Billing code 77331: Radiation dosimetryMedicare rate & RVUs in Redding
Reports specialized radiation dose measurement, such as TLD-based dosimetry, when a radiation oncology team needs more than routine treatment-planning calculations.
In Redding, Medicare pays $68.21 for 77331 in the office.
Check a contract rate as a % of Medicare · 77331 nationwide
Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.
On this page 11 sections
What 77331 covers
This service covers specialized measurement of radiation dose, including methods such as thermoluminescent dosimetry (TLD) or microdosimetry. A radiation oncology physicist typically performs or interprets the work, with technical staff and measurement equipment supporting the test. It may be used when the team needs a patient-specific dose measurement or verification beyond routine dose calculations in a radiation treatment plan.
Select the code for the specialized measurement actually performed, not simply because a treatment plan includes dose calculations. Documentation should identify the measurement method, its clinical purpose, and the findings or interpretation. CMS treats the service as having professional and technical components: report modifier 26 for the interpretation, modifier TC for the equipment and staff, or neither modifier when billing the global service. The record should support the component billed and show that the specialized measurement was performed.
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.
How Redding compares for 77331
Across 109 of 109 payment localities, the office rate for 77331 runs from $59.38 in Arkansas to $82.98 in San Jose-Sunnyvale-Santa Clara (San Benito Cnty). Redding pays $68.21. The RVUs are the same everywhere; the geographic indexes change the dollars.
- Redding · this page$68.21
- Bakersfield · California$68.39+$0.18
- Chico · California$68.21
- El Centro · California$68.21
- Fresno · California$68.21
- Hanford-Corcoran · California$68.21
- Los Angeles-Long Beach-Anaheim (Los Angeles/Orange Cnty) · California$72.15+$3.94
Other areas in California first, then benchmark localities. Bars start at $0.
Every other payment area
| Payment locality | Office | Facility |
|---|---|---|
| MaderaCalifornia | $68.21 | — |
| MercedCalifornia | $68.21 | — |
| ModestoCalifornia | $68.21 | — |
| NapaCalifornia | $77.25 | — |
| Oxnard-Thousand Oaks-VenturaCalifornia | $71.68 | — |
| Rest Of CaliforniaCalifornia | $68.21 | — |
| Riverside-San Bernardino-OntarioCalifornia | $68.76 | — |
| Sacramento-Roseville-FolsomCalifornia | $71.10 | — |
| SalinasCalifornia | $70.81 | — |
| San Diego-Chula Vista-CarlsbadCalifornia | $72.09 | — |
| San Francisco-Oakland-Berkeley (Marin Cnty)California | $81.30 | — |
| San Francisco-Oakland-Berkeley (San Francisco/San Mateo/Alameda/Contra Costa Cnty)California | $81.25 | — |
| San Jose-Sunnyvale-Santa Clara (San Benito Cnty)California | $82.98 | — |
| San Jose-Sunnyvale-Santa Clara (Santa Clara Cnty)California | $82.75 | — |
| San Luis Obispo-Paso RoblesCalifornia | $69.71 | — |
| Santa Cruz-WatsonvilleCalifornia | $72.49 | — |
| Santa Maria-Santa BarbaraCalifornia | $70.97 | — |
| Santa Rosa-PetalumaCalifornia | $73.20 | — |
| StocktonCalifornia | $68.21 | — |
| VallejoCalifornia | $77.17 | — |
| VisaliaCalifornia | $68.21 | — |
| Yuba CityCalifornia | $68.21 | — |
| Dc + Md/Va SuburbsDistrict of Columbia | $73.10 | — |
| MiamiFlorida | $69.12 | — |
| ChicagoIllinois | $67.67 | — |
| ManhattanNew York | $73.61 | — |
| Alaska*Alaska | $80.86 | — |
| AlabamaAlabama | $60.02 | — |
| ArkansasArkansas | $59.38 | — |
| ArizonaArizona | $63.80 | — |
| ColoradoColorado | $67.35 | — |
| ConnecticutConnecticut | $68.75 | — |
| DelawareDelaware | $64.68 | — |
| Fort LauderdaleFlorida | $66.94 | — |
| Rest Of FloridaFlorida | $64.43 | — |
| AtlantaGeorgia | $66.11 | — |
| Rest Of GeorgiaGeorgia | $61.66 | — |
| Hawaii, GuamHawaii | $69.23 | — |
| IowaIowa | $61.14 | — |
| IdahoIdaho | $61.45 | — |
| East St. LouisIllinois | $64.02 | — |
| Rest Of IllinoisIllinois | $63.02 | — |
| Suburban ChicagoIllinois | $67.57 | — |
