Which of the following is used for permanent interstitial implant brachytherapy –

Permanent implants of interstitial brachytherapy :- Cesium -131, Yttrium, Gold - 198 (Au - 198), 125I, Radon - 222 (Rn - 222), Pallidum -103 (Pd -103). Temporary implants of Interstitial brachytherapy :- Iridium -  192 (Ir - 192), Cesium - 137 (Cs - 137), Cobalt - 60 (Co - 60),            Californium, Radium - 226 (Ra - 226), Tantolum.