Eggert H R, Blazek V
Department of Neurosurgery, University of Freiburg, Federal Republic of Germany.
Neurosurgery. 1987 Oct;21(4):459-64. doi: 10.1227/00006123-198710000-00003.
Considering the increasing use of lasers in neurosurgery and the increasing number of wavelengths of laser light becoming available, we evaluated optical properties between 200 and 900 nm of meninges, normal human brain tissue, and brain tumors. We used a two-beam spectral photometer with an integrating sphere as the measuring instrument. The material consisted of 13 brains and 1 specimen each of dura mater, falx, and arachnoid obtained at autopsy and 30 samples of brain tumors removed during operation. In tissue samples more than 5 mm thick, the relative levels of absorption and scattering were estimated from the relative level of reflection measured according to the Kubelka-Munk theory. In thin tissue slices, penetration depth was calculated according to Beer's law from measurements of reflection and transmission. Generally, in all tissues there was an increase of reflection, scattering, and penetration depth and a decrease of absorption from the ultraviolet up to the near infrared spectral range interrupted by the absorption bands of hemoglobin. Within the ultraviolet spectral range, no major differences of optical properties were observed. Within the visible and near infrared spectral range, white matter reflected most of the incident power and showed the lowest level of absorption and the shortest penetration depth. Low grade gliomas revealed optical properties similar to those of gray matter. In comparison with normal brain tissue, meningiomas and glioblastomas showed significantly higher levels of absorption calculated according to the Kubelka-Munk theory from reflection measurements in thick tissue samples, but also deeper penetration obtained from measurements of reflection and transmission in thin slices, especially within the near infrared spectral range.
鉴于激光在神经外科手术中的应用日益广泛，且可用激光波长数量不断增加，我们评估了脑膜、正常人类脑组织和脑肿瘤在200至900纳米之间的光学特性。我们使用带有积分球的双光束光谱光度计作为测量仪器。材料包括13个大脑以及尸检时获取的硬脑膜、大脑镰和蛛网膜各1个标本，还有手术中切除的30个脑肿瘤样本。对于厚度超过5毫米的组织样本，根据库贝尔卡 - 蒙克理论，通过测量反射的相对水平来估计吸收和散射的相对水平。对于薄组织切片，根据比尔定律，通过测量反射和透射来计算穿透深度。一般来说，在所有组织中，从紫外线到近红外光谱范围，反射、散射和穿透深度增加，吸收减少，但被血红蛋白的吸收带打断。在紫外光谱范围内，未观察到光学特性的重大差异。在可见光和近红外光谱范围内，白质反射了大部分入射光，吸收水平最低，穿透深度最短。低级别胶质瘤的光学特性与灰质相似。与正常脑组织相比，根据库贝尔卡 - 蒙克理论，从厚组织样本的反射测量计算得出，脑膜瘤和胶质母细胞瘤的吸收水平显著更高，但从薄片的反射和透射测量获得的穿透深度也更深，尤其是在近红外光谱范围内。
