# CPT 77523

> Not at a published national rate. CPT 77523 carries status C (carrier-priced) in the Q2 2018 release. Your Medicare Administrative Contractor prices this code case by case, usually after reviewing documentation. Treat the blank amount as unpriced, not as $0.

## What it is

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.

## Selected release

- Release: Q2 2018 (2018 B)
- Effective: April 1 – June 30, 2018
- Status indicator: C
- Office (non-facility) national allowed amount: not published
- Facility national allowed amount: not published
- Sequestration: not applied

## RVUs and formula

- Work RVU: not published
- Office (non-facility) practice expense RVU: not published
- Facility practice expense RVU: not published
- Malpractice RVU: not published
- Conversion factor: 35.9996
- Formula: `(work_rvu × work_gpci + pe_rvu × pe_gpci + mp_rvu × mp_gpci) × conversion_factor`

## Source and citation

- Source: Physician relative value file (Q2 2018)
- CMS file: https://www.cms.gov/medicare/medicare-fee-for-service-payment/physicianfeesched/downloads/rvu18b.zip
- Parsed file: PPRRVU18_APR.csv, row 12,911
- Canonical page: https://localishealth.com/cpt/77523/2014/B
- Release-specific citation URL: https://localishealth.com/cpt/77523/2018/B
- Last significant update: 2026-08-04T03:08:19+00:00