Multicolor photoacoustic imaging by a single transducer with piezoelectric copolymer film in a wide frequency range

Tsutomu Ohmori; Miya Ishihara; Kazuhiro Tsujita; Isao Bansaku; Makoto Kikuchi

doi:10.1117/12.841948

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25 February 2010 Multicolor photoacoustic imaging by a single transducer with piezoelectric copolymer film in a wide frequency range

Tsutomu Ohmori, Miya Ishihara, Kazuhiro Tsujita, Isao Bansaku, Makoto Kikuchi

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Proceedings Volume 7564, Photons Plus Ultrasound: Imaging and Sensing 2010; 75642V (2010) https://doi.org/10.1117/12.841948
Event: SPIE BiOS, 2010, San Francisco, California, United States

Abstract

We built a photoacoustic tomographic (PAT) imaging system by scanning a single detector (φ 3.5 mm) made of piezoelectric copolymer poly(vinylidene difluoride-trifluoroethylene), P(VDF-TrFE), which had been fabricated for diagnostic photoacoustic measurement of cartilage tissues in our group. The PAT images of a phantom were obtained at two excitation wavelength of 687.5 nm and 795 nm. The phantom was made of agar including a black hair and agarose gels dissolving indocyanine green (ICG) and methylene blue (MB). Laser pulses (685-900 nm) were generated from a Ti:Sappire tunable laser to excite ICG and MB molecules. The PAT image at 687.5 nm shows signals due to all absorption sources. This is good agreement with dimension of the phantom. The PAT image at 795 nm shows a strong signal due to the ICG-dyed gel and almost no signal due to the MB-dyed gel. This result indicated that absorption sources were extracted by excitation wavelength according to their absorption spectra. The signal/noise ratio of the PAT images were compared between the P(VDF-TrFE) transducer in our group and a PZT transducer (Parametrics V309, 5 MHz, φ 12.7 mm) which is commercially available. The P(VDF-TrFE) transducer was more sensitive by 9 times (120 times per area) than the PZT transducer. By using this imaging system with a P(VDF-TrFE) transducer which is highly sensitive in a wide frequency range, we will achieve frequency analysis of the PAT images to associate photoacoustic waveforms with physical properties of sample tissues.

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Tsutomu Ohmori, Miya Ishihara, Kazuhiro Tsujita, Isao Bansaku, and Makoto Kikuchi "Multicolor photoacoustic imaging by a single transducer with piezoelectric copolymer film in a wide frequency range", Proc. SPIE 7564, Photons Plus Ultrasound: Imaging and Sensing 2010, 75642V (25 February 2010); https://doi.org/10.1117/12.841948

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