FIELD MEASUREMENTS, ABSORBED DOSE, AND BIOLOGIC DOSIMETRY OF MICROWAVES *

A technique for microwave dosimetry was established using rats. Two microwave exposure arrangements were used: a multimodal resonating cavity system, in which the animal serves as the load and is exposed multilaterally; and a far-field exposure system in an anechoic chamber, in which the animal is exposed unilaterally to a well-defined incident field. Four major conclusions were made: 1) The mass absorption density appears to be a useful dose unit for comparing biologic effects produced with different exposure arrangements. Other measures, such as silhouette area absorption density, may be useful for a particular geometry but not for others. 2) The use of models for estimating energy absorption by animals must take into consideration the geometry of the exposure arrangement. With cavity irradiation, the mass of the load appears to be the important factor. In unilateral far-field irradiations, the silhouette surface area of the object is the important factor. 3) It may not be possible to generalize information derived from cavity irradiations to far-field exposure conditions. 4) A safety standard based on incident field densities and based on data from experiments with far-field exposures may not be applicable under conditions where multilateral irradiations occur. (auth-JWP)