ESTRO 2024 - Abstract Book

S5235 ESTRO 2024 observers provided acute toxicity scores based on the images only. The DL classifier was used as sixth observer. Observer variation was evaluated using the Krippendorff’s alpha coefficient, and classification accuracy was evaluated with respect to clinical scores. Radiobiology - Normal tissue radiobiology

For RIF, which is scored with a leg contraction assay on a scale 0-4 in steps of 1, we know from histology that fibrosis occurs all around the mouse foot, and subcutaneous fat is decreased in the process. To quantify RIF, we performed a pilot study, imaging fresh-frozen mouse legs from earlier studies with a microCT system. Our self built imaging setup consisted of a microfocus x-ray source (Hamamatsu L9421-02), and a flat panel detector with a 49.5 µm pixel pitch (Rayence 0505a, 1176x1104 pixels). 720 projections were acquired with 3x magnification, and reconstructed into a 3D volume with 27 µm isotropic voxels. Subcutaneous fat volume was manually segmented around the ankle and compared between different RIF categories.