system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
M in 99Tc"' stands for?
assistant
The correct answer is  Metastable REF: Nuclear Physics: Principles And Applications by Lilley Page 20 "In 99Tcm the superscript M denotes that the technetium 99 is not in its ground state but a long lived metastable excited state"