Development of a (68)Ga‐labelled PET tracer for carbonic anhydrase IX‐overexpressed tumors using the artificial sweetener saccharin

In this study, we developed a saccharin (SAC)‐based radiopharmaceutical ((68)Ga‐NOTA‐SAC) and evaluated the possibility of its application as a PET tracer in the diagnosis of carbonic anhydrase IX (CA IX)‐overexpressed tumors. We did a water‐soluble tetrazolium assay and flow cytometry analysis to identify the cell viability decrease by SAC. The radiochemical purity and stability of (68)Ga‐ NOTA‐SAC in human and mouse serum was greater than 98%. The small animal PET image‐based radioactivity distribution of all organs decreased over time.(68)Ga‐NOTA‐SAC presented the highest tumor‐to‐muscle ratio at 90 min post injection (p.i). The growth rates of tumor‐to‐muscle ratios of (68)Ga‐NOTA‐SAC were 88% at 60 min and 220% at 90 min, compared to 30 min p.i. The potential of (68)Ga‐NOTA‐SAC as a PET tracer is expected to contribute to the diagnostic research on CA IX‐overexpressed tumors with the advantages of a relatively simple synthesis method.