Simpson C R, Kohl M, Essenpreis M, Cope M
University College London, Department of Medical Physics and Bioengineering, UK.
Phys Med Biol. 1998 Sep;43(9):2465-78. doi: 10.1088/0031-9155/43/9/003.
The absorption and transport scattering coefficients of caucasian and negroid dermis, subdermal fat and muscle have been measured for all wavelengths between 620 and 1000 nm. Samples of tissue 2 mm thick were measured ex vivo to determine their reflectance and transmittance. A Monte Carlo model of the measurement system and light transport in tissue was then used to recover the optical coefficients. The sample reflectance and transmittance were measured using a single integrating sphere 'comparison' method. This has the advantage over conventional double-sphere techniques in that no corrections are required for sphere properties, and so measurements sufficiently accurate to recover the absorption coefficient reliably could be made. The optical properties of caucasian dermis were found to be approximately twice those of the underlying fat layer. At 633 nm, the mean optical properties over 12 samples were 0.033 mm(-1) and 0.013 mm(-1) for absorption coefficient and 2.73 mm(-1) and 1.26 mm(-1) for transport scattering coefficient for caucasian dermis and the underlying fat layer respectively. The transport scattering coefficient for all biological samples showed a monotonic decrease with increasing wavelength. The method was calibrated using solid tissue phantoms and by comparison with a temporally resolved technique.
已对620至1000纳米之间的所有波长测量了白种人和黑人的真皮、皮下脂肪和肌肉的吸收系数与输运散射系数。对2毫米厚的组织样本进行离体测量，以确定其反射率和透射率。然后使用测量系统和组织中光输运的蒙特卡罗模型来恢复光学系数。使用单积分球“比较”方法测量样本的反射率和透射率。与传统的双球技术相比，这种方法的优势在于无需对球体特性进行校正，因此可以进行足够精确的测量，以可靠地恢复吸收系数。发现白种人真皮的光学特性约为其下方脂肪层的两倍。在633纳米处，12个样本的白种人真皮及其下方脂肪层的吸收系数平均光学特性分别为0.033毫米⁻¹和0.013毫米⁻¹，输运散射系数分别为2.73毫米⁻¹和1.26毫米⁻¹。所有生物样本的输运散射系数均随波长增加而单调下降。该方法使用固体组织体模并通过与时间分辨技术比较进行校准。
