Todoidal transducer with two large focal zones for increasing the coagulated volume

Jeremy Vincenot (1) , David Melodelima (1) , Alexandre Vignot , Francoise Chavrier (1) , Jean-Yves Chapelon (2)

1 Applications des ultrasons à la thérapie
2 LabTAU - Application des ultrasons à la thérapie

In this work, a toroidal High Intensity Focused Ultrasound (HIFU) transducer was developed for the treatment of liver metastases. It generates an enlarged focal zone composed of a first ring-shaped focus (located at the focal plane) and an overlap of ultrasound beams between the transducer and this focal ring. The objective was to combine this toroidal geometry with electronic focusing of the ultrasound beam. This was done in order to create a coagulated volume sufficient for the destruction of a metastasis with a diameter up to 3 cm. The working frequency of the transducer was 2.5 MHz. The transducer is divided into 32 rings of 77 mm² each. In vitro tests were conducted and have shown that this toroidal geometry and the use of electronic beam steering allows the creation of lesions with a diameter of 40 mm and a depth of 38 mm. This treatment was obtained in 10 minutes without any mechanical displacement of the transducer. In conclusion, these results indicate that the treatment of a liver metastasis up to 3 cm in diameter is conceivable with safety margins using a single exposure which is obtained rapidly and without juxtaposing single lesions.

Mots clés: HIFU; Beam steering; Toroidal transducer; Liver metastases

Domaines: Acoustique [physics.class-ph]

Jeremy Vincenot, David Melodelima, Alexandre Vignot, Francoise Chavrier, Jean-Yves Chapelon. Todoidal transducer with two large focal zones for increasing the coagulated volume. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00810839⟩