¹²⁴Iodine: A Longer-Life Positron Emitter Isotope—New Opportunities in Molecular Imaging

Abstract

124Iodine (124I) with its 4.2 d half-life is particularly attractive for in vivo detection and quantification of longer-term biological and physiological processes; the long half-life of 124I is especially suited for prolonged time in vivo studies of high molecular weight compounds uptake. Numerous small molecules and larger compounds like proteins and antibodies have been successfully labeled with 124I. Advances in radionuclide production allow the effective availability of sufficient quantities of 124I on small biomedical cyclotrons for molecular imaging purposes. Radioiodination chemistry with 124I relies on well-established radioiodine labeling methods, which consists mainly in nucleophilic and electrophilic substitution reactions. The physical characteristics of 124I permit taking advantages of the higher PET image quality. The availability of new molecules that may be targeted with 124I represents one of the more interesting reasons for the attention in nuclear medicine. We aim to discuss all iodine radioisotopes application focusing on 124I, which seems to be the most promising for its half-life, radiation emissions, and stability, allowing several applications in oncological and nononcological fields.

Optical and nuclear imaging of glioblastoma with phosphatidylserine-targeted nanovesicles

“…124 I is a relatively ‘long-lived’ (half-life of 4.2 days) positron emitter, which unlike commonly used, short-lived radio nuclides ( 18 F, 11 C), allows for prolonged evaluation of residence time of the radionuclide within the tumor [34, 35] and extended assessment of the pharmacokinetics of SapC-DOPS. In addition, PET/CT with 124 I can be used clinically to estimate tumor-absorbed dose for pre-therapy dosimetry prior to implementation of ( 125 I)/( 131 I)-radiochemical therapies [36].…”

Past, Present, and Future: Development of Theranostic Agents Targeting Carbonic Anhydrase IX

“…However, the high energy gamma emissions of 131 I and reliance on collimators for detection can lead to poor resolution images that limit quantification 51 . 124 I is an alternative iodine radionuclide that has been used for radiolabeling cG250 52 . As a positron emitter, 124 I facilitates the use of mAbs for PET imaging, which uses coincidence detection to greatly enhance sensitivity and resolution.…”

Hypoxia in cervical cancer: from biology to imaging

“…However, previous studies provide no evidences that these tracers are superior to the most widely used nitroimidazole, 18F-FMISO [ 103 ]. Furthermore, 124-Iodine (124I) is a long-lived positron emitter with chemical properties similar to 18F, and may thus allow for imaging at later timepoints after intravenous injection [ 104 ]. This could be an advantage for nitroimidazoles, having slow biokinetics.…”