Figure 5.

Spectrally-resolved quantitative fluorescence imaging using a ratiometric approach during in vivo glioblastoma surgery. Intraoperative images under (A,E,I) conventional white light illumination, (B,F,J) blue light illumination for vFI using a commercial system, and (C,G,K) quantitative fluorescence images using a ratiometric approach at the beginning (top row), near the end (middle row), and at the end (bottom row) of surgery. Near the end of surgery, high levels of PpIX were found using qFI (G) but not using vFI (C) with histological corroboration of tumor (L). Spectra at the beginning of surgery (D) show expected PpIX peaks and near the end of surgery (H) in the area of residual tumor (G). Figure adapted with permission from Valdés et al. (22).