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CPT 77438: Orthovoltage Surface Radiation Therapy, Single Fraction

CPT code 77438 designates a single-fraction surface radiation therapy (SRT) treatment delivered with orthovoltage X rays in the >150–500 kV range for skin cancers and other superficial lesions requiring penetration up to approximately 4 cm. Nationally, this code is relevant to oncology practices, dermatology clinics offering radiation therapy, and payers managing coverage for non-invasive treatment options that can avoid more extensive surgical procedures.

Key payers included in the analysis are Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of clinical context and service setting, typical payer coverage considerations, and benchmarking topics such as utilization patterns and reimbursement parameters where available. The publication summarizes how CPT code 77438 fits within the SRT and superficial radiation therapy service line and highlights common operational and billing touchpoints for one-fraction orthovoltage treatment.

Content covers clinical description, typical sites of service, common documentation elements needed to support medical necessity, and how this code is used in practice. Data not available in the input is noted where applicable.

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Billing Code Overview

CPT code 77438 describes a single-fraction delivery of surface radiation therapy (SRT) using orthovoltage X rays in the >150 to 500 kilovoltage (kV) range. This technique is intended for treatment of skin cancers and other superficial lesions that require somewhat deeper penetration than very superficial modalities; orthovoltage beams can penetrate up to about 4 cm from the skin surface.

Service type: Surface radiation therapy using orthovoltage X-ray beam for one treatment session (per fraction).
Typical site of service: Outpatient radiation oncology clinic or hospital outpatient department providing superficial/orthovoltage radiation treatments.

Data not available in the input.

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CPT 77438: Orthovoltage Surface Radiation Therapy, Single Fraction

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Billing Code Overview

Service type: Surface radiation therapy using orthovoltage X-ray beam for one treatment session (per fraction).
Typical site of service: Outpatient radiation oncology clinic or hospital outpatient department providing superficial/orthovoltage radiation treatments.

Data not available in the input.

Clinical & Coding Specifications

Clinical Context

A 72-year-old patient presents to a radiation oncology clinic with a biopsy-proven squamous cell carcinoma of the nasal ala measuring 1.8 cm in greatest diameter and extending into the superficial subcutaneous tissues. Given tumor depth (involving dermis and superficial subcutis) and location where cosmesis and tissue preservation are priorities, the multidisciplinary team elects orthovoltage surface radiation therapy. On the day of treatment, the patient is evaluated by the radiation oncologist, treatment field and applicator size are documented, immobilization and shielding are applied as needed, and a single fraction of orthovoltage kilovoltage X-ray therapy is delivered using the orthovoltage unit. Nursing documents patient tolerance and skin care instructions. Typical site of service is an outpatient radiation oncology department or hospital-based radiation therapy suite. The procedure represented by 77438 is performed when lesions require slightly deeper penetration than superficial SRT (up to ~4 cm) and when external beam megavoltage therapy is not necessary or when orthovoltage provides optimal dose distribution for skin and superficial subcutaneous tumors.

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 medically necessary E/M visit is performed and documented on the same day as `77438` distinct from the radiation treatment planning or delivery
`27`	Multiple outpatient hospital E&M encounters on the same date	Use when multiple distinct outpatient E/M encounters occur on the same date of service related to `77438` billing rules requiring `27`
`59`	Distinct procedural service	Use when `77438` is billed alongside another procedure on the same day that is distinct and separately reportable
`76`	Repeat procedure or service by same physician	Use when an orthovoltage treatment fraction (`77438`) is repeated the same day by the same provider
`77`	Repeat procedure by another physician	Use when a second physician repeats the treatment procedure on the same day
`RT`	Right side	Use to identify laterality when treatment is applied to a right-sided lesion
`LT`	Left side	Use to identify laterality when treatment is applied to a left-sided lesion
`GA`	Waiver of liability statement on file (ABN)	Use when the patient has signed an advance beneficiary notice for non-covered SRT services
`XE`	Separate encounter, a service that is distinct because it occurred during a separate encounter	Use for a distinct encounter related to `77438` when supported by documentation
`XP`	Separate practitioner, a service that is distinct because it was performed by a different practitioner	Use when portions of planning or delivery are performed by different practitioners and distinct billing is appropriate

