短波容性加温治疗仪体模内热场分布的研究  

Study on thermal map distribution in phantom by short wave capacitance coupled heating

作　　者：贺晓东[1] 翁霞[2] 叶影[1] 苏斌[1] 祝建三[1] 贺大强 

机构地区：[1]上海市肺科医院放疗科,上海市政民路507号上海200433 [2]上海市新华医院放疗科 [3]上海蓝亚电子科技发展有限公司,上海200433

出　　处：《中国医学物理学杂志》2003年第4期203-206,共4页Chinese Journal of Medical Physics

摘　　要：目的:研究3MHz短波容性加温治疗时非均匀体模内热场分布之规律。为临床治疗提供定量依据。方法:自制400mm×220mm×220mm肌肉等效均质体模及220mm×220mm×220mm之非均质体模。在体模内有效加温容积内垂直和水平放置100mm×25mm的猪骨各1根;并放置100mm×5.6mm的硅胶导管1根,12mm×0.7mm的订书针1根作为金属材料。用抗干扰热电偶型数字化实时测温仪进行实时动态同步测温。加热仪采用3MHz肿瘤射频热治疗仪。结果:3MHz短波容性(射频)加温治疗之治疗深度可达200mm。其电势分布表现在一是发散得很开。二是有边缘聚集效应。在体模中心水平平面,有效加热范围为60%。非均匀体模内不同介质周围有不同的温升规律。结论:(1)在使用合适的耦合水袋时,中心温度比表面温度晚约4min达到设定温度,而水袋温度平均每4min上升1℃。因此,可通过降低表面水袋1℃的办法使得中心温度与表面温度在控温时保持一致;(2)恒温后10min,金属旁2.5mm处的温度比体模中心的温度可高出约3℃;(3)导管旁和骨旁的温度实际升温与中心升温基本一致。因此,在加热区域有骨或引流管时,射频热疗是安全的;(4)反射波的调节能力对热场分布有决定性作用。Objective: It is very important to know the electromagnetic power deposition,and to know that if the bolus and heterogeneity materials can induce a variation in the thermal map- both superficially and deeply. The aim of this study is to evaluate the above-mentioned characteristics- in order to support basic concepts and data for clinical practice. Methods: The thermal distribution generated by a capacitance coupled Radiofrequency (short wave)heating machine. The frequency and the highest power applied are 3 MHz and 500 W separately. The size of self made uniformity and heterogeneity phantom are 400mm×220 mm×220 mm and 220 mm×220 mm×220 mm separately. For heterogeneity phantom- 2 bones of pig with size 100 mm×25 mm.was inserted perpendicularly each other- and also inserted 1 radix of 100 mm×5.6 mm silicon catheter- and 1 staple of size 12 mm×0.7 mm. The way of measurement is of multi-points and online synchronization measuring. Two pairs of coupled water bags with different components are used in order to study electromagnetic match between the biological tissue and the applicator surface and to locally modify the skin temperature. Results: The penetration depth of short wave therapy with frequency ranged between 3 MHz can be 200 mm or more.The electric voltage field has a strong edge congregating effect. In the center horizontal plan of phantom- the effective heating area is 60% of the area of electronic pole board. The different materials have their own temperature rising laws. Conclusions: For an appropriate coupled water bag- the temperature rising time at center of phantom is 4 min latter than that of the superficial temperature ascending. As for superficial temperature- the rising speed is 1 ℃/4 min. The objective or final temperature both of the center and superficial can arrive in the same time by depressing 1 ℃ more of the water bag. After keeping 10 min of final temperature- the temperature 2.5 mm away from the staple is 3 ℃ higher than that in the phantom center. And the rising speed of

关 键 词：热疗 射频 短波 非均质体模 热场分布 

分 类 号：R811.1[医药卫生—放射医学]