ABSTRACT

Imaging agents used in single photon emission computed tomography (SPECT) and positron emission tomography (PET) were radioisotopes or basic modifications thereof. Radiochemistry nowadays can be considered one of the main motors of PET and SPECT research. Radiochemists synthesize radiotracers and base their names on the molecular structure. Fundamental physical parameters for radionuclear imaging are the physical half-life and the energy ranges and intensities of the main gamma-ray emission peaks. The radiopharmaceutical preparation is directly affected by the physical half-life. A radioisotope with slower physical decay may be advantageous when translating a radiotracer from preclinical experiments to the clinic. A number of physicochemical properties of radiotracers affect the interaction with biological matter and thus the pharmacokinetics. Translating small molecule PET radiotracer research into clinical diagnostics appears to be more straightforward compared to SPECT, in particular for small molecules and considering the radioisotopes fluorine-18 or carbon-11 compared to technetium-99m.