Rietveld P J, Lumori M L, van der Zee J, van Rhoon G C
University Hospital Rotterdam-Daniel den Hoed Cancer Center, Department of Radiation Oncology, The Netherlands.
Phys Med Biol. 1998 Aug;43(8):2207-20. doi: 10.1088/0031-9155/43/8/015.
SAR distributions from four different E-field-orientated 2 x 2 arrays of incoherently driven Lucite cone applicators (LCAs) were investigated. The LCAs operated at 433 MHz with an aperture of 10.5 cm x 10.5 cm each. Two techniques were used to obtain SAR distributions in flat layered phantoms: Gaussian beam (GB) predictions and thermographical (TG) imaging. The GB predictions showed that the effective field size of the different array configurations varied by up to 3%. The TG-measured SAR distribution showed significant deviations from the GB-predicted SAR distributions (maximum 34.6%). The difference between GB-predicted and TG-measured SAR levels (averaged per 10% GB-predicted SAR intervals) equalled less than 11.3% for the parallel E-field orientated array and respectively 15.1% for the clockwise-orientated array. When antennae in the clockwise-orientated array were more widely spread (array aperture 23 cm x 23 cm) in order to diminish their mutual interactions, these differences decreased to 12.4%. However, the overall difference within the 50% SAR or higher range decreased from 14% to 9%. The results lead us to conclude that LCAs can be used clinically and their antenna interactions are not considered to be a problem under clinical conditions.
研究了由四个不同电场方向的2×2非相干驱动的有机玻璃锥形 applicators（LCA）阵列产生的比吸收率（SAR）分布。这些LCA在433MHz下运行，每个孔径为10.5cm×10.5cm。使用两种技术在扁平分层体模中获取SAR分布：高斯光束（GB）预测和热成像（TG）成像。GB预测表明，不同阵列配置的有效场大小变化高达3%。TG测量的SAR分布与GB预测的SAR分布存在显著偏差（最大偏差为34.6%）。对于平行电场方向的阵列，GB预测和TG测量的SAR水平之间的差异（按10%GB预测的SAR间隔平均）小于11.3%，对于顺时针方向的阵列分别为15.1%。当顺时针方向阵列中的天线分布更广泛（阵列孔径为23cm×23cm）以减少它们之间的相互作用时，这些差异降至12.4%。然而，在50%SAR或更高范围内的总体差异从14%降至9%。结果使我们得出结论，LCA可用于临床，并且在临床条件下其天线相互作用不被视为问题。
