Chou C K, McDougall J A, Chan K W, Luk K H
Department of Radiation Research, City of Hope National Medical Center, Duarte, California 91010.
Med Phys. 1991 Nov-Dec;18(6):1164-70. doi: 10.1118/1.596627.
Heating rate (HR) patterns in cylindrical structures were studied with inhomogeneous limb phantoms. These phantoms, arm and thigh models consisting of fat, bone, and muscle material, were heated with Clini-Therm L, M, and MS applicators at 915 MHz. The thigh model is 18 cm in diameter with 2.65-cm-thick fat on the outside and a 4-cm-diam bone in the center. The arm model is 9 cm in diameter with 1.35-cm-thick fat and 2-cm-diam bone. All models are 29 cm long with phantom muscle in the space between fat and bone and were heated with their long axes parallel or perpendicular to the E field. HR patterns in the transverse and longitudinal planes were obtained thermographically. A large water bolus, with the water channels parallel to the E field, was used in every case. In the thigh model, maximum heating was in the muscle for both L and M applicators when the E field was parallel to the long axis. When it was perpendicular, the maximum heating occurred in the fat layer. However, the peak HR in the fat remained about the same for both E field orientations. For the small applicator, heating was mostly in the fat, and the two field orientations did not cause much difference in the heating pattern. In the arm model, the maximum heating of all three applicators occurred mostly in the muscle for both E-field orientations. However, the maximum HR was reduced by a factor of 2 to 3 when the E field was perpendicular rather than parallel to the long axis.(ABSTRACT TRUNCATED AT 250 WORDS)
利用非均匀肢体模型研究了圆柱形结构中的加热速率（HR）模式。这些模型，即由脂肪、骨骼和肌肉材料组成的手臂和大腿模型，在915MHz频率下使用Clini-Therm L、M和MS型 applicator进行加热。大腿模型直径为18cm，外部有2.65cm厚的脂肪，中心有直径4cm的骨骼。手臂模型直径为9cm，有1.35cm厚的脂肪和直径2cm的骨骼。所有模型长29cm，在脂肪和骨骼之间的空间有模拟肌肉，且以其长轴平行或垂直于电场的方式进行加热。通过热成像获得了横向和纵向平面上的HR模式。每种情况下均使用了一个大的水囊，其水通道与电场平行。在大腿模型中，当电场平行于长轴时，L型和M型 applicator在肌肉中的加热均达到最大值。当电场垂直时，最大加热出现在脂肪层。然而，两种电场方向下脂肪中的HR峰值大致相同。对于小型 applicator，加热主要发生在脂肪中，两种电场方向在加热模式上并未造成太大差异。在手臂模型中，对于两种电场方向，所有三种 applicator的最大加热大多发生在肌肉中。然而，当电场垂直而非平行于长轴时，最大HR降低了2至3倍。（摘要截取自250字）
