University of Amsterdam, Amsterdam UMC, Cancer Center Amsterdam, Amsterdam Cardiovascular Sciences,, The Netherlands.
The Netherlands Cancer Institute, Department of Surgery, Amsterdam, The Netherlands.
J Biomed Opt. 2021 Feb;26(2). doi: 10.1117/1.JBO.26.2.025004.
We recently developed a model for the reflectance measured with (multi-diameter) single-fiber reflectance (SFR) spectroscopy as a function of the reduced scattering coefficient μs', the absorption coefficient μa, and the phase function parameter psb. We validated this model with simulations.
We validate our model experimentally. To prevent overfitting, we investigate the wavelength-dependence of psb and propose a parametrization with only three parameters. We also investigate whether this parametrization enables measurements with a single fiber, as opposed to multiple fibers used in multi-diameter SFR (MDSFR).
We validate our model on 16 phantoms with two concentrations of Intralipid-20% (μs'=13 and 21 cm - 1 at 500 nm) and eight concentrations of Evans Blue (μa = 1 to 20 cm - 1 at 605 nm). We parametrize psb as 10 - 5 · ( p1 ( λ / 650 ) + p2(λ/650)2 + p3(λ/650)3 ) .
Average errors were 7% for μs', 11% for μa, and 16% with the parametrization of psb; and 7%, 17%, and 16%, respectively, without. The parametrization of psb improved the fit speed 25 times (94 s to <4 s). Average errors for only one fiber were 50%, 33%, and 186%, respectively.
Our recently developed model provides accurate results for MDSFR measurements but not for a single fiber. The psb parametrization prevents overfitting and speeds up the fit.
我们最近开发了一种模型，用于将（多直径）单纤维反射率（SFR）光谱测量的反射率表示为散射系数μs'、吸收系数μa和相函数参数 psb 的函数。我们使用模拟对该模型进行了验证。
我们通过实验验证我们的模型。为了防止过度拟合，我们研究了 psb 的波长依赖性，并提出了一个仅用三个参数进行参数化的方法。我们还研究了这种参数化方法是否能够使用单根光纤进行测量，而不是多直径 SFR（MDSFR）中使用的多根光纤。
我们在 16 个具有两种 Intralipid-20%浓度（在 500nm 时μs'=13 和 21 cm-1）和 8 种 Evans Blue 浓度（在 605nm 时μa=1 至 20 cm-1）的仿体上验证了我们的模型。我们将 psb 参数化为 10-5·（p1(λ/650)+p2(λ/650)2+p3(λ/650)3）。
对于μs'、μa 和 psb 参数化的平均误差分别为 7%、11%和 16%；而没有参数化的平均误差分别为 7%、17%和 16%。psb 参数化将拟合速度提高了 25 倍（从 94 秒到<4 秒）。只用一根光纤的平均误差分别为 50%、33%和 186%。
我们最近开发的模型为 MDSFR 测量提供了准确的结果，但不适用于单根光纤。psb 参数化可防止过度拟合并加快拟合速度。
