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CPT code 77338: MLC design, per IMRT plan2026 Medicare rate & RVUs in Montana

Reports design of multileaf collimator devices that shape radiation fields for intensity-modulated radiation therapy, counted per IMRT plan.

CMS RVU26DEffective Oct 1, 2026One payment locality211.7K Medicare services in 2024

In Montana, Medicare pays $474.94 for 77338 in the office.

$474.94Office (non-facility)
Not available in this settingHospital or facility
−0.0%vs the national office rate ($474.96)

Check a contract rate as a % of Medicare · 77338 nationwide

Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.

We’ll open 77338 for the payment locality that covers the ZIP.

On this page 11 sections
  1. Rate in Montana
  2. What 77338 covers
  3. Compared with other areas
  4. Rate map
  5. How it’s calculated
  6. Payment rules
  7. Related codes
  8. Rate history
  9. Where it applies
  10. Billing questions
  11. Sources

What 77338 covers

This service covers planning the multileaf collimator (MLC) leaf positions needed to shape and modulate radiation fields for an intensity-modulated radiation therapy (IMRT) plan. A medical physicist or dosimetrist typically performs the technical design work as part of radiation treatment planning, with the radiation oncologist directing the treatment approach. The work supports delivery of the planned dose to the target while shaping radiation around nearby normal tissues.

Report the service per IMRT plan, not per treatment fraction. Documentation should connect the MLC design to the specific IMRT plan and identify the design work performed. CMS recognizes professional and technical components: modifier 26 identifies the professional component, modifier TC identifies the technical component, and an unmodified claim represents the global service. The IMRT dose plan itself is reported separately when supported; MLC device design is distinct from dose calculation and from design of other treatment aids.

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 Montana compares for 77338

Across 109 of 109 payment localities, the office rate for 77338 runs from $424.80 in Arkansas to $630.98 in San Benito County, CA. Montana pays $474.94. The RVUs are the same everywhere; the geographic indexes change the dollars.

77338 in Montana vs other payment areas
  1. Montana · this page$474.94
  2. Los Angeles, CA · California$537.72+$62.78
  3. Washington, DC area · District of Columbia$541.65+$66.71
  4. Miami, FL · Florida$501.14+$26.20
  5. Chicago, IL · Illinois$488.39+$13.45
  6. Manhattan, NY · New York$541.76+$66.82
  7. Alaska · Alaska$562.27+$87.33

Other areas in Montana first, then benchmark localities. Bars start at $0.

Every other payment area

77338 in every other Medicare payment locality
Payment localityOfficeFacility
AlabamaAlabama$430.46—
ArkansasArkansas$424.80—
ArizonaArizona$463.62—
Bakersfield, CACalifornia$505.74—
Chico, CACalifornia$504.85—
El Centro, CACalifornia$504.89—
Fresno, CACalifornia$504.85—
Hanford, CACalifornia$504.85—

77338 rates by state

Office rate range in each state. Select a state to see its payment localities.

MEWIVTNHMTNDMNMINYMARIWAIDWYSDIAILINOHPANJCTORNVUTCONEMOKYWVVAMDDECAAZNMKSOKARTNNCSCDCTXLAMSALGAFLAKHI

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.

$424.80

$567.92

Color shows the midpoint of each state’s locality range.

View every state and territory as a table
77338 office rate range by state
State / territoryOffice rate rangeLocalities
AK$562.271
AL$430.461
AR$424.801
AZ$463.621
CA$504.85–$630.9829
CO$495.741
CT$504.691
DC$541.651
DE$470.891
FL$464.77–$501.143
GA$441.25–$482.292
GU$516.241
HI$516.241
IA$442.131
ID$444.401
IL$451.21–$491.214
IN$446.801
KS$439.431
KY$437.951
LA$437.01–$456.802
MA$492.83–$543.202
MD$479.60–$541.653
ME$445.64–$468.942
MI$447.59–$469.242
MN$478.571
MO$429.62–$459.283
MS$427.331
MT$474.941
NC$450.041
ND$470.001
NE$444.591
NH$487.321
NJ$511.44–$536.642
NM$449.501
NV$473.891
NY$456.13–$552.855
OH$446.581
OK$438.111
OR$471.17–$511.352
PA$447.69–$492.492
PR$478.431
RI$487.501
SC$448.861
SD$469.421
TN$441.341
TX$444.94–$493.258
UT$454.491
VA$466.95–$541.652
VI$478.431
VT$467.571
WA$492.11–$554.642
WI$455.451
WV$435.721
WY$472.791

See 77338 in every payment locality

How the 77338 rate is calculated

Each of 77338’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 · 77338

RVUs × geographic indexes × conversion factor

Office or facility?

