Measurement of ultrasonic properties of muscle and blood biological phantoms

Abstract

Oncology hyperthermia refers to an artificial elevation of temperature in biological tissue to remove tumor cells. This temperature increase is reached by applying ultrasound or electromagnetic waves. Working with biological tissues implies a high effort; furthermore, biological material changes its properties with time. Also, it is necessary a knowledge of the handling of biological material and a specialized infrastructure. For these reasons, for some years our research laboratory has dedicated part of its researches to develop mimicking materials to emulate muscle and other tissue ultrasonic properties. A blood phantom was developed in our laboratory for its use in the transit time flow measurement (blood flow). The properties of interest for the muscle and for the blood phantoms are ultrasonic attenuation and ultrasound velocity. This work refers to the phantom preparation and their ultrasonic properties measurement. These phantoms emulate the mentioned ultrasonic characteristics. In the case of muscle, there are two types of phantoms: solid phantom with graphite and phantom with scatterers. The procedure of preparation of the phantoms is described. They have a different composition to that published for Doppler blood phantoms. Some ultrasonic properties of muscle and of blood have been already published and they are referred to one temperature. An originality of the results reported in this paper is that the behavior of the ultrasonic properties is presented at different temperatures: ranging from 22 ∘C to 470 ∘C. This range includes the temperatures used in our experimental work in hyperthermia treatment.