  In neurosurgical procedures maximizing the resection of tumor tissue while
avoiding healthy tissue is of paramount importance and a difficult task due to
many factors, such as surrounding eloquent brain. Swiftly identifying tumor
tissue for removal could increase surgical outcomes. The TumorID is a
laser-induced fluorescence spectroscopy device that utilizes endogenous
fluorophores such as NADH and FAD to detect tumor regions. With the goal of
creating an endoscopic tool for intraoperative tumor detection in mind, a study
of the TumorID was conducted to assess how the angle of incidence (AoI) affects
the collected spectral response of the scanned tumor. For this study, flat and
convex NADH/FAD gellan gum phantoms were scanned at various AoI (a range of 36
degrees) to observe the spectral behavior. Results showed that spectral
signature did not change significantly across flat and convex phantoms, and the
Area under Curve (AUC) values calculated for each spectrum had a standard
deviation of 0.02 and 0.01 for flat and convex phantoms, respectively.
Therefore, the study showed that AoI will affect the intensity of the spectral
response, but the peaks representative of the endogenous fluorophores are still
observable and similar. Future work includes conducting an AoI study with a
longer working-distance lens, then incorporating said lens to design an
endoscopic, intraoperative tumor detection device for minimally invasive
surgery, with first applications in endonasal endoscopic approaches for
pituitary tumors.
