of ultrasound and micelles in cancer treatment 总被引:1,自引:0,他引:1
The high toxicity of potent chemotherapeutic drugs like Doxorubicin (Dox) limits the therapeutic window in which they can be applied. This window can be expanded by controlling the drug delivery in both space and time such that non-targeted tissues are not adversely affected. Recent research has shown that ultrasound (US) can be used to control the release of Dox and other hydrophobic drugs from polymeric micelles in both time and space. It has also been shown using an in vivo rat tumor model that Dox activity can be enhanced by ultrasound in one region, while in an adjacent region there is little or no effect of the drug. In this article, we review the in vivo and in vitro research being conducted in the area of using ultrasound to enhance and target micellar drug delivery to cancerous tissues. Additionally, we summarize our previously published mathematical models that attempt to represent the release and re-encapsulation phenomena of Dox from Pluronic P105 micelles upon the application of ultrasound. The potential benefits of such controlled chemotherapy compels a thorough investigation of the role of ultrasound (US) and the mechanisms by which US accomplishes drug release and/or enhances drug potency. Therefore we will summarize our findings related to the mechanism involved in acoustically activated micellar drug delivery to tumors. 相似文献