3.

A plot of the boundary above which bioeffects, including teratological effects, have been detected in animal models of thermal exposure. The data indicate concern for a 6°C temperature elevation for 1 min declining to 4°C for 16 min, which might be within the range of somespectral Doppler exposures based on the Thermal Index display. Extending the boundary for small elevations above normal body temperature results in very long times (e. g., 4 h 16 min for 39°C) relative to any normal ultrasound examination durations at a fixed scan plane.