3. Biodistribution of needle-injections and needle-free jet-injections visualized by a 3D- Fluorescent Imaging Cryomicrotome System 78 to visualize the fluorescent-labeled TCA suspension. A reflection image at 549 nm was used to reconstruct the tissue borders. Figure 1. 3D FICS. 1: Sample holder, 2: Lens (Olympus SZX16 stereo microscope system), 3: Tunable supercontinuum laser, 4: UV led illumination, 5: Tunable filter wheel, 6: Camera Image analysis The 2D images were first cropped using LabVIEW (National Instruments, Austin, Texas, USA) and the resulting stack of images was resampled to a volume image with a resolution of (x,y,z) = 27.4 x 27.4 x 35.0 µm, which was sufficient to observe and quantify the fluorescent-labeled TCA. The 3D model of the fluorescent distribution (Figure 2) was obtained by image segmentation using custom software (Dobbe, 2019). During segmentation, all voxels in the fluorescent region above a pragmatically chosen intensity threshold (2000) were included, while excluding voxels representing autofluorescent tissue as much as possible. The volume of the segmented fluorescent regions represents the fluorescent TCA volume. This is not equivalent to the actual injected TCA volume due to the point spread function of the imaging system and the chosen arbitrary intensity threshold. However, the measured fluorescent TCA volume enables comparison of the arbitrary fluorescent TCA volumes between samples.
RkJQdWJsaXNoZXIy MTk4NDMw