CPT code 77423: Neutron beam treatment, complex delivery2026 Medicare rate & RVUs in California

CMS doesn’t publish an office rate for 77423 in California.

Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.

What 77423 covers

This code identifies complex radiation treatment delivered with a neutron beam. Neutron therapy is used for selected malignancies, including adenoid cystic carcinoma of the salivary glands. It is provided at specialized radiation oncology centers equipped for neutron treatment. The radiation oncologist directs the treatment course, while the facility’s radiation therapy team delivers the planned beam and reports the technical service.

Medicare assigns this CPT code physician fee schedule status C, or carrier priced: CMS publishes no national payment, and the Medicare Administrative Contractor sets payment for each claim. The code covers the technical component only; a separate code covers interpretation. It represents neutron-beam delivery, not the physician’s interpretation or radiation treatment management.

This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.

Where 77423 pays more and less in California

The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.

29 of 29 payment localities

How the 77423 rate is calculated

Each of 77423’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.

Payment rules and modifiers for 77423

The CMS indicators that decide how 77423 is paid alongside other services.

77423 compared with similar codes

How to choose

77424Intraoperative radiationX-ray delivery

77424 describes intraoperative radiation delivery using x-rays. Use 77423 for complex neutron-beam delivery, not the intraoperative x-ray method.

77425Intraoperative radiationElectron beam

77425 describes intraoperative radiation delivery using electrons. It differs from the neutron-beam treatment reported with 77423.

77412Radiation deliveryComplex treatment

77412 is a level-based radiation treatment delivery code. 77423 identifies complex neutron-beam delivery specifically.

Codes related to 77423

Related codes aren’t interchangeable: bill the code that matches the service performed.

Where these rates come from

FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.

CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027

Open CMS sourceHow we calculate rates