Caren van Roekel

201 Dose-effect relationships of holmium-166 radioembolization in colorectal cancer 80 Gy for every tumor. Partition-modeling and multiple injection positions can be used to reach that objective. In other words, planning should be primarily based on applying a safe parenchymal-absorbed dose threshold, and selection of patients on a sufficient tumor-absorbed dose. CONCLUSION In CRC patients treated with 166 Ho-radioembolization, a positive association between tumor-absorbed dose and metabolic response was established. Survival for patients with a mean tumor-absorbed dose >90 Gy was significantly better than for patients with a mean tumor-absorbed dose <90 Gy. There also was a positive association between parenchymal-absorbed dose and both laboratory and clinical toxicity. A treatment approach with selection of patients based on the activity distribution of the 166 Ho-scout and personalized treatment activity calculation is advocated. 7