PhD defense : Assistance to High Intensity Focused Ultrasound (HIFU) therapy: Real-time physiological motion compensation using motion tracking by ultrasound imaging

PhD defense : Laure Anaïs CHANEL

Team : AVR

Title : Assistance to High Intensity Focused Ultrasound (HIFU) therapy: Real-time physiological motion compensation using motion tracking by ultrasound imaging

Abstract : High Intensity Focused Ultrasound (HIFU) therapy is a non-invasive and non-ionizing method for ablation of solid tumors. However, intra-abdominal organ motion, mainly due to breathing, prevent ultrasound beam from targeting the tumor correctly. In this context, an all-in-one HIFU robotized system which compensate motion in real-time during HIFU treatment was developed. At this aim, an ultrasound visual servoing working at a frequency of 20 Hz, relying on a fast ultrasonic speckle tracking method for motion estimation, was designed. It uses an interleaved imaging/HIFU sonication sequence, which duty cycle is 80%, for avoiding wave interferences. The robotized HIFU system was tested on a tissue mimicking phantom undergoing a 1D and a 2D sinusoidal motion at a typical respiratory motion frequency of 0.25 Hz. As a result, a motion reduction of more than 80 % was obtained and the beneficial effect of the motion compensation on the accuracy of thermal lesions was demonstrated in vitro.

This thesis was supervised by Michel de Mathelin (professor at the University of Strasbourg) and co-diriged by Jonathan Vappou (CNRS researcher) and Florent Nageotte (associate professor at the University of Strasbourg).

The presentation will take place on Thursday, March 3th at 2pm in the Hirsch lecture hall at IRCAD. This thesis will be supported in french.