| IndianaIndiana | $61.71 | — |
| KansasKansas | $60.94 | — |
| KentuckyKentucky | $61.10 | — |
| New OrleansLouisiana | $63.29 | — |
| Rest Of LouisianaLouisiana | $61.03 | — |
| Metropolitan BostonMassachusetts | $72.92 | — |
| Rest Of MassachusettsMassachusetts | $67.11 | — |
| Baltimore/Surr. CntysMaryland | $68.54 | — |
| Rest Of MarylandMaryland | $65.70 | — |
| Rest Of MaineMaine | $61.69 | — |
| Southern MaineMaine | $64.20 | — |
| DetroitMichigan | $65.05 | — |
| Rest Of MichiganMichigan | $62.30 | — |
| MinnesotaMinnesota | $64.97 | — |
| Metropolitan Kansas CityMissouri | $62.95 | — |
| Metropolitan St. LouisMissouri | $63.45 | — |
| Rest Of MissouriMissouri | $60.25 | — |
| MississippiMississippi | $59.82 | — |
| Montana**Montana | $65.13 | — |
| North CarolinaNorth Carolina | $62.18 | — |
| North Dakota**North Dakota | $64.14 | — |
| NebraskaNebraska | $61.39 | — |
| New HampshireNew Hampshire | $66.36 | — |
| Northern NjNew Jersey | $72.65 | — |
| Rest Of New JerseyNew Jersey | $69.66 | — |
| New MexicoNew Mexico | $62.56 | — |
| Nevada**Nevada | $64.89 | — |
| Nyc Suburbs/Long IslandNew York | $75.01 | — |
| Poughkpsie/N Nyc SuburbsNew York | $70.09 | — |
| QueensNew York | $74.07 | — |
| Rest Of New YorkNew York | $62.88 | — |
| OhioOhio | $62.09 | — |
| OklahomaOklahoma | $61.01 | — |
| PortlandOregon | $69.05 | — |
| Rest Of OregonOregon | $64.50 | — |
| Metropolitan PhiladelphiaPennsylvania | $67.40 | — |
| Rest Of PennsylvaniaPennsylvania | $62.16 | — |
| Puerto RicoPuerto Rico | $65.49 | — |
| Rhode IslandRhode Island | $66.65 | — |
| South CarolinaSouth Carolina | $62.22 | — |
| South Dakota**South Dakota | $64.02 | — |
| TennesseeTennessee | $61.17 | — |
| AustinTexas | $67.03 | — |
| BeaumontTexas | $61.86 | — |
| BrazoriaTexas | $64.68 | — |
| DallasTexas | $65.01 | — |
| Fort WorthTexas | $64.68 | — |
| GalvestonTexas | $64.83 | — |
| HoustonTexas | $65.74 | — |
| Rest Of TexasTexas | $63.18 | — |
| UtahUtah | $62.86 | — |
| VirginiaVirginia | $64.04 | — |
| Virgin IslandsUnited States Virgin Islands | $65.49 | — |
| VermontVermont | $63.96 | — |
| Rest Of WashingtonWashington | $66.96 | — |
| Seattle (King Cnty)Washington | $74.21 | — |
| WisconsinWisconsin | $62.50 | — |
| West VirginiaWest Virginia | $61.26 | — |
| Wyoming**Wyoming | $64.70 | — |
77331 rates by state
Office rate range in each state. Select a state to see its payment localities.
Explore a state
Local rates. Clear comparisons.
Hover or focus a tile to see its rate range. Select it to open the state’s fee schedule.
$59.38
$80.86
Color shows the midpoint of each state’s locality range.
View every state and territory as a table
| State / territory | Office rate range | Localities |
|---|---|---|
| AK | $80.86 | 1 |
| AL | $60.02 | 1 |
| AR | $59.38 | 1 |
| AZ | $63.80 | 1 |
| CA | $68.21–$82.98 | 29 |
| CO | $67.35 | 1 |
| CT | $68.75 | 1 |
| DC | $73.10 | 1 |
| DE | $64.68 | 1 |
| FL | $64.43–$69.12 | 3 |
| GA | $61.66–$66.11 | 2 |
| GU | $69.23 | 1 |
| HI | $69.23 | 1 |
| IA | $61.14 | 1 |
| ID | $61.45 | 1 |
| IL | $63.02–$67.67 | 4 |
| IN | $61.71 | 1 |
| KS | $60.94 | 1 |
| KY | $61.10 | 1 |
| LA | $61.03–$63.29 | 2 |
| MA | $67.11–$72.92 | 2 |
| MD | $65.70–$73.10 | 3 |
| ME | $61.69–$64.20 | 2 |
| MI | $62.30–$65.05 | 2 |
| MN | $64.97 | 1 |
| MO | $60.25–$63.45 | 3 |
| MS | $59.82 | 1 |
| MT | $65.13 | 1 |
| NC | $62.18 | 1 |
| ND | $64.14 | 1 |
| NE | $61.39 | 1 |
| NH | $66.36 | 1 |
| NJ | $69.66–$72.65 | 2 |
| NM | $62.56 | 1 |
| NV | $64.89 | 1 |
| NY | $62.88–$75.01 | 5 |
| OH | $62.09 | 1 |
| OK | $61.01 | 1 |
| OR | $64.50–$69.05 | 2 |
| PA | $62.16–$67.40 | 2 |
| PR | $65.49 | 1 |
| RI | $66.65 | 1 |
| SC | $62.22 | 1 |
| SD | $64.02 | 1 |
| TN | $61.17 | 1 |
| TX | $61.86–$67.03 | 8 |
| UT | $62.86 | 1 |
| VA | $64.04–$73.10 | 2 |
| VI | $65.49 | 1 |
| VT | $63.96 | 1 |
| WA | $66.96–$74.21 | 2 |
| WI | $62.50 | 1 |
| WV | $61.26 | 1 |
| WY | $64.70 | 1 |
How the 77331 rate is calculated
Each of 77331’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 · 77331
RVUs × geographic indexes × conversion factor
Swap in your local Medicare rate.
