微波天线阵列在骨肿瘤组织中产生电磁场分布的模拟与调控

目前临床上已广泛应用同轴探头及其阵列治疗骨肿瘤并取得了良好疗效。从对单天线在骨肿瘤组织中产生电磁场分布的模拟研究中发现，由单天线产生的电磁场能量往往分布于有限区域内，故只能实现对小范围肿瘤组织的治疗，当肿瘤体积较大时，则需要采用由多天线组成的天线阵列，从而实现电磁场能量在大范围肿瘤组织内的较均匀分布。本研究将针对特定的骨肿瘤模型，分析天线间距及激励相位对天线阵列在骨肿瘤组织中产生电磁场能量分布的影响。     

肿瘤微波热疗中电极的设计研究

微波热疗作为癌症的一种辅助治疗方法 ,由于其治疗效果显著 ,毒副作用低 ,近年来受到了日益广泛的重视。它既可以利用微波能量直接通过热效应杀灭癌细胞 ,也可以与化疗和放疗结合使用 ,提高癌细胞对放疗、化疗的敏感性。微波热疗研究的核心问题是 :设计合理的微波电极 ,使其产生的电磁场分布 ,能精确、均匀地加热位于身体各个部位的肿瘤组织 ,而对附近的正常组织损伤很小。一、微波热疗电极设计的一般方法由于被治疗组织一般由多种结构和电参数不同的有耗媒质组成 ,且处于热疗电极的近场区 ,直接影响电极辐射的场分布 ,无法通过解析的方法 ,…     

1639例慢性鼻炎微波治疗疗效分析

目的 探讨慢性鼻炎微波治疗的疗效。方法 使用EBC-Ⅳ型微波综合治疗仪治疗1639例慢性鼻炎患者，其中单纯性鼻炎623例，肥厚性鼻炎1016例，输出功率为40W左右，治疗时间120s，将微波辐射探头紧贴／插入肿，肥大的下鼻甲组织／内，然后用脚踏开关控制输出微波时间，使微波辐射探头周围组织凝固变白，并有一定的治疗深度，不断转换治疗部位，使肿／肥大之下鼻甲不断缩小至正常。结果 单纯性鼻炎治愈586例(占据94．06％)，肥厚性鼻炎937例(占92．24％)，单纯性鼻炎好转37例(占5．94％)，肥厚性鼻炎好转79例占(占7．76％)。结论 微波治疗不同于电凝，冷冻和激光治疗，微波治疗作用主要是热效应和非热效应，有效控制微波剂量，适当的治疗广度与深度是微波治疗疗效好坏的关键。特征：损伤部位边界清楚，无焦痂，也无即刻反应。只要在辐射场中，同一组织损伤几乎是一致的，而后三者对组织有一个热和冷的传导过程，导致组织近治疗部位损伤重远侧轻。故微波治疗鼻炎的疗效优于其他治疗。     

体外高频热疗治疗前列腺电气化切除术后尿痛的疗效观察

2005年以来我科采用HG2000体外高频热疗机（珠海市和佳医疗设备有限公司生产）治疗前列腺电气化切除术后排尿疼痛，通过应用频率为13．56MHz高频振荡电流产生高频电磁场作用人体，电磁场的能量被组织吸收转变为热量，使组织温度升高而治疗疾病，效果满意，现报告如下。     

短波、微波对离体组织作用深度的实验

目的探讨高频电不同频率对不同组织的作用深度.方法采用短波、微波对离体组织不同的模型进行加温.观察不同频率作用于组织的温升变化、不同模型加温时组织的温升变化和不同频率作用时作用深度的比较.结果对模型1加温时,短波作用下,温度最高点在皮下脂肪,微波作用下,温度最高点在浅层肌肉.对模型2加温时,在短波电场作用下浅层肌肉温度明显高于模型1.微波辐射作用时则模型1的浅层肌肉温度明显高于模型2.结论不同频率作用于组织时,微波对深部肌肉组织热作用优于短波;不同模型加温时,多层模型的能量吸收与单一内容物模型的能量吸收有重要的差别.     

