Organic synthesis has a very important role in pharmaceutical study. Exchanging radioisotope can be used to produce radiolabelled pharmaceuticals that help in the diagnosis of various diseases like cancers, brain disorders and heart malfunctioning. Nowadays, the diagnosis of diseases has been frequently checked by PET (Positron Emission Tomography). So, our group is synthesizing radiolabelled carbocyclic nucleosides as PET tracer materials. The representative scheme is shown below.