Patient 9. 90Y radioembolization of an organ other than the liver. KIT-negative GIST with bulky metastasis to the right adrenal gland, refractory to tyrosine kinase inhibitors. Angiography was previously shown in part 1 . (a) Catheter-directed CT angiogram of the right inferior adrenal artery delineates the targeted right adrenal tumor measuring 10.1 × 6.3 cm. (b) Post-radioembolization 90Y PET/CT depicts microsphere biodistribution in high resolution, with concordant activity within targeted regions of contrast-enhancing tumor. Low-grade activity seen in the adjacent right liver lobe is due to 90Y radioembolization of a segment IV metastasis. (c) Isodose map by voxel dosimetry of the corresponding trans-axial slice of the right adrenal tumor provides a visual representation of dose heterogeneity within the tumor and adjacent right liver lobe and displays the full dose range from 0 to >1,000 Gy. (d) Follow-up contrast-enhanced CT of the abdomen at 9.5 months shows a moderate size reduction to 7.6 × 4.6 cm, representing a partial response.