CPT 77301 in Medical Billing: IMRT Planning in 2026 and the Codes Around It
CPT 77301 is intensity modulated radiotherapy planning, including dose-volume histograms for target and critical structure partial tolerance specifications: the inverse-planned dose plan behind an IMRT or VMAT course, reported once per course. In 2026 it is billed with a delivery code that no longer names IMRT.
It is the largest single planning line a radiation oncology practice bills, and the one payers scrutinize most closely.
Where you see it
| Place | What goes there |
|---|---|
| CMS-1500 box 24D | 77301 global in a freestanding center; 77301-26 for the physician and the technical work on the facility claim in a hospital setting |
| 837P electronic claim | Loop 2400, SV1: 77301, modifier if any, one unit |
| Medicare Physician Fee Schedule (RVU26D) | Status A, PC/TC indicator 1, global XXX; 58.69 non-facility RVUs global, 12.55 professional, 46.14 technical |
| Medicare MUE table (October 1, 2026) | 1 unit per date of service |
| Plan documents | The approved plan with dose-volume histograms, dose constraints for targets and critical structures, and the physician’s and physicist’s signatures |
What 77301 includes
The 2026 NCCI policy manual, chapter 9, section F, sets the Medicare rules:
- “IMRT plan (CPT code 77301) includes therapeutic radiology simulation-aided field settings.” 77280 to 77290 are not reported separately, and the edit “shall not be circumvented by performing the 2 procedures … on different dates of service.” Nor are simulation codes reported “for verification of the treatment field during a course of IMRT treatment.”
- “IMRT planning (CPT code 77301) includes many treatment device(s) required for IMRT. Multi-leaf collimator (MLC) device(s) (CPT code 77338) may be reported separately once per IMRT plan.”
Payer manuals go further. eviCore’s 2026 manual for Cigna states that 77280, 77285, 77290, 77295, 77306, 77307, 77321, 77331, 77370 and 77399 “are included in the payment for CPT code 77301 (IMRT planning) and cannot be reported separately,” that image fusion is included, that 77301 “cannot be reported for boost planning,” and that adaptive replanning has no code of its own (eviCore Radiation Oncology Coding Manual V1.0.2026). UnitedHealthcare’s policy says IMRT planning “includes special dosimetry” (77331).
The codes around it
| Code | What it is | Relationship to 77301 |
|---|---|---|
| 77338 | MLC device(s) for IMRT, per plan | Reported separately, once per IMRT plan (NCCI); not when the IMRT is compensator based |
| 77300 | Basic radiation dosimetry calculation | Not on the NCCI or eviCore included lists; Medicare MUE 10 per date; the number of calculations per plan is a payer-by-payer question |
| 77370 | Special medical radiation physics consultation | A technical-only code under the Claims Processing Manual; included in 77301 under eviCore’s manual; expect payer variation |
| 77295 | 3D radiotherapy plan | One of 77295 or 77301 per course under eviCore; payers question both for the same volume |
| 77263 | Complex clinical treatment planning | The physician’s clinical plan, billed once before 77301; see CPT 77263 |
| 77336 | Continuing medical physics consultation | Per five fractions during treatment; NCCI edits pair it with 77301 on the same date |
What changed in 2026
The CPT Editorial Panel deleted 77385 and 77386 (IMRT delivery) and 77014 (CT guidance), and CMS deleted G6001 to G6017, effective January 1, 2026. Delivery is now reported by level: 77407 for a single-isocenter IMRT or VMAT course and 77412 when a Level 3 criterion is met, with image guidance inside both. The physician’s review of the daily images is 77387-26 in every setting; the technical component of guidance pays nothing on its own.
77301 was not part of that change; its RVUs, indicators and MUE are unchanged in the 2026 fee schedule files. What did change is the relationship between the plan and the delivery lines: in 2025 an IMRT plan led to an IMRT delivery code; in 2026 the same plan is followed by 77407 unless the daily record shows multiple isocenters, active motion management, total skin electrons or mixed fields. A chart with 77301 and 77412 on every fraction, and no breath hold or gating in the record, is the mismatch reviewers now look for. See 77407 vs 77412.
Medical necessity by site, in general terms
Payers pay for IMRT when the site or the anatomy requires it, not because it was planned. UnitedHealthcare’s commercial policy (2026T0407HH, effective March 1, 2026) lists IMRT as proven and medically necessary for definitive therapy of, among others, anal, cervical, endometrial, esophageal and pancreatic cancers; head and neck cancers of the pharynx, larynx, salivary glands, oral cavity and sinuses; central nervous system tumors; prostate cancer; unresectable liver tumors; Hodgkin lymphoma and mediastinal tumors; limited-stage small cell and selected non-small cell lung cancer; retroperitoneal sarcoma; vulvar cancer; and breast cancer only when the left internal mammary nodes are treated or for partial breast irradiation of up to five fractions. For any other site it requires a case-by-case exception supported by “a comparison of treatment plans for the IMRT and non-IMRT technique” showing that the non-IMRT plan would exceed normal tissue tolerance, or prior irradiation of the same or an adjacent area (UHC Intensity-Modulated Radiation Therapy policy).
