Lee R J, Suh H
Department of Radiation Oncology, Ewha Womans University Mokdong Hospital, Seoul, Korea.
Int J Hyperthermia. 2003 Sep-Oct;19(5):563-74. doi: 10.1080/02656730310001608002.
For evaluating the feasibility of treating recurrent lesions in the vaginal cuff by hyperthermia, a 2-element ultrasound applicator was designed, constructed and characterized. A half-cylindrical transducer (d=1 cm, length=1 cm) was used to construct the 2-element ultrasound applicator. Each element of this applicator was operated at 1.5 MHz and characterized by measuring transducer efficiency and acoustic power distribution. Thermocouple probes were used to measure the temperature rise in the phantom. The element sizes used in this study were selected to be comparable to a high dose rate brachytherapy colpostat applicator. Each element was powered separately to achieve a desired temperature pattern in a target. The acoustic output power as a function of applied electric power of elements 1 and 2 were linear over this 1-40 W range and efficiencies were 32.2 +/- 3.4% and 46.2 +/- 0.8%, respectively. The temperature measurements in the phantom showed that a 6 degrees C temperature rise was achieved 2 cm from the applicator surface. As a conclusion, the ability of the ultrasound colpostat applicator to be used for hyperthermia was demonstrated by measuring acoustic output power, ultrasound field distribution and temperature rise in the phantom. Based on the characteristics of this applicator, it has the potential to be useful for inducing hyperthermia to the vaginal cuff in the clinic.
为评估热疗治疗阴道断端复发病变的可行性，设计、制作并表征了一种二元超声换能器。使用一个半圆柱形换能器（直径 = 1 cm，长度 = 1 cm）制作二元超声换能器。该换能器的每个元件工作频率为1.5 MHz，并通过测量换能器效率和声功率分布进行表征。使用热电偶探头测量体模中的温度升高。本研究中使用的元件尺寸选择为与高剂量率近距离放射治疗阴道施源器相当。每个元件单独供电以在靶区实现所需的温度分布。在1 - 40 W范围内，元件1和2的声输出功率随施加电功率的变化呈线性，效率分别为32.2±3.4%和46.2±0.8%。体模中的温度测量表明，在距换能器表面2 cm处温度升高了6℃。结论是，通过测量声输出功率、超声场分布和体模中的温度升高，证明了超声阴道施源器用于热疗的能力。基于该施源器的特性，它有可能在临床上用于诱导阴道断端热疗。
