CPT code 77385 – Simple IMRT delivery (deleted January 1, 2026)

Key takeaways

CPT 77385 described simple IMRT delivery per session, and it was deleted on January 1, 2026, together with 77386.

Simple meant prostate, breast, or any site treated with physical compensator-based IMRT, whatever the field count or plan complexity.

Sessions delivered on or before December 31, 2025, still bill as 77385 on original, corrected, and appealed claims.

From 2026, IMRT delivery bills as 77407 (Level 2) or 77412 (Level 3), chosen by isocenters and motion management.

Image guidance is now bundled into delivery, so physicians report only the professional component as 77387-26.

What was CPT code 77385? Simple IMRT delivery, deleted in 2026

CPT code 77385 was the code for intensity modulated radiation treatment delivery (IMRT), simple, including guidance and tracking when performed. The AMA deleted it from the CPT code set on January 1, 2026, along with its complex counterpart, 77386.

The code is no longer valid for any session delivered from that date. IMRT delivery now bills under the level-based codes CPT 77407 (Level 2) and CPT 77412 (Level 3). These codes no longer distinguish IMRT from 3D conformal treatment.

Why the AMA deleted 77385 and 77386

From 2015 to 2025, Medicare ran two parallel code sets for radiation treatment delivery. Hospitals reported IMRT with 77385 and 77386, while freestanding centers billed Medicare with G-codes such as HCPCS G6015.

In 2023, the RUC flagged the delivery and image guidance codes as potentially misvalued, because their inputs had last been valued in 2014. The revaluation that followed rebuilt the family around delivery complexity instead of technique.

According to ASTRO’s summary of the 2026 changes, the result is one set of three levels used in both hospital and freestanding settings. IMRT stopped being a separate category, so its two delivery codes had no place left in the family.

How simple and complex IMRT were defined before 2026

The split between 77385 and 77386 depended on the treatment site and the IMRT technique. It did not depend on the number of fields, the number of segments, or how hard the plan was to optimize.

A head and neck IMRT plan with multileaf collimator delivery was therefore complex, however simple the plan looked. A head and neck plan delivered with physical compensators was simple. This matters when you audit or correct a pre-2026 claim, because the site and technique in the record decide the code.

CPT 77385 crosswalk: Which 2026 code replaces it

There is no one-to-one replacement for 77385. Each session is now coded by its delivery level, so the same patient group can land in two different codes.

Payment figures are national amounts from ASTRO’s 2026 physician fee schedule final rule summary. Local amounts vary with geographic adjustment, and hospital claims are paid under HOPPS instead.

Most sessions that were simple IMRT under 77385 now bill as 77407. A single-isocenter prostate plan treated without intrafraction tracking is the typical example.

Some former 77385 sessions qualify for 77412 instead. A left breast treated with deep inspiration breath hold uses active motion management. A breast plan that adds a second isocenter for the nodal fields has multiple isocenters. The diagram below walks one session through both decisions, date first and setup second.

Image guidance after 77385: 77387-26 only

The old 77385 descriptor already bundled guidance and tracking into the delivery code. From 2026, every delivery level works the same way, and CT guidance code 77014 is deleted.

The physician still reports the professional review of guidance images as CPT 77387 with modifier 26. Medicare does not pay the technical component separately in either setting.

Billing 77385 for dates of service before January 1, 2026

The date of service decides the code, whenever the claim is submitted. A simple IMRT session delivered on or before December 31, 2025, is still reported as 77385.

• Late original claims: bill 77385 for 2025 sessions. Medicare allows 12 months from the date of service, so the last December 2025 sessions must be filed by December 2026.
• Corrected claims and appeals: keep 77385 on the corrected line for a 2025 session. In 2025, 77407 described non-IMRT intermediate delivery, so switching codes miscodes the session.
• Courses that crossed the new year: code 2025 sessions as 77385 and 2026 sessions as 77407 or 77412. One course can carry both on separate claim lines.
• Prior authorizations: an authorization issued for 77385 may not cover 2026 sessions. Check whether the payer needs it updated to the new code.

Legacy 77385 claims still need the records that supported simple IMRT. Keep these on file for audits and appeals, because a clean claim depends on them:

1. A signed radiation oncologist order naming IMRT, the dose, the fractionation, and the treatment site.
2. The approved IMRT plan (77301), showing the site or the physical compensator technique that made it simple.
3. A daily treatment record for each session, with the date, the machine, and the dose delivered.
4. Documentation of any guidance and tracking performed, since 77385 already included it.

Common billing errors in the 2026 transition

Most denials in the first year come from claims built on the old framework. Each denied line comes back with one of the standard denial codes naming the cause. Tracking which of these errors drives your rejections is a useful start for denial management.

Documentation that supports the 2026 delivery level

The new levels turn on facts that the old IMRT codes never asked for. The treatment record for each session should show what the level depends on:

• The number of isocenters in the approved plan.
• The motion management method used, such as breath hold or surface guidance, if any.
• The modality, including any mixed electron and photon fields.
• The guidance imaging performed, and the physician’s review note supporting 77387-26.

A record that names the technique without these details leaves the level open to challenge. That was rarely a risk under 77385, because the treatment site settled the code on its own.

How Pabau supports radiation oncology billing through the code change

A code deletion leaves two sets of rules running side by side for a year. Billing teams work 2025 corrections under 77385 while every new session goes out as 77407 or 77412.

Pabau links the treatment record to claim generation, so the delivery level, the 77387-26 line, and the date of service travel together. Its claims management software sends claims through Claim.MD and brings remittance back as ERA files.

That lets your team see which sessions paid at the new levels and which came back for a code that no longer exists.

Bill radiation oncology sessions with confidence

Pabau’s claims management tools connect each treatment session to its claim line, so 2026 delivery codes go out with the right date and guidance line.

Book a demo

Conclusion

CPT code 77385 now belongs to 2025 and earlier. Keep it for late, corrected, and appealed claims on those dates, and nowhere else.

For 2026 sessions, the useful habit is to stop thinking in simple and complex IMRT. Read the isocenters and the motion management in each record, then pick 77407 or 77412.

Pabau keeps the delivery level, the guidance line, and the date of service together from record to claim. To see that on a full treatment course, book a demo.

Continue your research

Need to understand how claims reach a payer? Medical claims clearinghouse guide explains how electronic claims are validated, routed, and tracked before reaching Medicare or a commercial payer.

Reading denials on 2026 radiation oncology claims? Electronic remittance advice (ERA) guide covers how to read 835 files, identify CARC denial reasons, and automate payment posting.

Want to reduce rework on radiation oncology claims? Medical billing fundamentals outlines the end-to-end billing cycle and where radiation oncology practices lose the most revenue to preventable errors.

Cleaning 2026 charge lists of deleted guidance codes? CPT code 77014 covers the CT guidance code that was deleted alongside 77385 in 2026.

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