Jossinet J
Institut National de la Santé et de la Recherche, Médicale, INSERM U281, Lyon, France.
Med Biol Eng Comput. 1996 Sep;34(5):346-50. doi: 10.1007/BF02520002.
The impedivity of six groups of breast tissue is measured between 0.488 kHz and 1 MHz using a hand-held probe, ensuring a constant geometry factor, and a microcomputer-controlled impedance spectroscopy system. 120 spectra are collected in excised tissue samples from 64 patients undergoing breast surgery. Each spectrum consists of 12 frequency points. The mean m, the standard deviation s, and the 'reduced standard error' (epsilon = s/(m N)) of the magnitude and the phase angle of the impedivity are calculated at each frequency for all groups of tissues. The variability at low frequency (f < 10 kHz) is attributed to the dispersion in measurement errors. This contributed to the choice of 32 KHz as the lower limit of measurement frequency in constructed electrical impedance tomograph. The collected data also show that frequencies larger than 1 MHz are needed for the bio-electrical characterisation of breast tissue. In the frequency range used in electrical impedance tomography the reduced standard error of impedivity in breast tissue is about 0.1 or less. The lowest dispersions are observed in the adipose tissue, carcinoma and fibro-adenoma.
使用手持探头，在保持恒定几何因子的情况下，通过微机控制的阻抗谱系统，在0.488千赫兹至1兆赫兹之间测量六组乳腺组织的阻抗率。从64名接受乳腺手术的患者的切除组织样本中收集了120个频谱。每个频谱由12个频率点组成。针对所有组织组，在每个频率下计算阻抗率的大小和相角的平均值m、标准差s以及“简化标准误差”（ε = s/(m√N)）。低频（f < 10千赫兹）时的变异性归因于测量误差的离散性。这促使在构建电阻抗断层扫描仪时选择32千赫兹作为测量频率的下限。收集的数据还表明，乳腺组织的生物电特性需要高于1兆赫兹的频率。在电阻抗断层扫描所使用的频率范围内，乳腺组织中阻抗率的简化标准误差约为0.1或更小。在脂肪组织、癌组织和纤维腺瘤中观察到的离散性最低。
