CPT 77331
Special radiation dosimetry
CPT 77331 at a glance
- Code
- 77331
- Code type
- CPT/HCPCS
- Short descriptor
- Special radiation dosimetry
- Category
- ASC Ancillary
- ASC payment status
- Payable in an ASC (ancillary)
- CMS addendum
- BB (Ancillary)
- Typical setting
- Ambulatory surgery center (POS 24) or hospital outpatient department (POS 22).
What is CPT code 77331?
CPT 77331 is a CPT/HCPCS procedure code. Its official CMS short descriptor is "Special radiation dosimetry". In the ASC context it is grouped under ASC Ancillary.
Is CPT 77331 payable in an ambulatory surgery center (ASC)?
CPT 77331 is a covered ancillary service (CMS Addendum BB). Medicare reimburses it in the ASC setting when it is integral to a covered ASC surgical procedure.
Where is CPT 77331 typically performed?
Ambulatory surgery center (POS 24) or hospital outpatient department (POS 22).
Which specialties use CPT 77331?
CPT 77331 is most associated with Diagnostic Radiology.
Reference information compiled from the CMS April 2026 ASC payment addenda (AA, BB, EE). Codes, descriptors, and ASC payment status change with each CMS update. This is a coding reference, not billing, coding, or legal advice. Always verify against the current CMS addenda and individual payer policy before billing. CPT is a registered trademark of the American Medical Association.