| Popis: |
The electrical impedance from 100 Hz to 40 MHz was measured for two types of human tumor xenografts. The measurements were made non-invasively, in vivo during hyperthermia treatments. Each impedance spectrum was fit using the sum of two Cole-Cole dispersions. The conductivity at the relaxation frequency (F/sub c/) of each dispersion (/spl sigma//sub Fc/), and the conductivity at 10 MHz (/spl sigma//sub 10M/) were selected for subsequent use. Using the /spl sigma/-ratios /spl sigma//sub 10M///spl sigma//sub Fc/ temperature-dependent effects were minimized and two different aspects of the cellular damage sequence were able to be followed during the hyperthermia treatments. Using each /spl sigma/ and its temperature coefficient, the temperature changes can be simultaneously estimated in the usual way. |
