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Radio frequency electrode system for optical lesion size estimation in functional neurosurgery
Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology. (MINT)ORCID iD: 0000-0002-0012-7867
2005 (English)In: Journal of Biomedical Optics, ISSN 1083-3668, E-ISSN 1560-2281, Vol. 10, no 3, 1-6 p.Article in journal (Refereed) Published
Abstract [en]

Radiofrequency(RF) lesioning in the human brain is one possible surgicaltherapy for severe pain as well as movement disorders. Oneobstacle for a safer lesioning procedure is the lack ofsize monitoring. The aim of this study was to investigateif changes in laser Doppler or intensity signals could beused as markers for size estimation during experimental RF lesioning.A 2 mm in diameter monopolar RF electrode was equippedwith optical fibers and connected to a digital laser Dopplersystem. The optical RF electrode's performance was equal to astandard RF electrode with the same dimensions. An albumin solutionwith scatterers was used to evaluate the intensity and laserDoppler signal changes during lesioning at 70, 80, and 90 °C.Significant signal changes were found for these three different clotsizes, represented by the temperatures (p<0.05,  n=10). The volume, width, andlength of the created coagulations were correlated to the intensitysignal changes (r=0.88, n=30, p<0.0001) and to the perfusion signalchanges (r=0.81, n=30, p<0.0001). Both static and Doppler-shifted light canbe used to follow the lesioning procedure as well asbeing used for lesion size estimation during experimental RF lesioning.

Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2005. Vol. 10, no 3, 1-6 p.
National Category
Atom and Molecular Physics and Optics
Identifiers
URN: urn:nbn:se:liu:diva-14232DOI: 10.1117/1.1924615ISI: 000235127400040PubMedID: 16229664Scopus ID: 2-s2.0-24144476322OAI: oai:DiVA.org:liu-14232DiVA: diva2:22959
Available from: 2007-01-26 Created: 2007-01-26 Last updated: 2017-12-13Bibliographically approved
In thesis
1. On optical methods for intracerebral measurements during stereotactic and functional neurosurgery: Experimental studies
Open this publication in new window or tab >>On optical methods for intracerebral measurements during stereotactic and functional neurosurgery: Experimental studies
2007 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Radio frequency (RF) lesioning and deep brain stimulation (DBS) are the two prevailing surgical treatments for movement disorders within the field of stereotactic and functional neurosurgery. For RF-lesioning, a small volume of brain tissue is coagulated and knowledge of the lesion size and growth is of great importance for the safety and outcome of the procedure. This thesis deals with adapting the laser Doppler perfusion monitoring (LDPM) technique for measurements in brain tissue during RF-lesioning. The relation between LDPM signal changes and developed lesion size was investigated. LDPM measurements were evaluated both in vitro (albumin protein solution) and in vivo in the porcine brain during RF-lesioning corresponding to a bilateral thalamotomy in man. The investigated signals from the LDPI measurements can be used for following the lesioning time course and to detect if a lesion was created, both in vitro and in the animal model. For the albumin model, both the total backscattered light intensity and the perfusion signal can be used as markers for estimating the final coagulation size, while in the animal model this conclusion was not statistical verified.

Independent on surgical method, RF-lesioning or DBS, intracerebral guidance is an important aspect within stereotactic and functional neurosurgery. To increase the accuracy and precision of reaching the correct target, different methods for intracerebral guidance exist, such as microelectrode recording and impedance methods. In this thesis, the possibility of developing an optical intracerebral guidance method has been investigated. Diffuse reflectance spectroscopy served as technology and all measurements were performed stereotactically in both porcine and human brain. Measurements of white and gray matter showed large differences, with higher reflectivity for white brain matter, both in porcine and in human brain. For the human measurements during DBS-implants, large differences between white matter and functional targets were found. Additionally, differences between native and lesioned porcine brain matter were detected. Both studies support the idea of using diffuse reflectance spectroscopy for developing an intracerebral guidance method.

Place, publisher, year, edition, pages
Institutionen för medicinsk teknik, 2007
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1070
Keyword
Laser Doppler perfusion monitoring, Diffuse reflectance spectroscopy, Functional and stereotactic neurosurgery
National Category
Medical Laboratory and Measurements Technologies
Identifiers
urn:nbn:se:liu:diva-8081 (URN)978-91-85715-91-6 (ISBN)
Public defence
2007-02-02, Elsa Brändströms sal, Södra Entreén, Universitetssjukhuset, Linköping, 09:15 (English)
Opponent
Supervisors
Available from: 2007-01-26 Created: 2007-01-26 Last updated: 2016-05-04
2. Optical measurements in brain tissue during radio frequency lesioning
Open this publication in new window or tab >>Optical measurements in brain tissue during radio frequency lesioning
2004 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Radio frequency (RF) lesioning is a well well-known procedure within the field of stereotactic neurosurgery, commonly used for the treatment of movement disorders. During the intervention, an RF-electrode is inserted into the deeper parts of the brain, where a small volume of malfunctioning brain tissue will be coagulated. This procedure is irreversible, as a result, the size and position of the created lesion is crucial in order to avoid unwanted side effects. In this thesis a further development of the RF-technology is presented in order to follow a lesioning process and to estimate the created lesion size. Software, electronics, fiber optics and an RF-electrode equipped with optical fibers was developed and evaluated.

Diffuse reflectance spectroscopy measurements at 450-800 nm in the central gray of porcine brain have been performed with the developed RF-electrode. Measurements of white and gray brain matter showed a large reflectance difference in the investigated wavelength interval, with higher reflectivity for white brain matter. Reflectance differences between native and coagulated, white and gray brain matter were also found .

In-vitro laser Doppler perfusion monitoring measurements at 633 nm have also been performed in a newly designed flow model. An albumin solution with added glass microspheres was placed on top of a revolving disc. The motion of the liquid surrounding the electrode tip simulated a perfusion situation. Changes in both laser Doppler perfusion and total backscattered light intensity signals were collected during the creation of different sized coagulations. The volume, width and length of the created coagulations are correlated to the measured signal changes in-vitro, where larger coagulations displayed larger signal changes. The laser Doppler perfusion and backscattered light intensity signals can be used to follow the lesioning time course and estimate the developed lesion size in-vitro.

Place, publisher, year, edition, pages
Linköping: Linköpings universitet, 2004. 33 p.
Series
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 1114
Series
LiU-TEK-LIC, 43
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-22099 (URN)1192 (Local ID)91-85295-29-9 (ISBN)1192 (Archive number)1192 (OAI)
Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2013-11-13

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Antonsson, JohanEriksson, OlaWårdell, Karin

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