Evaluation of ^99mTc-CN5DG as a broad-spectrum SPECT probe for tumor imaging

Previously, we reported a [^99mTc(ǀ)]⁺ labeled d-glucoamine derivative (^99mTc-CN5DG) and evaluated it as a tumor imaging agent in mice bearing A549 tumor xenografts. In this paper, ^99mTc-CN5DG was further studied in U87 MG (human glioma cells), HCT-116 (human colon cancer cells), PANC-1 (human pancreatic cancer cells) and TE-1 (human esophageal cancer cells) tumor xenografts models to verify its potential application for imaging of different kinds of tumors. The biodistribution data showed that ^99mTc-CN5DG had a similar biodistribution pattern in four tumor models at 2 h post-injection with high accumulation in tumors and kidneys. The tumor/muscle ratios (from 4.08 ± 0.42 to 9.63 ± 3.53) and tumor/blood ratios (from 17.18 ± 7.40 to 53.17 ± 16.16) of ^99mTc-CN5DG in four tumor models were high. All four kinds of tumors could be clearly seen on their corresponding SPECT/CT images. Pharmacokinetic study in healthy CD-1 mice demonstrated that ^99mTc-CN5DG cleared fast from blood (2 min, 12.97 ± 0.88%ID/g; 60 min, 0.33 ± 0.06%ID/g) and the blood distribution, elimination half-life was 5.81 min and 21.16 min, respectively. No abnormality was observed through the abnormal toxicity study. All of the above results demonstrated that ^99mTc-CN5DG could be a broad-spectrum SPECT probe for tumor imaging and its further clinical application is warranted.