Lamaitre G, Van Dijk J D, Gelvich E A, Wiersma J, Schneider C J
Department of Radiotherapy, University of Amsterdam, The Netherlands.
Int J Hyperthermia. 1996 Mar-Apr;12(2):255-69. doi: 10.3109/02656739609022513.
The Effective Field Sizes (EFS) and the Effective Heating Depths (EDH) of Contact Flexible Microstrip Applicators (CFMA), tuned at a frequency of 434 MHz, were determined on two fat/muscle phantoms. One phantom was box-shaped with a flat top layer of 1 cm thick artificial fat and the other one a tube of which the cross-section was elliptically shaped (25 x 36 cm) having a fat equivalent shell of 1 cm thick. For the muscle material a 6 g/l saline (NaCl) solution was used. On the flat rectangular phantom, the effective field size at 1 cm depth in saline was measured to be 4.7 x 13.5 cm, 17.5 x 17.7 cm and 12.5 x 14.0 cm for the 1H-applicator, the 3H-applicator and the 5H-applicator, respectively. For the 3H-and the 5H-applicator, the Specific absorption rate (SAR) distribution at 1 cm depth showed a single maximum of SAR for a thin bolus, which split into two separate "hot spots' for a thicker bolus. The Effective Heating Depths in the phantom with a flat surface were of the order of that of a plane wave (approximately 1.4 cm), whereas a larger EHD of 2.4 cm was achieved below the 3H-applicator bent to fit the elliptical phantom. Due to the large effective field size and the "flatness' of the SAR distribution, the applicators 3H and 5H are suitable to adequately treat large superficial tumours.
在两个脂肪/肌肉体模上测定了频率调谐为434 MHz的接触式柔性微带辐射器（CFMA）的有效场大小（EFS）和有效加热深度（EDH）。一个体模是盒形的，顶部有一层1厘米厚的人工脂肪平面，另一个是管形的，其横截面为椭圆形（25×36厘米），有一层1厘米厚的等效脂肪外壳。肌肉材料使用6克/升的盐水（NaCl）溶液。在扁平矩形体模上，对于1H辐射器、3H辐射器和5H辐射器，在盐水中1厘米深度处的有效场大小分别测得为4.7×13.5厘米、17.5×17.7厘米和12.5×14.0厘米。对于3H和5H辐射器，在1厘米深度处的比吸收率（SAR）分布显示，对于薄推注，SAR有一个单一最大值，而对于较厚推注，该最大值分裂为两个单独的“热点”。表面平坦的体模中的有效加热深度与平面波的有效加热深度相当（约1.4厘米），而弯曲以适配椭圆形体模的3H辐射器下方实现了2.4厘米的更大有效加热深度。由于有效场大小较大以及SAR分布的“平坦度”，3H和5H辐射器适合充分治疗大型浅表肿瘤。
