The Qualifier None is identified by letter "Z" and occupies the 6th position in the ICD10-PCS procedure code structure.
Below a selection of ICD 10 PCS codes related to CW56YZ
Nonimag Nucl Med Prob of Chest & Neck using Indium 111
Nonimag Nucl Med Prob of Chest & Neck using Oth Radionuclide
Nonimag Nucl Med Prob of Chest & Neck using Technetium 99m