CPT code 77520 denotes the technical component of proton beam radiation therapy delivered using a simple technique: a single non–tangential port without compensators. This code captures the facility or technical services associated with delivering proton therapy beams rather than the professional planning or interpretation. Nationally, accurate use of 77520 matters for appropriate facility billing, resource tracking at proton therapy centers, and consistent reporting of advanced radiation modalities.

Key payers in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of what 77520 represents clinically and operationally, common payer coverage considerations, and where this code fits within radiation oncology service lines.

This publication provides benchmarks and billing context related to proton beam technical services, highlights common modifiers and claim components (list provided separately), and summarizes clinical context for simple proton treatments. Data not available in the input is noted where applicable. The content is aimed at billing managers, revenue cycle professionals, and policy analysts seeking a national perspective on use and classification of proton beam technical services under CPT code 77520.