New cross-talk measure of near-infrared spectroscopy and its application to wavelength combination optimization.
In near-infrared spectroscopy, concentration changes in oxygenated and deoxygenated hemoglobin are calculated from the changes in the attenuation of the measurement light. This is done by solving a linear equation based on the modified Lambert-Beer law. To solve this equation, we need to know the partial optical pathlengths in the activated region in the brain. Because they are difficult to know, a wavelength-independent constant or a wavelength-dependent total optical pathlength has been substituted for these values in actual measurements. This kind of substitution inevitably produces errors, called cross-talk, when calculating concentration changes. In this paper, we propose a new cross-talk measure for dual and triple wavelength measurements, and analyze it over various wavelength combinations. The results indicate that constant substitution is not inferior to total path-length substitution in dual wavelength measurements, and that total path-length substitution is very effective for triple wavelength measurements.
Umeyama
Shinji
S
National Institute of Advanced Industrial Science and Technology, Neuroscience Research Institute, 1-1-1 Umezono Central 2, Tsukuba-shi, Ibaraki 305-8568, Japan. s.umeyama@aist.go.jp
Yamada
Toru
T
D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology; D002555:Cerebrospinal Fluid / Q000737:chemistry; D003198:Computer Simulation; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D008954:Models, Biological; D009010:Monte Carlo Method; D010108:Oxyhemoglobins / Q000032:analysis; D019047:Phantoms, Imaging; D012886:Skull / Q000033:anatomy & histology; D019265:Spectroscopy, Near-Infrared / Q000379:methods*
D006454:Hemoglobins; D010108:Oxyhemoglobins; C100003:deoxyhemoglobin