**Author Listing - Lead/ Submitting Author (we will be communicating with this individual): Name, Institution, City and State where the work was done. Co-authors will be added in a separate section.**
Panagiota Efstathia Nikolaou
nayanik@pharm.uoa.gr
(1)	Laboratory of Pharmacology, School of Pharmacy, National & Kapodistrian University of Athens, Athens, Greece 
(2)	National Centre for Scientific Research "Demokritos", Athens, Greece

**Main Body of the Abstract**
Background: Nuclear imaging can provide a non-invasive method for early detection and quantification of the amyloid. Technetium-99m (99mTc)-based bone tracers are already widely used in the diagnosis of transthyretin amyloidosis (ATTR). 99mTc-based radiotracers have significant advantages, wide availability, and low cost. 
Aims: We aimed to develop 99mTc-based radiotracers for light chain amyloidosis (AL). 
Methods: We evaluated the binding of three compounds-complexes, (benzothiazole and benzimidazole derivatives based on the thioflavin-T structure), in AL amyloid deposits. We generated AL amyloidoma-bearing mice by subcutaneously injecting Balb/c male mice between the scapulae with a solution of 80 mg amyloid fibrils from patient-derived light chains. The distribution of the 99mTc-complexes’ was evaluated with real-time imaging (γ-eye™, BIOEMTECH) and with biodistribution studies at 2, 30, or 90 minutes after intravenous administration of the radiotracer. Results: Dynamic imaging indicated that the 99mTc-1 and 99mTc-3 complexes are distributed within the amyloidoma, with no uptake at the site of injection. 99mTc-2 was not localized within the amyloidoma. The 99mTc-3 complex showed a rapid distribution from the blood to organs commonly affected by AL in 2 minutes. It was rapidly distributed within the amyloidoma and was not cleared at 30 and 90 minutes after administration.  Importantly, 99mTc-3 was cleared from the heart at 30 minutes (while still present in the amyloidoma), suggesting that it is suitable for detection of cardiac AL at this timepoint. 
Conclusions: We observed a differential binding of three compounds-complexes in the AL amyloidoma model. 99mTc-3 shows the best profile and is currently investigated for further development.



**Author Listing - Lead/ Submitting Author (we will be communicating with this individual): Name, Institution, City and State where the work was done. Co-authors will be added in a separate section.**
Panagiota Efstathia Nikolaou
nayanik@pharm.uoa.gr
(1)	Laboratory of Pharmacology, School of Pharmacy, National & Kapodistrian University of Athens, Athens, Greece 
(2)	National Centre for Scientific Research "Demokritos", Athens, Greece

**Main Body of the Abstract**
**Background:** Nuclear imaging can provide a non-invasive method for early detection and quantification of the amyloid. Technetium-99m (^99m^Tc)-based bone tracers are already widely used in the diagnosis of transthyretin amyloidosis (ATTR). ^99m^Tc-based radiotracers have significant advantages, wide availability, and low cost. 
**Aims:** We aimed to develop ^99m^Tc-based radiotracers for light chain amyloidosis (AL). 
**Methods:** We evaluated the binding of three compounds-complexes, (benzothiazole and benzimidazole derivatives based on the thioflavin-T structure), in AL amyloid deposits. We generated AL amyloidoma-bearing mice by subcutaneously injecting Balb/c male mice between the scapulae with a solution of 80 mg amyloid fibrils from patient-derived light chains. The distribution of the ^99m^Tc-complexes’ was evaluated with real-time imaging (γ-eye™, BIOEMTECH) and with biodistribution studies at 2, 30, or 90 minutes after intravenous administration of the radiotracer. **Results:** Dynamic imaging indicated that the **^99m^Tc-1** and **^99m^Tc-3** complexes are distributed within the amyloidoma, with no uptake at the site of injection. ^9**9m**^**Tc-2** was not localized within the amyloidoma. The **^99m^Tc-3** complex showed a rapid distribution from the blood to organs commonly affected by AL in 2 minutes. It was rapidly distributed within the amyloidoma and was not cleared at 30 and 90 minutes after administration.  Importantly, **^99m^Tc-3** was cleared from the heart at 30 minutes (while still present in the amyloidoma), suggesting that it is suitable for detection of cardiac AL at this timepoint. 
**Conclusions:** We observed a differential binding of three compounds-complexes in the AL amyloidoma model. **^99m^Tc-3** shows the best profile and is currently investigated for further development.



Development of novel technetium-99m  complexes as light chain amyloidosis radiodiagnostic tracers PB111 (#276)

We invite you to attend the XIX International Symposium on Amyloidosis to be held in Rochester, MN.

This symposium is organized as a hybrid meeting (with the focus on in-person) held from Sunday, May 26 through Thursday, May 30, 2024.

Together with the ISA Board and members of Mayo Clinic, a very attractive scientific hybrid program is being planned. The program will cover a variety of types of systemic amyloidosis: ATTR (hereditary and wild-type), AL (light-chain), AA and less frequent forms. There will be key lectures, specific symposia including those company sponsored, oral presentations and poster sessions of accepted abstracts.

COURSE DESCRIPTION
This program will provide a comprehensive review of state-of-the-art education in systemic amyloidosis: basic science, pathophysiology, diagnosis, current and emerging treatments. Scientific presentations will include competitive oral and poster abstracts. The rapid evolution of scientific discovery and expanding treatment options has created tremendous interest in the field and this meeting will fill and important gap in educating scientists and clinicians.