The Radionuclide Oxygen 15 (O is identified by letter "M" and occupies the 5th position in the ICD10-PCS procedure code structure.
Below a selection of ICD 10 PCS codes related to C23GM
PET Imag of Myocardium using Fluorine 18
PET Imag of Myocardium using Oth Radionuclide
PET Imag of Myocardium using Nitrogen 13
PET Imag of Myocardium using Oxygen 15
PET Imag of Myocardium using Rubidium 82