RT Journal Article SR Electronic T1 68Ga-4HMSA, a target for inflammation ? JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1623 OP 1623 VO 60 IS supplement 1 A1 Kahn Ali, Shigufa YR 2019 UL http://jnm.snmjournals.org/content/60/supplement_1/1623.abstract AB 1623Objectives: Currently, 67Ga-Citrate is used in nuclear medicine for the imaging of inflammation but unfortunately is has some disadvantages such as a long half-life and a lack of specificity. However, 68Ga, a positron-emitting radionuclide with a short half-life of 68 minutes (Wu et al., 2013) has showed, recently, a lot of potential for positron emission tomography (PET) imaging by offering a better spatial resolution and could be a great replacement for 67Ga. Our group has recently developed a chelator with four N-hydroxy-N-methyl succinamide pendant arms (4HMSA) that forms a strong complex with Ga(III). The aim of this study was to prove that 68Ga-4HMSA is as effective as 68Ga-citrate for PET imaging of inflammation while having a better specificity, pharmacokinetic and a lower dosimetry. Methods: Balb/c mice were injected in the left paw (intraplantar) with 0,5mg/mL of CFA (complete Freund’s adjuvant). The inflammation was followed for several days, 1, 2, 3 and 7 days. The animals were injected with 8-9 Mbq of either 68Ga-4HMSA or 68Ga-Citrate and PET/CT scans were performed. Both 68Ga-4HMSA and 68Ga-Citrate were obtained by a 68Ge/68Ga generator. 1 hour post-injection, the mice were euthanized and then biodistribution of the organs was done. Results: It is well known in the literature that the 68Ga-Citrate is a non-specific tracer (Petrik et al., 2014) and the results obtained confirmed it. Indeed, the accumulation of the 68Ga-Citrate in the organs remained the same at different inflammation times, whereas, for the 68Ga-4HMSA, at 2 days post-inflammation, we can see an accumulation in the blood, plasma and kidneys. These results suggest that the tracer’s uptake might be modulated according to the inflammation response. The majority of the inflamed tissue to organ ratios are higher for 68Ga-4HMSA, which suggest a specificity for inflammation. Conclusions: The results of this work showed that 68Ga-4HMSA has a better biodistribution profile as well as a lower dosimetry compared to the 68Ga-Citrate which makes it a very interesting tracer for PET imaging of inflammation. More experiments with a cellular model of inflammation will be done to understand better the mechanism of this tracer.