**10. Methods of radiolabeling**

The radiolabeling of antibiotics, drugs, peptides, proteins and organic species with different radiotracer has increased reasonably from imaging point of view in medical, biochemical and other associated fields. In the field of medical imaging, compounds are labeled with two types of radionuclides: (a) compound labeled with those radionuclide that emitted the gamma radiation and have large number of application and especially used for in vivo imaging of a number of organs and (b) secondly, the compounds are labeled with radionuclide that emitted the *β*-radiation and have limited in vitro study and therapeutic treatment of the disease site. During the labeling process of a compound with a radiotracer, atoms or group of atoms of compound are replaced by different or similar atoms or group of atoms of the radiotracers [13]. In order to obtain, certain type of the labeling, the labeling process is carried out under constant conditions of temperature, pressure and incubation time. There are mainly six methods for labeling of the compound with radiotracer as shown in **Table 7**.


**Table 7.**

*Methods for labeling of the compound with radiotracers [13].*
