Physiological Motion Compensation during High Intensity Focused Ultrasound (HIFU) therapy
High Intensity Focused Ultrasound (HIFU) is the only non-invasive, non-ionizing method for the ablation of solid tumors. During HIFU therapy, high intensity ultrasound beams are focused within the region to be treated (e.g., tumor), and the absorption of the acoustic energy allows for localized heating of the tissue, leading to its ablation within the focal region. Despite its great potential, the use of HIFU therapy is very limited, due to major technological challenges that still need to be addressed. Physiological motion compensation is one of the essential challenges that need to be solved: it is essential to ensure that the focus follows accurately the region to be treated and to avoid unwanted damage to surrounding, healthy tissue. This project aims at developping and characterizing an all-in-one robotized HIFU system with active compensation of physiological motion. Real-time feedback control is achieved through the estimation of motion by ultrasound imaging: 2D displacements are estimated in real time using an ultrafast normalized cross-correlation algorithm. This displacement estimate is considered as an error to be minimized in a visual servoing loop operating at 20 Hz. Accuracy and performance of the method has been assessed in gelatin phantoms and on chicken breast in vitro.
Keywords: HIFU, Ultrasound Imaging, Motion compensation
Jonathan Vappou, Florent Nageotte
The project has benefited from a PhD funding by the LABEX CAMI (2012-2016).