Sn-117m is a 14 day half-life gamma (159 keV) and conversion electron (130 keV) isotope that has historically been produced in reactors at low (up to 20 Ci/g) specific activities and used for bone pain palliation studies.Recently, this isotope has also found application in investigative efforts to image and treat vulnerable plaque.However, this application requires high (carrier-free) specific activity Sn-117m that can only be produced with accelerators.A new production method has, therefore, been developed that uses the Cd-116(α,3n) reaction with a 47 MeV alpha beam striking an electroplated Cd-116 target.Resulting yields were confirmed to be high (∼0.15 mCi/μAh) with minimal undesirable byproducts.An ion exchange column method was used to isolate the Sn-117m resulting in a very pure high specific activity (∼20,000 Ci/g) product.This isotope has subsequently been attached to biol. targeting mols. and used in pre-clin. and clin. studies to treat vulnerable plaque.