CPT code 77789 represents low–dose–rate (LDR) brachytherapy procedures in which a radioactive source is applied directly to the surface of the target area using surface applicators, needles, seeds, or suspensions. This code captures a focused radiation delivery technique used for localized malignancies or lesions where direct surface or interstitial placement of sources is clinically appropriate. Nationally, LDR brachytherapy is a specialized, resource‑intensive service with implications for procedural coding, facility site-of-service designation, and payer coverage policies.

Key payers considered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The report outlines typical sites of service and clinical context, and provides benchmarking and policy-relevant highlights commonly reviewed by health plans and provider billing teams.

Readers will learn what CPT code 77789 denotes clinically and operationally, how it is commonly performed, and which payers are most frequently involved in coverage decisions. The publication summarizes billing considerations, common modifiers used with procedural codes (listed separately), and the types of facilities where the service is delivered. Data not available in the input are noted where applicable. The content is intended for billing managers, compliance officers, and clinical leaders seeking a concise national overview of this brachytherapy procedure code.