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Medical optical imaging

April 27, 2023

Medical optical imaging is the use of light as an investigational imaging technique for medical applications. Examples include optical microscopy, spectroscopy, endoscopy, scanning laser ophthalmoscopy, laser Doppler imaging, and optical coherence tomography. Because light is an electromagnetic wave, similar phenomena occur in X-rays, microwaves, and radio waves.

Optical imaging systems may be divided into diffusive[1][2] and ballistic imaging[3] systems. A model for photon migration in turbid biological media has been developed by Bonner et al.[2] Such a model can be applied for interpretation data obtained from laser Doppler blood-flow monitors and for designing protocols for therapeutic excitation of tissue chromophores.

Diffusive optical imaging

Diffuse optical imaging (DOI) is a method of imaging using near-infrared spectroscopy (NIRS) [4] or fluorescence-based methods.[5] When used to create 3D volumetric models of the imaged material DOI is referred to as diffuse optical tomography, whereas 2D imaging methods are classified as diffuse optical topography.

The technique has many applications to neuroscience, sports medicine, wound monitoring, and cancer detection. Typically DOI techniques monitor changes in concentrations of oxygenated and deoxygenated hemoglobin and may additionally measure redox states of cytochromes. The technique may also be referred to as diffuse optical tomography (DOT), near infrared optical tomography (NIROT) or fluorescence diffuse optical tomography (FDOT), depending on the usage.

In neuroscience, functional measurements made using NIR wavelengths, DOI techniques may classify as functional near infrared spectroscopy (fNIRS).

Ballistic optical imaging

Ballistic photons are the light photons that travel through a scattering (turbid) medium in a straight line. Also known as ballistic light. If laser pulses are sent through a turbid medium such as fog or body tissue, most of the photons are either randomly scattered or absorbed. However, across short distances, a few photons pass through the scattering medium in straight lines. These coherent photons are referred to as ballistic photons. Photons that are slightly scattered, retaining some degree of coherence, are referred to as snake photons.

If efficiently detected, there are many applications for ballistic photons especially in coherent high resolution medical imaging systems. Ballistic scanners (using ultrafast time gates) and optical coherence tomography (OCT) (using the interferometry principle) are just two of the popular imaging systems that rely on ballistic photon detection to create diffraction-limited images. Advantages over other existing imaging modalities (e.g., ultrasound and magnetic resonance imaging) is that ballistic imaging can achieve a higher resolution in the order of 1 to 10 micro-meters, however it has limited imaging depth. Furthermore, more scattered 'quasi-ballistic' photons are often measured as well to increase the signal 'strength' (i.e., signal-to-noise ratio).

Due to the exponential reduction (with respect to distance) of ballistic photons in a scattering medium, often image processing techniques are applied to the raw captured ballistic images, to reconstruct high quality ones. Ballistic imaging modalities aim to reject non-ballistic photons and retain ballistic photons that carry useful information. To perform this task, specific characteristics of ballistic photons vs. non-ballistic photons are used, such as time of flight through coherence gated imaging, collimation, wavefront propagation, and polarization.[6]

See also

References

  1. ^ Durduran T; et al. (2010). "Diffuse optics for tissue monitoring and tomography". Rep. Prog. Phys. 73 (7): 076701. Bibcode:2010RPPh...73g6701D. doi:10.1088/0034-4885/73/7/076701. PMC 4482362. PMID 26120204.
  2. ^ a b A. Gibson; J. Hebden; S. Arridge (2005). "Recent advances in diffuse optical imaging" (PDF). Phys. Med. Biol. 50 (4): R1–R43. doi:10.1088/0031-9155/50/4/r01. PMID 15773619. S2CID 23029891.[permanent dead link]
  3. ^ S. Farsiu; J. Christofferson; B. Eriksson; P. Milanfar; B. Friedlander; A. Shakouri; R. Nowak (2007). "Statistical Detection and Imaging of Objects Hidden in Turbid Media Using Ballistic Photons" (PDF). Applied Optics. 46 (23): 5805–5822. Bibcode:2007ApOpt..46.5805F. doi:10.1364/ao.46.005805. PMID 17694130.
  4. ^ Durduran, T; et al. (2010). "Diffuse optics for tissue monitoring and tomography". Rep. Prog. Phys. 73 (7): 076701. Bibcode:2010RPPh...73g6701D. doi:10.1088/0034-4885/73/7/076701. PMC 4482362. PMID 26120204.
  5. ^ . Archived from the original on June 16, 2012. Retrieved August 20, 2012.
  6. ^ Lihong V. Wang; Hsin-i Wu (26 September 2012). Biomedical Optics: Principles and Imaging. John Wiley & Sons. pp. 3–. ISBN 978-0-470-17700-6.

