While X-ray, CT, and MRI visualize changes in configurations, PET (positron emission tomography) visualizes changes in vital functions such as bloodstream and metabolic rates. PET inspections are making a dramatic leap forward these days, and are widely used for examining cerebropathy, cardiac diseases, cancers, and the like. In particular, FDG-PET inspections, demand for which is on the rise, are used for cancer screening. This report covers a brief history of FDG-PET, and a newly developed synthesis module for the 18F labeled compound. The 18F labeled compound is used for exploring compounds, a practice that makes up for the shortcomings of FDG inspections. FDG-PET is expected to contribute to the development of radiation chemistry.