Control of interstitial thermal coagulation: Comparative evaluation of microwave and ultrasound applicators
Control of interstitial thermal coagulation: Comparative evaluation of microwave and ultrasound applicators
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DOI：
10.1118/1.1334606
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发表时间：
2001-01-01
期刊：
影响因子：
3.8
通讯作者：
Nau, WH
中科院分区：
文献类型：
--
作者：
Deardorff, DL;Diederich, CJ;Nau, WH
本研究介绍了微波（MW）和超声（US）间隙应用器对加热和热凝控制的比较评价。采用水冷的外置导管（直径2.2 mm）对螺旋线圈式毫瓦天线（长度为17 mm和25 mm的辐射天线）进行测试。美国管状换能器（直径2.2和2.5 mm，长度10mm，单元件和3元件）采用直接耦合配置和内部水冷却。测量电场分布（以毫瓦计）和声束分布（以美国计）来表征施加器的能量输出。在不同的加热功率（20-40 W微波，15-35 W超声）和加热时间（0.5-5 min）下，通过体外（牛肝脏）和体内（猪大腿肌肉和肝脏）的多次加热试验来评估热性能。在加热过程中记录组织的轴向温度分布，并测量热凝损伤的尺寸。MW和US涂抹器在单次加热时间为5分钟的情况下产生了8至20厘米(3)的大体积组织凝固。随着加热时间和功率水平的增加，MW和US喷雾器的病灶径向深度都增加了，尽管US喷雾器产生的病灶直径明显更大（US喷雾器30-42毫米，而MW喷雾器18-26毫米）。加热5分钟)。应用器之间的特征差异在轴向能量分布，组织温度和热病变形状观察。随着施加的功率水平和/或加热时间的增加，MW病变的轴向尺寸（超出有效涂抹器长度）显着增加，并且病变形状通常不均匀。US提供了更好的加热控制和均匀性，能量沉积和热损伤的轴向范围与主动传感器的长度相对应。美国涂抹器所证明的控制热凝程度的改进能力为靶向组织的特定区域提供了更大的潜力。(C) 2001年美国医学物理学家协会。
This study presents a comparative evaluation of the control of heating and thermal coagulation with microwave (MW) and ultrasound (US) interstitial applicators. Helical coil MW antennas (17 mm and 25 mm length radiating antennae) were tested using an external implant catheter (2.2 mm o.d.) with water-cooling. US applicators with tubular transducers (2.2 and 2.5 mm o.d., 10 mm length, single-element and 3-element) were utilized with a direct-coupled configuration and internal water-cooling. Measurements of E-field distributions (for MW) and acoustic beam distributions (for US) were used to characterize the applicator energy output. Thermal performance was evaluated through multiple heating trials in vitro (bovine liver) and in vivo (porcine thigh muscle and liver) at varied levels of applied power (20-40 W for microwave, 15-35 W for ultrasound) and heating times (0.5-5 min). Axial temperature distributions in the tissue were recorded during heating, and dimensions of the resulting lesions of thermal coagulation were measured. Both MW and US applicators produced large volumes of tissue coagulation ranging from 8 to 20 cm(3) with singular heating times of 5 min. Radial depth of lesions for both MW and US applicators increased with heating duration and power levels, though US produced notably larger lesion diameters (30-42 mm for US vs 18-26 mm for MW. 5 min heating). Characteristic differences between the applicators were observed in axial energy distribution, tissue temperatures, and thermal lesion shapes. MW lesions increased significantly in axial dimensions (beyond the active applicator length) as applied power level and/or heating duration was increased, and lesion shapes were generally not uniform. US provided greater control and uniformity of heating, with energy deposition and axial extent of thermal lesions corresponding to the length of the active transducer(s). The improved ability to control the extent of thermal coagulation demonstrated by the US applicators provides greater potential to target a specific region of tissue. (C) 2001 American Association of Physicists in Medicine.