Transarterial radioembolization (TARE) is a treatment for liver tumors based on injection of radioactive microspheres in the hepatic arteries under angiography guidance. Conventionally, there is no feedback on the dose distribution during treatment and dosimetry can only be evaluated after treatment. As holmium-166 microspheres used for TARE can be quantified with MRI, we investigated the feasibility and safety of performing TARE in a 3-T MRI in six patients. Multi-echo gradient echo imaging was performed at set time points during administration and provided intraprocedural insight into the microsphere distribution. Our findings may prove useful for providing a personalized approach to TARE.