The affect of pulse light source on Near-Infrared biomedical Imaging

Near infrared (NIR) biomedical probes have attracted a great deal attention for many years because of its advantages of non-invasion, safety, economy, simplicity, and portability. If changes caused by re-distribution of blood volume and oxygenation level are detected, more pathophysiologic information will be revealed. But most of NIR biomedical probes use continuous-wave (CW) light source, which can not reveal enough information about abnormal vascularization because light beams are heavily scattered and diffused by tissues. The frequency of light source is an important factor in absorption and scattering. The goal of this work is to study how the pulse light source affects the near-infrared imaging. The imaging apparatus is composed of NIR light source, lens, CCD (minimal illumination: 0.0003 Lux, S/N ratio: #48 Db), capture card with high precision of 10 bit AD converter and computer. The imaging apparatus make pulse light illuminate the hand with external pressure, using the CCD camera recording the whole course. The date collection sequence is processed via some algorithm to show active blood vessel changes. This trial can monitor continuously the dynamic response of the tissue and output dynamic signature curves of the light intensity