Chapelon J Y, Margonari J, Bouvier R, Cathignol D, Gorry F, Gelet A
INSERM U281, Lyon.
Prog Urol. 1991 Apr;1(2):231-43.
Tissue lesions can be induced at the focal point of highly focused transducers with a frequency of 1 and 2.25 MHz for exposure times of less than 1 second. The energy generated by a high power amplifier (7.5 kilowatts effective at 1 MHz) is delivered in the form of series of impulses lasting between 10 and 1,000 milliseconds. The experimentation was conducted in the rat kidney (the left kidney, normally supplied by its vascular pedicle, was exteriorised during ultrasound treatment and then returned to the abdomen). The animal was sacrificed 3 days later and the lesions were studied by serial histological sections. 248 ultrasound shots were performed between January and September 1990. They allowed the definition of the time and intensity constants necessary to induce total destruction of the renal tissue at the focal point. Depending on the energy delivered, an elliptical cavity with a mean height of 1.2 to 4.6 mm and a mean diameter of 0.6 to 3 mm is observed at the focal point after a single shot. No cell structures were visible in the cavities and, in general, the cavity was prolonged by a cone-shaped region of coagulated necrosis with an inferior base. The mechanism responsible for this focused ultrasonic tissue destruction (FUTD) involves a variable combination of thermal and mechanical effects which depends on the ultrasound intensity delivered at the focal point of the transducer.
使用频率为1兆赫和2.25兆赫的高聚焦换能器,在小于1秒的暴露时间内,可在焦点处诱发组织损伤。高功率放大器产生的能量(在1兆赫时有效功率为7.5千瓦)以一系列持续10至1000毫秒的脉冲形式传递。实验在大鼠肾脏上进行(左肾,通常由其血管蒂供血,在超声治疗期间将其外置,然后放回腹腔)。3天后处死动物,通过连续组织切片研究损伤情况。1990年1月至9月期间进行了248次超声照射。这些照射确定了在焦点处诱发肾组织完全破坏所需的时间和强度常数。根据传递的能量,单次照射后在焦点处可观察到一个平均高度为1.2至4.6毫米、平均直径为0.6至3毫米的椭圆形空洞。空洞内未见细胞结构,一般来说,空洞由一个底部在下的锥形凝固性坏死区域延续。这种聚焦超声组织破坏(FUTD)的机制涉及热效应和机械效应的多种组合,这取决于在换能器焦点处传递的超声强度。