Taxonomy Code	Specialty	Notes
`2085R0200X`	Radiation Oncology	Primary specialty delivering orthovoltage surface radiation therapy
`207L00000X`	Dermatology	Often involved in diagnosis and coordination for skin cancers treated with orthovoltage
`207P00000X`	Dermatopathology	Performs diagnostic biopsies and pathology that guide use of `77438`
`201Q00000X`	Internal Medicine - Oncology	Medical oncologists involved in multidisciplinary care for complex skin cancers
`363A00000X`	Radiation Therapist	Allied professional who delivers the orthovoltage treatment under supervision

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`C44.311`	Basal cell carcinoma of right upper eyelid, including canthus	Common cutaneous malignancy treated with orthovoltage for deeper superficial tumors in delicate sites
`C44.321`	Basal cell carcinoma of left upper eyelid, including canthus	As above; laterality is relevant for documentation and modifier reporting
`C44.511`	Squamous cell carcinoma of right lower eyelid, including canthus	Squamous cell carcinomas of the skin often require radiation when surgery is not feasible or for margin-positive disease
`C44.612`	Squamous cell carcinoma of left unspecified ear	Lesions in complex anatomic sites may be treated with orthovoltage to spare deeper structures
`C44.90`	Skin cancer, unspecified, site unspecified	Used when site-specific code is not yet determined or when billing requires a general skin cancer diagnosis
`D04.9`	Carcinoma in situ of skin, unspecified	In situ lesions with limited invasion may be treated with surface radiation techniques including orthovoltage
`L91.8`	Other hypertrophic disorders of skin	Occasionally used for benign but symptomatic hypertrophic lesions considered for radiation when indicated

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`77300`	Special medical radiation physics consultation, for therapy service, including chart review	Performed prior to or during treatment planning when complex dosimetry or special considerations for orthovoltage are required
`77336`	Continuing medical physics consultation, technical direction and planning for radiation treatment delivery	Used for ongoing physics oversight during a course of radiation therapy that may include orthovoltage fractions
`77427`	Radiation treatment management, 5 treatments	Used to report radiation treatment management for a portion of a course of therapy; orthovoltage fractions such as `77438` are part of the overall management series
`17000`	Destruction of premalignant lesions (e.g., topical procedures) ; first lesion	May be performed for superficial lesions in the same patient but is an alternative local therapy rather than combined with `77438`
`11102`	Tangential biopsy of skin lesion including closure, when performed for diagnosis	May be performed prior to `77438` to obtain definitive histologic diagnosis supporting radiation therapy
`77499`	Unlisted radiation procedure	Used only when a specific orthovoltage-related service cannot be reported by an established code; not routine for standard `77438` delivery

