Page 134 - Cellular Imaging in Regenerative Medicine, Cancer and Osteoarthritis

Chapter 6
The tumor-to-kidney absorbed dose ratio of [177Lu]Lu-Albutate-1 is 1.5 ± 0.5. The tumor-to-pancreas absorbed dose ratio is 3.9 ± 0.4 and the tumor-to-bone marrow absorbed dose ratio is 2.4 ± 0.9.
2.5. Dosimetry
All organ time-activity curves could be fitted with an exponential function, for parameters and goodness of fits. The blood curve of [177Lu]Lu-Albutate-1 followed a single exponential clearance pattern with T1/2 = 27.5 ± 2.6 h. The blood concentration and total number of disintegrations in the bone marrow cavities were calculated (Table 1). In Table 2 the absorbed dose per administered activity to the major organs is described. SSTR2 positive organs, (such as intestines, pancreas, adrenals, etc.) encountered a high absorbed dose per administered activity.
Table 1 Dosimetry to bone marrow cavities, CF cellularity factor, time-integrated activity coefficient of blood in BM compartment Ãblood/IA, blood self-dose Dself and cross dose Dcross by activity in other organs, both per injected activity IA.
Sternum 8% 41 104 24 Spine 52% 6617 741 27 Skull 11% 499 170 26 Ribs 8% 142 81 47
CF
Ãblood/IA (s)
Dself/IA (mGy/MBq)
Dcross /IA (mGy/MBq)
Arms 5% Lower legs 4% Pelvis 7% Scapulae 3%
Femurs 10%
76 74 15 118 67 11 272 108 29
31 42 43 171 169 58
Table 2 Absorbed dose per administered activity to the major organs in 22g weight mice for [177Lu]Lu- Albutate-1.
Tumor 1455 Adrenals 1073 Kidney 958 BM spine 765 Intestines 566 Spleen 538 Liver 422 Pancreas 373 Total body 253 Stomach 247 Femur 211
mGy/MBq
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