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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
1. Ability to detect deeply 1. Limited Path length
situated tumor and its 2. Temperature Dependence
vasculature
3. Weak absorption at short
2. Monitors angiogenesis
wavelengths
3. High resolution
4. Compatible to Ultra
Sound
5. High Penetration depth
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TIMELINE
Time
03/01 03/08
03/15 03/22
Task
Presentation 1
(Background,
Preparation and
plan)
Literature
Review
First Draft of
Paper
Improvisation of
first draft
Presentation 2
(Progress,results)
Second draft of
paper
Improvisation of
second draft
Presentation 3
Final Review
Paper
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03/29 04/05
04/12 04/19 04/26
05/03
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, 277–300
[2] Hou, Y., et al., Optical generation of high frequency ultrasound using twodimensional 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
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