%0 Journal Article
%T Optimized Schlieren imaging for real-time visualization of high-intensity focused ultrasound waves.
%A Nawrath H
%A Holl A
%A Bedarf L
%A Mai D
%A Alfke H
%A Gröbner J
%J Biomed Tech (Berl)
%V 0
%N 0
%D 2024 Jun 12
%M 38860648
%F 1.426
%R 10.1515/bmt-2024-0002
%X <B>OBJECTIVE: </B>This article presents an low-cost experimental setup for visualizing refraction anomalies caused by high-intensity focused ultrasound (HIFU). The technique is based on Schlieren imaging, commonly used to visualize temperature and pressure differences in a medium. With this setup, double images of the Schlieren or their shadows to be investigated occur, so that the experimental setup is modified to avoid these double image artifacts.<BR><B>METHODS: </B>The optical setup mainly consists of a point light source, a parabolic mirror, and a camera. Birefringence artifacts are avoided by placing the point light source at a certain vertical distance to the camera, so that the light beam passes through the medium only once. The soundfield is generated by a HIFU transducer in a water tank placed in the beam path of the optical setup.<BR><B>RESULTS: </B>The experimental setup is capable of capturing Schlieren or shadow images. These images show the soundfield without disturbing double images and enable further analysis and qualitative assessment of the soundfield.<BR><B>CONCLUSIONS: </B>The presented setup provides a reliable and efficient method for visualizing refraction anomalies caused by the sonic field of a HIFU transducer and allows for accurate depiction of the refraction anomalies. The double images that usually occur are avoided.