CPT code 77280 – Simple simulation in radiation treatment planning

Key takeaways

CPT Code 77280 covers a simple radiation therapy simulation: one treatment area, one or two fields, isocenter placement and portal imaging verification.

Three or more fields or a special technique moves the session to 77290, while 77263 covers the physician’s complex treatment planning as a separate service.

Billing 77290 when the simulation note documents only one or two fields invites downcoding and denial, so the note has to carry the field count.

Claims management software such as Pabau flags missing fields on 77280 claims before submission and tracks each claim across payers.

CPT Code 77280: Official descriptor and procedure overview

CPT Code 77280 is the code for a simple radiation therapy simulation. The American Medical Association descriptor reads: Therapeutic radiology simulation-aided field setting; simple.

That “simple” qualifier carries the code’s clinical and billing weight. It means one treatment area, set up with one or two fields and standard patient positioning. The isocenter is placed and confirmed with portal imaging or digitally reconstructed radiographs (DRRs). Arc or rotational techniques, irregular field geometry and multi-field arrangements all take the session out of this code.

The procedure is performed jointly by a radiation oncologist and a medical physicist or dosimetrist. The oncologist determines the treatment site and field orientation. The physics staff handle beam setup, block or multileaf collimator (MLC) placement, and verification film acquisition. Both roles must be documented for a clean claim.

Common clinical scenarios billed under 77280 include:

• Single anterior field for palliative bone metastasis treatment
• Parallel-opposed fields for mediastinal or nodal irradiation
• Single-field electron setup for superficial skin lesions

CPT 77280 vs 77290 vs 77263: Choosing the right simulation code

Coders often mix up 77280, 77290 and 77263 because the three codes sit close together. They describe different services, and the table shows where each one applies.

77263 sits apart from the other two. It’s a professional treatment planning service that pays for the radiation oncologist’s work defining target volumes and dose constraints. It needs its own signed physician note documenting how complex that planning decision was.

Billing 77280 and 77263 on the same date requires distinct documentation for each service. Payer policies vary on whether the pair is allowed at all, so check each payer before submitting both.

When can you bill CPT Code 77280? Coverage criteria and medical necessity

CPT Code 77280 is billable when the simulation session meets all of these criteria:

• Field count: one or two treatment fields are set up and verified
• Patient positioning: standard immobilization without custom devices (e.g., no thermoplastic masks, vacuum bags for complex anatomical sites)
• Isocenter placement: documented in the simulation note with coordinates or field alignment notation
• Verification imaging: portal films or DRRs acquired and retained in the medical record
• Physician order: a signed radiation oncologist order for the simulation is present before the service date
• Diagnosis support: an ICD-10 malignancy or other qualifying diagnosis code supports the oncological indication

Simulations with three or more fields, arc or rotational techniques, tissue compensation, or special techniques such as IMRT field verification fall under 77290.

When the setup includes CT-based localization on the same date, 77014 may be billed alongside 77280 as a companion code. That pairing is widely accepted, but confirm your payer has no bundling edit before submitting both on one claim. The decision path below shows how the simulation note settles the code.

Medicare reimbursement rates for CPT 77280

Medicare reimbursement for CPT Code 77280 comes from the Physician Fee Schedule (MPFS). Relative value units (RVUs) are multiplied by the Medicare conversion factor, then adjusted for geographic locality.

Rates change with each annual MPFS update, so the table below shows the payment structure rather than a fixed dollar amount. Always verify the current-year rate using the CMS Physician Fee Schedule lookup tool, selecting the applicable year and locality.

For current RVU values, use the FastRVU lookup tool, which pulls directly from the CMS MPFS data file. Enter code 77280, select the applicable year and modifier (if any), and note both the facility and non-facility payment amounts. The non-facility rate typically applies to freestanding radiation oncology offices. The facility rate applies at hospital outpatient departments.

Companion codes: What can be billed alongside CPT Code 77280?

Several codes are commonly submitted on the same claim as or concurrent with CPT Code 77280. Each has specific conditions that govern whether it can be billed on the same date of service.

Modifier 59 (distinct procedural service) is the most commonly applied modifier when submitting companion codes. Use it only when a bundling edit exists and the record justifies separate billing. Applying it without supporting documentation is an audit risk in its own right.

Prior authorization requirements for CPT 77280

Traditional Medicare (fee-for-service) does not generally require prior authorization for CPT Code 77280. The picture changes significantly with Medicare Advantage plans, commercial payers, and plans managed through authorization vendors.

• Medicare Advantage plans: Many require prior authorization for radiation oncology services, including simulation codes. Requirements vary by plan and market. Check each plan’s provider portal before scheduling.
• eviCore-managed plans: eviCore Healthcare manages radiation oncology prior authorization for a number of commercial and Medicare Advantage payers. Their substitution rules, effective January 1, 2025, affect how simulation codes are reviewed and approved. Practices billing eviCore-managed plans should review their current submission requirements directly at eviCore’s provider portal.
• Highmark: Highmark’s medical policy explicitly addresses radiation oncology CPT code coverage. Their policy documents detail which simulation codes require authorization and what clinical documentation must accompany the request.
• Commercial plans generally: Authorization requirements vary. Some plans require the radiation oncologist’s initial consultation note, the treatment plan summary, and a diagnosis-specific clinical rationale before approving simulation.

Maintaining medical billing compliance across payer types means checking authorization when the simulation is scheduled. By the time a claim reaches coding, an unresolved prior authorization has already become a denial. That denial is harder to overturn than a problem caught before the appointment.

Documentation requirements to support a 77280 claim

A complete CPT Code 77280 claim rests on documentation that covers six elements. Missing any one of them is sufficient cause for denial.

• Signed physician order: A radiation oncologist’s dated order for the simulation, referencing the treatment site and diagnosis
• Simulation note: Documents the field configuration (number of fields, entry points, gantry angles), isocenter coordinates or alignment description, and patient positioning setup
• Portal films or DRRs: Verification imaging acquired during or immediately after the simulation session; must be retained in the electronic medical record
• Isocenter notation: Explicit reference to where the isocenter was placed. A note that says only “simulation performed” without field detail will not survive a payer audit
• Treatment site and laterality: Documented with sufficient specificity to support the ICD-10 diagnosis code submitted on the claim
• Physics or dosimetry attestation: Where 77336 or other physics codes are co-billed, a separate, signed physics note must support those codes independently

The superbill documentation process for radiation oncology should capture all six elements at the point of service. Retroactively reconstructing a simulation note after a denial is difficult and raises additional audit concerns about record integrity.

Common claim denials for CPT 77280 and how to avoid them

Denial patterns for CPT Code 77280 are consistent enough across payers that a targeted pre-submission checklist catches most of them. Understanding denial management in healthcare starts with knowing which denials are preventable at submission.

Timing matters as well as complexity. A June 2019 HHS Office of Inspector General audit (A-09-18-03026) looked at planning services billed separately from a 3D conformal plan, 77295.

Simulation codes, 77280 among them, were on its list. Medicare paid hospitals an extra $125.4 million for these services from 2008 through 2017. Most were billed up to 14 days before the plan, where same-date edits didn’t catch them.

• Upcoding to 77290 without documented field complexity: Bill 77280 unless the simulation note specifies three or more fields or a special technique. Auditors look at the field count documented in the simulation note, not the code billed.
• Unbundling 77280 and 77263 on the same date without separate documentation: Some payers apply a bundling edit to these two codes when submitted together. Without a distinct, signed physician planning note supporting 77263, the second code will be denied or downcoded.
• Wrong place-of-service code: POS 22 (outpatient hospital) versus POS 11 (office) affects both the rate paid and payer processing rules. A mismatch between the POS billed and the actual facility type is an administrative denial that adds weeks to payment cycles.
• Missing physician signature on the simulation note: A simulation note unsigned by the treating radiation oncologist fails medical necessity documentation requirements for most payers.
• Prior authorization not obtained: For plans that require auth, submitting without an authorization number results in a non-clinical denial that is difficult to reverse retroactively.
• ICD-10 diagnosis code mismatch: The diagnosis code must specifically support radiation oncology treatment. An unspecified or non-oncological code paired with 77280 triggers medical necessity review.

When a denial does arrive, build the appeal from four documents. Include the original simulation note, the portal films or DRRs, the signed physician order, and a written explanation of how the service met medical necessity. Reference the denial codes in medical billing to correctly categorize the denial reason before drafting the appeal letter.

CPT Code 77280 billing workflow: Step-by-step claim submission

This step-by-step process covers the full claim lifecycle for CPT Code 77280, from scheduling through submission. Each step targets a handoff point where 77280 claims tend to fail.

1. Verify medical necessity before scheduling: Confirm the patient has a qualifying oncological diagnosis and an active radiation oncologist order for simulation. Check the payer’s authorization requirements before the simulation appointment is set.
2. Confirm simulation complexity level at setup: Before the simulation begins, the physics team and oncologist should agree on the expected field count. If the case may cross into 77290 territory (three or more fields), document that determination in the pre-simulation planning note.
3. Capture physician and physics documentation during the session: The simulation note must be generated on the date of service. Defer-to-later documentation is a denial risk. Note field count, isocenter placement, patient positioning devices, and gantry angles.
4. Confirm portal films or DRRs are acquired and stored: Verification imaging must be present in the record before the claim goes to billing.
5. Assign the correct ICD-10 diagnosis code: Match the primary malignancy or qualifying diagnosis code to the treatment site. Use the most specific code available. Unspecified neoplasm codes raise the risk of medical necessity review.
6. Apply modifiers if companion codes are present: If 77014 is billed on the same date, verify no bundling edit exists. If 77263 is co-billed, apply modifier 59 or XS per payer policy and attach the separate physician planning note.
7. Submit with the correct place-of-service code: POS 22 for hospital outpatient, POS 11 for freestanding office. Confirm facility type matches the actual service location before claim generation.
8. Run a pre-submission audit: Before releasing the batch, confirm the physician signature, the diagnosis, the POS code and any required authorization number.

How Pabau catches 77280 claim errors before submission

In many radiation oncology offices, a biller checks each 77280 claim by hand. They confirm the field count, the physician signature, the place-of-service code and the authorization number, often days after the simulation.

Pabau’s claims management software moves that review ahead of submission. It flags missing fields before the claim reaches the clearinghouse. A missing signature or the wrong POS code gets fixed while the chart is still fresh.

Claims then go out through Pabau’s US clearinghouse integration with Claim.MD. It supports 837P claim formats, real-time eligibility verification and electronic remittance advice (ERA/835). When a claim returns, its CARC denial reason code comes with it, so your team can start the appeal sooner.

Streamline radiation oncology billing with Pabau

Pabau’s claims management tools help radiation oncology teams track CPT Code 77280 claims and catch POS mismatches before submission. Denial reasons show up as soon as claims return.

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Conclusion

Let the simulation note pick the code. If it can’t show the field count, the isocenter and the verification images, no code choice will survive a payer review.

The fixes are cheap: a note written on the day, a place-of-service check and an authorization number on file before the appointment. A few minutes of review per claim costs far less than weeks of appeal work later. Book a demo to see how Pabau flags missing fields on radiation oncology claims before they reach the clearinghouse.

Continue your research

Need to understand how clearinghouses process radiation oncology claims? How a medical claims clearinghouse works explains the 837P submission pathway, ERA processing, and how CARC codes surface on returned claims.

Looking to understand the full revenue cycle behind radiation oncology billing? What is revenue cycle management maps the end-to-end process from eligibility verification through payment posting.

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