Spectral Approach in Medical System Design and Image Analysis -Surgical Illuminant Development and Rodent Skip Flap Analysis-

In this lecture, two spectral-based research topics are presented. The first topic is the design and prototyping of a spectrally tunable LED light source for surgery, and the second is the image analysis of blood flow and blood components in a rodent skin flap to understand necrosis. First topic: In delicate operations or follow-up assessments, the appearance of organs and tissues is a crucial factor for surgeons and nurses to evaluate the hemodynamic state. In open surgery, the spectral characteristics of surgical illumination play a vital role in ensuring successful outcomes. In our first study, we designed an optimal surgical illuminant to enhance microvascular structures and implemented it using 14 types of light-emitting diodes (LEDs). Through evaluation experiments conducted on rats, we confirmed the effectiveness of the illuminant. Additionally, we are developing a monitoring system that combines the spectrally tunable LED light source with a three-band color camera. Second topic: Hypoxia and a low red blood cell ratio in blood can cause tissue necrosis and dysfunction. The purpose of this study is to investigate the effects of blood components and flow on tissue using a rat flap model, which involves a partially detached thick skin segment with preserved blood circulation. In this study, we controlled the oxygen saturation and blood flow in vivo and captured reflection images of the entire flap using a hyperspectral camera, a high-definition color camera, and an infrared camera. These images were analyzed multidimensionally to study the vascular structure, blood flow, and their changes over time. In the presentation, a portion of this image analysis will be demonstrated.