Caren van Roekel

298 Chapter 11 FIGURE 6. Relationship between mean tumor-absorbed dose per patient and metabolic response to treatment at three-months follow-up. The bullets show the mean tumor- absorbed dose per patient. Black vertical lines are the 95%CIs of the mean doses per response category (complete- or partial response CRPR, stable disease SD, progressive disease PD), with the white dot in the middle indicating the mean tumor-absorbed dose per response category. In chapter 7, the dose-response relation in 166 Ho-radioembolization was further analyzed in a homogeneous cohort of 40 mCRC patients. Also, the dose-toxicity relation was explored using the parenchymal-absorbed dose and clinical and laboratory toxicity based on the CTCAE grading system. Again, a significant dose-response relationship was established at both patient- and tumor-level. Using a threshold of 100% sensitivity (meaning that below this dose, no patient had response), a mean tumor-absorbed dose of 90 Gy was identified. This could be used for future treatment planning. Also, a dose-toxicity relation was found: patients with a higher parenchymal-absorbed dose had more toxicity (Figure 7).