Kaatee R S, Kampmeijer A G, van Hooije C M, van Rhoon G C, Kanis A P, Levendag P C, Visser A G
Department of Radiation Oncology, Dr Daniel den Hoed Cancer Center, Rotterdam, The Netherlands.
Int J Hyperthermia. 1995 Nov-Dec;11(6):785-96. doi: 10.3109/02656739509052335.
Temperature distribution is an important factor in thermo-radiotherapy and it is greatly dependent on the applied heating technique. Consistency of the heating method is therefore important in translating in vivo experimental data to the clinical situation. To further evaluate the combination of interstitial hyperthermia and interstitial radiotherapy, an experimental interstitial hyperthermia system has been developed for small (500-2000 mm3) tumours growing in the flank of a rat. The system used reproduces the properties of our clinical current source interstitial hyperthermia system. The heating system consists of four applicators, each with independent tuning and power control. The applicators are situated inside plastic afterloading catheters and are capacitively coupled with the surrounding tissue. The tumour is heated through dissipation of a 27 MHz current flowing to an external ground plane. An effective RF-filter allows reliable thermocouple temperature measurements when the power is switched on. The tumour temperature is easily controlled by means of a continuous temperature read-out and a clear temperature display. A minimum temperature up to 46 degrees C can be reached within 4-10 min and maintained (+/-0.5 degrees C) throughout the treatment period. Modelling calculations performed for this heating system indicate that the applicator temperatures should be kept equal in order to minimize the difference between maximum and minimum temperature. Significantly higher applicator currents are needed at larger distances from the ground plane. In addition, the homogeneity of the temperature distribution is improved when either the tumour is isolated or when the environmental temperature is increased. The calculations also show that temperature distribution is strongly dependent on effective heat conductivity. A description of the system and its performance is presented.
温度分布是热放疗中的一个重要因素，它在很大程度上取决于所应用的加热技术。因此，加热方法的一致性对于将体内实验数据转化为临床情况至关重要。为了进一步评估间质热疗与间质放疗的联合应用，已开发出一种用于大鼠侧腹生长的小肿瘤（500 - 2000立方毫米）的实验性间质热疗系统。所使用的系统再现了我们临床电流源间质热疗系统的特性。加热系统由四个施源器组成，每个施源器都有独立的调谐和功率控制。施源器位于塑料后装导管内，并与周围组织电容耦合。肿瘤通过流向外部接地平面的27兆赫电流的耗散来加热。一个有效的射频滤波器在电源开启时允许可靠的热电偶温度测量。肿瘤温度通过连续的温度读数和清晰的温度显示很容易控制。在4 - 10分钟内可达到最低温度46摄氏度，并在整个治疗期间保持（±0.5摄氏度）。对该加热系统进行的建模计算表明，应使施源器温度保持相等，以尽量减小最高温度与最低温度之间的差异。离接地平面距离越大，所需的施源器电流就越高。此外，当肿瘤被隔离或环境温度升高时，温度分布的均匀性会得到改善。计算还表明，温度分布强烈依赖于有效热导率。本文介绍了该系统及其性能。
