Adapted directivity approach for photoacoustic imaging reconstruction

D. Piras, M. Heijblom, W. Xia, Ton van Leeuwen, Wiendelt Steenbergen, Srirang Manohar

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

Abstract

In photoacoustic imaging, upon short laser pulse irradiation, absorbers generate N-shaped pulses which can be detected by ultrasound transducers. Radio frequency signals from different spatial locations are then reconstructed taking into account the ultrasound transducer angular response. Usually, the directivity is part of the "a priori" characterization of the transducer and it is assumed to be constant in the reconstruction algorithm. This approach is valid in both transmission and reflection ultrasound imaging, where any echo resembles the transducer frequency response. Center frequency and bandwidth of any echo are almost the same, and the ultrasound transducer collect signals with the same "fixed" acceptance angle. In photoacoustics, instead, absorbers generate echoes whose time duration is proportional to the absorber size. Large absorbers generate low frequency echoes, whereas small absorber echoes are centered at higher frequencies. Thus for different absorber sizes, different pulse frequencies are obtained and different directivities need to be applied. For this purpose once a radio-frequency signal is aquired, it is pre-processed with a sliding window: every segment is Fourier transformed to extract the central frequency. Then, a proper directivity can be estimated for each segment. Finally signals can be reconstructed via a backprojection algorithm, according to the system's geometry. Echoes are backprojected over spheres with the angular extension being adapted to the frequency content of the photoacoustic sources. Simulation and experimental validation of this approach are discussed showing promising results in terms of image contrast and resolution.
Original languageEnglish
Title of host publicationPhotons Plus Ultrasound: Imaging and Sensing 2012
PublisherSPIE
Pages-
Number of pages6
DOIs
Publication statusPublished - 2012
EventPhotons Plus Ultrasound: Imaging and Sensing, SPIE BiOS 2012 - San Francisco, United States
Duration: 22 Jan 201224 Jan 2012

Publication series

Name
PublisherSPIE
Volume8223
ISSN (Print)0277-786X

Conference

ConferencePhotons Plus Ultrasound: Imaging and Sensing, SPIE BiOS 2012
Abbreviated titleSPIE BiOS
CountryUnited States
CitySan Francisco
Period22/01/1224/01/12

Fingerprint

directivity
absorbers
echoes
transducers
radio frequencies
pulses
image resolution
image contrast
acceptability
frequency response
sliding
low frequencies
bandwidth
irradiation
geometry
lasers
simulation

Keywords

  • IR-83161
  • METIS-289260

Cite this

Piras, D., Heijblom, M., Xia, W., van Leeuwen, T., Steenbergen, W., & Manohar, S. (2012). Adapted directivity approach for photoacoustic imaging reconstruction. In Photons Plus Ultrasound: Imaging and Sensing 2012 (pp. -). SPIE. https://doi.org/10.1117/12.907990
Piras, D. ; Heijblom, M. ; Xia, W. ; van Leeuwen, Ton ; Steenbergen, Wiendelt ; Manohar, Srirang. / Adapted directivity approach for photoacoustic imaging reconstruction. Photons Plus Ultrasound: Imaging and Sensing 2012. SPIE, 2012. pp. -
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title = "Adapted directivity approach for photoacoustic imaging reconstruction",
abstract = "In photoacoustic imaging, upon short laser pulse irradiation, absorbers generate N-shaped pulses which can be detected by ultrasound transducers. Radio frequency signals from different spatial locations are then reconstructed taking into account the ultrasound transducer angular response. Usually, the directivity is part of the {"}a priori{"} characterization of the transducer and it is assumed to be constant in the reconstruction algorithm. This approach is valid in both transmission and reflection ultrasound imaging, where any echo resembles the transducer frequency response. Center frequency and bandwidth of any echo are almost the same, and the ultrasound transducer collect signals with the same {"}fixed{"} acceptance angle. In photoacoustics, instead, absorbers generate echoes whose time duration is proportional to the absorber size. Large absorbers generate low frequency echoes, whereas small absorber echoes are centered at higher frequencies. Thus for different absorber sizes, different pulse frequencies are obtained and different directivities need to be applied. For this purpose once a radio-frequency signal is aquired, it is pre-processed with a sliding window: every segment is Fourier transformed to extract the central frequency. Then, a proper directivity can be estimated for each segment. Finally signals can be reconstructed via a backprojection algorithm, according to the system's geometry. Echoes are backprojected over spheres with the angular extension being adapted to the frequency content of the photoacoustic sources. Simulation and experimental validation of this approach are discussed showing promising results in terms of image contrast and resolution.",
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Piras, D, Heijblom, M, Xia, W, van Leeuwen, T, Steenbergen, W & Manohar, S 2012, Adapted directivity approach for photoacoustic imaging reconstruction. in Photons Plus Ultrasound: Imaging and Sensing 2012. SPIE, pp. -, Photons Plus Ultrasound: Imaging and Sensing, SPIE BiOS 2012, San Francisco, United States, 22/01/12. https://doi.org/10.1117/12.907990

