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. 2019 Oct 2;9:947. doi: 10.3389/fonc.2019.00947

Figure 1.

Figure 1

Examples of the optical technologies for brain needle biopsies. (A) Images from the fluorescence optical needle endoscope described by Göbel et al. (22) for PpIX visualization in the tumor (left column) and vessel visualization using ICG (right column) in a mouse model. Adapted with permission from Göbel et al. (22)© The Optical Society. (B) Illustration of PpIX spectroscopy method for tumor detection during stereotactic biopsy described by Haj-Hosseini et al. (28). The top two panels show the probe positioned in the stereotactic frame and the concept of measurements along the trajectory. The bottom panels show an MR image with calculated targets, spectral data of PpIX along the injection trajectory, and the histopathology slide of the target. Adapted with permission from Haj-Hosseini et al. (28)© The Optical Society. (C) Stain-less reflectance imaging method from Ramakonar et al. (27). Left panel shows a photo of an imaging needle rolled over a vessel of 650 μm. The imaging window of the probe is not visible and is facing toward the tissue. The upper right panel displays OCT B-scan consisting of A-scans. The tissue surface corresponds to the top of the image. Depth increases going down the image. The bottom right panel displays a speckle decorrelation image calculated form the OCT scan with high decorrelation as white and low decorrelation as dark red. Adapted from Ramakonar et al. (27) under Creative Commons Attribution license. (D) Schematic summary of advanced optical methods and tool designs, for increasing safety of stereotactic brain biopsies. OCT, optical coherence tomography; PpIX, protoporphyrin IX; ICG, indocyanine green; SRH, Stimulated Raman Histology.