Extended Data Fig. 2: Ultrasound exposure safety.
From: Transcranial volumetric imaging using a conformal ultrasound patch
a, System set-up for characterizing ultrasound exposure safety. The hydrophone is controlled by a 3D linear motor in a water tank. A formalin-fixed human skull sample is used to evaluate skull induced attenuation. b, Ultrasound intensity measured by the hydrophone. The maximum derated intensities of both diverging and focused beamforming strategies before derating are set to around 370 mW cm−2. The average intensity loss of the ultrasound beams after skull penetration is around 83% for both beamforming strategies. All of the measured results are lower than the maximum level recommended by the Food and Drug Administration (that is, 720 mW cm−2)27.
