Optimization of Surgical Illuminant Spectra for Organ Microstructure Visualization

In a delicate operation, the appearance of organs and tissues is an essential factor for surgeons to figure out the hemodynamic state of the tissue or identify vascular regions. In open surgery, surgeons have a direct view of the surgical area with the naked eye or through a microscope. Under these circumstances, the spectral characteristics of a surgical illuminant are the most effective factor to ensure successful operations. In this study, we designed an optimal surgical illuminant to enhance microvascular structures. Two factors were used in the design: illuminant whiteness and the contrast between tissues and blood vessels. We subsequently prototyped a tunable light source using 14 types of light-emitting diodes (LEDs) with different spectral radiances to reproduce the illuminant spectra of the designed and conventional surgical illuminant. Using this light source, we conducted subjective evaluation experiments with three rat ceca whose detected vessel regions were measured with a conventional and optimal illuminant. We confirmed that the optimal illuminant was significantly superior to the conventional illuminant to view fine vascular structures.