Maxime POLICHETTI : 3-D spatio-temporal monitoring of cavitation using ultrasound imaging. Application to monitoring of ultrasound therapy

Abstract : Extracoporeal ultrasound probes allow treating biological tissues in a non-invasive way. Focused ultrasound waves are responsible of ultrasound cavitation: the key mechanism involved in many ultrasound treatment. Cavitation corresponds to the nucleation of gas bubbles which oscillate and implose in biological tissues to be treated (blood clots, tumors,...). However, such a complex mechanism hinders the developpement of an efficient and reproducible therapeutic tool. Namely, some bubbles can appear out of the focus of the probe, and dammage healthy tissues.

The spatial monitoring of cavitation activity is essential to control the region which is actually treated. So, an ultrasound imaging probe is used to passively receive acoustic emissions from the cavitation bubbles. The Passive Acoustic Mapping (PAM) algorithm allows the mapping of the deposited cavitation energy during the treatment using the passively received ultrasound emissions. However, the PAM algorithm suffers form weak resolution and contrast, which prevents from efficiently monitoring the cavitation activity.

This PhD thesis is focused on studying, comparing, and developping adaptive passive imaging algorithms that maximize cavitation information and minimize interferences and noise on such energy maps