微波热疗对肝组织炭化作用的实验研究

目的　研究微波热疗在肝组织中炭化形成的条件 ,趋利避害 ,扩大超声引导下微波在肝脏中的凝固范围。方法　应用MET -Ⅱ型微波治疗仪进行离体猪肝共 196个点次试验 ,检测炭化形成的功率、温度、时间、阻抗 ,观察炭化的大体及组织病理变化。结果　产生炭化的温度为 ( 170 .0± 4.6)℃ ;3 5W以下的微波辐射不发生炭化 ;3 5～ 45W发生轻微炭化 ,45W以上发生明显炭化。并进一步确定了不同功率产生炭化的微波时间 ;炭化带的阻抗为 12 0kΩ ,大于凝固区 ( 4 7kΩ)、边缘区 ( 3 2kΩ)、正常肝组织 ( 2 9kΩ)。结论　超声引导下微波热疗可以通过合理设定和反馈调控避免和减少炭化 ,扩大在肝组织中的凝固范围     

结肠镜射频治疗安全性的实验研究

目的探讨结肠镜射频治疗的组织损伤宽度、深度及安全性。方法采用射频对2条新鲜猪结肠上段和下段黏膜以不同的输出功率和不同的作用时间进行烧灼，精密直尺测量组织损伤宽度，光学显微镜观察组织损伤深度及组织学改变。并设立热探头对照组进行比较。结果射频和热探头在持续烧灼15S以内，即使以最高功率（45W，30J）输出，组织损伤深度也不超过2mm，仅达浅肌层。治疗时间设定于5S时，低功率（15和30W）射频损伤的宽度要大于低功率（10和20T）热探头损伤的宽度（P〈0．01）。结论射频和热探头用于结肠病变的内镜下治疗均是相当安全的；射频比热探头更适用于相对较大病变的内镜治疗。     

射频肿瘤热疗机的操作体会

射频肿瘤热疗机是治疗肿瘤的一项新技术,它是利用物理疗法,采用微波加热的方法,在计算机控制下,使肿瘤区域温度高于正常温度5～10℃,从而使肿瘤细胞造成热损伤,使其生长受阻,甚至凋亡的一种治疗方式,既可独立应用于治疗,也可在综合治疗中发挥增敏作用.我科2005-03引进恒埔科技HY7000型射频肿瘤热疗机,该机工作频率为40.68 MHz,采用上下、左右两对辐射器交替加热,最大输出功率1 500W.它将人体的局部(病灶区域)作为一种介质置于两个电极之间,当频率为40.68MHz的电磁场通过病灶区域时,体内的带电粒子、带电胶体和极性分子间发生碰撞、摩擦等运动,从而直接产生热,可使人体组织迅速产热.当局部聚热把肿瘤邻近正常组织加热至43℃时,正常细胞因血液循环好,将大量的热能带走,而不会损伤,但肿瘤内部血循环差,散热困难热量积聚,内部将达到48～53℃,使肿瘤细胞凋亡,达到杀死肿瘤组织的目的.     

微波子宫内膜去除术组织损伤的研究

目的 探讨微波子宫内膜去除术（MEA）中微波的不同作用方式对子宫组织损伤的程度.方法 于月经后早卵泡期分别对离体和在体子宫行MEA.设置MEA作用过程中微波探头“Z”形烧灼宫腔或“Z＋W”形烧灼宫腔,将作用后的子宫标本进行HE、尼可酰胺腺嘌呤核苷酸-黄递酶（NADH-d）染色,观察组织热损伤的改变并测量热损伤深度.结果 采用“Z”形和“Z＋W”形烧灼方法行MEA,对子宫体的组织破坏深度可达4.0～6.2 mm.“Z＋W”形烧灼的组织损伤深度明显深于“Z”形烧灼者（P＜0.05）.结论 “Z＋W”形烧灼宫腔,内膜破坏充分是适宜的MEA作用方法.     

微波治疗慢性宫颈炎260例

经本院妇科检查确诊,并经药物治疗未愈的慢性宫颈炎患者260例,均已婚,年龄27～56岁;病程2～13年;病情Ⅰ度108例,Ⅱ度84例,Ⅲ度68例。采用北京产ＷＮＺ型微波治疗仪,频率2450ＭＨｚ,输出功率0～160Ｗ可调,时间控制0～180ｓ/ｍｉｎ(手术/热疗)可调。　　于停经后3～7ｄ,患者取膀胱截石位,外阴阴道常规消毒,暴露宫颈。按仪器使用说明进行治疗操作,输出功率一般为40～50Ｗ,将辐射器(长12ｃｍ,直径0.8ｃｍ)置入阴道内,接触宫颈糜烂面稍加压,根据糜烂面大小、辐射深度选择时间约3～4ｓ,探头下方的组织凝固变白至微黄为宜,依次由内向外往复移动至正…     

Heating rabbit joint by microwave applicator

Heating the joint to high temperatures using a microwave device may inhibit metabolic activity of the synovial tissue and enable higher penetration of antiinflammatory drugs into the joint cavity. To measure the temperature distribution of local thermotherapy, the hind joints of eight rabbits were heated by a 915 MHz microwave power source, using a special applicator. Temperatures of 44.0 +/- 2.8C, 36.1 +/- 3.8C, 39.6 +/- 2.3C, and 35.2 +/- 1.5C were measured after heating in the joint cavity, cartilage, muscle, and skin, respectively. The only significant increase in the temperature was recorded in the heated joint cavity (p less than 0.01). This new microwave device can be a therapeutic tool in treating joint diseases because of its advantage of heating the target organ only, eg, synovium, while sparing the adjacent tissues.     

