CPT code 77321: Radiation plan, special port plan2026 Medicare rate & RVUs in Maine
A special teletherapy port plan supports radiation treatment using nonstandard field arrangements, such as mantle or inverted-Y fields, when standard isodose planning categories do not fit.
Medicare pays $88.95–$93.35 for 77321 in the office in Maine, from Rest of Maine to Southern Maine, ME. Which amount applies depends on the service address.
Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.
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What 77321 covers
A radiation oncologist and the radiation physics team use this planning service to develop a special external-beam treatment arrangement. It is associated with distinctive field designs such as mantle or inverted-Y fields, rather than routine teletherapy isodose plans. The planning work supports the prescribed treatment geometry and dose distribution in radiation oncology settings.
Report 77321 when the documented plan is a special teletherapy port plan, not merely because a conventional plan involves multiple fields or is technically demanding. The record should identify the treatment arrangement and support why this special plan category was used. CMS separately prices the professional and technical components: modifier 26 represents the professional interpretation, and modifier TC represents the technical work, equipment, and staff. Reporting without either modifier represents the global service.
This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.
Where 77321 pays more and less in Maine
| Payment locality | Office | Facility |
|---|---|---|
| Rest of Maine | $88.95 | Unavailable |
| Southern Maine, ME | $93.35 | Unavailable |
How the 77321 rate is calculated
Each of 77321’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.
How the rate is built · 77321
RVUs × geographic indexes × conversion factor
Work0.93
0.93 RVUs× 1.000 GPCI
Practice expense1.85
1.85 RVUs× 1.000 GPCI
Malpractice0.05
0.05 RVUs× 1.000 GPCI
Adjusted RVUs
2.8300
Conversion factor
$33.4009
Medicare rate
$94.52
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 77321
The CMS indicators that decide how 77321 is paid alongside other services.
CMS payment indicators · 77321
Radiation plan, special port plan
| Rule | CMS value | What it means |
|---|---|---|
| Global period | XXX | The global surgery concept doesn’t apply. |
| Multiple procedures | 0 | No multiple-procedure reduction. |
| Bilateral (modifier 50) | 0 | The 150% bilateral adjustment doesn’t apply. |
| Assistant at surgery (80/81/82/AS) | 0 | Not paid without supporting documentation. |
| Co-surgeons (62) | 0 | Not permitted. |
| Team surgery (66) | 0 | Not permitted. |
| Professional/technical | 1 | Diagnostic test with separate professional (26) and technical (TC) components. |
What modifiers do to the payment
Modifier 26 · payment effect
With and without the modifier
77321 without 26 · national office
$94.52
Radiation plan, special port plan
77321-26 · Professional component
$49.77
Pays only the interpretation and report.
77321 compared with similar codes
Compare codes · National
5 codes, side by side
How to choose
- 77306Radiation planSimple teletherapy plan
- This code is for a simple teletherapy isodose plan. Choose 77321 when the documented plan is a special port arrangement, such as a mantle or inverted-Y field.
- 77307Isodose planningComplex teletherapy plan
- This code describes a complex teletherapy isodose plan. Complexity alone does not make a plan a special port plan for 77321.
- 77301IMRT planningDose optimization and volume analysis
- This code is for IMRT planning. Use 77321 for a special teletherapy port plan that is not an IMRT plan.
- 77331Radiation dosimetrySpecial measurement
- This code covers special radiation dosimetry, a dosimetry service distinct from developing the special teletherapy port plan reported with 77321.
77321 billing questions
When should 77321 be chosen instead of 77306 or 77307?
Use 77321 for a special teletherapy port arrangement, such as a mantle or inverted-Y field. Codes 77306 and 77307 describe simple or complex teletherapy isodose plans, respectively.
Does a plan qualify for 77321 just because it is complex?
No. The documentation should support a special port plan, rather than relying only on the number of fields or the general difficulty of planning.
How are the professional and technical components reported?
Modifier 26 identifies the professional component, and modifier TC identifies the technical component. Without either modifier, the claim represents the global service.
Can 77300 be reported with 77321?
A separately performed basic radiation dosimetry calculation may be reported with the plan when the record supports that distinct work.
What documentation supports 77321?
Document the special field arrangement and the planning work performed. The record should make clear why the service is a special port plan rather than a routine simple or complex isodose plan.
Where these rates come from
FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.
CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027
Show the CMS file lines behind this rate
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