Visible to NIR DLP hyperspectral imaging system for surgical utility using inherent chromophores and fluorescent probes

Visible DLP® hyperspectral reflectance imaging in medical applications is limited by the lack of penetration of visible light for visualization of deeper vessels and tissues. The longer, near infrared (NIR) wavelengths, capable of facilitating chromophore and fluorophore visualization, penetrate deeper allowing visualization of anatomical structures in surgical settings. Digital micromirror device (DMD) chips allow for digital programming of complex spectral illuminations with bandwidths as low as 7nm. Furthermore, fluorescence can be maximized by programming the DMD chip to illuminate with light precisely configured to contain excitation spectra. We have developed a "mid-range" system that extends from the visible light range into the NIR (525nm - 1050nm) and has been characterized and configured for fluorescence of indocyanine green (ICG). The DMD-based light source was found to be within the manufacturer's spectral specifications and proved to be very versatile in both spectral behavior and application. Fluorescence of ICG was successfully optimized by this system and demonstrated in capillary tubes and excised tissue.