Tufts University, Department of Biomedical Engineering, Medford, Massachusetts, United States.
Northeastern University, Department of Bioengineering, Boston, Massachusetts, United States.
J Biomed Opt. 2023 Jul;28(7):077001. doi: 10.1117/1.JBO.28.7.077001. Epub 2023 Jul 22.
Diffuse flow cytometry (DiFC) is an emerging fluorescence sensing method to non-invasively detect labeled circulating cells . However, due to signal-to-noise ratio (SNR) constraints largely attributed to background tissue autofluorescence (AF), DiFC's measurement depth is limited.
The dual ratio (DR)/dual slope is an optical measurement method that aims to suppress noise and enhance SNR to deep tissue regions. We aim to investigate the combination of DR and near-infrared (NIR) DiFC to improve circulating cells' maximum detectable depth and SNR.
Phantom experiments were used to estimate the key parameters in a diffuse fluorescence excitation and emission model. This model and parameters were implemented in Monte Carlo to simulate DR DiFC while varying noise and AF parameters to identify the advantages and limitations of the proposed technique.
Two key factors must be true to give DR DiFC an advantage over traditional DiFC: first, the fraction of noise that DR methods cannot cancel cannot be above the order of 10% for acceptable SNR. Second, DR DiFC has an advantage, in terms of SNR, if the distribution of tissue AF contributors is surface-weighted.
DR cancelable noise may be designed (e.g., through the use of source multiplexing), and indications point to the AF contributors' distribution being truly surface-weighted . Successful and worthwhile implementation of DR DiFC depends on these considerations, but results point to DR DiFC having possible advantages over traditional DiFC.
漫射流式细胞术（Diffuse Flow Cytometry，DiFC）是一种新兴的荧光传感方法，可无创性检测标记的循环细胞。然而，由于信噪比（Signal-to-Noise Ratio，SNR）的限制，主要归因于背景组织自发荧光（Autofluorescence，AF），DiFC 的测量深度有限。
双比（Dual Ratio，DR）/双斜率是一种光学测量方法，旨在抑制噪声并提高 SNR，以达到深层组织区域。我们旨在研究 DR 和近红外（Near-Infrared，NIR）DiFC 的结合，以提高循环细胞的最大可检测深度和 SNR。
采用体模实验估计漫射荧光激发和发射模型中的关键参数。该模型和参数在蒙特卡罗中实现，以模拟 DR DiFC，同时改变噪声和 AF 参数，以确定所提出技术的优势和局限性。
要使 DR DiFC 优于传统 DiFC，必须满足两个关键因素：首先，DR 方法无法消除的噪声部分不能超过可接受 SNR 的 10%左右。其次，从 SNR 的角度来看，如果组织 AF 贡献者的分布是表面加权的，那么 DR DiFC 具有优势。
DR 可消除的噪声可以设计（例如，通过使用源多路复用），并且有迹象表明 AF 贡献者的分布确实是表面加权的。DR DiFC 的成功和有价值的实施取决于这些考虑因素，但结果表明 DR DiFC 可能比传统 DiFC 具有优势。
