Summary & Overview
CPT 77373: Stereotactic Body Radiation Therapy, Technical Component, Single Fraction
CPT code 77373 denotes the technical component of stereotactic body radiation therapy (SBRT) for extracranial targets, representing a single fraction in a course of up to five fractions. SBRT is a high‑precision external beam radiation technique that localizes and ablates small lesions using a three‑dimensional coordinate system, and the technical component covers machine and delivery resources rather than professional planning or interpretation.
This code matters nationally because SBRT volumes and payment policies influence access to high‑precision oncology care, capital utilization for radiation therapy infrastructure, and payer coverage decisions across major national plans. Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare.
Readers will find a compact briefing on clinical context and service settings, plus coverage and billing considerations relevant to payers listed above. The publication summarizes benchmark elements such as typical use across a course of up to five fractions, expected site‑of‑service patterns (hospital outpatient and freestanding radiation centers), and common modifier usage (provided separately). It also outlines areas where policy updates or clinical practice patterns can affect billing — for example, fractionation limits and delineation of technical versus professional components. Data not available in the input is noted where applicable.
Billing Code Overview
CPT code 77373 describes the technical component of stereotactic body radiation therapy (SBRT) delivered to targets other than the brain and spinal cord. The procedure uses a three‑dimensional coordinate system to precisely locate small lesions and destroy them with externally generated ionizing radiation. This code applies to a single fraction within a course of treatment that may include up to five fractions.
Service Type: Stereotactic body radiation therapy (technical component), single fraction
Typical Site of Service: Hospital outpatient radiation oncology department, freestanding radiation oncology center, or other ambulatory radiation therapy facility
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult with one or a small number of extracranial, extracerebral solid tumor lesions (for example, a solitary lung metastasis or a primary early-stage non-small cell lung cancer) referred for stereotactic body radiation therapy (SBRT). The patient has completed multidisciplinary evaluation including diagnostic imaging (CT and/or PET) and tumor board review, and is ambulatory with Karnofsky performance status adequate for ablative radiation. The clinical workflow: consultation with a radiation oncologist, simulation with immobilization and high-resolution CT (often 4D-CT for thoracic lesions), image fusion with diagnostic CT/PET/MRI as needed, target and normal-structure delineation, treatment planning using a stereotactic plan and dose constraints, plan review and physics QA, and daily or fraction-specific image guidance for precise setup. Billing for the technical component of a single SBRT fraction is reported with 77373 for one of up to five fractions in the course. The technical services include delivery of stereotactic body radiation, image guidance and immobilization, and technical QA. Documentation typically includes treatment consent, simulation notes, target volumes, fractionation schedule, image guidance registrations, and machine parameters.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
TC | Technical component | When billing the technical portion only; often represents the technical component for a single fraction |