CPT code 77771: HDR brachytherapy, interstitial or intracavitary, intermediate2026 Medicare rate & RVUs in Michigan
Reports intermediate-complexity high-dose-rate brachytherapy delivery through interstitial catheters or an intracavitary applicator for a treatment session.
Medicare pays $570.48–$600.36 for 77771 in the office in Michigan, from Rest of Michigan to Detroit, MI. 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 77771 covers
A radiation oncologist uses a remote afterloader to send a temporary high-dose-rate radioactive source through interstitial catheters or an intracavitary applicator. The source delivers radiation at planned positions and is withdrawn after treatment. Common clinical settings include gynecologic brachytherapy using an intracavitary applicator and interstitial treatment using implanted catheters. This code identifies the intermediate-complexity level of HDR delivery, rather than superficial skin treatment or permanent source implantation.
Select the intermediate level using the documented complexity of the delivery and the applicable CPT criteria; do not assign it solely from the treatment site or fraction count. The record should support the applicator or catheter arrangement, treatment delivery, and level selected. The service covers management of the HDR source as part of delivery. CMS lists separately priced professional and technical components: modifier 26 identifies the professional interpretation, modifier TC identifies equipment and staff, and billing 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 77771 pays more and less in Michigan
| Payment locality | Office | Facility |
|---|---|---|
| Detroit, MI | $600.36 | Unavailable |
| Rest of Michigan | $570.48 | Unavailable |
How the 77771 rate is calculated
Each of 77771’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 · 77771
RVUs × geographic indexes × conversion factor
Work3.71
3.71 RVUs× 1.000 GPCI
Practice expense14.31
14.31 RVUs× 1.000 GPCI
Malpractice0.27
0.27 RVUs× 1.000 GPCI
Adjusted RVUs
18.2900
Conversion factor
$33.4009
Medicare rate
$610.90
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 77771
The CMS indicators that decide how 77771 is paid alongside other services.
CMS payment indicators · 77771
HDR brachytherapy, interstitial or intracavitary, intermediate
| 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
77771 without 26 · national office
$610.90
HDR brachytherapy, interstitial or intracavitary, intermediate
77771-26 · Professional component
$199.40
Pays only the interpretation and report.
77771 compared with similar codes
Compare codes · National
4 codes, side by side
How to choose
- 77770HDR brachytherapySingle channel, per fraction
- Both describe HDR interstitial or intracavitary delivery, but 77770 is the simple level. Choose between them using the documented complexity and CPT criteria.
- 77772HDR brachytherapyMore than 12 channels
- Both describe HDR interstitial or intracavitary delivery, but 77772 is the complex level. The treatment site alone does not establish which level applies.
- 77767Skin brachytherapyOne channel
- 77767 is for superficial-skin HDR brachytherapy. Use 77771 when the source is delivered through interstitial catheters or an intracavitary applicator.
77771 billing questions
How does 77771 differ from 77770 and 77772?
These codes distinguish simple, intermediate, and complex HDR interstitial or intracavitary delivery. Use the level supported by the documented delivery complexity and CPT criteria, not an assumption based only on site.
Is 77771 reported per fraction?
The code covers delivery for one or more fractions. Follow the applicable CPT reporting instructions and document the treatment delivered; do not infer a separate unit for every fraction.
When should modifier 26 or TC be used?
Modifier 26 identifies the professional interpretation component, and TC identifies the technical equipment-and-staff component. Without either modifier, the claim represents the global service.
Does 77771 describe superficial skin brachytherapy?
No. It is for interstitial or intracavitary HDR delivery. Superficial skin HDR treatment is represented by the separate 77767–77768 code family.
What documentation supports the intermediate level?
Document the HDR delivery, the interstitial catheter or intracavitary applicator configuration, and the details that support intermediate rather than simple or complex delivery under CPT criteria.
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
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