liu.seSearch for publications in DiVA
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Simulation of reflected light intensity changes during navigation and radio frequency lesioning in the brain
Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. (MINT)
Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.ORCID iD: 0000-0002-3454-6576
Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology. (MINT)ORCID iD: 0000-0002-0012-7867
Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
2009 (English)In: Journal of Biomedical Optics, ISSN 1083-3668, E-ISSN 1560-2281, Vol. 14, no 044040Article in journal (Refereed) Published
Abstract [en]

An electrode with adjacent optical fibers for measurements during navigation and radio frequency lesioning in the brain was modeled for Monte Carlo simulations of light transport in brain tissue. Relative reflected light intensity at 780 nm, I780, from this electrode and probes with identical fiber configuration were simulated using the intensity from native white matter as reference. Models were made of homogeneousnative and coagulated gray, thalamus, and white matter as well as blood. Dual layermodels, including models with a layer of cerebrospinal fluid between the fibers andthe brain tissue, were also made. Simulated I780 was 0.16 for gray matter, 0.67 forcoagulate gray matter, 0.36 for thalamus, 0.39 for coagulated thalamus, unity forwhite matter, 0.70 for coagulated white matter and 0.24 for blood. Thalamic matterhas also been found to reflect more light than gray matter and less than white matterin clinical studies. In conclusion the reflected light intensity can be used todifferentiate between gray and white matter during navigation. Furthermore,coagulation of light gray tissue, such as the thalamus, might be difficult to detectusing I780, but coagulation in darker gray tissue should result in a rapid increase of I780.

Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2009. Vol. 14, no 044040
Keyword [en]
Brain, Monte Carlo simulations, diffuse reflectance, navigation, radio-frequency lesioning
National Category
Bioengineering Equipment
Identifiers
URN: urn:nbn:se:liu:diva-15930DOI: 10.1117/1.3210781ISI: 000270540100046PubMedID: 19725751Scopus ID: 2-s2.0-73349106860OAI: oai:DiVA.org:liu-15930DiVA: diva2:128392
Note

Original Publication: Johannes D. Johansson, Ingemar Fredriksson, Karin Wårdell and Ola Eriksson, Simulation of reflected light intensity changes during navigation and radio frequency lesioning in the brain, Journal of Biomedical Optics, (14), 044040, (2009). http://dx.doi.org/10.1117/1.3210781 Copyright 2009 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.

Available from: 2008-12-16 Created: 2008-12-16 Last updated: 2017-12-14Bibliographically approved
In thesis
1. Impact of Tissue Characteristics on Radio-Frequency Lesioning and Navigation in the Brain: Simulation, experimental and clinical studies
Open this publication in new window or tab >>Impact of Tissue Characteristics on Radio-Frequency Lesioning and Navigation in the Brain: Simulation, experimental and clinical studies
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Radio-Frequency (RF) lesioning, or RF ablation, is a method that uses high frequency currents for thermal coagulation of pathological tissue or signal pathways. The current is delivered from an electrode, which also contains a temperature sensor permitting control of the current at a desired target temperature. In the brain, RF lesioning can e.g. be used for treatment of severe chronic pain and movement disorders such as Parkinson’s disease. This thesis focuses on modelling and simulation with the aim of gaining better understanding and predictability of the lesioning process in the central brain.

 

The finite element method (FEM), together with experimental comparisons, was used to study the effects of electric and thermal conductivity, blood perfusion (Paper I), and cerebrospinal fluid (CSF) filled cysts (Paper II) on resulting lesion volume and shape in brain tissue. The influence of blood perfusion was modelled as an increase in thermal conductivity in non-coagulated tissue. This model gave smaller simulated lesions with increasing blood perfusion as heat was more efficiently conducted from the rim of the lesion. If the coagulation was not taken into consideration, the lesion became larger with increasing thermal conductivity instead, as the increase in conducted heat was compensated for through an increased power output in order to maintain the target temperature. Simulated lesions corresponded well to experimental in-vivo lesions. The electric conductivity in a homogeneous surrounding had little impact but this was not true for a heterogeneous surrounding. CSF has a much higher electric conductivity than brain tissue, which focused the current to the cyst if the electrode tip was in contact with both a cyst and brain tissue. Heating of CSF could also cause considerable convective flow and as a result a very efficient heat transfer. This affected both simulated and experimental lesion sizes and shapes. As a result both very large and very small lesions could be obtained depending on whether sufficient power was supplied or if the heating was mitigated over a large volume.

 

Clinical (Paper IV) and experimental (Paper III) measurements were used for investigation of changes in reflected light intensity from undamaged and coagulating brain tissue respectively. Monte Carlo (MC) simulations for light transport were made for comparison (Paper V). For the optical measurements, an RF electrode with adjacent optical fibres was used and this electrode was also modelled for the optical simulations. According to the MC simulations, coagulation should make grey matter lighter and white matter darker, while thalamic light grey should remain approximately the same. Experiments in ex-vivo porcine tissue gave an increase in reflected light intensity from grey matter at approximately 50 °C but the signal was very variable and the isotherm 60 °C gave better agreement between simulated and experimental lesions. No consistent decrease in reflected light intensity could be seen during coagulation of white matter. Clinical measurements were performed during the creation of 21 trajectories for deep brain stimulation electrodes. In agreement with the simulations, reflected light intensity was found to differentiate well between undamaged grey, light grey and white matter.

 

In conclusion, blood perfusion and CSF in particular may greatly affect the lesioning process and can be important to consider when planning surgery. Reflected light intensity seems unreliable for the detection of coagulation in light grey brain matter such as the thalamus. However, it seems very promising for navigation in the brain and for detection of coagulation in other tissue types such as muscle.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2009. 74 p.
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1230
Keyword
Brain, Radio frequency ablation, Finite element method, Monte Carlo simulation, light reflectance
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-15749 (URN)978-91-7393-723-8 (ISBN)
Public defence
2009-01-16, Linden, ingång 65, Campus US, Hälsouniversitetet, Linköpings universitet, Linköping, 09:15 (Swedish)
Opponent
Supervisors
Available from: 2008-12-17 Created: 2008-12-02 Last updated: 2017-02-10Bibliographically approved

Open Access in DiVA

fulltext(293 kB)708 downloads
File information
File name FULLTEXT01.pdfFile size 293 kBChecksum SHA-512
54d4decbba9a24301b3d74bca2698e417919acb0c7abd02dd5829c98f41fb41ab30107349bf2d848676d2b110454624832e1bc439722cec20859f47601866f02
Type fulltextMimetype application/pdf

Other links

Publisher's full textPubMedScopusLink to the Ph.D. Thesis

Authority records BETA

Johansson, Johannes D.Fredriksson, IngemarWårdell, KarinEriksson, Ola

Search in DiVA

By author/editor
Johansson, Johannes D.Fredriksson, IngemarWårdell, KarinEriksson, Ola
By organisation
The Institute of TechnologyBiomedical Instrumentation
In the same journal
Journal of Biomedical Optics
Bioengineering Equipment

Search outside of DiVA

GoogleGoogle Scholar
Total: 708 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
pubmed
urn-nbn

Altmetric score

doi
pubmed
urn-nbn
Total: 783 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf