Find policies, billing codes, payers, states, and providers

CPT 77293: Respiration-Correlated (4D) CT Simulation for Radiation Planning

CPT code 77293 denotes a respiration-correlated (4D) CT simulation study performed in addition to a 3D radiotherapy or intensity-modulated radiation therapy (IMRT) plan. The code captures advanced imaging used to quantify tumor and organ motion with respiration so that radiation treatment planning can incorporate motion management strategies. Nationally, use of respiration-correlated CT is important for improving targeting accuracy and reducing normal-tissue exposure in thoracic and upper abdominal radiotherapy.

Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of clinical context for 4D CT simulation, common billing considerations, and national benchmarking themes where available. The publication summarizes service definitions, typical sites of service, and commonly associated modifiers and payment considerations. It also outlines how CPT code 77293 fits into modern radiotherapy workflows including 3D planning and IMRT.

This summary is intended to inform revenue cycle, coding, and clinical teams about the clinical purpose and billing context for CPT code 77293, and to provide a national perspective on operational and policy-relevant aspects of respiration-correlated CT simulation.

Customize your policy alerts

Sign up for cpt 77293 policy alerts

Get alerted when payer policies referencing 77293 are released or updated.

Monitor payer policy activity

Receive email alerts as soon as relevant payer policies are published or updated.

Billing Code Overview

CPT code 77293 describes a respiration-correlated or 4D CT simulation study performed in addition to a 3D radiotherapy plan or intensity-modulated radiation therapy (IMRT) plan. This service documents acquisition of four-dimensional imaging to account for respiratory motion when developing a radiation treatment plan.

Service type: Advanced radiation therapy simulation (4D CT / respiration-correlated CT) performed as an adjunct to a 3D or IMRT planning study.
Typical site of service: Radiation oncology departments or hospital-based radiation therapy centers where CT simulation and treatment planning for radiotherapy are performed.

Data not available in the input.

Find policies, billing codes, payers, states, and providers

CPT 77293: Respiration-Correlated (4D) CT Simulation for Radiation Planning

Customize your policy alerts

Sign up for cpt 77293 policy alerts

Get alerted when payer policies referencing 77293 are released or updated.

Monitor payer policy activity

Receive email alerts as soon as relevant payer policies are published or updated.

Billing Code Overview

Service type: Advanced radiation therapy simulation (4D CT / respiration-correlated CT) performed as an adjunct to a 3D or IMRT planning study.
Typical site of service: Radiation oncology departments or hospital-based radiation therapy centers where CT simulation and treatment planning for radiotherapy are performed.

Data not available in the input.

Clinical & Coding Specifications

Clinical Context

A 62-year-old patient with a newly diagnosed, centrally located non–small cell lung cancer is referred for definitive radiation therapy. The radiation oncology team plans an intensity–modulated radiation therapy (IMRT) course. Because the tumor exhibits significant motion with respiration on diagnostic imaging and the treatment target is in the thorax, a respiration–correlated (4D) CT simulation is performed in addition to the standard 3D/IMRT planning CT. During the visit the radiation therapist acquires a 4DCT while the patient breathes normally using an external respiratory monitoring device; images are reconstructed into multiple breathing-phase datasets and an internal target volume (ITV) is delineated by the radiation oncologist. The physics team uses the 4D dataset to account for motion during contouring and dose calculation, and the dosimetrist generates an IMRT plan that incorporates the motion information. The 4DCT simulation is billed in conjunction with the 3D/IMRT planning services to document that respiration–correlated imaging was performed to guide planning and motion management.

Coding Specifications

Modifier	Description	When to Use
`11`	Office or other outpatient visit	Use when service is provided in an outpatient radiation oncology setting by the reporting practitioner.
`22`	Increased procedural services	Use when complexity or time substantially exceeds typical for simulation/planning and documentation supports it.
`23`	Unusual anesthesia	Use if general anesthesia or deep sedation was required during simulation.
`26`	Professional component	Use when billing physician work only for interpretation/review of the 4DCT planning study.
`50`	Bilateral procedure	Use if separate billing rules require designation for bilateral target sites (rare for 4DCT).
`52`	Reduced services	Use when 4DCT study was curtailed or incomplete but still clinically useful.
`53`	Discontinued procedure	Use if the 4DCT was started but terminated due to patient intolerance.
`59`	Distinct procedural service	Use to indicate the 4DCT simulation is a distinct service from other imaging/therapy codes when needed for bundling edits.
`76`	Repeat procedure by same physician	Use if the 4DCT simulation is repeated on the same day by the same provider.
`78`	Return to operating/procedure room by same physician following initial procedure	Use when an unplanned repeat simulation/procedure requires the physician to return under facility reporting rules.

Taxonomy Code	Specialty	Notes
`2085R0200X`	Radiation Oncology	Physician specialty that directs simulation, contouring, and treatment planning.
`174H00000X`	Radiation Therapist	Allied health professional who performs CT simulation and respiratory monitoring.
`263RM0800X`	Medical Dosimetry	Dosimetrist who creates IMRT/3D plans using 4DCT data.
`2086S0202X`	Medical Physicist	Physicist who performs image acquisition QA and incorporates motion data into dose calculations.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`C34.90`	Malignant neoplasm of unspecified part of unspecified bronchus or lung	Primary lung cancers commonly require 4DCT for motion assessment prior to thoracic RT planning.
`C34.11`	Malignant neoplasm of upper lobe, right bronchus or lung	Tumors in upper lobes with respiratory motion benefit from 4DCT to define ITV.
`C78.01`	Secondary malignant neoplasm of lung	Pulmonary metastases undergoing RT may require motion-correlated simulation for accurate targeting.
`C50.912`	Malignant neoplasm of unspecified site of right female breast	Left or right breast tumors close to the chest wall or requiring respiratory gating may require 4DCT for planning.
`G60.9`	Data not relevant - placeholder	Data not available in the input.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`77292`	Therapeutic radiology simulation-aided field setting; complex RT simulation, including use of contrast materials and/or custom immobilization	Often performed as the base simulation service to which the 4DCT (`77293`) is added when respiratory motion must be assessed.
`77295`	Special simulation for stereotactic radiation therapy guidance (separate session)	May be used for stereotactic cases where dedicated special simulation is performed in addition to motion-correlated imaging.
`77301`	Radiation treatment planning, complex (e.g., IMRT); plan, dosimetry, and documentation	The IMRT planning code represents the planning process that uses the 4DCT data to generate treatment fields and dose distributions.
`77334`	Special dosimetry (e.g., for intensity modulated radiotherapy)	Used when advanced dosimetric measurements or verification are performed that utilize the 4DCT-derived plan.
`77014`	Computed tomography guidance for placement of radiation therapy fields (separate procedure)	May be reported when CT guidance is used during setup or verification and is related to the 4D planning dataset.

CPT 77261: Radiation Treatment Planning, Initial

CPT-77262-RADIATION-THERAPY-TREATMENT-PLANNING-DETAILED

CPT 77262: Detailed Radiation Therapy Treatment Planning

CPT-77263-RADIATION-THERAPY-TREATMENT-PLANNING

CPT 77263: Radiation Therapy Treatment Planning and Design

CPT-77280-RADIATION-THERAPY-SIMULATION-SIMPLE

CPT 77280: Radiation Therapy Simulation, Simple

CPT-77285-RADIATION-THERAPY-SIMULATION-PORT-LOCALIZATION

CPT 77285: Radiation Therapy Simulation for Port Localization

CPT-77290-RADIATION-TREATMENT-SIMULATION-PLANNING

CPT 77290: Radiation Treatment Simulation and Planning

CPT-77295-3D-DOSE-RECONSTRUCTION-VOLUMETRIC-DOSE-CALCULATION

CPT 77295: 3D Dose Reconstruction and Volumetric Dose Calculation

CPT-77299-THERAPEUTIC-RADIOLOGY-TREATMENT-PLANNING-UNLISTED

CPT 77299: Therapeutic Radiology Clinical Treatment Planning, Unlisted

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Jul 29, 2026.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.

Published by

Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Modifier	Description	When to Use
`11`	Office or other outpatient visit	Use when service is provided in an outpatient radiation oncology setting by the reporting practitioner.
`22`	Increased procedural services	Use when complexity or time substantially exceeds typical for simulation/planning and documentation supports it.
`23`	Unusual anesthesia	Use if general anesthesia or deep sedation was required during simulation.
`26`	Professional component	Use when billing physician work only for interpretation/review of the 4DCT planning study.
`50`	Bilateral procedure	Use if separate billing rules require designation for bilateral target sites (rare for 4DCT).
`52`	Reduced services	Use when 4DCT study was curtailed or incomplete but still clinically useful.
`53`	Discontinued procedure	Use if the 4DCT was started but terminated due to patient intolerance.
`59`	Distinct procedural service	Use to indicate the 4DCT simulation is a distinct service from other imaging/therapy codes when needed for bundling edits.
`76`	Repeat procedure by same physician	Use if the 4DCT simulation is repeated on the same day by the same provider.
`78`	Return to operating/procedure room by same physician following initial procedure	Use when an unplanned repeat simulation/procedure requires the physician to return under facility reporting rules.

Taxonomy Code	Specialty	Notes
`2085R0200X`	Radiation Oncology	Physician specialty that directs simulation, contouring, and treatment planning.
`174H00000X`	Radiation Therapist	Allied health professional who performs CT simulation and respiratory monitoring.
`263RM0800X`	Medical Dosimetry	Dosimetrist who creates IMRT/3D plans using 4DCT data.
`2086S0202X`	Medical Physicist	Physicist who performs image acquisition QA and incorporates motion data into dose calculations.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`C34.90`	Malignant neoplasm of unspecified part of unspecified bronchus or lung	Primary lung cancers commonly require 4DCT for motion assessment prior to thoracic RT planning.
`C34.11`	Malignant neoplasm of upper lobe, right bronchus or lung	Tumors in upper lobes with respiratory motion benefit from 4DCT to define ITV.
`C78.01`	Secondary malignant neoplasm of lung	Pulmonary metastases undergoing RT may require motion-correlated simulation for accurate targeting.
`C50.912`	Malignant neoplasm of unspecified site of right female breast	Left or right breast tumors close to the chest wall or requiring respiratory gating may require 4DCT for planning.
`G60.9`	Data not relevant - placeholder	Data not available in the input.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`77292`	Therapeutic radiology simulation-aided field setting; complex RT simulation, including use of contrast materials and/or custom immobilization	Often performed as the base simulation service to which the 4DCT (`77293`) is added when respiratory motion must be assessed.
`77295`	Special simulation for stereotactic radiation therapy guidance (separate session)	May be used for stereotactic cases where dedicated special simulation is performed in addition to motion-correlated imaging.
`77301`	Radiation treatment planning, complex (e.g., IMRT); plan, dosimetry, and documentation	The IMRT planning code represents the planning process that uses the 4DCT data to generate treatment fields and dose distributions.
`77334`	Special dosimetry (e.g., for intensity modulated radiotherapy)	Used when advanced dosimetric measurements or verification are performed that utilize the 4DCT-derived plan.
`77014`	Computed tomography guidance for placement of radiation therapy fields (separate procedure)	May be reported when CT guidance is used during setup or verification and is related to the 4D planning dataset.

CPT 77261: Radiation Treatment Planning, Initial

CPT-77262-RADIATION-THERAPY-TREATMENT-PLANNING-DETAILED

CPT 77262: Detailed Radiation Therapy Treatment Planning

CPT-77263-RADIATION-THERAPY-TREATMENT-PLANNING

CPT 77263: Radiation Therapy Treatment Planning and Design

CPT-77280-RADIATION-THERAPY-SIMULATION-SIMPLE

CPT 77280: Radiation Therapy Simulation, Simple

CPT-77285-RADIATION-THERAPY-SIMULATION-PORT-LOCALIZATION

CPT 77285: Radiation Therapy Simulation for Port Localization

CPT-77290-RADIATION-TREATMENT-SIMULATION-PLANNING

CPT 77290: Radiation Treatment Simulation and Planning

CPT-77295-3D-DOSE-RECONSTRUCTION-VOLUMETRIC-DOSE-CALCULATION

CPT 77295: 3D Dose Reconstruction and Volumetric Dose Calculation

CPT-77299-THERAPEUTIC-RADIOLOGY-TREATMENT-PLANNING-UNLISTED

CPT 77299: Therapeutic Radiology Clinical Treatment Planning, Unlisted

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Jul 29, 2026.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.

Published by

Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

OpenPayer

CPT 77293: Respiration-Correlated (4D) CT Simulation for Radiation Planning

Sign up for cpt 77293 policy alerts

Billing Code Overview

Catch payer policy changes before they impact reimbursement

Catch payer policy changes before they impact reimbursement

OpenPayer

CPT 77293: Respiration-Correlated (4D) CT Simulation for Radiation Planning

Sign up for cpt 77293 policy alerts

Billing Code Overview

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

References

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

References

CPT 77293: Respiration-Correlated (4D) CT Simulation for Radiation Planning

Sign up for cpt 77293 policy alerts

Billing Code Overview

CPT 77293: Respiration-Correlated (4D) CT Simulation for Radiation Planning

Sign up for cpt 77293 policy alerts

Billing Code Overview

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

What clinical purpose does CPT 77293 serve?

When should 77293 be performed in relation to 3D/IMRT planning?

Which modifiers are commonly relevant when billing CPT 77293?

What related CPT codes are frequently billed with 77293?

Which payers are noted as covering CPT 77293 and where can I find reimbursement details?

References

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

What clinical purpose does CPT 77293 serve?

When should 77293 be performed in relation to 3D/IMRT planning?

Which modifiers are commonly relevant when billing CPT 77293?

What related CPT codes are frequently billed with 77293?

Which payers are noted as covering CPT 77293 and where can I find reimbursement details?

References