Medicare contractors focus on documentation rather than a site list. Noridian’s radiation oncology page says IMRT documentation must support medical necessity and be available on request, and that the prescription must include specific dose constraints for the targets and nearby critical structures. The comparison plan meets both requirements.
Worked example: a 35-fraction prostate IMRT course
Illustrative figures from the CMS RVU26D file at 33.4009 per RVU, national non-facility, before geographic adjustment and sequestration. Single isocenter, daily cone beam CT, no motion management, freestanding center billing globally.
| Line | Units | RVUs each | Allowed |
|---|---|---|---|
| 77263 clinical treatment planning, complex | 1 | 5.04 | 168.34 |
| 77301 IMRT plan | 1 | 58.69 | 1,960.30 |
| 77338 MLC devices for IMRT | 1 | 14.22 | 474.96 |
| 77334 custom immobilization | 1 | 3.78 | 126.26 |
| 77407 delivery, Level 2 | 35 | 9.28 | 10,848.60 |
| 77387-26 image guidance, professional | 35 | 1.09 | 1,274.35 |
| 77427 treatment management | 7 | 5.85 | 1,367.80 |
| 77336 continuing physics | 7 | 2.76 | 645.33 |
| Course total | 16,865.94 |
In a hospital department the physician’s claim keeps 77263, 77301-26 (12.55 RVUs, 419.18), 77338-26 (225.12), 77334-26 (60.12), 35 units of 77387-26 and 7 units of 77427; the delivery, physics and technical planning lines belong to the hospital under OPPS. A 2025 version of the freestanding claim would have carried 35 units of 77386 or G6015 plus 35 technical guidance lines; the 2026 version carries 77407 and nothing for technical guidance.
What to do
- Authorize IMRT before 77301 is performed (see radiation therapy prior authorization in 2026), and keep the comparison plan or the site-based justification with the plan.
- Bill 77301 once per course, with 77338 once per plan and no simulation codes on any date of the course. A boost plan is not a second 77301.
- Match the delivery level to the daily record, not to the plan type, and make sure 77387-26 reaches the physician’s claim for each imaged fraction.
- Denials to recognize: CARC 50 when the payer finds IMRT not medically necessary for the site or the authorization is missing (appeal with the comparison plan and the policy citation); CARC 97 with M15 when 77280 to 77290, 77331 or 77295 is billed with 77301 (bundled; remove the line); CARC 151 with N362 for a second 77301 in the course; CARC 16 with N56 or M51 when 77385, 77386 or 77014 is sent for a 2026 date (correct and resubmit with 77407 or 77412 and 77387-26).
- Iridium Suite’s CodePath audits scheduling, delivery, coding and billing against the treatment plan.
Related terms
- CPT 77334 and 77338: treatment devices
- 77407 vs 77412: choosing the delivery level
- 77387 modifier 26: image guidance in 2026
- CPT 77263: treatment planning and Z51.0
- Radiation therapy prior authorization in 2026
- The 2026 radiation treatment delivery code changes
Further reading: Medicare NCCI Policy Manual, Chapter 9, Radiology Services (2026), section F; CY 2026 Physician Fee Schedule final rule, Radiation Oncology Treatment Delivery (Federal Register full text); CMS PFS Relative Value File RVU26D; Noridian JE Part B: Radiation Oncology.
Frequently asked
What is CPT 77301?
CPT 77301 is intensity modulated radiotherapy planning, including dose-volume histograms for target and critical structure partial tolerance specifications. It is the inverse-planned dose plan behind an IMRT or VMAT course, with professional and technical components, reported once per course of treatment.
What does 77301 include that cannot be billed separately?
The NCCI policy manual states that IMRT planning includes simulation-aided field settings (77280 to 77290), which may not be reported separately or on a different date to avoid the edit, and that it includes many of the treatment devices required for IMRT. The multileaf collimator device set, 77338, is the exception and is reported once per IMRT plan. Payer manuals add 77295, 77306, 77307, 77331 and 77370 to the included list.
Is IMRT delivery still billed with 77385 and 77386?
No. Both were deleted January 1, 2026, along with CT guidance 77014 and the G-codes G6001 to G6017. IMRT delivery is now reported with 77407 (single isocenter) or 77412 (a Level 3 criterion such as active motion management), and the physician's image guidance work is 77387-26. The planning code 77301 itself did not change.
When do payers consider IMRT medically necessary?
Policies list sites where IMRT is covered as definitive therapy, commonly head and neck, prostate, anal, cervical and endometrial, esophageal, pancreatic, central nervous system, selected breast and lung presentations, and re-irradiation. For other sites they generally require a comparison plan showing that a non-IMRT technique would exceed normal tissue tolerance. Check the specific payer policy and authorize before planning.