Table 1. Biodistribution and Tumor-to-Normal Tissue Ratios of ⁶⁸Ga-Labeled CCZ01099 in Male C57BL/6J Mice Bearing B16–F10 Melanoma at 1 and 2 h p.i. Blocking was Performed by Co-Injection of 0.5 mg of MC1R-Specific Inhibitor BMS 470539 (Two-Way ANOVA Analysis was Performed Comparing 1 h p.i. vs 1 h p.i. Blocked, Multiple Comparisons Were Corrected Using the Holm–Sidak Method, *p < 0.05, ***p < 0.001)^a.

tissue	1 h p.i. unblocked (n = 5)	2 h p.i. unblocked (n = 4)	1 h p.i. blocked (n = 5)
B16F10 tumor	6.33 ± 1.48	5.22 ± 1.30	0.60 ± 0.15***
blood	0.65 ± 0.12	0.19 ± 0.01	0.27 ± 0.04
fat	0.09 ± 0.04	0.02 ± 0.01	0.04 ± 0.02
seminal glands	0.11 ± 0.06	0.04 ± 0.01	0.07 ± 0.03
testes	0.20 ± 0.06	0.07 ± 0.01	0.10 ± 0.02
intestine	0.34 ± 0.07	0.53 ± 0.38	0.17 ± 0.05
spleen	0.35 ± 0.08	0.19 ± 0.03	0.52 ± 0.28
pancreas	0.17 ± 0.04	0.07 ± 0.01	0.08 ± 0.01
stomach	0.22 ± 0.11	0.20 ± 0.16	0.19 ± 0.12
liver	0.53 ± 0.07	0.44 ± 0.08	0.38 ± 0.11
adrenal glands	0.79 ± 0.72	0.33 ± 0.19	0.45 ± 0.29
kidneys	5.59 ± 0.88	4.42 ± 0.55	2.62 ± 0.91***
heart	0.24 ± 0.06	0.08 ± 0.01	0.13 ± 0.02
lungs	0.69 ± 0.11	0.31 ± 0.05	0.34 ± 0.13
thyroid	0.30 ± 0.08	0.16 ± 0.03	0.13 ± 0.05
bone	0.33 ± 0.18	0.10 ± 0.03	0.17 ± 0.10
muscle	0.16 ± 0.05	0.04 ± 0.00	0.08 ± 0.03
brain	0.05 ± 0.04	0.01 ± 0.00	0.03 ± 0.02
tumor to normal tissue ratios
tumor/muscle	40.6 ± 11.9	125 ± 29.6	7.98 ± 1.35***
tumor/blood	9.94 ± 2.93	27.7 ± 5.34	2.24 ± 0.40
tumor/bone	23.3 ± 12.1	52.7 ± 13.4	4.19 ± 1.80***
tumor/liver	11.9 ± 2.26	11.8 ± 2.72	1.79 ± 0.88*
tumor/kidneys	1.13 ± 0.22	1.21 ± 0.44	0.26 ± 0.12

^aValues are in percentage of injected dose per gram of tissue (%ID/g, mean ± standard deviation).