Work 0.85Practice expense 1.05Malpractice 0.05
All indexes start at 1.000 (the national rate). Enter a ZIP or drag a slider.
The exact Redding inputs and CMS source lines
PPRRVU2026_Oct_nonQPP.csv
9,071
- Code
- 77331
- Physician work
- 0.85
- Practice expense
- 1.05
- Malpractice
- 0.05
GPCI2026.csv
19
- Locality
- Redding
- Physician work
- 1.017
- Practice expense
- 1.096
- Malpractice
- 0.536
| Component | RVU | Locality factor | Adjusted |
|---|---|---|---|
| Physician work | 0.85 | × 1.017 | 0.8644 |
| Practice expense | 1.05 | × 1.096 | 1.1508 |
| Malpractice | 0.05 | × 0.536 | 0.0268 |
| Total RVUs | 2.0421 | ||
| Conversion factor | × 33.4009 | ||
Office rate, Redding$68.21
Office: (0.85 × 1.017 + 1.05 × 1.096 + 0.05 × 0.536) × $33.4009 = $68.21
Payment rules and modifiers for 77331
The CMS indicators that decide how 77331 is paid alongside other services.
CMS payment indicators · 77331
Radiation dosimetry
| 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
77331 without 26 · national office
$65.13
Radiation dosimetry
77331-26 · Professional component
$45.76
Pays only the interpretation and report.
How 77331 has changed in Redding
77331 · Office / nonfacility
$68.21
Effective 2026-10-01
The base rate is $1.65 higher than on 2025-10-01, moving from $66.56 to $68.21 (2.5%).
It is unchanged from the immediately preceding available release, effective 2026-07-01.
One bar per available release, ordered by effective date. Missing rates remain gaps. These comparisons hold the code, setting and locality identifiers constant; they do not isolate which policy or input caused a change.
What changed, release by release
January 1, 2026
RVU26A
$66.56changed to$68.21
- Conversion factor 32.3465 changed to 33.4009
- Work RVU 0.87 changed to 0.85
- Work GPCI 1.014 changed to 1.017
- Practice expense GPCI 1.093 changed to 1.096
- Malpractice GPCI 0.560 changed to 0.536
Held through RVU26B, RVU26C, RVU26D.
January 1, 2025
RVU25A
Earliest loaded release: $66.56
Held through RVU25B, RVU25C, RVU25D.
| Effective from | Office | Facility | CMS release |
|---|---|---|---|
| 2026-10-01 | $68.21 | Not available in this setting | RVU26D |
| 2026-07-01 | $68.21 | Not available in this setting | RVU26C |
| 2026-04-01 | $68.21 | Not available in this setting | RVU26B |
| 2026-01-01 | $68.21 | Not available in this setting | RVU26A |
| 2025-10-01 | $66.56 | Not available in this setting | RVU25D |
| 2025-07-01 | $66.56 | Not available in this setting | RVU25C |
| 2025-04-01 | $66.56 | Not available in this setting | RVU25B |
| 2025-01-01 | $66.56 | Not available in this setting | RVU25A |
Where the Redding rate applies
Redding is a Medicare payment area, not a city. Our Census mapping connects it to 32 cities and communities in California. Some span more than one payment area; confirm with the service ZIP.
77331 billing questions
How is this different from 77300?
Use 77300 for routine radiation dose calculations. Report 77331 when specialized measurement, such as TLD or microdosimetry, is performed rather than relying only on those calculations.
Which modifier identifies the interpretation?
Append modifier 26 for the professional interpretation. Modifier TC identifies the technical component, including equipment and staff; billing without either modifier represents the global service.
What documentation supports reporting 77331?
Document the specialized measurement method, why it was needed, and the measured results or interpretation. The record should make clear that the work was more than routine treatment-planning calculation.
Can 77331 be reported with a radiation dose plan?
It may accompany a dose-planning service when the specialized measurement is a distinct service actually performed. The record should distinguish the measurement from the plan's routine calculations.
Does this code describe a radiation treatment aid?
No. It describes specialized dose measurement; codes 77332–77334 describe radiation treatment aids, such as devices used to shape or support treatment delivery.
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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