Abstract: The present invention relates to a method for implantation of Xe isotopes in a matrix for production of 125I sources that do not shed radioactive atoms. 125Xe implanted at 12 kV in steel, titanium and gold does not evolve after more than 10 half-lives (380 h) and 125I from the decay of implanted 125Xe is equally stable for 2 half-lives (120 d). The matrix having radioxenon implanted is useful as a medical device, for instance as a “seed” for radiotherapeutic uses or in production of stents. Methods of treatment utilizing such devices are also encompassed by the present invention.