Nanospect ct

Three Balb/C mice (8 weeks, 28.5 g in average) were purchased from Slac Laboratory animal (China) and recruited in this research. Animal care and all experimental procedures were performed under the approval of the Animal Care Committee of Fudan University. SPECT/CT imaging was operated in the Department of Nuclear Medicine, Shanghai Cancer Center, Fudan University. Preparation of ^99mTc-labeled DTNs-AS1411: Briefly, the mixtures of DTNs-AS1411 and NHS-MAG₃ in HEPES buffer (pH = 8.0) were incubated at room temperature for 2 h and then purified on a P4 column with 0.1 M PBS as eluent. The peak fractions were collected and quantitated by UV spectrophotometry. For radiolabeling, 18.5 MBq ^99mTc-pertechnetate generator elute was added into a mixed solution of 40 μL (10 μg) of MAG₃-DTNs-AS1411 in PBS, 15 μL tartrate buffer (pH = 8.5), and 5 μg SnCl₂·2H₂O in 0.01 M HCl. The solution was heated to 50 °C for 20 min. The ^99mTc-labeled DTNs-AS1411 was purified by size exclusion radio-HPLC. Aiming for the preliminary evaluation of biodistribution and in vivo metabolic mechanism, ^99mTc-DTNs-AS1411 (18.5 MBq/mouse) was administered to Balb/C mice via tail vein injection. At 3 h post injection, mice were anesthetized via 2 % isoflurane inhalation and scanned via NanoSPECT/CT (Bioscan, Washington, DC) for 20 min.

Conjugates were administered by tail vein injection of 100 μl solution (0.2 and 0.9 MBq) to each animal. Between 4 and 7 mice were sacrificed by neck dislocation under Sevoflurane gas anesthesia at each time point after cardiac puncture for blood sampling. Tumor sizes at injection of conjugates varied between 120 and 1800 mm³. Studies were conducted as described in reference [28 (link)]. Comparisons between average values were done using t-tests with a significance level of 0.05.
A pilot In vivo SPECT/CT was performed on 2 mice with Ramos subcutaneous xenografts with diameters around 12 mm in their right flank in a nanoSPECT/CT (Bioscan Inc., Washington DC, USA). SPECT/CT acquisitions were performed at 3, 24 and 48 hours after treatment injection in mouse 1 and after 24 hours in mouse 2. Activities measured by SPECT/CT were compared with ex-vivo measurements done at 48 hours after treatment administration. Mice were injected i.v. with 150 μl of 10 MBq of ¹⁷⁷Lu-HH1 and were anaesthetized with 2% Isofluran for image acquisition.