Pharmacokinetics radioactive tracers

E = 137keV). The accompanying emission of 7-radiation can be used for scintigraphic imaging but also makes patient isolation necessary. The different half-lifes and /3 -energies allow individual therapeutic demands such as the pharmacokinetics of the tracer molecule, the linear energy transfer of the nuclides or the biodistribution and clearance of the radiolabeled drug to be met. The principles of the application of radioactive materials for therapy are summarized in an excellent review. ... 

The concept of using a tracer species to measure the mixing characteristics is not limited to chemical reactors. In the area of pharmacokinetics, the time course of renal excretion of species originating from intravenous injections in mans wa s resembles the input of a pulse of tracer into a chemical reactor. Normally, a radioactive labeled ( H, etc.) version of a drug is used to follow the pharmacokinetics of the drug... 

In biodistribution, metabolic, and pharmacokinetic studies, the radiolabelled tracer is administered to the subject and samples of tissues are subsequently taken to be measured in a scintillation counter in order to quantify the amount of radioactivity present in that sample. For this type of application any of the radionuclides listed in Table 1 may be used. In animal studies the amount of radioactivity which needs to be administered will be determined by the efficiency of the detection rstem and normal radiation safety considerations. For studies in human subjects the radiation dose to the recipient is likely to be paramount. For these reasons iodine-125 will probably be the radionuclide of choice for this type of study and the labelling procedure described above may be used. 

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