PHOTOACOUSTIC PROBE FOR TUMOR DETECTION

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PHOTOACOUSTIC PROBE FOR TUMOR DETECTION

• HAIFENG WANG
• SUBHASHINI PAKALAPATI
• VU TRAN
• Department of Electrical and Computer Engineering
• University of Massachusetts Lowell

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OUTLINE

• Introduction
• Principle of Ultrasound
• What is Photoacoustic (PA)
• Fiber-optic Source and Receiver
• System of PA
• How to fabricate
• How PA system can detect tumor
• Advantages and Disadvantages
• Timeline
• Tasks
• Reference

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INTRODUCTION

• Cancer killed 570 000 people in 2010 in the USA.
• Lot of methods to detect/predict tumor US,
  x-ray, CT, MRI, PET, SPECT, etc.
• Photoacoustic (PA) takes advantage of fiber optic
  and ultrasound to detect tumor

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PRINCIPLE OF ULTRASOUND

• Transducer emit ultrasound wave and get signals
  back from object
• D t.v
• Scan volume to get image

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WHAT IS PHOTOACOUSTIC?

• Conversion of photons to acoustic wave due to
  absorption and localized thermal excitation.
• Pulses of light is absorbed, energy will be
  radiated as heat.
• Heat causes detectable sound waves due to
  pressure variation.

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PHOTOACOUSTIC (Cont.)
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DIAGRAM OF A TYPICAL PA SYSTEM

• Themo-elastic Ultrsound Generation
• Extrinsic fiber hydrophone, based on a
  Fabry-Perot interferometer

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FIBER OPTIC ULTRASONIC SOURCE BASED ON
OPTO-ACOUSTIC CONVERSION
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FIBER OPTIC ULTRASONIC RECEIVER BASED ON
ACOUSTO-OPTIC CONVERSION
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TRANSMISSION STRUCTURE

• 2D gold nanoparticle array sandwiched between a
  transparent substrate and a PDMS layer

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GOLD NANOSTRUCTURE
The top view (a) and sketch of the side view( b)
of the gold nanostructure.
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DETECTION OF TUMOR USING PAI

• Tumors have dense and unorganized vasculature.
• High density of blood vessels in tumors enhances
  PAI contrast.

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DETECTION OF TUMOR (CONT.)

• Endogenous PA contrast
• Melanin
• Oxy Hemoglobin
• Deoxy Hemoglobin
• Exogenous PA contrast (Highly sensitive to deeply
  situated tumors)
• Au NP
• Alexa Fluor
• Indocyanine Green

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ADVANTAGES
DISADVANTAGES

• Ability to detect deeply situated tumor and its
  vasculature
• Monitors angiogenesis
• High resolution
• Compatible to Ultra Sound
• High Penetration depth

1. Limited Path length 2. Temperature Dependence 3
. Weak absorption at short wavelengths
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TIMELINE
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TASKS

• HAIFENG WANG
• Principle of Photoacoustic
• Fabricate PA structure
• SUBHASHINI PAKALAPATI
• Principle and procedure of tumor detection using
  PA
• AuNP enhanced
• VU TRAN
• Compare other methods to detect tumor
• AuNP enhanced

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REFERENCES

• 1 Jemal,A. et al. Cancer Statistics, 2010. CA
  CancerJ.Clin. 60, 277300
• 2 Hou, Y., et al., Optical generation of high
  frequency ultrasound using two-dimensional gold
  nanostructure. Applied Physics Letters, 2006.
  89(9) p. 093901-3.
• 3 Mallidi, S., G.P. Luke, and S. Emelianov,
  Photoacoustic imaging in cancer detection,
  diagnosis, and treatment guidance. Trends
  Biotechnol, 2011.
• 4 Tang, M.X., et al., Photoacoustics,
  thermoacoustics, and acousto-optics for
  biomedical imaging. Proc Inst Mech Eng H, 2010.
  224(2) p. 291-306.
• 5 Wang, X., et al., Photoacoustic tomography a
  potential new tool for prostate cancer. Biomed
  Opt Express, 2011. 1(4) p. 1117-1126.

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THANK YOU