C3 and neoplasm: The time required for the tumor volume to increase by 5-fold relative to the initial volume (5Td) was 4.7 ± 0.5 and 5.2 ± 0.5 days for the vehicle and [NatCu]NOTA-C3-TP groups, which significantly increased to 6.6 ± 1 and 9 ± 0.5 days for the CRT groups injected with 70 MBq or 137 MBq of [64Cu]NOTA-C3-TP, respectively.