Caren van Roekel

172 Chapter 6 168 Gy (95%CI 122-232 Gy), STBD 147 Gy (95% CI: 113-191 Gy) and PD 117 Gy (95% CI: 87-159 Gy). Significant differences between response categories CR and STBD (p=0.01) and CR and PD (p=0.0008) were found. The p-value for trend was 0.0005. An example of a patient exhibiting CR in several tumors with a good preferential microsphere accumulation in and around the tumors is shown in Figure 2. FIGURE 2. Exemplar case in which good spatial correspondence between pretreatment tumor metabolism (A and D) and absorbed dose (D avg 120 Gy) (B and E) led to a complete response (C and F). Tumor outlines are transferred from the pretreatment FDG-PET/CT to the Absorbed dose maps through rigid registration of the appurtenant CTs of the SPECT/CT and FDG-PET/CTs. In many cases, this registration is imperfect, resulting in slight registration errors, such as evident in panel B. Patient-Level Response There were 2 patients with complete metabolic liver response, 11 patients with PR, 14 patients with STBD, and 9 patients with PD. Geometric mean tumor absorbed doses in the response categories at a patient-level were as follows: complete or partial response (CRPR) 210 Gy (95% CI: 161-274 Gy), STBD 152 Gy (95% CI: 117-198 Gy) and PD 116 Gy (95% CI: 81-165 Gy). The p-value for trend was 0.005.