The Isotope 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 DW21HZ
Stereotactic Gamma Beam Radiosurgery of Head and Neck
Stereotactic Other Photon Radiosurgery of Head and Neck
Stereotactic Particulate Radiosurgery of Head and Neck