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Proceedings Paper

Near-infrared photoacoustic diagnostics in biomedicine: analysis of thermal safety and light-tissue interactions
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Paper Abstract

Medical diagnostic devices based on photoacoustics represent an emerging area with significant potential for evaluation of brain injury and chemical agent exposure, as well as detection of pandemic diseases and cancer. However, few studies have addressed photothermal safety of these devices which emit high-power laser pulses to generate rapid, selective, yet non-destructive heating of subsurface structures. Towards elucidation of laser-tissue interactions and factors of safety for photothermal injury, we have developed a three-dimensional numerical model including light propagation, heat transfer and thermal damage algorithms. Literature surveys were performed to identify appropriate optical properties and the range of device exposure levels implemented in prior in vivo studies. Initial simulations provided model validation against results from the literature. Simulations were then performed based on breast tissue with discrete blood vessels irradiated by a train of laser pulses (10 Hz) at 800 and 1064 nm. For a constant exposure level, increasing beam diameter from 0.2 to 2.0 cm led to a factor of 2.5 increase in subsurface heat generation rates. Our preliminary modeling results indicate that for a 10 second tissue exposure under standard photoacoustic imaging conditions, irradiance-based safety limits should provide a factor of safety of 6 or greater over exposure levels that induce thermal coagulation. Opticalthermal modeling represents a powerful tool for elucidating photothermal effects relevant to the safety and effectiveness of photoacoustic systems.

Paper Details

Date Published: 31 May 2013
PDF: 12 pages
Proc. SPIE 8719, Smart Biomedical and Physiological Sensor Technology X, 87190X (31 May 2013); doi: 10.1117/12.2018311
Show Author Affiliations
Taylor Gould, U.S. Food and Drug Administration (United States)
Quanzeng Wang, U.S. Food and Drug Administration (United States)
Do-Hyun Kim, U.S. Food and Drug Administration (United States)
Joshua Pfefer, U.S. Food and Drug Administration (United States)


Published in SPIE Proceedings Vol. 8719:
Smart Biomedical and Physiological Sensor Technology X
Brian M. Cullum; Eric S. McLamore, Editor(s)

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