Evaluation of technetium Tc 99m-labeled biotin for scintigraphic detection of soft tissue inflammation in horses.

The study investigates the usage of technetium Tc 99m-labeled EDTA-biotin monomer for detecting soft tissue inflammation in horses. The research demonstrates that this compound is safe for usage in horses and able to identify inflammation, offering an extended duration for acquiring scintigraphic images compared to another compound, technetium Tc 99m-hydroxymethylene diphosphonate.

Background and Methodology

• The study evaluated technetium Tc 99m-labeled EDTA-biotin monomer, known as (99m)Tc-EB1 as a scintigraphic imaging agent to detect inflammation in soft tissues of horses.
• The safety of the agent, its blood-tissue clearance, and the most effective imaging protocol were determined during the first phase of the study involving six adult horses.
• Each horse was injected with (99m)Tc-EB1 only once and images were captured at different intervals within a 24-hour period.

Inflammation Induction and Imaging

• In the second phase of the study, inflammation was experimentally induced in two horses through injections of mepivacaine into the horse’s right neck musculature and along the nerves in the proximal palmar metacarpal region of the right forelimb.
• Following the induction of inflammation, (99m)Tc-EB1 was injected into the horses. After eight hours, comparative soft tissue images were taken using technetium (99m)Tc-hydroxymethylene diphosphonate ((99m)Tc-HDP), another imaging agent.

Results

• The study found no discernible adverse effects following injections with (99m)Tc-EB1, as indicated by physical examinations, complete blood counts (CBCs), and serum biochemical analysis.
• The agent was quickly cleared from the blood, and its uptake in the soft tissues was immediate, remaining evident up to four hours after injection.
• After six hours, the mepivacaine-induced inflammation was successfully detected using (99m)Tc-EB1.
• The use of (99m)Tc-EB1 allowed for a more extended period of scintigraphic imaging compared to the use of (99m)Tc-HDP.

Conclusion

• Results of the study confirm the safety of (99m)Tc-EB1 for use in horses. It also demonstrated the agent’s capability to identify soft tissue inflammation without concurrent uptake in bone.
• The use of (99m)Tc-EB1 extends the period of scintigraphic image acquisition compared to (99m)Tc-HDP, providing longer window for detection of inflammation.