Abstract
Parkinson's disease is a neuro-degenerative disease affecting the globus pallidus (GP), a deep brain gray matter structure surrounded by white matter. During a pallidotomy a thin radio frequency probe is inserted into the GP to generate a small lesion. A fiber optic reflectance probe was developed and used during surgery. This instrument provides real-time display of the optical reflectance spectra as well as assisted lesion localization. Our 1.5-mm probe contains seven 100-μm fibers, one delivers light and six return the reflected light to a spectrometer. During clinical studies, the probe was placed against the surface of the brain and the spectrum between 350-850 nm was recorded. Measurements were repeated at 1-mm increments from the surface of the brain to 60-mm deep (GP level). This provided optical reflectance signals from both gray and white matter. Clinical results show that gray matter reflectance is approximately 50% of white matter between 650-800 nm. By calculating the slope between 700-850 nm, the signals can be differentiated between gray and white matter. We can quantify the absorption and scattering coefficients of the locally measured brain tissue by fitting the two-flux theory of Kubelka and Munk with our measurements.
Original language | English (US) |
---|---|
Pages (from-to) | 70-78 |
Number of pages | 9 |
Journal | Proceedings of SPIE - The International Society for Optical Engineering |
Volume | 3595 |
State | Published - 1999 |
Externally published | Yes |
Event | Proceedings of the 1999 Biomedical Diagnostic, Guidance, and Surgical-Assist Systems - San Jose, CA, USA Duration: Jan 26 1999 → Jan 27 1999 |
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Computer Science Applications
- Applied Mathematics
- Electrical and Electronic Engineering