Nishimura Goro, Kida Ikuhiro, Tamura Mamoru
Biophysics Laboratory, Research Institute for Electronic Science, Hokkaido University, Sapporo 060-0812, Japan.
Phys Med Biol. 2006 Jun 7;51(11):2997-3011. doi: 10.1088/0031-9155/51/11/021. Epub 2006 May 24.
Time- and space-resolved diffuse reflectance measurements were used to identify the optical parameters, the reduced scattering and absorption coefficients, of bulk living tissue in the region from 1.15 to 1.52 microm. Although in this region the detector was limited in its temporal resolution, we applied a peak-time shift analysis successfully to determine these coefficients in a human forearm, and then determined the absorption spectrum by space-resolved diffuse reflectance measurements. The absorption spectrum of a water content of 52% determined by magnetic resonance imaging experiments is in good agreement with the absorption coefficient obtained by optical measurements. Moreover, magnetic resonance imaging measurements suggest that the deviation of the absorption coefficients from the water spectrum in the strong water absorption band is caused by the heterogeneity of water distribution in tissue: the low content of water in the skin. These findings indicate that this optical method is potentially applicable to the non-invasive measurement of water in tissue, especially in a region lower than about 1.3-1.35 microm, which may be useful in monitoring oedema and tissue swelling.
采用时间和空间分辨漫反射测量方法来确定1.15至1.52微米区域内活体组织的光学参数，即约化散射系数和吸收系数。尽管在该区域探测器的时间分辨率有限，但我们成功应用了峰值时间偏移分析来确定人体前臂中的这些系数，然后通过空间分辨漫反射测量确定吸收光谱。通过磁共振成像实验确定的含水量为52%时的吸收光谱与光学测量获得的吸收系数高度吻合。此外，磁共振成像测量表明，在强吸水带中吸收系数与水光谱的偏差是由组织中水分布的不均匀性引起的：皮肤中的水含量较低。这些发现表明，这种光学方法有可能适用于组织中水分的无创测量，特别是在低于约1.3 - 1.35微米的区域，这可能有助于监测水肿和组织肿胀。
