Commentary on Iodine-124

Author(s): Frank Wuest

The use of radiopharmaceuticals for molecular imaging of biochemical and physiological processes in vivo has evolved into an important diagnostic tool in modern nuclear
medicine and medical research. Positron emission tomography (PET) is currently the most sophisticated molecular imaging methodology, mainly due to the unrivalled high sensitivity which allows for the studying of biochemistry in vivo on the molecular level. The
most frequently used radionuclides for PET have relatively short half-lives (e.g. 11 C: 20.4
min; 18 F: 109.8 min) which may limit both the synthesis procedures and the time frame
of PET studies. Iodine-124 ( 124 , t 1/2 = 4.2 d) is an alternative long-lived PET radionuclide
attracting increasing interest for long term clinical and small animal PET studies. The
present review gives a survey on the use of 124 I as promising PET radionuclide for
molecular imaging. The first part describes the production of 124 I. The second part covers
basic radiochemistry with 124 I focused on the synthesis of 124 I-labeled compound for
molecular imaging purposes.