This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
[{'content': 'Which of the following is used for permanent interstitial implant brachytherapy – \nSelect and explain. \nA. Boron, B. Cesium – 131, C. Phosphorus, D. Iridium', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Permanent implants of interstitial brachytherapy\xa0:-\xa0Cesium -131,\xa0Yttrium, Gold - 198 (Au - 198),\xa0125I, Radon - 222 (Rn - 222), Pallidum\xa0-103 (Pd -103).\nTemporary implants of Interstitial brachytherapy\xa0:- Iridium - \xa0192 (Ir - 192), Cesium - 137 (Cs - 137), Cobalt - 60 (Co - 60),\n\n\xa0 \xa0 \xa0 \xa0 \xa0 \xa0Californium, Radium - 226 (Ra - 226), Tantolum.', 'role': 'assistant'}]