3 March 2014 Differentiating fatty and non-fatty tissue using photoacoustic imaging
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In this paper, we demonstrate a temporal-domain intensity-based photoacoustic imaging method that can differentiate between fatty and non-fatty tissues. PA pressure intensity is partly dependent on the tissue’s speed of sound, which increases as temperature increases in non-fatty tissue and decreases in fatty tissue. Therefore, by introducing a temperature change in the tissue and subsequently monitoring the change of the PA intensity, it is possible to distinguish between the two types of tissue. A commercial ultrasound system with a 128-element 5-14 MHz linear array transducer and a tunable ND:YAG laser were used to produce PA images. Ex-vivo bovine fat and porcine liver tissues were precooled to below 10°C and then warmed to room-temperature over ~1 hour period. A thermocouple monitored the temperature rise while PA images were acquired at 0.5°C intervals. The averaged intensity of the illuminated tissue region at each temperature interval was plotted and linearly fitted. Liver samples showed a mean increase of 2.82 %/°C, whereas bovine fat had a mean decrease of 6.24 %/°C. These results demonstrate that this method has the potential to perform tissue differentiation in the temporal-domain.
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Leo Pan, Leo Pan, Robert Rohling, Robert Rohling, Purang Abolmaesumi, Purang Abolmaesumi, Septimiu Salcudean, Septimiu Salcudean, Shuo Tang, Shuo Tang, "Differentiating fatty and non-fatty tissue using photoacoustic imaging", Proc. SPIE 8943, Photons Plus Ultrasound: Imaging and Sensing 2014, 894354 (3 March 2014); doi: 10.1117/12.2041047; https://doi.org/10.1117/12.2041047

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