Experimental Methods for Improved Spatial Control of Thermal Lesions in Magnetic Resonance-Guided Focused Ultrasound Ablation

Magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU, or MRgFUS) is a hybrid technology that was developed to provide efficient and tolerable thermal ablation of targeted tumors or other pathologic tissues, while preserving the normal surrounding structures. Fast 3-D ablation strategies are feasible with the newly available phased-array HIFU transducers. However, unlike fixed heating sources for interstitial ablation (radiofrequency electrode, microwave applicator, infra-red laser applicator), HIFU uses propagating waves. Therefore, the main challenge is to avoid thermo-acoustical adverse effects, such as energy deposition at reflecting interfaces and thermal drift of the focal lesion toward the near field. We report here our investigations on some novel experimental solutions to solve, or at least to alleviate, these generally known tolerability problems in HIFU-based therapy. Online multiplanar MR thermometry was the main investigational tool extensively used in this study to identify the problems and to assess the efficacy of the tested solutions. We present an improved method to cancel the beam reflection at the exit window (i.e., tissue-to-air interface) by creating a multilayer protection, to dissipate the residual HIFU beam by bulk scattering. This study evaluates selective de-activation of transducer elements to reduce the collateral heating at bone surfaces in the far field, mainly during automatically controlled volumetric ablation. We also explore, using hybrid US/MR simultaneous imaging, the feasibility of using disruptive boiling at the focus, both as a far-field self-shielding technique and as an enhanced ablation strategy (i.e., boiling core controlled HIFU ablation).     

Catheter Ablation of the Atrioventricular Junction Using a Helical Microwave Antenna: A Novel Means of Coupling Energy to the Endocardium

Catheter ablation with either direct current defibrillator discharges or radiofrequency energy produces tissue injury via current flow from an electrode into the adjacent myocardium. In order to affect tissue at a distance, excessive power density may be produced at the electrode-tissue interface with the possibility of explosive gas formation or coagulum formation. A novel microwave catheter was developed with a helical antenna distally. This coil, although not in direct contact with the endocardium, radiates an electromagnetic field into the tissue that, in turn, causes thermal injury. The utility of this system for ablation was assessed in six dogs. The antenna catheter was introduced percutaneously and positioned so as to record the largest His electrogram. Microwave power (50 watts at 2,450 MHz) was applied for 114 +/- 118 seconds. Complete AV block was produced in all six animals with 1.8 +/- 1.2 applications. There was no ventricular ectopy or change in blood pressure during microwave ablation. One dog died 6 days after ablation. The remaining five dogs had persistent, complete AV block during 6 weeks of follow-up. Pathological analysis at 6 weeks revealed a large (mean 2.8 x 4.7 mm) fibrovascular scar in the region of the AV junction. Percutaneous microwave ablation of the endocardium appears feasible. By radiating an electromagnetic field without direct contact, this system can produce large lesions without being limited by desiccation of tissue and impedance rise.     

Acoustic field of a ballistic shock wave therapy device

Shock wave therapy (SWT) refers to the use of focused shock waves for treatment of musculoskeletal indications including plantar fascitis and dystrophic mineralization of tendons and joint capsules. Measurements were made of a SWT device that uses a ballistic source. The ballistic source consists of a handpiece within which compressed air (1-4 bar) is used to fire a projectile that strikes a metal applicator placed on the skin. The projectile generates stress waves in the applicator that transmit as pressure waves into tissue. The acoustic fields from two applicators were measured: one applicator was 15 mm in diameter and the surface slightly convex and the second was 12 mm in diameter the surface was concave. Measurements were made in a water tank and both applicators generated a similar pressure pulse consisting of a rectangular positive phase (4 micros duration and up to 8 MPa peak pressure) followed by a predominantly negative tail (duration of 20 micros and peak negative pressure of -6 MPa), with many oscillations. The rise times of the waveforms were around 1 micros and were shown to be too long for the pulses to be considered shock waves. Measurements of the field indicated that region of high pressure was restricted to the near-field (20-40 mm) of the source and was consistent with the Rayleigh distance. The measured acoustic field did not display focusing supported by calculations, which demonstrated that the radius of curvature of the concave surface was too large to effect a focusing gain. Other SWT devices use electrohydraulic, electromagnetic and piezoelectric sources that do result in focused shock waves. This difference in the acoustic fields means there is potentially a significant mechanistic difference between a ballistic source and other SWT devices.     

