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PHOTOACOUSTIC IMAGING TO DETECT TUMOR. HAIFENG WANG SUBHASHINI PAKALAPATI VU TRAN Department of Electrical and Computer Engineering University of Massachusetts Lowell. OUTLINE. Introduction Brief Principle of Photoacoustic (PA) Different Techniques of PAI - PowerPoint PPT Presentation


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Department of Electrical and Computer EngineeringUniversity of Massachusetts Lowell1OUTLINEIntroductionBriefPrinciple of Photoacoustic (PA)Different Techniques of PAIComparison of Various Imaging TechniquesAdvantages and DisadvantagesConclusionReference22BriefConversion of photons to acoustic waves 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.

33D photoacoustic imaging of melanoma in vivo.

4The picture is from Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis

Ultrasound applications:Ultrasound in optical fibersIntroduction of Ultrasound

Advantages of the all optical fiber ultrasonic generator-receiver: compact size. Can be used in a limited space such as artery.5Principle of photoacousticOptical fiberEnergy absorption layerLaser excitation

Acoustic signalsThe light energy is converted into thermal energy via energy absorption layer;The thermal energy converts into mechanical wave because of thermal expansion;An acoustic wave is generated.Principle of photoacoustic by gold nanoparticleOptical fiberEnergy absorption layerGoldnanoparticleLaser pulseSound pulseLaser excitation

Acoustic signalsExperimental set up of photoacoustic molecular imaging

The pictureSeunghan Ha, Andrew Carson, Ashish Agarwal, Nicholas A. Kotov, and Kang Kim; Detection and monitoring of the multiple inflammatory responses by photoacoustic molecular imaging using selectively targeted gold nanorods Seunghan Ha, Andrew Carson, Ashish Agarwal, Nicholas A. Kotov, and Kang Kim; Detection and monitoring of the multiple inflammatory responses by photoacoustic molecular imaging using selectively targeted gold nanorods , Optical Society of America , 1 March 2011 / Vol. 2, No. 3 / BIOMEDICAL OPTICS EXPRESS 645 8A typical PAT/TAT system9

The picture is from OptoSonics, Inc and Fairway Medical Technologies, Inc.

Photoacoustic waves are generated proportional to the distribution of optical absorption in the target, and are detected by an ultrasonic transducer9Tumor Detection Using Endogenous Contrast

Xueding Wang, William W. Roberts, Paul L. Carson, David P. Wood and J. Brian Fowlkes, Photoacoustic tomography: a potential new tool for prostate cancer, 2010 :Vol. 1, No. 4 : Biomedical Optics Express 1117

Using Exogenous Contrast3-D photoacoustic imaging Evans Blue acted as a contrast agent.Deep lying blood vessels in real tissue samples were imaged at depths of 5 mm and at 9 mm from the plane of detection.The sensitivity of the technique was proven by photoacoustic detection of single red blood cells upon a glass plate. C.G.A Hoelen,1998PAImaging Using Gold Nano Particles13

Qizhi Zhang,201014

Qizhi Zhang,2010COMPARISON OF DIFFERENT IMAGING TECHNIQUES:ULTRASOUNDTransducer emit ultrasound wave and get signals back from object. D= t.vScan volume to get imagePros & cons: No side effects but low resolution

15COMPUTED TOMOGRAPHYUse X-ray to collect dataDetector collects the sum of absorption factors in one directionUsing the computing algorithms, the absorption factor of each voxel will be calculated.3D image will be constructed based on these factors. Pros & cons: 3D, high resolution but increase the risk of cancer in those exposed16

MRIA powerful magnetic field is used to align the magnetization of Hydrogen atoms in the bodyRadio frequency fields are used to alter the alignment of this magnetizationNuclei to produce a rotating magnetic field detectable by the scannerPros and Cons: 3D, good contrast but make acoustic noise and may effect on some implants in patients17

POSITRON EMISSION TOMOGRAPHYPositron-emitting radionuclide (tracer) is introduced into the body on a biologically active moleculeSystem detects pairs of gamma rays emitted indirectly by a tracerThree-dimensional images of tracer concentration within the body are then constructed by computer analysis18

