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 CP23YZ
Tomo Nucl Med Imag of Skull, Cerv Spine using Technetium 99m
Tomo Nucl Med Imag Skull, Cerv Spine w Oth Radionuclide