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 C51N1Z
Planar Nucl Med Imag R Up Extrem Vein w Oth Radionuclide
Planar Nucl Med Imag R Up Extrem Vein w Technetium 99m