Figure 2 | Scientific Reports

Figure 2

From: Characterization of different bubble formulations for blood-brain barrier opening using a focused ultrasound system with acoustic feedback control

Figure 2

Flow chart for the feedback control algorithm. The digitizer captures the acoustic emissions from stimulated microbubbles during sonication, and a Fast Fourier transform (FFT) is then performed on the raw data. The area under curve (AUC) is calculated for sub-/ultra-harmonics (band width ± 0.05MHz). The mean AUC across 3 separate acquisitions is then compared to a target AUC threshold. If the measurement falls within a pre-defined error dead-band (Threshold ± ε), the pressure will be maintained, otherwise, a ±0.01–0.03 MPa adjustment will be applied to the transducer prior to the next acquisition. This algorithm runs continuously during the BBB exposure until the desired treatment time is reached.

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