https://ejnmmipharmchem.springeropen.com/articles/10.1186/s41181-019-0066-3. Intrahepatic visualisation of Ho-166-microspheres after SIRT. T2-weighted MRI of the liver in a patient with several ocular melanoma liver metastases, outlined by coloured regions of interest (a). After SIRT, the distribution of Ho-166-PLLA-microspheres within the liver was visualized by single-photon-emission CT (b) and R2-weighted MRI (c). Reprinted from The Lancet Oncology, Vol. 13, Smits et al., Holmium 166 SIRT in patients with unresectable, chemorefractory liver metastases (HEPAR trial): a phase 1, dose-escalation study, 1025–1034, Copyright 2012, with permission from Elsevier.