Work4.18

4.18 RVUs× 1.000 GPCI

Practice expense9.79

9.79 RVUs× 1.000 GPCI

Malpractice0.25

0.25 RVUs× 1.000 GPCI

Adjusted RVUs

14.2200

Conversion factor

$33.4009

Medicare rate

$474.96

Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.

The exact Montana inputs and CMS source lines

PPRRVU2026_Oct_nonQPP.csv

9,084

Code
77338
Physician work
4.18
Practice expense
9.79
Malpractice
0.25

GPCI2026.csv

71

Locality
Montana
Physician work
1.000
Practice expense
1.000
Malpractice
0.998
Office calculation for 77338 in Montana
ComponentRVULocality factorAdjusted
Physician work4.18× 1.0004.1800
Practice expense9.79× 1.0009.7900
Malpractice0.25× 0.9980.2495
Total RVUs14.2195
Conversion factor× 33.4009

Office rate, Montana$474.94

Office: (4.18 × 1 + 9.79 × 1 + 0.25 × 0.998) × $33.4009 = $474.94

Open 77338 in the RVU calculator

Payment rules and modifiers for 77338

The CMS indicators that decide how 77338 is paid alongside other services.

CMS payment indicators · 77338

MLC design, per IMRT plan

RuleCMS valueWhat it means
Global periodXXXThe global surgery concept doesn’t apply.
Multiple procedures0No multiple-procedure reduction.
Bilateral (modifier 50)0The 150% bilateral adjustment doesn’t apply.
Assistant at surgery (80/81/82/AS)0Not paid without supporting documentation.
Co-surgeons (62)0Not permitted.
Team surgery (66)0Not permitted.
Professional/technical1Diagnostic test with separate professional (26) and technical (TC) components.

What modifiers do to the payment

Modifier 26 · payment effect

With and without the modifier

77338 without 26 · national office

$474.96

MLC design, per IMRT plan

77338-26 · Professional component

$225.12

Pays only the interpretation and report.

When to use modifier 26

Codes related to 77338

Related codes aren’t interchangeable: bill the code that matches the service performed.

Codes related to 77338
CodeHow it relatesOffice range, Montana
Often billed with
77301IMRT planning, dose optimization and volume analysisRepresents IMRT dose planning, commonly associated with the MLC design for the same plan.$1,960.25
Used instead
77306Radiation plan, simple teletherapy planSimple teletherapy isodose planning may be used for a conventional plan instead of IMRT planning.$150.30
77307Isodose planning, complex teletherapy planComplex teletherapy isodose planning is a conventional planning approach rather than IMRT MLC design.$290.24

How 77338 has changed in Montana

77338 · Office / nonfacility

$474.94

Effective 2026-10-01

The base rate is $13.53 higher than on 2025-10-01, moving from $461.41 to $474.94 (2.9%).

It is unchanged from the immediately preceding available release, effective 2026-07-01.

Base rate by release · bars start at $0 · select a bar to compare

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

  1. January 1, 2026

    RVU26A

    $461.41changed to$474.94

    • Conversion factor 32.3465 changed to 33.4009
    • Work RVU 4.29 changed to 4.18
    • Practice expense RVU 9.73 changed to 9.79
    • Malpractice GPCI 0.978 changed to 0.998

    Held through RVU26B, RVU26C, RVU26D.

  2. January 1, 2025

    RVU25A

    $467.82changed to$461.41

    • Conversion factor 33.2875 changed to 32.3465
    • Practice expense RVU 9.50 changed to 9.73
    • Malpractice RVU 0.27 changed to 0.25

    Held through RVU25B, RVU25C, RVU25D.

  3. March 9, 2024

    RVU24AR

    $460.19changed to$467.82

    • Conversion factor 32.7442 changed to 33.2875

    Held through RVU24B, RVU24C, RVU24D.