Endohyperthermia--experimental evaluation of a new therapeutic approach for treatment of biliary carcinoma

BACKGROUND AND STUDY AIMS: To improve the prognosis of patients with unresectable, locally advanced bile duct carcinoma, new treatment strategies need to be evaluated. Hyperthermia has been successfully applied as part of multimodal therapy in esophageal and rectal carcinoma. We performed in-vitro and in-vivo experiments with a new intraluminal hyperthermia system in the biliary tract. METHODS: A radiofrequency system (13.56 MHz, Endoradiotherm XERT-200A; Olympus Optical Co., Tokyo, Japan) was used with a special intraluminal microelectrode (diameter 4.5 mm, length 40 mm) covered by a silicone balloon with cooling water and a large counter electrode for focusing the electromagnetic field around the electrode. The heating capacity of the endohyperthermia unit was examined in vitro in a muscle-equivalent phantom (agar 4 %), in isolated livers of pigs and cows, as well as in vivo in anesthetized sheep. Continuous thermometry was done with thermosensors at the applicator surface, and with multichannel thermocouple probes in the environment of the applicator. RESULTS: Endohyperthermia induced a homogeneous heating of the phantom and the isolated liver bile duct preparation to a temperature > or = 40 degrees C in an area at least 10 mm in depth. After placement of the applicator into the common bile duct of anesthetized sheep, endohyperthermia led to a consistent and repeatable heating of the surrounding tissue to 40.5 +/- 0.5 degrees C at 1 cm distance, and 39.9 +/- 0.7 degrees C at 2 cm distance. Blood pressure, heart rate, and systemic temperature did not change in vivo. Histological examination of the bile duct showed superficial mucosal necrosis (depth 100-200 microm), microvascular damage with petechiae, congestion and edema of the bile duct wall and adventitia after hyperthermia treatment in vivo. CONCLUSIONS: The intraluminal endohyperthermia system produces consistent and repeatable heating of the surrounding tissue. Since effective thermal power can reach a depth of up to 2 cm, tumors may also be heated adequately.     

An experimental study of conductive heating using a concentric double-electrode applicator

With hyperthermia for treatment of superficial tumors in mind, a prototype applicator with two electrodes arranged concentrically on a disk was designed for efficient local heating, and a basic heating test was carried out. Frequencies as low as 200 kHz were used in order to simplify the configuration of the power device. The applicator consists of two electrodes, a circular inner electrode and another looped outer electrode, arranged concentrically. Water was passed through the applicator as a cooling mechanism; it was placed in direct contact with the target tissue to be heated and then charged with electricity. In the heating test using a phantom, oval hot spots were noted below the inner electrode. Using cooling water at 3°C and 8.2 W, an isothermal line of 45°C was located at a 5-mm radius circle around the central axis with 9 mm depth. A similar temperature distribution map was obtained in heating tests on the thigh muscle of a mongrel adult dog. The temperature distribution maps obtained from these tests corresponded closely with the results of theoretical analysis carried out according to the finite-element method. Since a comparatively low frequency was employed for this applicator the power device was simplified, which made adequate heating possible with low electric power. The temperature distribution map indicated that efficient local heating of superficial tumors could be achieved.     