External links

  • Medical Optics Group at ICFO, Barcelona, Spain
  • – Resource to better understand the benefits of Near-Infrared imaging.
  • DOI at Massachusetts General Hospital, Boston
  • Biomedical Imaging Group at Dartmouth
  • DOS/I Lab at the Beckman Laser Institute, University of California, Irvine
  • A review article in the field by A.P. Gibson et al.
  • Illinois ECE 460 Principles of Optical Imaging Course lecture notes
  • MRRA Inc. fNIRS Systems [1]

April 27, 2023
medical, optical, imaging, light, investigational, imaging, technique, medical, applications, examples, include, optical, microscopy, spectroscopy, endoscopy, scanning, laser, ophthalmoscopy, laser, doppler, imaging, optical, coherence, tomography, because, li. Medical optical imaging is the use of light as an investigational imaging technique for medical applications Examples include optical microscopy spectroscopy endoscopy scanning laser ophthalmoscopy laser Doppler imaging and optical coherence tomography Because light is an electromagnetic wave similar phenomena occur in X rays microwaves and radio waves Optical imaging systems may be divided into diffusive 1 2 and ballistic imaging 3 systems A model for photon migration in turbid biological media has been developed by Bonner et al 2 Such a model can be applied for interpretation data obtained from laser Doppler blood flow monitors and for designing protocols for therapeutic excitation of tissue chromophores Contents 1 Diffusive optical imaging 2 Ballistic optical imaging 3 See also 4 References 5 External linksDiffusive optical imaging EditDiffuse optical imaging DOI is a method of imaging using near infrared spectroscopy NIRS 4 or fluorescence based methods 5 When used to create 3D volumetric models of the imaged material DOI is referred to as diffuse optical tomography whereas 2D imaging methods are classified as diffuse optical topography The technique has many applications to neuroscience sports medicine wound monitoring and cancer detection Typically DOI techniques monitor changes in concentrations of oxygenated and deoxygenated hemoglobin and may additionally measure redox states of cytochromes The technique may also be referred to as diffuse optical tomography DOT near infrared optical tomography NIROT or fluorescence diffuse optical tomography FDOT depending on the usage In neuroscience functional measurements made using NIR wavelengths DOI techniques may classify as functional near infrared spectroscopy fNIRS Ballistic optical imaging EditBallistic photons are the light photons that travel through a scattering turbid medium in a straight line Also known as ballistic light If laser pulses are sent through a turbid medium such as fog or body tissue most of the photons are either randomly scattered or absorbed However across short distances a few photons pass through the scattering medium in straight lines These coherent photons are referred to as ballistic photons Photons that are slightly scattered retaining some degree of coherence are referred to as snake photons If efficiently detected there are many applications for ballistic photons especially in coherent high resolution medical imaging systems Ballistic scanners using ultrafast time gates and optical coherence tomography OCT using the interferometry principle are just two of the popular imaging systems that rely on ballistic photon detection to create diffraction limited images Advantages over other existing imaging modalities e g ultrasound and magnetic resonance imaging is that ballistic imaging can achieve a higher resolution in the order of 1 to 10 micro meters however it has limited imaging depth Furthermore more scattered quasi ballistic photons are often measured as well to increase the signal strength i e signal to noise ratio Due to the exponential reduction with respect to distance of ballistic photons in a scattering medium often image processing techniques are applied to the raw captured ballistic images to reconstruct high quality ones Ballistic imaging modalities aim to reject non ballistic photons and retain ballistic photons that carry useful information To perform this task specific characteristics of ballistic photons vs non ballistic photons are used such as time of flight through coherence gated imaging collimation wavefront propagation and polarization 6 See also EditBallistic photon Diffuse optical imaging Optical coherence tomography Optical tomography Photon diffusion Photon diffusion equation Laser Doppler imagingReferences Edit Durduran T et al 2010 Diffuse optics for tissue monitoring and tomography Rep Prog Phys 73 7 076701 Bibcode 2010RPPh 73g6701D doi 10 1088 0034 4885 73 7 076701 PMC 4482362 PMID 26120204 a b A Gibson J Hebden S Arridge 2005 Recent advances in diffuse optical imaging PDF Phys Med Biol 50 4 R1 R43 doi 10 1088 0031 9155 50 4 r01 PMID 15773619 S2CID 23029891 permanent dead link S Farsiu J Christofferson B Eriksson P Milanfar B Friedlander A Shakouri R Nowak 2007 Statistical Detection and Imaging of Objects Hidden in Turbid Media Using Ballistic Photons PDF Applied Optics 46 23 5805 5822 Bibcode 2007ApOpt 46 5805F doi 10 1364 ao 46 005805 PMID 17694130 Durduran T et al 2010 Diffuse optics for tissue monitoring and tomography Rep Prog Phys 73 7 076701 Bibcode 2010RPPh 73g6701D doi 10 1088 0034 4885 73 7 076701 PMC 4482362 PMID 26120204 Harvard edu Diffuse Optical Imaging Archived from the original on June 16 2012 Retrieved August 20 2012 Lihong V Wang Hsin i Wu 26 September 2012 Biomedical Optics Principles and Imaging John Wiley amp Sons pp 3 ISBN 978 0 470 17700 6 External links EditMedical Optics Group at ICFO Barcelona Spain Understanding Near Infrared Imaging Resource to better understand the benefits of Near Infrared imaging Diffuse Optics Lab at University of Pennsylvania Philadelphia DOI at Massachusetts General Hospital Boston Biomedical Imaging Group at Dartmouth DOS I Lab at the Beckman Laser Institute University of California Irvine A review article in the field by A P Gibson et al An article on optical breast imaging Illinois ECE 460 Principles of Optical Imaging Course lecture notes MRRA Inc fNIRS Systems 1 Retrieved from https en wikipedia org w index php title Medical optical imaging amp oldid 1146695589, wikipedia, wiki, book, books, library,

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