  4. January 1, 2024

    RVU24A

    $469.48changed to$460.19

    • Conversion factor 33.8872 changed to 32.7442
    • Practice expense RVU 9.31 changed to 9.50
    • Malpractice RVU 0.26 changed to 0.27

  5. January 1, 2023

    RVU23A

    $465.94changed to$469.48

    • Conversion factor 34.6062 changed to 33.8872
    • Practice expense RVU 8.92 changed to 9.31
    • Malpractice GPCI 0.977 changed to 0.978

    Held through RVU23B, RVU23C, RVU23D.

  6. January 1, 2022

    RVU22A

    $480.31changed to$465.94

    • Conversion factor 34.8931 changed to 34.6062
    • Practice expense RVU 9.27 changed to 8.92
    • Malpractice RVU 0.21 changed to 0.26

    Held through RVU22B, RVU22C, RVU22D.

  7. January 1, 2021

    RVU21A

    $499.84changed to$480.31

    • Conversion factor 36.0896 changed to 34.8931
    • Practice expense RVU 9.26 changed to 9.27
    • Malpractice RVU 0.23 changed to 0.21
    • Malpractice GPCI 1.304 changed to 0.977

    Held through RVU21B, RVU21C, RVU21D.

  8. January 1, 2020

    RVU20A

    $515.77changed to$499.84

    • Conversion factor 36.0391 changed to 36.0896
    • Practice expense RVU 9.63 changed to 9.26
    • Malpractice RVU 0.24 changed to 0.23
    • Malpractice GPCI 1.631 changed to 1.304

    Held through RVU20B, RVU20C, RVU20D.

  9. January 1, 2019

    RVU19A

    $532.85changed to$515.77

    • Conversion factor 35.9996 changed to 36.0391
    • Practice expense RVU 10.12 changed to 9.63

    Held through RVU19B, RVU19C, RVU19D.

  10. January 1, 2018

    RVU18AR1

    $520.49changed to$532.85

    • Conversion factor 35.8887 changed to 35.9996
    • Practice expense RVU 9.87 changed to 10.12
    • Malpractice GPCI 1.429 changed to 1.631

    Held through RVU18B, RVU18C, RVU18D.

  11. January 1, 2017

    RVU17A

    $515.38changed to$520.49

    • Conversion factor 35.8043 changed to 35.8887
    • Practice expense RVU 9.81 changed to 9.87
    • Malpractice GPCI 1.226 changed to 1.429

    Held through RVU17B, RVU17C, RVU17D.

  12. January 1, 2016

    RVU16A

    $510.57changed to$515.38

    • Conversion factor 35.9335 changed to 35.8043
    • Practice expense RVU 9.60 changed to 9.81
    • Malpractice RVU 0.26 changed to 0.24

    Held through RVU16B, RVU16C, RVU16D.

  13. July 1, 2015

    RVU15C

    $508.03changed to$510.57

    • Conversion factor 35.7547 changed to 35.9335

    Held through RVU15D.

  14. January 1, 2015

    RVU15A

    $503.41changed to$508.03

    • Conversion factor 35.8228 changed to 35.7547
    • Practice expense RVU 9.46 changed to 9.60
    • Malpractice GPCI 1.165 changed to 1.226

    Held through RVU15B.

  15. January 1, 2014

    RVU14A

    $502.10changed to$503.41

    • Conversion factor 34.0230 changed to 35.8228
    • Practice expense RVU 10.17 changed to 9.46
    • Malpractice RVU 0.27 changed to 0.26
    • Malpractice GPCI 1.103 changed to 1.165

    Held through RVU14B, RVU14C, RVU14D.

  16. January 1, 2013

    RVU13AR

    Earliest loaded release: $502.10

    Held through RVU13B, RVU13C, RVU13D.

