Abstract
High intensity focused ultrasound (HIFU) is a powerful noninvasive tool for targeted tissue ablation. Monitoring of the treatment process and efficacy in real time, however, remains challenging. The tissue necrosis during the HIFU exposure leads to changes in optical absorption and scattering coefficients. In this paper, we explore the use of acousto-optic imaging (AOI), a hybrid technique that combines ultrasound with diffuse light to obtain deep-tissue optical contrast at ultrasound resolution, to sense the changes in optical contrast at depth in tissue associated with the onset formation and development of the necrosed tissue region. In this technique, the tissue to be treated is illuminated with near-infrared light and a continuous, amplitude-modulated focused ultrasound beam is used to induce thermal tissue necrosis as well as the acousto-optic (AO) interaction. The AOI signal is detected via a photorefractive crystal (PRC)-based interferometer, and then fed into a lock-in amplifier tuned to the ultrasound modulation frequency. As a thermal lesion forms in the ultrasound focal zone, which is also the zone of AO interaction, the AOI signal diminishes in amplitude owing to enhanced optical attenuation. It is further shown that the reduction of the AOI signal is correlated with the volume of ensuing lesion. Therefore, the evolution of AOI signal as a function of time provides a means for continuous monitoring of HIFU treatment process as well as exposure guidance.
Original language | English |
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Title of host publication | Photons Plus Ultrasound |
Subtitle of host publication | Imaging and Sensing 2010 |
Volume | 7564 |
DOIs | |
Publication status | Published - 3 May 2010 |
Externally published | Yes |
Event | Photons Plus Ultrasound: Imaging and Sensing 2010 - San Francisco, CA, United States Duration: 24 Jan 2010 → 26 Jan 2010 |
Conference
Conference | Photons Plus Ultrasound: Imaging and Sensing 2010 |
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Country/Territory | United States |
City | San Francisco, CA |
Period | 24/01/10 → 26/01/10 |
Keywords
- Acousto-optic imaging
- High intensity focused ultrasound
- Lesion volume
- Photorefractive crystal
- Treatment monitoring and guidance
- Ultrasound-modulated optical tomography
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Electronic, Optical and Magnetic Materials
- Biomaterials
- Radiology Nuclear Medicine and imaging