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Proceedings Paper

Regional sensitivity comparison between optical and acousto-optic sensing
Author(s): Sonny Gunadi; Terence S. Leung
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Paper Abstract

Optical systems based on near infrared spectroscopy probe biological tissue oxygenation of a relatively large region. The acousto-optic (AO) method can tag photons by focused ultrasound in a region of interest within the tissue for potential localized oxygenation sensing. This study aimed to compare the regional sensitivity between the optical and AO sensing techniques. The regional sensitivity was defined as the amount of change observed in the measured signal in response to a small localized change in the optical absorption. In both reflection and transmission configurations, optical systems based on a single source and detector have been shown to be more sensitive to the absorption variation in the superficial region. The results demonstrate that the AO sensitivity region depends on the location of the ultrasound focal region as well as the distribution of the optical fluence. In the transmission mode, the optimal AO sensitivity region has been found to be in the ultrasound focal region. In the reflection mode, however, the optimal sensitivity region of AO does not always coincide with the location of the ultrasound focal region. Instead, the AO measurement is also sensitive to the local absorption change in regions between the ultrasound focal region and the optical probes. In general, the AO method can probe deeper into the phantom as compared to the optical measurements.

Paper Details

Date Published: 28 February 2011
PDF: 7 pages
Proc. SPIE 7899, Photons Plus Ultrasound: Imaging and Sensing 2011, 78992Q (28 February 2011); doi: 10.1117/12.874033
Show Author Affiliations
Sonny Gunadi, Univ. College London (United Kingdom)
Terence S. Leung, Univ. College London (United Kingdom)

Published in SPIE Proceedings Vol. 7899:
Photons Plus Ultrasound: Imaging and Sensing 2011
Alexander A. Oraevsky; Lihong V. Wang, Editor(s)

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