Rates in every CMS release
Effective fromOfficeFacilityCMS release
2026-10-01$474.94Not available in this settingRVU26D
2026-07-01$474.94Not available in this settingRVU26C
2026-04-01$474.94Not available in this settingRVU26B
2026-01-01$474.94Not available in this settingRVU26A
2025-10-01$461.41Not available in this settingRVU25D
2025-07-01$461.41Not available in this settingRVU25C
2025-04-01$461.41Not available in this settingRVU25B
2025-01-01$461.41Not available in this settingRVU25A
2024-10-01$467.82Not available in this settingRVU24D
2024-07-01$467.82Not available in this settingRVU24C
2024-04-01$467.82Not available in this settingRVU24B
2024-03-09$467.82Not available in this settingRVU24AR
2024-01-01$460.19Not available in this settingRVU24A
2023-10-01$469.48Not available in this settingRVU23D
2023-07-01$469.48Not available in this settingRVU23C
2023-04-01$469.48Not available in this settingRVU23B
2023-01-01$469.48Not available in this settingRVU23A
2022-10-01$465.94Not available in this settingRVU22D
2022-07-01$465.94Not available in this settingRVU22C
2022-04-01$465.94Not available in this settingRVU22B
2022-01-01$465.94Not available in this settingRVU22A
2021-10-01$480.31Not available in this settingRVU21D
2021-07-01$480.31Not available in this settingRVU21C
2021-04-01$480.31Not available in this settingRVU21B
2021-01-01$480.31Not available in this settingRVU21A
2020-10-01$499.84Not available in this settingRVU20D
2020-07-01$499.84Not available in this settingRVU20C
2020-04-01$499.84Not available in this settingRVU20B
2020-01-01$499.84Not available in this settingRVU20A
2019-10-01$515.77Not available in this settingRVU19D
2019-07-01$515.77Not available in this settingRVU19C
2019-04-01$515.77Not available in this settingRVU19B
2019-01-01$515.77Not available in this settingRVU19A
2018-10-01$532.85Not available in this settingRVU18D
2018-07-01$532.85Not available in this settingRVU18C
2018-04-01$532.85Not available in this settingRVU18B
2018-01-01$532.85Not available in this settingRVU18AR1
2017-10-01$520.49Not available in this settingRVU17D
2017-07-01$520.49Not available in this settingRVU17C
2017-04-01$520.49Not available in this settingRVU17B
2017-01-01$520.49Not available in this settingRVU17A
2016-10-01$515.38Not available in this settingRVU16D
2016-07-01$515.38Not available in this settingRVU16C
2016-04-01$515.38Not available in this settingRVU16B
2016-01-01$515.38Not available in this settingRVU16A
2015-10-01$510.57Not available in this settingRVU15D
2015-07-01$510.57Not available in this settingRVU15C
2015-04-01$508.03Not available in this settingRVU15B
2015-01-01$508.03Not available in this settingRVU15A
2014-10-01$503.41Not available in this settingRVU14D
2014-07-01$503.41Not available in this settingRVU14C
2014-04-01$503.41Not available in this settingRVU14B
2014-01-01$503.41Not available in this settingRVU14A
2013-10-01$502.10Not available in this settingRVU13D
2013-07-01$502.10Not available in this settingRVU13C
2013-04-01$502.10Not available in this settingRVU13B
2013-01-01$502.10Not available in this settingRVU13AR

Price 77338 for an earlier date of service

Where the Montana rate applies

Montana is a Medicare payment area, not a city. Our Census mapping connects it to 497 cities and communities in Montana. Some span more than one payment area; confirm with the service ZIP.

  • Absarokee
  • Acton
  • Alberton
  • Alder
  • Alzada
  • Amsterdam
  • Anaconda-Deer Lodge County
  • Antelope

Browse all communities in Montana

77338 billing questions

How is 77338 distinguished from 77301?

77338 represents the MLC device design for an IMRT plan. 77301 represents the IMRT treatment planning work, including the dose plan; the services describe different parts of planning.

Is 77338 reported per treatment fraction or per plan?

Report it per IMRT plan, rather than once for each delivered fraction.

Which modifier identifies each component?

Use modifier 26 for the professional component and modifier TC for the technical component. Submit without a component modifier for the global service.

Does 77338 include the IMRT dose calculation?

No. It describes MLC device design; the dose-planning work is represented separately when applicable and documented.

What documentation supports 77338?

The record should identify the IMRT plan and show the MLC design work performed for that plan. It should support the per-plan unit reported.

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
RVUs for 77338PPRRVU2026_Oct_nonQPP.csv, line 9,084 (RVU26D)
Geographic factors for MontanaGPCI2026.csv, line 71 (RVU26D)

Open CMS sourceHow we calculate rates

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