Measurements of temperature-time profiles in an agar-graphite gell 'miniphantom' stepped horizontally through a larger phantom of degassed water have yielded distributions of initial rates of heating in the focal plane of Helios, a four-ring, 30-transducer ultrasound device designed for localized deep heating. Focal-plane heating patterns (initial degree C/min distributions) produced by the innermost of the four transducer rings operated under a variety of conditions are presented. The results suggest that at a depth of 10 cm in homogeneous muscle, heating patterns as narrow as 1. 8 cm (full width half maximum) with initial peak heating rates of more than 5 degree C/min can be anticipated. These studies also illustrate the potential for clinically relevant manipulation of lateral heating patterns through redistribution of power to transducers in a given ring.
|Number of pages||3|
|State||Published - Dec 1 1986|