Adapted directivity approach for photoacoustic imaging reconstruction. / Piras, D.; Heijblom, M.; Xia, W.; van Leeuwen, Ton; Steenbergen, Wiendelt; Manohar, Srirang.

Photons Plus Ultrasound: Imaging and Sensing 2012. SPIE, 2012. p. -.

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

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T1 - Adapted directivity approach for photoacoustic imaging reconstruction

AU - Piras, D.

AU - Heijblom, M.

AU - Xia, W.

AU - van Leeuwen, Ton

AU - Steenbergen, Wiendelt

AU - Manohar, Srirang

PY - 2012

Y1 - 2012

N2 - In photoacoustic imaging, upon short laser pulse irradiation, absorbers generate N-shaped pulses which can be detected by ultrasound transducers. Radio frequency signals from different spatial locations are then reconstructed taking into account the ultrasound transducer angular response. Usually, the directivity is part of the "a priori" characterization of the transducer and it is assumed to be constant in the reconstruction algorithm. This approach is valid in both transmission and reflection ultrasound imaging, where any echo resembles the transducer frequency response. Center frequency and bandwidth of any echo are almost the same, and the ultrasound transducer collect signals with the same "fixed" acceptance angle. In photoacoustics, instead, absorbers generate echoes whose time duration is proportional to the absorber size. Large absorbers generate low frequency echoes, whereas small absorber echoes are centered at higher frequencies. Thus for different absorber sizes, different pulse frequencies are obtained and different directivities need to be applied. For this purpose once a radio-frequency signal is aquired, it is pre-processed with a sliding window: every segment is Fourier transformed to extract the central frequency. Then, a proper directivity can be estimated for each segment. Finally signals can be reconstructed via a backprojection algorithm, according to the system's geometry. Echoes are backprojected over spheres with the angular extension being adapted to the frequency content of the photoacoustic sources. Simulation and experimental validation of this approach are discussed showing promising results in terms of image contrast and resolution.

AB - In photoacoustic imaging, upon short laser pulse irradiation, absorbers generate N-shaped pulses which can be detected by ultrasound transducers. Radio frequency signals from different spatial locations are then reconstructed taking into account the ultrasound transducer angular response. Usually, the directivity is part of the "a priori" characterization of the transducer and it is assumed to be constant in the reconstruction algorithm. This approach is valid in both transmission and reflection ultrasound imaging, where any echo resembles the transducer frequency response. Center frequency and bandwidth of any echo are almost the same, and the ultrasound transducer collect signals with the same "fixed" acceptance angle. In photoacoustics, instead, absorbers generate echoes whose time duration is proportional to the absorber size. Large absorbers generate low frequency echoes, whereas small absorber echoes are centered at higher frequencies. Thus for different absorber sizes, different pulse frequencies are obtained and different directivities need to be applied. For this purpose once a radio-frequency signal is aquired, it is pre-processed with a sliding window: every segment is Fourier transformed to extract the central frequency. Then, a proper directivity can be estimated for each segment. Finally signals can be reconstructed via a backprojection algorithm, according to the system's geometry. Echoes are backprojected over spheres with the angular extension being adapted to the frequency content of the photoacoustic sources. Simulation and experimental validation of this approach are discussed showing promising results in terms of image contrast and resolution.

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BT - Photons Plus Ultrasound: Imaging and Sensing 2012

PB - SPIE

ER -

Piras D, Heijblom M, Xia W, van Leeuwen T, Steenbergen W, Manohar S. Adapted directivity approach for photoacoustic imaging reconstruction. In Photons Plus Ultrasound: Imaging and Sensing 2012. SPIE. 2012. p. - https://doi.org/10.1117/12.907990