Ageing effect on 18 F-DOPA and 123 I-MIBG uptake: A cross-sectional study

Background The aim of this study was to investigate the relationship between age and uptake of fluorine-18-l-dihydroxyphenylalanine (18 F-DOPA) in the brain and myocardial uptake of iodine-123-metaiodobenzylguanidine (123 I-MIBG) in normal adult participants. Participants and methods To this end, a total of 72 healthy participants were enroled. Of these, 37 individuals (male, 21; female, 16; mean age: 60±12 years; age range: 38-85 years) underwent 18 F-DOPA PET/CT, whereas 35 individuals (male, 19; female, 16; mean age: 61±17 years; age range: 17-87 years) underwent 123 I-MIBG scintigraphy. For 18 F-DOPA PET/CT, regions of interest were placed on the caudate nucleus, globus pallidus and putamen by means of the WFU Pickatlas tool implemented in SPM8 and further analysed after a normalization process. For 123 I-MIBG scintigraphy, regions of interest were set over the upper mediastinum and a heart-To-mediastinum count ratio was calculated. The relation between age and normalized 18 F-DOPA values or heart-To-mediastinum ratio values was examined using correlation analysis of variance and Pearson's correlation coefficient. Results We did not find any significant relationship between age and 18 F-DOPA and 123 I-MIBG uptake, respectively. Conclusion Our findings suggest that both brain 18 F-DOPA PET/CT and cardiac 123 I-MIBG scintigraphy represent age-independent biomarkers whose analyses of quantitative uptake may not require adjustment for patients' age.