Photoacoustic ImagingPAI: Combine advantages of optical (high contrast) and ultrasound (great imaging depth and high resolution): high optical contrast images microscale resolution reasonable penetration depth19ADVANTAGESAbility to detect deeply situated tumor and its vasculatureMonitors angiogenesisHigh resolutionCompatible to Ultra SoundHigh penetration depthNon-ionizing/Non-radioactivitySmall sizeEasy to clean and maintenanceNo acoustic noise

1. Limited path length2. Temperaturedependence3. Weak absorption at short wavelengths

DISADVANTAGES20ConclusionPAI has an edge over other imaging modalities.Though it is in its infancy and there have as yet been no large clinical trials,many initial studies have demonstrated the possibilities for its application in the biomedical field. Clearly, we should expect to see many exciting clinical applications of PA technologies in the near future.21References1.Fass, L., Imaging and cancer: A review. Molecular oncology, 2008. 2(2): p. 115-152.2.Hall, E.J. and D.J. Brenner, Cancer risks from diagnostic radiology. Br J Radiol, 2008. 81(965): p. 362-378.3.De Santis, M., et al., Radiation effects on development. Birth Defects Res C Embryo Today, 2007. 81(3): p. 177-82.4.Brenner, D., Should we be concerned about the rapid increase in CT usage? Reviews on environmental health, 2010. 25(1): p. 63-68.5.Rapacholi, M.H., Essentials of Medical Ultrasound: A Practical Introduction to the Principles, Techniques and Biomedical Applications. 1982.6.Khan, T.S., et al., 11C-metomidate PET imaging of adrenocortical cancer. Eur J Nucl Med Mol Imaging, 2003. 30(3): p. 403-10.7.Minn, H., et al., Imaging of Adrenal Incidentalomas with PET Using 11C-Metomidate and 18F-FDG. J Nucl Med, 2004. 45(6): p. 972-979.8.Young, H., et al., Measurement of clinical and subclinical tumour response using [18F]-fluorodeoxyglucose and positron emission tomography: review and 1999 EORTC recommendations. European Organization for Research and Treatment of Cancer (EORTC) PET Study Group. European journal of Cancer, 1999. 35(13): p. 1773-1782.9.Amen, D.G. and B.D. Carmichael, High-Resolution Brain SPECT Imaging in ADHD. Annals of Clinical Psychiatry, 1997. 9(2): p. 81-86.10.Amen, D.G., C. Hanks, and J. Prunella, Predicting positive and negative treatment responses to stimulants with brain SPECT imaging. J Psychoactive Drugs, 2008. 40(2): p. 131-8.11.Bonte, F.J., et al., Tc-99m HMPAO SPECT in the differential diagnosis of the dementias with histopathologic confirmation. Clin Nucl Med, 2006. 31(7): p. 376-8.12.Massoud, T.F. and S.S. Gambhir, Molecular imaging in living subjects: seeing fundamental biological processes in a new light. Genes Dev, 2003. 17(5): p. 545-80.13.Gibson, A.P., J.C. Hebden, and S.R. Arridge, Recent advances in diffuse optical imaging. Phys Med Biol, 2005. 50(4): p. R1-43.14.Kovar, J.L., et al., A systematic approach to the development of fluorescent contrast agents for optical imaging of mouse cancer models. Anal Biochem, 2007. 367(1): p. 1-12.15.Frangioni, J.V., New Technologies for Human Cancer Imaging. Journal of Clinical Oncology, 2008. 26(24): p. 4012-4021.16.Zhang, H.F., et al., Functional photoacoustic microscopy for high-resolution and noninvasive in vivo imaging. Nat Biotechnol, 2006. 24(7): p. 848-51.17.Siphanto, R.I., et al., Serial noninvasive photoacoustic imaging of neovascularization in tumor angiogenesis. Opt Express, 2005. 13(1): p. 89-95.18.Emelianov, S.Y., et al., Synergy and Applications of Combined Ultrasound, Elasticity, and Photoacoustic Imaging. IEEE Ultrasonics Symposium (2006), 2006: p. 405-415.19.Jose, J., et al., Imaging of tumor vasculature using Twente photoacoustic systems. Journal of Biophotonics, 2009. 2(12): p. 701-717.