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.