Prionas S D, Raftery K A, Edmonds P D, Constantinou C E
Department of Radiation Oncology, Stanford University School of Medicine, CA 94305.
Int J Hyperthermia. 1991 Mar-Apr;7(2):367-83. doi: 10.3109/02656739109005002.
The influence of perfusate flow rate on the two-dimensional (2-D) temperature distributions induced by hyperthermia in the canine kidney was evaluated. Localized hyperthermia was induced by ultrasound (frequency 2.040 MHz, transducer diameter 6.7 cm) in the ex-vivo perfused kidney. Temperatures were mapped using shielded copper/constantan thermocouple sensors. The 2-D temperature distribution of the kidney was obtained by pulling these sensors through a planar array of eight stainless-steel trocars inserted along its longitudinal axis. The perfusion system allowed for the control of internal/external organ temperature and type of perfusate, and it simulated vasodilation and vasoconstriction by changing the arterial volume flow rate. The temperature data obtained at flow rates ranging from 0 to 570 ml/min and power levels from 0 to 150 W showed that acoustic power densities in excess of 1.5 W/cm2 were required to maintain therapeutic temperatures in this system. Contour maps for characterizing the 2-D temperature distributions induced in this system were analysed with the introduction of a quantitative measure based on the area within a given isotherm. They show the effects of tissue heterogeneity, flow rate, and non-uniform power deposition. Time constants computed from the exponentially decaying temperatures measured following power off ranged from 5 to 555 s. These findings provide a basis for comparison with temperature measurements being acquired in the in-vivo kidney system. Information acquired from this system may facilitate the process of developing tissue-equivalent dynamic phantoms for ultrasound-induced hyperthermia. The ex-vivo model presented in this paper might be used to study the performance of alternative heating applicators, the effect of haematocrit, blood viscosity, and the use of vasoactive drugs.
评估了灌注液流速对犬肾热疗诱导的二维（2-D）温度分布的影响。在离体灌注肾中，通过超声（频率2.040 MHz，换能器直径6.7 cm）诱导局部热疗。使用屏蔽铜/康铜热电偶传感器绘制温度图。通过将这些传感器沿肾脏纵轴插入的八个不锈钢套管针的平面阵列拉动，获得肾脏的二维温度分布。灌注系统可控制内部/外部器官温度和灌注液类型，并通过改变动脉体积流速模拟血管舒张和血管收缩。在流速范围为0至570 ml/min和功率水平为0至150 W时获得的温度数据表明，在该系统中维持治疗温度需要超过1.5 W/cm2的声功率密度。引入基于给定等温线内面积的定量测量方法，分析了用于表征该系统中诱导的二维温度分布的等高线图。它们显示了组织异质性、流速和不均匀功率沉积的影响。从断电后测量的指数衰减温度计算出的时间常数范围为5至555 s。这些发现为与体内肾脏系统中获取的温度测量结果进行比较提供了基础。从该系统获取的信息可能有助于开发用于超声诱导热疗的组织等效动态体模的过程。本文提出的离体模型可用于研究替代加热 applicators 的性能、血细胞比容、血液粘度的影响以及血管活性药物的使用。
