Methods of producing high specific activity Sn-117m with commercial cyclotrons

Sn-117m is a theragnostic isotope of increasing interest. It has ideal imaging and therapeutic properties for many applications. Production of high specific activity Sn-117m can only be achieved with accelerators and the Sb(p,x) and Cd-116(α,3n) reactions provide the highest yields for this isotope. This paper describes the production and a new purification method for obtaining commercial quantities of Sn-117m via the Cd-116(α,3n) reaction. The purified Sn-117m has subsequently been chelated with an aminobenzyl derivative of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) and then conjugated with annexin V-128 to produce an agent for the diagnosis and treatment of vulnerable plaque.