Amirkabir University of Technology, Department of Medical Radiation Engineering, 424 Hafez Avenue, Tehran 15875-4413, Iran.
Shahid Beheshti University of Medical Sciences, Department of Anesthesiology and Critical Care, Shohadaye Tajrish Hospital, Tajrish Square, Tehran 19899-34148, Iran.
J Biomed Opt. 2017 Jan 1;22(1):15004. doi: 10.1117/1.JBO.22.1.015004.
Fingertip-type pulse oximeters are popular, but their inconvenience for long-term monitoring in daily life means that other types of wearable pulse oximeters, such as reflectance pulse oximeters, need to be developed. For the purpose of developing reflection pulse oximetry, we have analyzed the light propagation in tissue to calculate and estimate the measured intensities of reflected light using the analytical and numerical solutions of the diffusion approximation equation. The reflectance of light from the biological tissue is investigated from theoretical and experimental perspectives, for light in the visible and near-infrared wavelengths. To establish the model, the calculated curves were compared with the analytical solution (AS) of the diffusion approximation equation in biological tissue. The results validated that the diffusion approximation equation could resolve the heterogeneous advanced tissue and the finite element method (FEM) could offer the simulation with higher efficiency and accuracy. Our aim has been to demonstrate the power of the FEM and AS in modeling of the steady-state diffusion approximation in a heterogeneous medium. Also, experimental data and the Monte Carlo model as a gold standard were used to verify the effectiveness of these methods.
指尖式脉搏血氧仪很受欢迎，但它们在日常生活中进行长期监测的不便性意味着需要开发其他类型的可穿戴脉搏血氧仪，例如反射式脉搏血氧仪。为了开发反射式脉搏血氧仪，我们分析了组织中的光传播，使用扩散近似方程的解析和数值解来计算和估计反射光的测量强度。从理论和实验的角度研究了生物组织中光的反射，光的波长在可见和近红外范围内。为了建立模型，将计算出的曲线与生物组织中扩散近似方程的解析解（AS）进行了比较。结果验证了扩散近似方程可以解决非均匀的高级组织，而有限元方法（FEM）可以提供更高效率和准确性的模拟。我们的目的是展示 FEM 和 AS 在非均匀介质中稳态扩散近似模型中的强大功能。此外，还使用实验数据和作为金标准的蒙特卡罗模型来验证这些方法的有效性。
