Individualized Dosimetry for Holmium-166-radioembolization in Patients With Unresectable Hepatocellular Carcinoma

Patients with hepatocellular carcinoma often die from intrahepatic disease because current treatment options are limited. Local treatment using 166Ho-radioembolization (166Ho-RE) offers a safe and effective treatment. Because 166Ho-microspheres are used as a scout dose for treatment simulaton and for the actual treatment itself, a tailored approach can be used. This concept has proven to be more predictive than the 90Y-radioembolization concept (current standard-of-care), which is a based on a surrogate scout dose (i.e. 99mTc-MAA). A personal treatment plan may be used for 166Ho-radioembolization to optimize efficacy, based on scout dose distribution. However, individualized treatment planning inherently leads to treatment doses that deviate from the currently approved 'one-size-fits-all' approach (i.e. 60 Gy average absorbed dose for all patients). Therefore, safety of individualized 166Ho-RE will be evaluated first to validate safety and confirm safety thresholds. These thresholds will be used in subsequent randomized controlled studies.