Theoretical Assumptions in Conductivity and Dielectric Properties Assessment of Biological Tissues - Errors and Resulting Consequences

Knowing the dielectric parameters of human tissue is a matter of fundamental importance for a correct medical diagnosis, considering that these values differ from a healthy tissue/organ to an affected one.The mathematical apparatus that ensures the operation of these working models is accompanied by a set of necessary conditions (assumptions about mathematical spaces and operators, their conditions of existence, initial conditions, etc.), which should not be violated. In this paper, we will analyze the circumstances in which the theoretical conditions could be violated and the consequences of their violation concerning recording the electrical properties of human tissue, and particularly the effects of the layers of tissues that cover the human brain, in the process of calculating their dielectric parameters. This is still an open issue with major implications for medical diagnosis. We analyze the local and global hypothesis of tissue isotropy, the errors that occur when these hypotheses are ignored and how these errors affect the medical diagnosis. We also make a flash on the results and the most inspired solutions found in the field; finally, we discuss our answer to this problem.