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Table 1 Biodistribution of 177Lu-octreotate in GOT1-bearing nude mice

From: Priming increases the anti-tumor effect and therapeutic window of 177Lu-octreotate in nude mice bearing human small intestine neuroendocrine tumor GOT1

A 177Lu activity concentration (%IA/g)
  With priming, (5+) 10 MBq (n = 9) Without priming, 15 MBq (n = 8)
Tissue 24 h 72 h 168 h 24 h 72 h 168 h
 Adrenals 1.4 (0.1)a 0.42 (0.20)a 0.36 (0.06) 0.60 (0.03)a 1.4 (0.1)a 0.30 (0.06)
 Blood 0.013 (0.001) 0.0048 (0.0005) 0.0017 (0.0004) 0.011 (0.001) 0.0055 (0.0002) 0.0021 (0.0002)
 Kidneys 4.5 (0.8) 1.5 (0.1) 0.71 (0.14)a 6.8 (0.3) 2.3 (0.4) 0.50 (0.04)a
 Liver 0.094 (0.008) 0.077 (0.009) 0.070 (0.009) 0.12 (0.06) 0.10 (0.01) 0.049 (0.004)
 Lungs 0.84 (0.10)a 0.43 (0.03) 0.31 (0.02)a 0.48 (0.04)a 0.33 (0.02) 0.15 (0.003)a
 Pancreas 0.54 (0.02)a 0.30 (0.02) 0.18 (0.02)a 0.36 (0.03)a 0.26 (0.04) 0.062 (0.011)a
 Spleen 0.080 (0.010) 0.090 (0.006) 0.090 (0.010) 0.10 (0.01) 0.088 (0.009) 0.061 (0.005)
 Tumor 2.5 (0.9) 4.6 (0.8)a 1.8 (0.5) 1.6 (0.1) 1.6 (0.2)a,b 0.84 (0.31)
B Tumor-to-normal tissue activity concentration ratio (T/N)
  With priming, (5+) 10 MBq (n = 9) Without priming, 15 MBq (n = 8)
Tissue 24 h 72 h 168 h 24 h 72 h 168 h
 Adrenals 1.7 (0.5) 23 (9) 4.6 (1.2) 2.7 (0.4) 1.1 (0.1) 3.8 (1.6)
 Blood 190 (62) 1100 (280) 1100 (360) 160 (34) 290 (21) 420 (160)
 Kidneys 0.62 (0.29) 3.1 (0.7)a 2.6 (0.8) 0.23 (0.02) 0.76 (0.19)a 1.5 (0.6)
 Liver 27 (10) 63 (14) 24 (5) 14 (1) 17 (2) 16 (6)
 Lungs 2.9 (1.1) 10 (2) 5.4 (1.3) 3.4 (0.4) 4.9 (0.6) 5.8 (2.2)
 Pancreas 4.5 (1.5) 15 (2)a 10 (3) 4.4 (0.3) 6.6 (1.1)a 12 (4)
 Spleen 32 (13) 53 (11) 18 (4) 17 (1) 19 (3) 13 (5)
C Tumor cell proliferation assed by Ki67 staining (%)
  With priming, (5+) 10 MBq (n = 9) Without priming, 15 MBq (n = 8) Controls
Antibody 24 h 72 h 168 h 24 h 72 h 168 h 24 h 72 h 168 h
 Ki67 27 (4) 22 (2)c 25 (2)c 31 (1)c 29 (3)b 28 (2)c 45 (1)b 42 (1)b 42 (2)b
  1. A: 177Lu activity concentration (%IA/g), B: tumor-to-normal tissue activity concentration ratio, and C: percent of tumor cells with positive immunohistochemical staining from tumors after 5 + 10 or 15 MBq 177Lu-octreotate with or without priming activity, respectively, corrected for physical decay, in different tissues in GOT1 tumor-bearing nude mice at 24, 72, and 168 h after injection (n = 3/group). Values for the 5 + 10 MBq group (activity concentration and T/N) were estimated based on data from the 10 MBq administrations only i.e. therapeutic effect. Values are given as mean (SEM). Statistically significant difference (p < 0.05) between priming and single administration and between treated animals and controls is indicated by a and c, respectively, b n = 2