Fully Automated Synthesis of Nitrogen-13-NH3 by SHIs HM-18 Cyclotron and Dedicated Module for Routine Clinical...

The production of nitrogen-13 (¹³N)-NH₃ by ethanol method using automated synthesizer and accessing the production yield, quality control for clinical application.

¹³N, together with ¹⁸F, ¹⁵O, and ¹¹C, is one of the positron emitters that can be produced on the multi-gigabecquerel scale in biomedical cyclotrons. (¹³N)-ammonia is frequently used for cardiac PET studies. It is widely applied for the evaluation of myocardial perfusion in the clinical assessment of cardiac disorders. Simple, fast, and reliable preparation methods have contributed to the routine application of this tracer. Although only two methods are available, a challenge remains to adopt a more efficient and consistent approach to its production. For clinical application, routine production of this tracer is mandatory in compliance with regulatory guidelines. Being at hospital radiopharmacy it is our responsibility to support the clinical service with uninterrupted production and supply of (¹³N)-NH₃.

The chemicals were used commercially available from Sigma Aldrich, India, Ltd., and Fisher Scientific, India, Ltd. (Mumbai, India), Sep-Pak CM cartridges (Waters India, Pvt., Ltd.,). Radio-thin layer chromatography was carried out using aluminum sheets precoated with silica gel 60 F254 (E. Merck, India).

The protocol developed with MPS-100 synthesizer yield (¹³N)-NH₃95-97% (EOB) with a synthesis time of around 7 min.

With the installation of HM-18 cyclotron at our hospital, center is capable to produce (¹³N)-NH₃ of good yield and purity through the ethanol method, for mycocardial perfusion studies. Our protocol is simple, reproducible, and robust.