FIGURE S1 Probed conductivity (in red) and permittivity (in blue) of the ultrasound gel in a 4‐h time window at room temperature (22°C) (A) and across a temperature range of 22–58°C (B). Data are shown as mean ± SD of 3 measurements at different locations. (A) Measurement was performed every 20 min. Neither conductivity nor permittivity changes significantly in the 4‐h time window. (B) The gel was heated to 50°C and slowly cooled down in water bath. EPs and the corresponding temperature were measured simultaneously. Neither conductivity nor permittivity changes significantly from room temperature to 48°C

METHOD S1 Further details about the animal model and the histology procedure