The Radionuclide Iodine 131 (I is identified by letter "G" and occupies the 5th position in the ICD10-PCS procedure code structure.
Below a selection of ICD 10 PCS codes related to CT63G
Nonimag Nucl Med Assay of KUB using Oth Radionuclide
Nonimaging Nuclear Medicine Assay of KUB using Iodine 131
Nonimaging Nuclear Medicine Assay of KUB using Iodine 123
Nonimag Nucl Med Assay of KUB using Technetium 99m
Nonimaging Nuclear Medicine Assay of KUB using Iodine 125