An SBRT course is short, often three to five treatments, and every charge in it is high-dollar. That is exactly why errors cost so much: one wrong delivery code, a management charge billed twice, or a sixth fraction billed as SBRT can deny or underpay the entire course.
2026 added a new layer. Conventional treatment delivery was consolidated into 77402, 77407 and 77412, and IMRT delivery codes 77385 and 77386 were retired, so many teams are rechecking which SBRT codes still apply. This guide covers the codes that do, how they work together, and how to keep SBRT claims clean.
SBRT vs SRS: The Definitions That Decide the Codes
The number of fractions and the treatment site decide which stereotactic code family applies. Get this first, because everything else in the claim follows from it.
| Treatment | Fractions | Delivery code | Management code |
|---|---|---|---|
| Cranial SRS, single session | 1 | 77371 or 77372 | 77432 |
| SBRT (body sites) | 1 to 5 | 77373 per fraction | 77435 |
| Multi-fraction cranial SRS | 2 to 5 | 77373 per fraction | 77435 |
Two boundary rules matter most. A course cannot start with 77371 or 77372 and finish with 77373. And if all sites in an episode need more than five fractions, the course is not SBRT: report it with conventional or IMRT delivery and management codes instead (eviCore 2026 coding manual).
Treatment Delivery: Billing 77373
77373 is the SBRT treatment delivery code: one unit per fraction, to one or more lesions, including image guidance, for an entire course of no more than five fractions.
- It is still in use for 2026. Payer coding manuals effective January 1, 2026 continue to list 77373 for SBRT. Published 2026 change summaries cover conventional and IMRT delivery and do not list 77373 among the deleted codes.
- It is the technical component. In a freestanding center it is billed globally by the center; in a hospital outpatient setting the facility bills it.
- Image guidance is included. Do not add 77387 or 77417 on SBRT treatment days.
For how technical and professional charges split across settings, see our guide to radiation oncology professional and technical billing.
Treatment Management: 77435 Once per Course
77435 is the radiation oncologist’s professional management charge for an SBRT course. It is billed one unit per course, not per fraction and not per week.
- Report it once the course is complete, with the dates of the course documented.
- Do not bill weekly management (77427) or 77431 with SBRT. 77435 replaces them for the whole course.
- For single-session cranial SRS, 77432 is the management code instead.
Billing 77435 more than once, or alongside 77427, is one of the most common SBRT edit failures. Weekly management rules for conventional courses are covered in our post on radiation oncology charges that go missing.
Robotic G-Codes G0339 and G0340: When They Apply
G0339 and G0340 are HCPCS codes for robotic linear accelerator-based stereotactic radiosurgery:
- G0339: single-session treatment, or the first session of a fractionated course
- G0340: each additional session after the first, up to five sessions per course
Whether you bill these G-codes or 77373 depends on the place of service and the payer, not on the equipment alone (eviCore 2026 coding manual). Build the rule into charge capture per payer and setting, and confirm it at every contract or policy update. Separately, the 2026 retirement of the Physician Fee Schedule delivery G-codes (G6001 to G6017) does not apply to G0339 and G0340, so check current payer policy rather than assuming every radiation G-code is gone.
Planning, Physics and Image Guidance in an SBRT Course
SBRT carries the same planning work as any course, but several charges are limited or not allowed. Many payers apply edits like these:
| Charge | SBRT rule |
|---|---|
| 3D (77295) or IMRT (77301) treatment plan | One unit per episode, regardless of the number of lesions |
| Basic dosimetry calculation (77300) | Limited number of units per course (up to 10 in eviCore’s 2026 manual) |
| Image guidance (77387, 77417) | Not separately billable on SBRT delivery days |
| Special physics consultation (77370) | Not reportable with SBRT |
| Special treatment procedure (77470) | Not reportable with SBRT |
| Weekly management (77427, 77431) | Not reportable; use 77435 |
Clinical treatment planning (77261 to 77263), simulation and devices follow the course’s normal rules. Check each payer’s policy, because frequency limits vary.
Why SBRT Claims Are Denied and How to Prevent It
Most SBRT denials come from a short list of causes. Each one can be caught before the claim goes out.
- No prior authorization, or an authorization for the wrong technique. Most commercial and Medicare Advantage plans require approval for SBRT. If the plan changes to more than five fractions, get a new authorization for conventional or IMRT delivery. Our post on oncology prior authorization questions covers the process.
- More than five fractions billed as 77373. Re-code the episode with conventional or IMRT delivery codes.
- Duplicate management. 77435 billed twice, or with 77427.
- Bundled charges billed separately. Image guidance, 77370 or 77470 on SBRT days.
- Medical necessity gaps. The record must show why a stereotactic approach was chosen, the target, dose and fractions, and the image guidance used.
These patterns also show up in audits. See how one practice fixed them in our radiation oncology claim denials case study.
Conclusion: Clean SBRT Claims Start With the Course Definition
The key takeaway: define the course before you bill it. Up to five fractions on 77373 or the robotic G-codes the payer requires, one unit of 77435 for the whole course, and nothing billed separately for image guidance. If the plan changes, the codes and the authorization change with it.
If SBRT claims are coming back denied or partly paid, MBW RCM can help. Our radiation oncology billing specialists check authorizations before treatment starts and review each course against these rules.