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Optical Coherence Tomography for Dermatological Applications

Borup Thomsen, Jakob LU (2011) In Lund Reports on Atomic Physics LRAP-433.
Abstract (Swedish)
Popular Abstract in English

Cancer diagnostics is an increasingly important task in the modern world due to an increasing cancer incidence and because diagnostics and treatment are given higher priority. There are many requirements to a diagnostic system. First of all it is important to provide an accurate diagnosis to be able to choose the right treatment. In addition, it is preferable that the method is non-invasive opposite the common used biopsy. Moreover, a relative quick method without any post processing is advantageous. Finally, a relative cheap method is preferable not to prevent widespread use. In general there are no diagnostic systems today fulfilling all criteria mentioned above. Therefore intensive research in... (More)
Popular Abstract in English

Cancer diagnostics is an increasingly important task in the modern world due to an increasing cancer incidence and because diagnostics and treatment are given higher priority. There are many requirements to a diagnostic system. First of all it is important to provide an accurate diagnosis to be able to choose the right treatment. In addition, it is preferable that the method is non-invasive opposite the common used biopsy. Moreover, a relative quick method without any post processing is advantageous. Finally, a relative cheap method is preferable not to prevent widespread use. In general there are no diagnostic systems today fulfilling all criteria mentioned above. Therefore intensive research in new diagnostic systems is performed including optical methods. Optical coherence tomography (OCT) is a non-invasive optical technique providing real time images of tissue with a resolution of about 10 micrometer. The technique is simple and therefore relative low cost commercial systems are potentially realizable. However, it is still an open question whether OCT images can replace biopsies.



The scope of this project is to investigate if OCT can contribute to an improved diagnosis of skin diseases, in particular skin cancer. This has been accomplished by performing clinical measurements as well as improvement and tailoring of the technique. In cooperation with medical doctors, the main clinical study involved 100 patients with skin cancer and investigated the potential for diagnostics. This study revealed that technical improvements are needed before OCT might be used. An improved spatial resolution enables visualization of finer details in the images and could be important for the diagnostic value of OCT. The technical part of this project has therefore been focused on improving the resolution to a level enabling single cell visualization. An OCT system supporting imaging with a resolution of about 2 micrometer has been constructed. The system has been tested with preliminary light sources developed in an European collaboration with promising results. Unfortunately, the light sources have not been fully developed and therefore clinical measurements using the system have not been possible.



In addition to the diagnostic studies and development of the technique itself, monitoring of treatment has been attempted. Using a Doppler OCT system it is possible to detect the blood flow in the skin. During treatment of skin cancer using photodynamic therapy, measurement of changes in blood flow has been attempted because it is hypothesized that this could be used for determining the treatment effect. Potentially, the blood flow information could be used for tailoring the treatment individually to every patient and eventually improve the outcome. These introductory measurements have identified a number of problems and possible solutions are suggested. (Less)
Abstract
Optical coherence tomography (OCT) is a non-invasive optical imaging technique providing approximately 10 micrometer resolution of tissue in vivo. Within ophthalmology, OCT has already proven its value and is routinely used for diagnosing retinal diseases. In many other areas the potential of OCT is explored worldwide, while the technique itself is further developed with improved imaging speed, resolution and extensions such as functional imaging.



This thesis focuses on improvements and tailoring of OCT for applications within dermatology, especially skin cancer diagnostics. A two-fold approach combining clinical measurements and development of better suited OCT equipment has been attempted. The diagnostic value at the... (More)
Optical coherence tomography (OCT) is a non-invasive optical imaging technique providing approximately 10 micrometer resolution of tissue in vivo. Within ophthalmology, OCT has already proven its value and is routinely used for diagnosing retinal diseases. In many other areas the potential of OCT is explored worldwide, while the technique itself is further developed with improved imaging speed, resolution and extensions such as functional imaging.