低频脉冲电磁场治疗高龄骨关节疼痛效果研究

目的：探讨低频脉冲电磁场治疗老年骨关节疼痛的临床疗效。方法选取150例老年骨关节疼痛患者进行研究,并根据老年患者骨关节疼痛的病症分为三组：以骨质疏松症为主的50例为A组、以骨性关节炎为主的50例为B组、以股骨头缺血性坏死为主的50例为C组。对三组患者都采用低频脉冲电磁场进行治疗,治疗过程中采用扫描模式,频率每4分钟就需要变化1档。每周5次,每次30 min。持续治疗15次后休息1周,然后继续接受治疗。4周1疗程,所有患者均连续治疗3个疗程。观察三组患者的疼痛强度、疼痛缓解程度与临床实验室检查结果。结果三组治疗第4、12周的疼痛强度均明显低于较治疗前,差异均有统计学意义（t分别=5.58、5.23、5.15、4.79、6.23、5.33,P均＜0.05）。治疗结束后的第4周,A、B两组疼痛强度均较治疗前明显下降,差异均有统计学意义（t分别=5.13、5.87, P均＜0.05）,但C组未出现明显改变,差异无统计学意义（t=1.21,P均＞0.05）。三组患者经过12周的治疗后,A组、B组和C组总缓解率分别为90.00％、92.00％和70.00％。 A、B两组总缓解率均明显高于C组,差异均有统计学意义（χ2分别=6.12、5.79,P均＜0.05）。三组患者经过治疗后,对其生命体征与实验室检查,各指标与治疗前比较,差异均无统计学意义（t分别=0.27、2.01、1.52、2.03、1.12、1.13、3.15;1.79、2.11、3.10、3.15、0.89、1.09、1.13;0.97、0.96、1.23、1.15、2.03、2.56、2.05,P均＞0.05）。结论采用低频脉冲电磁场对不同原因所导致的骨关节疼痛老年患者进行治疗可以获得良好的效果,且安全性高。     

微波灭活建立兔股骨头坏死模型:最适宜灭活温度和作用时间的筛选

背景:理想的股骨头坏死模型是研究其病因、发病机制及治疗的基础,但到目前为止,仍无一种模型制作方法得到公认.目的:观察不同灭活温度和时间兔股骨头的坏死和修复情况,分析微波灭活建立兔股骨头坏死模型的适宜温度和时间.设计:随机对照动物实验.单位:昆明医学院动物实验中心.材料:实验于2004-09/2005-11在昆明医学院动物实验中心完成.选用健康成年新西兰大白兔48只,雌雄不拘,由昆明医学院动物实验中心提供.实验过程中对动物处置符合动物伦理学标准.微波灭活所用GW-92C型多功能微波治疗仪由格兰德医用设备(天津)有限公司生产.方法:将48只大白兔共96侧股骨头随机分为4组,每组24侧股骨头: 50℃ 10 min微波灭活组,55 ℃ 10 min微波灭活组,50℃ 20 min微波灭活组, 60 ℃ 10 min微波灭活组.应用多功能治疗仪进行微波灭活建立兔股骨头坏死模型,作用温度及时间同分组.主要观察指标:分于术后即刻,1,2,4,8和12周6个时间点进行指标观察,每个时间点2只兔(4侧股骨头).对标本及其周围组织进行大体观察.拍摄骨盆正位片,观察股骨头骨小梁排列、有无囊性变、头塌陷及髋关节破坏等.通过MRI检查,观察股骨头有无坏死及坏死范围.苏木精-伊红染色,光镜下观察股骨头标本坏死及修复情况.结果:50 ℃ 10 min微波灭活组术后1周部分骨髓组织凝固变性,术后8周时坏死骨小梁及骨髓组织完全吸收.55 ℃ 10 min微波灭活组术后1周骨髓组织凝固,术后2周时股骨头出现T1 相信号减低、T2相信号增高区;术后4周时坏死与修复同时进行,术后12周时骨修复停止,骨坏死继续,股骨头开始塌陷.50 ℃ 20 min微波灭活组、60 ℃ 10 min微波灭活组:术后8周所有股骨头塌陷变形.结论:55 ℃作用10 min微波灭活股骨头是制作兔股骨头坏死模型的适宜温度和时间.     

Deep heat therapy system with resonant cavity applicator for articular cartilage in knee osteoarthritis

[Purpose] Heat can prevent cartilage degeneration when applied to articular cartilage, but the size of the human knee joint makes it difficult to target cartilage during heat treatment. In this study, we aimed to establish a heat therapy method capable of safely applying heat to deep intra-articular tissues utilizing a resonant cavity applicator and to confirm the extent of cartilage heating in the human knee when using this system. [Participants and Methods] Heating experiments were carried out on the knees of healthy three volunteers using a resonant cavity applicator and a microwave diathermy system. After heat application, temperature distributions inside the knee were measured noninvasively using our measurement method based on ultrasound imaging techniques. [Results] We observed an increase in the temperature around the cartilage tissue in the knees of the volunteers using an ultrasonic thermometer; there was no increase in temperature in the overlying layers. During heating with up to 20 W of power, none of the volunteers experienced adverse reactions. [Conclusion] This study indicates the potential safety and effectiveness of the resonant cavity heat therapy system for knee osteoarthritis in a clinical setting.Key words: Heat therapy, Osteoarthritis, Cartilage