Alanen E, Lahtinen T, Nuutinen J
Department of Oncology, Kuopio University Hospital, Finland.
Phys Med Biol. 1998 Mar;43(3):475-85. doi: 10.1088/0031-9155/43/3/001.
A three-layer model of stratum corneum, epidermis/dermis and subcutaneous fat has been developed for the capacitance of an open-ended coaxial line in contact with human skin. Applying the model, the electrical properties of subcutaneous fat can be calculated from skin dielectric measurements with three probes of different sizes. The three-layer model is based on a variational formula for the capacitance of the coaxial probe. An accurate approximation for the dielectric constant of the multilayer cutaneous structure is presented for the inverse problem of solving the dielectric constants of various layers. The method was tested at 300 MHz with breast cancer patients who often have radiotherapy-induced late alterations in the structure of subcutaneous fat due to the development of subcutaneous fibrosis. Measurements from 206 sites yielded a good agreement between the dielectric constant of subcutaneous fat and the clinical score for subcutaneous fibrosis.
针对与人体皮肤接触的开口同轴电缆的电容，已开发出一种由角质层、表皮/真皮和皮下脂肪组成的三层模型。应用该模型，可通过使用三种不同尺寸的探头进行皮肤介电测量来计算皮下脂肪的电学特性。该三层模型基于同轴探头电容的变分公式。针对求解各层介电常数的反问题，给出了多层皮肤结构介电常数的精确近似值。该方法在300MHz频率下对乳腺癌患者进行了测试，这些患者由于皮下纤维化的发展，经常会出现放疗引起的皮下脂肪结构晚期改变。来自206个部位的测量结果表明，皮下脂肪的介电常数与皮下纤维化的临床评分之间具有良好的一致性。
