Multimodality tissue identification for neurosurgery: the NASA Smart Probe project

Real-time tissue identification can benefit procedures such as stereotactic brain biopsy, functional neurosurgery, and brain tumor excision. Optical scattering spectroscopy has been shown effective at discriminating cancer from non-cancerous conditions in the colon, bladder, and breast. The NASA Smart Probe extends the concept of "optical biopsy" by using neural network techniques to combine the output from three microsensors contained within a cannula 2.7 mm in diameter (i.e. the diameter of a stereotactic brain biopsy needle). Experimental data from five rats show the clear differentiation between tissues such as brain, nerve, fat, artery, and muscle that can be achieved with optical scattering spectroscopy alone. These data and previous findings with other modalities such as (1) analysis of the image from a fiberoptic neuroendoscope and (2) the output from a micro strain gauge suggest the Smart Probe multiple microsensor technique shows promise for real-time tissue identification in neurosurgical procedures.