Bioluminescence as Gold Standard for Validation of Optical Imaging Modalities in Peritoneal Carcinomatosis Animal Models

Background: The outcome of cytoreductive surgery in patients with peritoneal carcinomatosis is influenced by incomplete resection as a result of inadequate detection of a tumor, i.e. residual disease. The future perspective of complete resection, made possible by application of intraoperative near-infrared fluorescence imaging (NIRF), led to the development and validation of a bioluminescent colorectal peritoneal carcinomatosis xenograft rat model to act as the gold standard for the evaluation of new optical imaging modalities. Methods: Twenty nude rats were inoculated intraperitoneally with 2 x 10(6) luciferase-labeled human colorectal tumor cells (HT-29-luc-D6). The peritoneal carcinomatosis index (PCI) was estimated using visual observation (PCI-VO) and VO combined with bioluminescence imaging (PCI-BLI). Subsequently, the BL images were presented, and residual tumor tissue was localized by PCI-BLI scoring and compared with the PCI-VO. Results: BLI revealed additional tumor tissue, confirmed by HE staining, compared to VO alone in 7 out of 8 rats (p