Model for and analysis of intraoperative brain tumor boundary detection based on known spectral signatures of glioblastoma

Intraoperative imaging of brain tumors using spectral signatures of tissue, based on injected fluorescent dye such as 5-ALA, has enabled surgeons to target residual malignant tissue near the boundaries of the tumor cavity where extent of resection is most difficult. This paper presents a novel approach to intraoperative tumor boundary detection based on a moving excitation laser crossing a tumor boundary while measuring spectral signatures generated. In prior work, we have characterized the intrinsic spectral signatures of glioblastoma and healthy brain tissue from in vivo mouse models within the 400 to 700 nm range given a 405 nm excitation source at a single spot, without the use of injected dye. In this work, we present a theoretical model of expected spectral signature observations for a moving excitation laser across a tumor boundary based on discretized contribution of known spectral signatures (i.e. GBM, healthy) within the region of the laser spot on the surface of a tissue. This approach allows for improved intraoperative boundary detection despite having a laser spot size larger than the desired resolution of detection.