gms | German Medical Science

Objective: Fluorescence imaging can be an invaluable tool in the identification and precise resection of brain tumors; offering a generalized platform to guide an endoscopic system, identify remnant tumor, tumor borders and healthy tissue for minimal damage, guide microscopy and other approaches considered in this proposal. Therefore a fluorescence visualization approach is essential in endoscopic micro-dissection of brain tumors. This proposal therefore offers to develop a system beyond the current state of the art which implements simultaneous, video rate multispectral imaging capture and real-time correction of illumination and optical property inhomogenity contributions.

Method: For the purpose of this project two multispectral imaging systems were build. The first system consists of two imaging channels, one for color and one for fluorescence capturing. This system is intended for comparative study of multiple fluorescence probes. The second multispectral imaging system consists of a single CCD camera capable to capture simultaneously and in real time color and fluorescence images. In vivo blood flow of healthy brains and C6 glioma allografts was evaluated in rats. To evaluate future application in patients, fresh surgical resection specimen of different human tumors were examined.

Results: Each animal was intravenously injected with different diagnostic fluorescence probes. Color and fluorescence images were captured simultaneously, and then fused to result the pseudo-color image. This measurement demonstrates the ability to compare the diagnostic performance of different fluorescence probes. Furthermore, the system indicates the capability of the multispectral method to simultaneously capture color and fluorescence.

Conclusions: The combination of the above listed imaging technologies, allows to measure simultaneous and in real time, color images, multiple fluorescence signals originating from multiple fluorophores, additional spectral information which could be used to correct measurement for parameters such as: autofluorescence, illumination inhomogenities, and tissue optical properties. The simplicity of the technologies guaranties a quick and easy transition of intraoperative imaging from the research labs to standard clinical procedure incorporated in a surgical microscope.