CPT code 77778: Interstitial brachytherapy, complex source application2026 Medicare rate & RVUs

Reports complex placement of radioactive sources within tumor tissue for interstitial brachytherapy, rather than treatment delivered through a cavity or surface applicator.

CMS RVU26DEffective Oct 1, 2026109 payment localities3.3K Medicare services in 2024

Medicare pays $932.89 for 77778 nationally in the office. Local office rates run $835.46–$1,233.96.

Medicare rate · 77778

Interstitial brachytherapy, complex source application

Office or facility?

Work RVUs
8.56
Total RVUs
27.93
Global days
000

National rate · 2026

$932.89

Office setting, before claim adjustments.

See every locality for 77778 →Billed by an NP, PA or therapist? →

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

Your location

Medicare pays by the payment locality where the service is performed.

On this page 10 sections
  1. Medicare rate
  2. What 77778 covers
  3. By payment locality
  4. Rate map
  5. How it’s calculated
  6. Payment rules
  7. Similar codes
  8. Related codes
  9. Billing questions
  10. Sources

What 77778 covers

This service covers complex interstitial brachytherapy, in which radioactive sources are placed directly within or alongside tumor tissue. A radiation oncologist, often working with a procedural specialist, may perform the application in an operating room or procedure suite. Prostate seed implantation is a familiar example; interstitial techniques may also be used for selected tumors at other sites. This approach differs from delivering radiation through a cavity applicator or across the skin surface.

Report the code when the documented service is a complex interstitial source application. The record should support the interstitial approach, treated site, source placement, and complexity. CMS identifies professional and technical components: modifier 26 represents the professional interpretation, modifier TC the equipment and staff, and no modifier the global service. The 0-day global period includes same-day preoperative and postoperative care. Modifier 50 is inappropriate for this service. Assistant-at-surgery payment requires documented medical necessity; co-surgeons and team surgery are not permitted.

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 77778 pays more and less

The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.

109 payment localities

$835.46 to $1233.96

$835.46$1034.71$1233.96
One dot per payment locality, office / nonfacility. Hover a dot to see the locality; select it to open that rate.

109 of 109 payment localities

77778 office and facility rates by payment locality
Payment localityOfficeFacility
Alabama$846.44Unavailable
Alaska$1,108.63Unavailable
Arizona$910.79Unavailable
Arkansas$835.46Unavailable
Atlanta, GA$947.43Unavailable
Austin, TX$967.88Unavailable
Bakersfield, CA$991.65Unavailable
Baltimore area, MD$987.65Unavailable
Beaumont, TX$875.00Unavailable
Brazoria, TX$925.55Unavailable

77778 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.

$835.46

$1,111.86

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

View every state and territory as a table
77778 office rate range by state
State / territoryOffice rate rangeLocalities
AK$1,108.631
AL$846.441
AR$835.461
AZ$910.791
CA$989.76–$1,233.9629
CO$972.621
CT$990.821
DC$1,062.321
DE$924.951
FL$914.29–$986.253
GA$868.42–$947.432
GU$1,011.461
HI$1,011.461
IA$868.551
ID$873.071
IL$888.32–$965.794
IN$877.701
KS$863.561
KY$861.541
LA$859.80–$898.232
MA$967.13–$1,064.642
MD$941.81–$1,062.323
ME$875.75–$920.572
MI$880.50–$923.252
MN$938.431
MO$845.62–$902.733
MS$840.761
MT$932.851
NC$884.241
ND$922.171
NE$873.241
NH$956.421
NJ$1,003.94–$1,052.762
NM$884.311
NV$930.501
NY$896.08–$1,085.515
OH$878.311
OK$861.571
OR$925.01–$1,002.662
PA$880.32–$967.302
PR$939.531
RI$957.131
SC$882.381
SD$920.911
TN$867.301
TX$875.00–$967.888
UT$893.311
VA$916.89–$1,062.322
VI$939.531
VT$917.691
WA$965.63–$1,086.652
WI$893.991
WV$858.271
WY$928.201

How the 77778 rate is calculated

Each of 77778’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 · 77778

RVUs × geographic indexes × conversion factor

Office or facility?

Work8.56

8.56 RVUs× 1.000 GPCI

Practice expense18.83

18.83 RVUs× 1.000 GPCI

Malpractice0.54

0.54 RVUs× 1.000 GPCI

Adjusted RVUs

27.9300

Conversion factor

$33.4009

Medicare rate

$932.89

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

Payment rules and modifiers for 77778

The CMS indicators that decide how 77778 is paid alongside other services.

CMS payment indicators · 77778

Interstitial brachytherapy, complex source application

RuleCMS valueWhat it means
Global period000Same-day global: pre- and post-op care on the day of the procedure is included.
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

77778 without 26 · national office

$932.89

Interstitial brachytherapy, complex source application

77778-26 · Professional component

$459.93

Pays only the interpretation and report.

When to use modifier 26

77778 compared with similar codes

Compare codes · National

4 codes, side by side

Office or facility?

  • 77778

    Interstitial brachytherapy, complex source application8.56 wRVU

    $932.89

  • 77763

    Brachytherapy application, complex intracavitary placement8.44 wRVU

    $791.94−$140.95

  • 77770

    HDR brachytherapy, single channel, per fraction1.9 wRVU

    $349.37−$583.52

  • 77767

    Skin brachytherapy, one channel1.02 wRVU

    $250.84−$682.05

How to choose

77763Brachytherapy applicationComplex intracavitary placement
Choose 77778 for complex interstitial source placement within tissue; choose 77763 for complex application through an intracavitary applicator.
77770HDR brachytherapySingle channel, per fraction
77770 describes high-dose-rate remote afterloading. This code describes complex interstitial source application, not that remote-afterloading service.
77767Skin brachytherapyOne channel
77767 is for high-dose-rate radiation delivered at the skin surface. This code is for complex interstitial placement within tissue.

77778 billing questions

How does this differ from an intracavitary application?

This code is for complex placement of sources within tissue. Use an intracavitary application code when radiation is delivered through an applicator positioned in a body cavity.

Can the professional and technical components be billed separately?

Yes. CMS identifies modifier 26 for the professional interpretation and modifier TC for the technical service; reporting without a modifier represents the global service.

Is modifier 50 appropriate for bilateral treatment?

No. CMS identifies bilateral adjustment as inappropriate for this code, so modifier 50 should not be used.

What same-day care is included?

The 0-day global period includes same-day preoperative and postoperative care.

When may an assistant at surgery be paid?

Assistant-at-surgery payment is allowed only when the medical necessity of the assistant is documented. Co-surgeons and team surgery are not permitted.

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 77778PPRRVU2026_Oct_nonQPP.csv, line 9,169 (RVU26D)

Open CMS sourceHow we calculate rates

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