Microwave dielectric properties of tissue. Some comments on the rotational mobility of tissue water.
Dielectric permitivity and conductivity data are reviewed for tissue over the frequency range of 0.1-10 GHz. The conductivity of muscle increases quadratically with frequency above 1 GHz, suggesting a Debye relaxation for tissue water centered at 20 GHz at room temperature, the same as for bulk water. Approximate mixture equations suggest that this "free" water accounts for about 70% of the tissue weight, showing that most of the tissue water has rotational mobilities similar to those in the bulk fluid.
D000818:Animals; D001834:Body Water / Q000502:physiology*; D004553:Electric Conductivity; D008433:Mathematics; D008872:Microwaves; D009132:Muscles / Q000502:physiology*