Ultrasound applicators with internal water-cooling for high-powered interstitial thermal therapy.
Ultrasound applicators with internal water-cooling for high-powered interstitial thermal therapy.
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具有内部水冷功能的超声波治疗头，用于高功率间质热疗。
DOI：
10.1109/10.871409
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Diederich,CJ
中科院分区：
文献类型：
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作者：
Deardorff,DL;Diederich,CJ
研究了直接耦合超声（US）应用于间质热疗（热疗和凝固热疗）的内部水冷却。植入式涂抹器采用管状US源（360角声发射，/spl sim/7 MHz），长度为10 mm，外径为1.5、1.8、2.2和2.5 mm。定向施胶器也使用2.2 mm外径管进行扇形，提供90和200声压度的主动声波扇形。一个水冷却机构被集成在涂敷器的内腔内，以从内部换能器表面去除热量。高水平的对流换热（2100-3800 W/m/sup 2/K）测量了实际水流量为20-80 mL/min。对比声学测量表明，内部水冷并没有显著降低US换能器的声强或波束分布。与以前的设计（风冷或不冷却）相比，水冷允许更高水平的应用电力（bbbb45 W），而不会损害涂抹器。在体内（猪肝和大腿肌肉）和体外（牛肝脏）使用这些涂抹剂进行的高温加热试验表明，热渗透和凝固得到改善。应用28-W功率，超声1-5分钟，从涂抹器表面的径向凝固深度为12至20毫米。更高的功率（41 W）在更短的时间（15 s）内增加了凝血深度（/spl sim/9 mm）。用定向涂敷器产生的热损伤尺寸（角向和轴向扩展）被控制和定向，并与传感器的活跃区域相对应。这些特征病变形状也通常随超声时间和功率的不同而不变，并且发现与先前使用风冷涂抹器进行的凝血研究一致。水冷的实施是超声间质热疗法（USITT）应用的重大进步，提供了更大的治疗量，更短的治疗时间，并有可能治疗具有形状病变的高度灌注组织。
Internal water-cooling of direct-coupled ultrasound (US) applicators for interstitial thermal therapy (hyperthermia and coagulative thermal therapy) was investigated. Implantable applicators were constructed using tubular US sources (360 angular acoustic emittance, /spl sim/7 MHz) of 10 mm length and 1.5, 1.8, 2.2, and 2.5 mm outer diameter (OD). Directional applicators were also constructed using 2.2 mm OD tubes sectored to provide active acoustic sectors of 90/spl deg/ and 200/spl deg/. A water-cooling mechanism was integrated within the inner lumen of the applicator to remove heat from the inner transducer surface. High levels of convective heat transfer (2100-3800 W/m/sup 2/K) were measured for practical water flow rates of 20-80 mL/min. Comparative acoustic measurements demonstrated that internal water-cooling did not significantly degrade the acoustic intensity or beam distribution of the US transducers. Water-cooling allowed substantially higher levels of applied electrical power (>45 W) than previous designs (with air-cooling or no cooling), without detriment to the applicators. High temperature heating trials performed with these applicators in vivo (porcine liver and thigh muscle) and in vitro (bovine liver) showed improved thermal penetration and coagulation. Radial depth of coagulation from the applicator surface ranged from 12 to 20 mm for 1-5 min of sonication with 28-W applied power. Higher powers (41 W) demonstrated increased coagulation depths (/spl sim/9 mm) at shorter times (15 s). Thermal lesion dimensions (angular and axial expanse) produced with directional applicators were controlled and directed, and corresponded to the active zone of the transducer. These characteristic lesion shapes were also generally unchanged with different sonication times and power, and were found to be consistent with previous coagulation studies using air-cooled applicators. The implementation of water-cooling is a significant advance for the application of ultrasound interstitial thermal therapy (USITT), providing greater treatment volumes, shorter treatment times, and the potential for treatment of highly perfused tissue with shaped lesions.