| 11. |
- Wårdell, Karin, 1959-, et al.
(författare)
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A laser Doppler system for intracerebral measurements during stereotactic neurosurgery
- 2007
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Ingår i: Engineering in Medicine and Biology Society, 2007. EMBS 2007. - : IEEE. - 9781424407873 - 9781424407880 ; , s. 4083-4086
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Konferensbidrag (refereegranskat)abstract
- A laser Doppler system for intracerebral measurements during stereotactic and functional neurosurgery is presented. The system comprises a laser Doppler perfusion monitor, an optical probe adapted for the Leksellreg stereotactic system and a personal computer with software for acquisition, data analysis and presentation. The software makes it possible to present both the perfusion and the total backscattered light intensity (TLI) in real-time. During intracerebral measurements, the perfusion signal records the tissue's microcirculation whereas the TLI signal may be used to distinguish between grey and white matter. Evaluation of the system has been done during stereotactic neurosurgery in relation to implantation of deep brain stimulation electrodes. Measurements were made along trajectories towards targets in the deep brain structure as well as in pre-calculated target areas. The measurements show that the system has a potential to be used for intracerebral guidance but further evaluation of the technique is needed.
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| 12. |
- Yavari, Nazila, et al.
(författare)
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In vitro measurements of optical properties of porcine brain using a novel compact device
- 2005
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Ingår i: Medical and Biological Engineering and Computing. - : Springer. - 0140-0118 .- 1741-0444. ; 43:5, s. 658-666
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge of the optical properties of tissues can be applied in numerous medical and scientific fields, including cancer diagnostics and therapy. There are many different ways of determining the optical properties of turbid media. The paper describes measurements of the optical properties of porcine brain tissue using novel instrumentation for simultaneous absorption and scattering characterisation of small turbid samples. Integrating sphere measurements are widely used as a reference method for determination of the optical properties of relatively thin turbid samples. However, this technique is associated with bulky equipment, complicated measuring techniques, interference compensation techniques and inconvenient sample handling. It is believed that the sphere for some applications can be replaced by a new, compact device, called the combined angular and spatially resolved head sensor, to measure the optical properties of thin turbid samples. The results compare very well with data obtained with an integrating sphere for well-defined samples. The instrument was shown to be accurate to within 12% for μa and 1% for μ s ′ in measurements of intralipid-ink samples. The corresponding variations of data were 17% and 2%, respectively. The reduced scattering coefficient for porcine white matter was measured to be 100 cm−1 at 633 nm, and the value for coagulated brain tissue was 65 cm−1. The corresponding absorption coefficients were 2 and 3 cm−1, respectively.
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| 13. |
- Yavari, Nazila, et al.
(författare)
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Measurements of optical properties of pig brain tissue in vitro using a novel compact device
- 2005
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Ingår i: Progress in Biomedical Optics and Imaging - Proceedings of SPIE. - : SPIE. - 1605-7422 .- 1042-4687. ; 5864, s. 1-11
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Konferensbidrag (refereegranskat)abstract
- In numerous medical and scientific fields, knowledge of the optical properties of tissues can be applied. Among many different ways of determining the optical properties of turbid media; integrating sphere measurements are widely used. However, this technique is associated with bulky equipment, complicated measuring techniques, interference compensation techniques, and inconvenient sample handling. This paper describes measurements of the optical properties of porcine brain tissue using novel instrumentation for simultaneous absorption and scattering characterization of small turbid samples. The system used measures both angularly and spatially resolved transmission and reflection and is called Combined Angular and Spatially-resolved Head (CASH) sensor. The results compare very well with data obtained with an integrating sphere for well-defined samples. The instrument was shown to be accurate to within 12 % for μa. and 1 % for μs' in measurements of intralipid-ink samples. The corresponding variations of data were 17 %, and 2 %, respectively. The reduced scattering coefficient for porcine white matter was measured to be 100 cm-1, while the value for coagulated brain tissue was 65 cm-1. The corresponding absorption coefficients were 2 and 3 cm-1, respectively. © 2005 SPIE and OSA.
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