Summary & Overview

CPT 77436: Surface Radiation Therapy Planning and Simulation

CPT code 77436 represents treatment planning and simulation–aided field setting for surface radiation therapy (SRT), a form of external beam radiation that uses low–energy X rays to treat cancers and other conditions on or near the skin surface. Nationally, accurate planning and simulation for SRT support precise field placement, reduce normal tissue exposure, and enable appropriate treatment delivery for dermatologic and superficial oncologic indications.

Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find clinical context for when planning is performed, the typical sites of service, and the operational role of CPT code 77436 in the radiation oncology service line. The publication covers benchmarks and policy-relevant considerations affecting coverage and coding practice, including payer coverage patterns, documentation expectations, and where CPT code 77436 fits with related radiation therapy services. It also highlights practical implications for billing workflows and payer communications. Data not available in the input where specific payer policy details, modifiers, taxonomies, ICD-10 pairings, and related codes are required.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicareCPT 77436surface radiation therapyradiation oncologytreatment planningsimulationexternal beam radiationSRToncology billingradiation therapy planning

Billing Code Overview

CPT code 77436 describes treatment planning and simulation–aided field setting for surface radiation therapy (SRT). This service involves planning the delivery of external beam radiation using low–energy X rays targeted to lesions on or near the skin surface. Planning typically includes determining the size, shape, and placement of radiation fields and may include imaging simulation to confirm accurate targeting.

Service Type: Radiation therapy planning and simulation for surface radiation therapy

Typical Site of Service: Radiation oncology clinic, hospital outpatient department, or freestanding radiation treatment center (procedures performed where external beam radiation equipment and simulation imaging are available)

Data not available in the input.

Clinical & Coding Specifications

Clinical Context

A typical patient is a 68-year-old with a superficial basal cell carcinoma on the nasal ala referred to radiation oncology after surgery was declined due to cosmesis and comorbidities. The outpatient workflow begins with a consultation by a radiation oncologist who reviews pathology, photographs the lesion, and determines that surface radiation therapy (SRT) is appropriate. On the simulation day the provider performs treatment planning and simulation–aided field setting (77436), which includes measuring the lesion, selecting applicator size, marking field borders, documenting set‑up photos, and optionally obtaining imaging or surface mapping to confirm beam geometry. The plan defines field size, depth, dose per fraction, total dose, and shielding or bolus needs. Following planning, treatment is delivered at subsequent visits using low‑energy X‑ray SRT applicators until the prescribed dose is completed. Typical site of service is an outpatient radiation oncology clinic or ambulatory procedure center equipped for superficial radiation therapy. Common patient considerations include prior surgeries, lesion location near sensitive structures (eyes, nose, ears), anticoagulation status, and mobility for positioning.

Coding Specifications

Modifier	Description	When to Use
`25`	Significant, separately identifiable evaluation and management service by the same physician on the day of a procedure	Use when a distinct E/M visit is performed the same day as for evaluation unrelated to routine preprocedural work

Taxonomy Code	Specialty	Notes
`207RC0000X`	Radiation Oncology	Primary specialty performing simulation and treatment planning for `77436`.
`208600000X`	Dermatology	Dermatologists may refer and co-manage superficial skin cancers treated with SRT; some dermatologic surgeons coordinate planning.
`363A00000X`	Radiation Therapist	Allied health professionals performing technical simulation and setup under physician direction.
`208500000X`	General Surgery	Surgeons may refer patients unsuitable for or refusing excision to radiation oncology for SRT.
`207L00000X`	Medical Oncology	Medical oncologists may be involved in multidisciplinary care when systemic therapy is relevant.

ICD-10 Code	Description	Clinical Relevance
`C44.311`	Basal cell carcinoma of right ala of nose	Superficial basal cell carcinomas of the nose are common indications for SRT planned with `77436`.
`C44.312`	Basal cell carcinoma of left ala of nose	Same as above for the left side; laterality guides RT field setting and modifier use.
`C44.219`	Squamous cell carcinoma of skin of trunk, unspecified	Superficial squamous cell cancers on the trunk may be treated with SRT when appropriate.
`C44.91`	Malignant neoplasm of unspecified skin, site unspecified	Represents cutaneous malignancies where SRT may be considered for superficial lesions.
`D22.9`	Melanocytic nevi, unspecified	Benign pigmented lesions are generally not treated with SRT but may appear in differential diagnosis during planning and localization.
`L57.0`	Actinic keratosis	Pre‑malignant superficial lesions sometimes treated with field therapies; included for clinical relevance during lesion assessment.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`77418`	Radiation treatment delivery, superficial and/or orthovoltage, per fraction	Delivers the prescribed superficial radiation fractions after planning and field setup performed with `77436`.
`77295`	Therapeutic radiology simulation-aided field setting, complex	Used for more complex simulation and field setting when three‑dimensional planning or more extensive immobilization/imaging is required compared with `77436`.
`77261`	Therapeutic radiology simulation-aided field setting, simple	Used for straightforward simulation that may be less involved than the planning described in `77436` depending on payer definitions.
`77300`	Ionizing radiation treatment delivery, simple; orthovoltage or superficial, per treatment session (technical component)	Technical delivery code that may be billed by the facility or technical provider for each treatment session following physician planning under `77436`.
`77336`	Continuing medical physics consultation, per week, when billed	Medical physics services that may support planning accuracy, dosimetry checks, or verification associated with SRT planning and delivery.

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