Accession Number:

ADA190118

Title:

Microwave Dispersion and Absorption in Tissues: Molecular Mechanisms

Descriptive Note:

Final rept. 1 Jan 1978-28 Feb 1986

Corporate Author:

PENNSYLVANIA UNIV PHILADELPHIA DEPT OF BIOENGINEERING

Personal Author(s):

Report Date:

1987-12-10

Pagination or Media Count:

15.0

Abstract:

We measured the dielectric properties of materials tissues, aqueous protein solutions, microemulsions, macroscopic suspensions from 0.1-18 GHz. These properties are determined over this frequency range by the dielectric properties of water and by ionic effects. Analysis of the data shows that the dielectric properties of the suspending water differ from those of the pure liquid, presumably due to interfacial effects. Similar effects are seen in diverse transport properties and even in nonaqueous systems. The results suggest that water within a couple of monolayers from surfaces have motional correlation times that are tenfold or so longer than those of the bulk liquid. We suggest that this motional restriction is a physical effect due to the presence of relatively immobile surfaces, rather than from chemically specific binding. This study has led to an improved understanding of the mechanisms of absorption of microwave energy in tissues, and shown the usefulness of comparative studies of transport processes in complex suspensions. Keywords Dielectric phenomena, Microwaves, Interfacial water, TissuesBiology.

Subject Categories:

  • Biology
  • Radiobiology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE