Proton Beam Radiation Treatment, Intermediate Delivery
CPT 77523
Reported for each proton therapy session of this complexity during a planned course of treatment, most often for tumors of the brain, head and neck, base of skull, spine, or prostate.
No national payment amount
Carrier-priced: no national payment amount.
Did Medicare pay separately for CPT 77523 in Q1 2025?
Not at a published national rate. CPT 77523 carries status C (carrier-priced) in the Q1 2025 release. Your Medicare Administrative Contractor prices this code case by case, usually after reviewing documentation. Treat the blank amount as unpriced, not as $0.
How often 77523 is billed
Across Original Medicare in CY2024, 77523 ranked #302 of the 7,879 CPT codes billed to Medicare that year, ranked by patients served or total allowed dollars. Patients who received it in 2024 were billed for it an average of 24.4 times that year — more than once per patient.
2024 Medicare fee-for-service only, national totals — Medicare Advantage, Medicaid and commercial volume are excluded, so real-world use runs higher. This is a calendar-year snapshot from the CMS Physician & Other Practitioners dataset, on a different cycle from the Q1 2025 fee schedule the rates above come from.
Common questions
Why is there no payment amount for 77523?
Its status indicator is C (carrier-priced). Your Medicare Administrative Contractor prices this code case by case, usually after reviewing documentation. The blank is deliberate: the amount is either unknown or paid under another provision, so reading it as $0 would be wrong.
Why would a Medicare claim for 77523 be denied or paid less?
Each item below comes from a CMS indicator on this page — not general billing advice.
- Its status indicator is C (carrier-priced) — Your Medicare Administrative Contractor prices this code case by case, usually after reviewing documentation. See status indicators
- Only a technical component exists for 77523 — there is no professional-component amount to bill. See billing policy
- Bilateral surgery: no bilateral adjustment. See billing policy
- Assistant at surgery: restricted without documentation. See billing policy
- Co-surgeons: not permitted. See billing policy
- Team surgery: not permitted. See billing policy
Payer-specific coverage and documentation rules live outside these files, so a claim that clears every check here can still be denied on other grounds.
When does this rate change?
CMS publishes a fee schedule release every quarter (January, April, July, October), and each is versioned here. See what changed each release, or get an email when a new release moves rates.
Sources: CMS Medicare Physician Fee Schedule Relative Value Files.
Saw this code on your bill?
What is a 77523 visit in patient-friendly terms?
In plain terms: One session of radiation therapy delivered with a proton beam rather than conventional x-rays. Protons deposit most of their energy at a set depth and stop there, so the dose can be concentrated on a tumor while sparing tissue behind it - the reason proton therapy is chosen for tumors sitting next to the spinal cord, optic nerves, brainstem, or a child's growing tissues. Proton delivery is split into simple, intermediate, and complex sessions; this middle tier covers treatments aimed from more than one direction and shaped with patient-specific hardware, which sits above a straightforward single-direction session but below the most involved setups that require multiple aiming points or fields matched together. Think of a patient lying still in a custom mold while a large rotating gantry aims a proton beam at a tumor from two or more angles, with milled blocks and compensators built for that person's anatomy shaping each beam. Treatment is painless and takes minutes, but it is repeated daily over several weeks, and each session is reported separately. You'll typically see CPT 77523 on a bill or explanation of benefits (EOB) when a clinician performs or bills for this service.
How this amount is computed
amount = (work RVU × work GPCI + PE RVU × PE GPCI + MP RVU × MP GPCI) × conversion factor. National amounts use GPCI = 1.000. To price an RVU figure of your own, use the RVU-to-dollars converter.
| Component | RVU |
|---|---|
| Work RVU | blank |
| Practice expense RVU (non-facility) | blank |
| Practice expense RVU (facility) | blank |
| Malpractice RVU | blank |
Every rate combines three parts: work (the clinician’s time, skill and effort), practice expense (office overhead — higher when the service is done in a doctor’s own office), and malpractice (the share of liability-insurance cost). A blank means CMS publishes no national number for that part. Read it as unknown, and never as zero.
Billing policy
What 77523's billing-policy indicators mean. These show for every code, priced or not: a restriction like "bilateral not allowed" still matters on a carrier-priced code.
| Policy | Value | What it means |
|---|---|---|
| Bilateral surgery | 0 | No bilateral adjustment. The 150% bilateral payment adjustment does not apply to this procedure. |
| Assistant at surgery | 0 | Restricted without documentation. Payment for an assistant at surgery is restricted for this procedure unless supporting documentation establishes medical necessity. |
| Co-surgeons | 0 | Not permitted. Medicare does not recognize co-surgeons (modifier 62) for this procedure. |
| Team surgery | 0 | Not permitted. Medicare does not recognize a surgical team (modifier 66) for this procedure. |
| Multiple procedures | 0 | No reduction. No payment reduction applies when this procedure is billed with other procedures on the same date — each is treated as unrelated. |
| Professional/technical split | 3 | Technical component only. Only a technical component exists for this code — there is no corresponding professional-component amount to bill. |
Rate history by release
National non-facility amount for 77523 across quarterly releases.
| Release | Status | Non-facility | Facility |
|---|---|---|---|
| Q3 2026 Jun 30, 2026 – present | C | — | — |
| Q2 2026 Mar 10, 2026 – Jun 29, 2026 | C | — | — |
| Q1 2026 Dec 29, 2025 – Mar 9, 2026 | C | — | — |
| Q4 2025 Sep 11, 2025 – Dec 28, 2025 | C | — | — |
| Q3 2025 Jun 5, 2025 – Sep 10, 2025 | C | — | — |
| Q2 2025 Jun 5, 2025 – Jun 4, 2025 | C | — | — |
| Q1 2025 Dec 23, 2024 – Jun 4, 2025 | C | — | — |
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Source & method
This is computed from CMS's Medicare Physician Fee Schedule Q1 2025 release (schedule pfs, effective January 2025). National amounts apply a GPCI of 1.000 and leave sequestration off. The status indicator decides payability, never the RVU values, so a blank RVU stays blank. Releases are immutable: a rate retrieved for a past quarter always reflects that release. Commercial and cash-pay figures anywhere on this page are arithmetic on the Medicare amount, using commonly cited reimbursement ranges. They're illustrative, and no nationwide claims database stands behind them.
Description written from primary sources: CMS Medicare Physician Fee Schedule Relative Value Files. Not derived from AMA CPT descriptor text.
Conversion factor $32.3465 read from the same file, row 11, column 25.
Use the (i) buttons next to each amount above for the exact row, columns, and math.
Cite this rate
This link keeps pointing at the Q1 2025 figures, even after a newer release lands.
CPT 77523 Medicare Physician Fee Schedule rate (Q1 2025). Localis. https://localishealth.com/cpt/77523/2025/A