The effects of molar activity on [18F]FDOPA uptake in patients with neuroendocrine tumors

Abstract Background 6-[ 18 F]fluoro- l -3,4-dihydroxyphenyl alanine ([ F]FDOPA) is a commonly used PET tracer for the detection and staging of neuroendocrine tumors. In tumors, [ F]FDOPA decarboxylated to F]dopamine via enzyme amino acid decarboxylase (AADC), leading increased uptake when there AADC activity. Recently, in our hospital, new GMP compliant multi-dose production has been developed, F]FDOPA-H, resulting higher activity yield, improved molar lower administered mass than conventional method F]FDOPA-L). Aims This study aimed investigate whether difference affects at physiological sites tumor lesions, patients with NET. It was anticipated that specific F]FDOPA-H would be equal or F]FDOPA-L. Methods We retrospectively analyzed 49 pathologically confirmed NETs stable disease who underwent scanning using both F]FDOPA-L within time span 5 years. A total 98 scans (49 average activities 8 107 GBq/mmol) were analyzed. The SUVmean calculated organ SUVmax lesions groups comparison, separately subjects low load (1–2 lesions) (3–10 lesions). Results Comparable slightly demonstrated various scanned compared F]FDOPA-L, large overlap being present interquartile ranges. Tumor group 3–10 lesion (SUVmax 6.83 vs. 5.19, p < 0.001). other groups, no significant differences seen between H L. Conclusion [18F]FDOPA-H provides offering possibility scan more one single production. Minor observed SUV’s, slight increases comparison finding not concern clinical practice, but could importance quantifying follow-up while introducing methods F]FDOPA.