Page 106 - 89Zr-Immuno-PET:Towards a Clinical Tool to Guide Antibody-based Therapy in Cancer

Chapter 5
confidence intervals (two-way random model, single measure, absolute agreement) were calculated using SPSS software (SPSS).
RESULTS
Raw list mode data was retrieved for 89Zr-antiCD20 mAb (7 patients, 20 scans), 89Zr-antiEGFR mAb (7 patients, 21 scans) and 89Zr-antiCD44 mAb (13 patients, 39 scans). List mode data was available for all scans at all time points, except for 1 patient in the 89Zr-antiCD20 mAb cohort who was originally only scanned at D0 and D6, and for which no D3 scan was available.
All original datasets were split and reconstructed (Figure 1). However, not all splits could be reconstructed due to technical limitations, leading to the exclusion of 7 out of 80 scans. Technical limitations consisted of reconstruction failure (2 scans) and missing dicom information in the original data (5 scans). Acquisition time in h p.i. (average ± SD (range min-max)) for the included data was 1.3 ± 0.5 (0.9-2.4), 72.5 ± 3.6 (65.7-77.5), 147.6 ± 8.0 (138.9-165.7) for 89Zr-antiCD20 mAb, 1.3 ± 0.5 (1.0-2.4), 68.4 ± 3.0 (64.6-72.8), 143.2 ± 2.9 (138.1-145.9) for 89Zr- antiEGFR and 1.5 ± 0.3 (1.1- 2.1), 22.1 ± 1.5 (19.9-25.0), 97.7 ± 5.3 (91.2-114.3) for 89Zr-antiCD44. The number of VOIs used for each analysis is denoted in Table 1, delineated organ and tumor volumes are presented in Supplemental Table 1.
Noise induced variability analysis
Normal tissue uptake. For 89Zr-antiCD20 mAb, examples of the Bland Altman plots for normal tissue are shown in Figure 2. The corresponding RC for all datasets are presented in Table 1, corresponding SUV are presented in Supplemental Table 2. Liver and lung show the best RC of all normal tissue VOI, <2% at all time points for 89Zr-antiCD20 (37 MBq74inj). Bone marrow, a fixed-size VOI, shows a relative large RC, ranging from 12 to 21% over time for 89Zr-antiCD20 (mAb 37 MBq74inj). This pattern, showing smaller RC for the manually delineated organs, and larger RC for blood pool and bone marrow, was observed for 89Zr-antiCD20 (37 MBq74inj and 18 MBq74inj) (Table 1 and Figure 2). The accompanying mean percentages differences were all near zero and are presented in Supplemental Table 3. The RC for 89Zr-antiCD20 mAb (37 MBq74inj) for all manually delineated organs combined (liver, spleen, kidney, lung, brain) increased from D0 to D6, but remained within 6% for all measured time points (Figure 3A).
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