Gopal M K, Hand J W, Lumori M L, Alkhairi S, Paulsen K D, Cetas T C
Department of Radiation Oncology, University of Arizona, Tucson 85724.
Int J Hyperthermia. 1992 Mar-Apr;8(2):227-40. doi: 10.3109/02656739209021778.
The current sheet applicator is an electromagnetic heating device whose size may be chosen virtually independent of frequency even though practical limitations may restrict it to VHF and UHF bands. In this paper we investigate absorbed power distributions in muscle tissue from current sheet applicators when used as elements of a planar array intended for superficial hyperthermic treatment of tumours. Advantages offered by current sheet applicators for tissue heating include compact size, a linear polarization of the induced electric field and relatively large heating area. It is shown that the effective field produced by a pair of these elements is continuous regardless of whether the common edges of the elements are perpendicular or parallel to the direction of impressed current. The feasibility of customizing the shape and size of the field is also illustrated. The absorbed power distribution patterns due to a coherently driven array operating around 434 MHz is relatively insensitive to phase variations of about 20 degrees but is sensitive to relative power level variations as low as 10%. Mutual coupling between array elements may be reduced to acceptable levels by incorporating suitable spacing between them. It is also demonstrated that there is good agreement between measurements of absorbed power distributions and predictions using the Gaussian beam model.
电流片式施加器是一种电磁加热装置，其尺寸实际上可以在不考虑频率的情况下进行选择，尽管实际限制可能会将其限制在甚高频和超高频频段。在本文中，我们研究了电流片式施加器用作平面阵列元件时，在用于肿瘤浅表热疗的情况下，肌肉组织中的吸收功率分布。电流片式施加器用于组织加热的优点包括尺寸紧凑、感应电场呈线性极化以及加热面积相对较大。结果表明，由一对这样的元件产生的有效场是连续的，无论元件的公共边与外加电流方向是垂直还是平行。还说明了定制场的形状和大小的可行性。在434MHz左右相干驱动的阵列所产生的吸收功率分布模式，对约20度的相位变化相对不敏感，但对低至10%的相对功率电平变化敏感。通过在阵列元件之间设置合适的间距，可以将元件之间的相互耦合降低到可接受的水平。还证明了吸收功率分布的测量结果与使用高斯光束模型的预测结果之间有很好的一致性。