This thesis focuses on improvements and tailoring of OCT for applications within dermatology, especially skin cancer diagnostics. A two-fold approach combining clinical measurements and development of better suited OCT equipment has been attempted. The diagnostic value at the current stage of OCT has been evaluated in a cooperation with medical doctors. The study included 100 patients and showed a need for further improvements of the technique to make accurate diagnosis possible. Studies with a smaller number of patients investigated the possibility of using OCT for thickness measurements of lesions and human nails. The results were in correlation with ultrasound measurements, but with a higher precision. In addition to these diagnostic studies, an attempt to monitor treatment progress of photodynamic therapy was initiated. The use of Doppler OCT for measuring blood flow changes has the potential to tailor the treatment individually eventually with an improved outcome. A Doppler OCT system was tested using phantoms and normal skin followed by patient investigations. Addressing the technical difficulties of performing these measurements and suggesting possible solutions was the major outcome.



Regarding the technical development, the primary concern was to improve the resolution of the imaging technique, in particular the depth resolution. A high depth resolution OCT system was constructed for imaging with a resolution of about 2 micrometer and this system was tested with a number of light sources. The possible advantages for diagnostic purposes were not evaluated because none of the light sources were suited for imaging. The focus has therefore been testing of the system showing promising results. With a suited light source the diagnostic value of an increased resolution might be evaluated using this system. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Prof Spigulis, Janis, Institute of Physics and Spectroscopy, University of Lativia, Latvia
organization
publishing date
type
Thesis
publication status
published
subject
keywords
medical imaging, skin cancer diagnostics, optical imaging, blood flow, treatment monitoring
in
Lund Reports on Atomic Physics
volume
LRAP-433
pages
150 pages
publisher
Division of Atomic Physics, Department of Physics, Faculty of Engineering, LTH, Lund University
defense location
Lecture hall B, Department of Physics, Professorsgatan 1, Lund University Faculty of Engineering
defense date
2011-04-07 13:15
ISSN
0281-2762
language
English
LU publication?
yes
id
36bc2611-bf3f-4df4-a212-e29837ed0258 (old id 1845238)
date added to LUP
2011-03-15 10:03:10
date last changed
2016-09-19 08:44:49
@phdthesis{36bc2611-bf3f-4df4-a212-e29837ed0258,
  abstract     = {Optical coherence tomography (OCT) is a non-invasive optical imaging technique providing approximately 10 micrometer resolution of tissue in vivo. Within ophthalmology, OCT has already proven its value and is routinely used for diagnosing retinal diseases. In many other areas the potential of OCT is explored worldwide, while the technique itself is further developed with improved imaging speed, resolution and extensions such as functional imaging.<br/><br>
<br/><br>
This thesis focuses on improvements and tailoring of OCT for applications within dermatology, especially skin cancer diagnostics. A two-fold approach combining clinical measurements and development of better suited OCT equipment has been attempted. The diagnostic value at the current stage of OCT has been evaluated in a cooperation with medical doctors. The study included 100 patients and showed a need for further improvements of the technique to make accurate diagnosis possible. Studies with a smaller number of patients investigated the possibility of using OCT for thickness measurements of lesions and human nails. The results were in correlation with ultrasound measurements, but with a higher precision. In addition to these diagnostic studies, an attempt to monitor treatment progress of photodynamic therapy was initiated. The use of Doppler OCT for measuring blood flow changes has the potential to tailor the treatment individually eventually with an improved outcome. A Doppler OCT system was tested using phantoms and normal skin followed by patient investigations. Addressing the technical difficulties of performing these measurements and suggesting possible solutions was the major outcome.<br/><br>
<br/><br>
Regarding the technical development, the primary concern was to improve the resolution of the imaging technique, in particular the depth resolution. A high depth resolution OCT system was constructed for imaging with a resolution of about 2 micrometer and this system was tested with a number of light sources. The possible advantages for diagnostic purposes were not evaluated because none of the light sources were suited for imaging. The focus has therefore been testing of the system showing promising results. With a suited light source the diagnostic value of an increased resolution might be evaluated using this system.},
  author       = {Borup Thomsen, Jakob},
  issn         = {0281-2762},
  keyword      = {medical imaging,skin cancer diagnostics,optical imaging,blood flow,treatment monitoring},
  language     = {eng},
  pages        = {150},
  publisher    = {Division of Atomic Physics, Department of Physics, Faculty of Engineering, LTH, Lund University},
  school       = {Lund University},
  series       = {Lund Reports on Atomic Physics},
  title        = {Optical Coherence Tomography for Dermatological Applications},
  volume       = {LRAP-433},
  year         = {2011},
}