Summary & Overview
HCPCS G9320: CT Documentation for Radiation Treatment Planning
HCPCS Level II code G9320 records documentation of medical reasons for not naming CT studies according to a provided standardized nomenclature, commonly arising in radiation treatment planning and image-guided radiation therapy delivery. Nationally, this code matters because it formalizes documentation when clinical workflow or treatment-specific imaging protocols prevent use of standard study labels, which can affect communication, recordkeeping, and claims processing across diverse oncology care settings.
Key payers included in this analysis are Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the code’s clinical context, typical sites of service, and the types of situations that generate its use. The publication outlines expected benchmarks where available, highlights relevant policy considerations that influence payer acceptance, and situates G9320 within radiation oncology documentation workflows.
The content covers: practical definition and clinical rationale for the code; which payers recognize or provide guidance on its use; common operational implications for imaging and radiation therapy teams; and where to look for policy updates affecting claims and documentation. Data not available in the input will be noted where applicable.
Billing Code Overview
HCPCS Level II code G9320 documents the medical reason(s) for not naming CT studies according to a standardized nomenclature provided, for example when CT studies are performed for radiation treatment planning or image-guided radiation treatment delivery. The code captures circumstances in which CT imaging was used in support of radiation oncology care but the studies were not labeled using the expected standardized naming convention.
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Service type: Imaging documentation related to radiation treatment planning and image-guided radiation therapy
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Typical site of service: Radiation oncology departments, hospital-based outpatient imaging units, and freestanding radiation treatment centers
Clinical & Coding Specifications
Clinical Context
A 64-year-old patient with locally advanced non-small cell lung cancer is scheduled for external beam radiation therapy. Prior to treatment planning, the radiation oncology team orders a CT simulation study performed on a multislice CT scanner with immobilization devices to capture anatomy in treatment position. Because this CT is obtained specifically for radiation treatment planning and image-guided radiation treatment delivery, the imaging study is documented using the facility’s internal naming convention rather than a standardized radiology nomenclature. The radiation oncologist documents the medical reason(s) for not naming the CT study according to a standardized nomenclature in the patient’s radiation oncology record, citing treatment-planning-specific parameters such as patient immobilization, gating/4D acquisition, contrast timing for target delineation, and fusion with prior diagnostic imaging. The clinical workflow includes CT simulation acquisition by radiation therapy therapists, image transfer to the treatment planning system, contouring by the radiation oncologist and dosimetrist, treatment plan generation by the dosimetrist and physicist, and image-guided delivery using cone-beam CT or planar imaging at the time of treatment. Documentation of the nonstandard naming and the clinical rationale is completed in the medical record prior to initial treatment delivery to support medical necessity, quality assurance, and correct image registration for treatment delivery.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component |