DEVELOPMENT OF ULTRASONIC HYPERTHERMIA SYSTEM FOR MALIGNANT TUMOR IN SMALL ANIMALS

超声热疗由于具有穿透性和聚焦性，已成为一种治疗癌症的方法。因此，研制了小动物恶性肿瘤超声热疗系统。该系统由超声波发生器、数据采集系统、测温系统、带温控器的循环器和脱气系统组成。该系统具有配备非聚焦超声换能器或聚焦超声换能器的涂抹器。采用琼脂-石墨混合薄膜，测量了薄膜加热后的二维温度分布。当频率为1.5 MHz时，可获得直径为1 ~ 4 cm、深度为2 cm的均匀加热模式。使用三氯乙酸改进了利用韦斯勒反应（利用超声空化从碘化钾中测定碘）的化学剂量计，并通过使用由100个小容器组成的“晶格”容器来估计吸收剂量分布。通过非热效应的超声增强透皮药物吸收也进行了研究。

Hyperthermia induced by ultrasound has been employed as a modality for cancer therapy because of the feasibility of penetration and focusing. Therefore, ultrasonic hyperthermia system for malignant tumor in small animals has been developed. This system consists of a ultrasonic generator, data accumulation system, temperature measurement system, a circulator with temperature controller and degassing system. This system has an applicator equipped with a non-focused ultrasound transducer or a focused one. Two dimensional temperature distributions for the phantom after heating were measured by using agar-graphite mixture phantom. Homogeneous heating pattern from 1 to 4 cm diameter with 2 cm depth was obtained when a frequency of 1.5 MHz was used. A chemical dosimeter utilizing the Weissler reaction (determination of iodine from potassium iodide due to ultrasonic cavitation) was improved with using trichloroacetic acid and the absorbed-dose distribution was estimated by using a "lattice" vessel consisting of 100 small containers. Enhancement of transdermal drug absorption by non-thermal effects of ultrasound has also been investigated.