Department of Biomedical Engineering, Yonsei University, Wonju 26493, Republic of Korea.
Department of Electrical Engineering, Sukkur IBA University, Sukkur 65200, Pakistan.
Sensors (Basel). 2023 Apr 4;23(7):3723. doi: 10.3390/s23073723.
Pulse oximetry is a non-invasive method for measuring blood oxygen saturation. However, its detection scheme heavily relies on single-point measurements. If the oxygen saturation is measured at a single location, the measurements are influenced by the profile of illumination, spatial variations in blood flow, and skin pigment. To overcome these issues, imaging systems that measure the distribution of oxygen saturation have been demonstrated. However, previous imaging systems have relied on red and near-infrared illuminations with different profiles, resulting in inconsistent ratios between transmitted red and near-infrared light over space. Such inconsistent ratios can introduce fundamental errors when calculating the spatial distribution of oxygen saturation. In this study, we developed a novel illumination system specifically designed for a pulse oximetry imaging system. For the illumination system, we customized the integrating sphere by coating a mixture of barium sulfate and white paint inside it and by coupling eight red and eight near-infrared LEDs. The illumination system created identical patterns of red and near-infrared illuminations that were spatially uniform. This allowed the ratio between transmitted red and near-infrared light to be consistent over space, enabling the calculation of the spatial distribution of oxygen saturation. We believe our developed pulse oximetry imaging system can be used to obtain spatial information on blood oxygen saturation that provides insight into the oxygenation of the blood contained within the peripheral region of the tissue.
脉氧仪是一种用于测量血氧饱和度的非侵入性方法。然而，其检测方案严重依赖单点测量。如果在单个位置测量氧气饱和度，则测量结果会受到照明轮廓、血流的空间变化和皮肤色素的影响。为了克服这些问题，已经展示了测量血氧饱和度分布的成像系统。然而，以前的成像系统依赖于具有不同轮廓的红光和近红外光照明，导致在空间上传输的红光和近红外光之间的比值不一致。这种不一致的比值在计算血氧饱和度的空间分布时会引入基本误差。在这项研究中，我们开发了一种专门为脉氧仪成像系统设计的新型照明系统。对于照明系统，我们通过在内部涂覆硫酸钡和白色涂料的混合物并用 8 个红光和 8 个近红外 LED 进行耦合，对积分球进行了定制。该照明系统创建了空间均匀的相同的红光和近红外照明图案。这使得传输的红光和近红外光之间的比值在空间上保持一致，从而能够计算血氧饱和度的空间分布。我们相信，我们开发的脉氧仪成像系统可以用于获得有关血氧饱和度的空间信息，从而深入了解组织外周区域内血液的氧合情况。
