Star W M, Marijnissen J P, van Gemert M J
Dr. Daniel den Hoed Cancer Centre, Rotterdam, The Netherlands.
J Photochem Photobiol B. 1987 Dec;1(2):149-67. doi: 10.1016/1011-1344(87)80023-4.
This paper is a report on the state of the art of light dosimetry in photomedicine and photobiology. The basic quantity of interest is the radiant energy fluence rate, which can either be measured using a suitable probe, or calculated theoretically from measured optical constants. First, theoretical models used to analyse experimental transmission and reflection data are briefly discussed. It is shown that a two-flux model derived from the transport equation in the diffusion approximation resembles the Kubelka-Munk and other heuristic models. This illustrates the limitations of these models and suggests their abandonment in favour of transport theory. For theoretical energy fluence rate calculations at least three optical constants are needed, namely the absorption coefficient, the scattering coefficient and the average cosine of the scattering angle. These three constants have been measured for very few tissues. In principle only two of the three constants can be measured directly on thin samples, independent of a theoretical model. The energy fluence rate can be measured quantitatively with a miniature fibre optic probe with isotropic response. Such measurements allow indirect determination of the three optical constants. It appears that we are just beginning to understand the distribution of light energy fluence rate in tissues. Tasks for the near future are comparison of methods to measure optical constants, quantitative checks of calculated and measured energy fluence rates in model tissues and optical phantoms and further development of theoretical models. Particular attention is required for boundary conditions, with and without refractive index matching.
本文是一篇关于光医学和光生物学中光剂量学现状的报告。感兴趣的基本量是辐射能注量率，它既可以使用合适的探头进行测量，也可以根据测量的光学常数进行理论计算。首先，简要讨论了用于分析实验透射和反射数据的理论模型。结果表明，在扩散近似下从输运方程导出的双通量模型类似于库贝尔卡 - 蒙克模型和其他启发式模型。这说明了这些模型的局限性，并建议放弃这些模型而采用输运理论。对于理论能量注量率计算，至少需要三个光学常数，即吸收系数、散射系数和散射角的平均余弦值。对于极少数组织测量了这三个常数。原则上，在薄样品上可以独立于理论模型直接测量这三个常数中的两个。能量注量率可以用具有各向同性响应的微型光纤探头进行定量测量。这样的测量允许间接确定这三个光学常数。看来我们才刚刚开始了解组织中光能注量率的分布。近期的任务是比较测量光学常数的方法、对模型组织和光学体模中计算和测量的能量注量率进行定量检查以及进一步发展理论模型。对于有和没有折射率匹配的边界条件，需要特别关注。
