Introduction to optoacoustic imaging Xos Lus Den Ben IBMI - - PowerPoint PPT Presentation

Introduction to optoacoustic imaging

Xosé Luís Deán Ben IBMI – Institute of Biological and Medical Imaging

16.01.2012

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Institute of Biological und Medical Imaging

Imaging: Seeing is believing

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Institute of Biological und Medical Imaging

Imaging modalities

Weissleder R. and Pittet M. J. Imaging in the era of molecular oncology. Nature 452:580-9 (2008)

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Institute of Biological und Medical Imaging

Why optical imaging?

(+) High resolution (+) Low cost (+) Safe, non-ionizing (+) Versatility of contrast agents (+) Intrinsic molecular and functional contrast (+) High sensitivity The interaction of photons with tissue components provides a suitable basis for functional and molecular imaging techniques

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Institute of Biological und Medical Imaging

Propagation of light within tissues (optical scattering)

No scattering Scattering

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Institute of Biological und Medical Imaging

Propagation of light within tissues (optical scattering)

Ntziachristos V. Going deeper than microscopy: the optical imaging frontier of biology. Nat. Methods 7:603-614 (2010)

No scattering Scattering

IBMI

Institute of Biological und Medical Imaging

Why diffuse optical imaging?

(+) High resolution (+) Low cost (+) Safe, non-ionizing (+) Versatility of contrast agents (+) Intrinsic molecular and functional contrast (+) High sensitivity The interaction of photons with tissue components provides a suitable basis for functional and molecular imaging techniques

Penetration depth [m] Imaging resolution [m] 10-6 10-5 10-2 10-3 10-2 10-3 10-4 10-5

Microscopy OPT SPIM 2P/MP Confocal MFT FMT DOT

?

Microscopic Mesoscopic Macroscopic

Optical imaging scales

Optoacoustics

The optoacoustic (photoacoustic) effect

Alexander Graham Bell (1847-1922)

Alexander Graham Bell discovered that you can generate sound by flashing a focused beam of light with rotating slotted disk onto selenium in 1880

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Institute of Biological und Medical Imaging

Optoacoustic imaging

Absorption of short- pulsed laser light Acoustic wave measurement at several locations Image reconstruction

Hardware Software

Optoacoustic imaging combines high contrast of pure optical methods with high spatial resolution of pure ultrasonic imaging Acoustic scattering is much lower than optical scattering in biological tissues

Intrinsic contrast (blood)

Laufer J. et al. Three-dimensional noninvasive imaging of the vasculature in the mouse brain using a high resolution photoacoustic scanner. Applied Optics 48:D299-306 (2009)

Optoacoustic tomography (reconstruction)

∫

− ∂ ∂ Γ =

) ( '

) ( ' | ' | ) ' ( 4 ) , (

t S

t dS H t c t p r r r r π

) , ( t p r

) ' (r H

Optical absorption Acoustic pressure Forward problem Inverse problem

?

Anatomical imaging

Brecht H. P. et al. Whole-body three-dimensional optoacoustic tomography system for small

• animals. Journal of Biomedical Optics 14:064007 (2009)

Anatomical imaging

Ma R. et al. Non-invasive whole-body imaging of adult zebrafish with optoacoustic tomography (under review)

Optoacoustic microscopy

Wang L. V. Multiscale photoacoustic microscopy and computed tomography. Nat. Photonics 3:503-9 (2009)

Functional imaging (single-wavelength)

Wang X. et al. Noninvasive laser-induced photoacoustic tomography for structural and functional in vivo imaging of the brain. Nat. Biotechnology 21:803-6 (2003)

Optoacoustic signals are sensitive to functional cerebral hemodynamic changes in response to whisker stimulation

Functional imaging (multiple wavelengths)

Zhang H. F. Functional photoacoustic microscopy for high-resolution and noninvasive in vivo imaging. Nat. Biotechnology 24:848-51 (2006)

Molecular imaging (multispectral optoacoustic tomography)

The spectral dependence of the absortion is different for different substances HbO2 GoldNR AF750 Hb The distribution of a given substance (component) is estimated by unmixing images at several wavelengths

Razansky D. et al. Multispectral photoacoustic imaging of fluorochromes in small animals. Optics Letters 32:2891-3 (2007)

Molecular imaging (multispectral optoacoustic tomography)

Razansky D. et al. Multispectral opto-acoustic tomography of deep-seated fluorescent proteins in vivo. Nat. Photonics 3:412-7 (2009)

Real-time imaging

Buehler A. et al. Video rate optoacoustic tomography of mouse kidney perfusion. Optics Letters 35:2475-7 (2010)

Endoscopy

Yang J. M. et al. Photoacoustic endoscopy. Optics Letters 34:1591-3 (2009)

• Neuroscience (probably with the help of cranial windows, where sO2

is related to neural activities)

Prospective applications

• Cancer research (angiogenesis is highly correlated with the severity
• f tumors)
• Cardiovascular imaging (hemoglobin provides an excellent contrast)
• Cancer radiotherapy and chemotherapy (hypoxia is often

responsible for resistance to therapy)

• Trauma evaluation (optical absorption is associated with both

hemorrhage and edema)

• Endoscopic imaging (with miniaturized optical and ultrasonic

components integrated into a single probe)

• Molecular Imaging (using endogenous and exogenous contrast)

Acknowledgments

INSTITUTE OF BIOLOGICAL AND MEDICAL IMAGING

• Prof. Dr. Vasilis Ntziachristos
• Dr. Daniel Razansky

All scientists and staff

Thank you