CPT 77427: Radiation Therapy Management, External Beam

CPT-77431-RADIOTHERAPY-MANAGEMENT-ONE-TWO-FRACTION-COURSE

CPT 77431: Radiotherapy Management for One- or Two-Fraction Courses

CPT-77432-SINGLE-SESSION-STEREOTACTIC-RADIOSURGERY-PROFESSIONAL

CPT 77432: Single-Session Stereotactic Radiosurgery, Professional Component

CPT-77435-STEREOTACTIC-BODY-RADIOTHERAPY-TREATMENT-MANAGEMENT

CPT 77435: Stereotactic Body Radiotherapy Treatment Management

CPT-77437-SUPERFICIAL-RADIATION-THERAPY-PER-FRACTION

CPT 77437: Surface Radiation Therapy (Superficial) Per Fraction

CPT-77439-ULTRASOUND-GUIDED-SRT-FIELD-PLACEMENT

CPT 77439: Ultrasound Guidance for Surface Radiation Therapy Field Placement

CPT-77469-INTRAOPERATIVE-RADIATION-THERAPY-IORT-DURING-SURGERY

CPT 77469: Intraoperative Radiation Therapy during Surgery

CPT-77470-SPECIAL-RADIOTHERAPY-MANAGEMENT

CPT 77470: Special Radiotherapy Procedure Management

CPT-77499-UNLISTED-THERAPEUTIC-RADIOLOGY-TREATMENT-MANAGEMENT

CPT 77499: Unlisted Therapeutic Radiology Treatment Management

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.

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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
`25`	Significant, separately identifiable evaluation and management service by the same physician on the day of a procedure	Use when a medically necessary E/M visit is performed and documented on the same day as `77438` distinct from the radiation treatment planning or delivery
`27`	Multiple outpatient hospital E&M encounters on the same date	Use when multiple distinct outpatient E/M encounters occur on the same date of service related to `77438` billing rules requiring `27`
`59`	Distinct procedural service	Use when `77438` is billed alongside another procedure on the same day that is distinct and separately reportable
`76`	Repeat procedure or service by same physician	Use when an orthovoltage treatment fraction (`77438`) is repeated the same day by the same provider
`77`	Repeat procedure by another physician	Use when a second physician repeats the treatment procedure on the same day
`RT`	Right side	Use to identify laterality when treatment is applied to a right-sided lesion
`LT`	Left side	Use to identify laterality when treatment is applied to a left-sided lesion
`GA`	Waiver of liability statement on file (ABN)	Use when the patient has signed an advance beneficiary notice for non-covered SRT services
`XE`	Separate encounter, a service that is distinct because it occurred during a separate encounter	Use for a distinct encounter related to `77438` when supported by documentation
`XP`	Separate practitioner, a service that is distinct because it was performed by a different practitioner	Use when portions of planning or delivery are performed by different practitioners and distinct billing is appropriate

Taxonomy Code	Specialty	Notes
`2085R0200X`	Radiation Oncology	Primary specialty delivering orthovoltage surface radiation therapy
`207L00000X`	Dermatology	Often involved in diagnosis and coordination for skin cancers treated with orthovoltage
`207P00000X`	Dermatopathology	Performs diagnostic biopsies and pathology that guide use of `77438`
`201Q00000X`	Internal Medicine - Oncology	Medical oncologists involved in multidisciplinary care for complex skin cancers
`363A00000X`	Radiation Therapist	Allied professional who delivers the orthovoltage treatment under supervision

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`C44.311`	Basal cell carcinoma of right upper eyelid, including canthus	Common cutaneous malignancy treated with orthovoltage for deeper superficial tumors in delicate sites
`C44.321`	Basal cell carcinoma of left upper eyelid, including canthus	As above; laterality is relevant for documentation and modifier reporting
`C44.511`	Squamous cell carcinoma of right lower eyelid, including canthus	Squamous cell carcinomas of the skin often require radiation when surgery is not feasible or for margin-positive disease
`C44.612`	Squamous cell carcinoma of left unspecified ear	Lesions in complex anatomic sites may be treated with orthovoltage to spare deeper structures
`C44.90`	Skin cancer, unspecified, site unspecified	Used when site-specific code is not yet determined or when billing requires a general skin cancer diagnosis
`D04.9`	Carcinoma in situ of skin, unspecified	In situ lesions with limited invasion may be treated with surface radiation techniques including orthovoltage
`L91.8`	Other hypertrophic disorders of skin	Occasionally used for benign but symptomatic hypertrophic lesions considered for radiation when indicated

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`77300`	Special medical radiation physics consultation, for therapy service, including chart review	Performed prior to or during treatment planning when complex dosimetry or special considerations for orthovoltage are required
`77336`	Continuing medical physics consultation, technical direction and planning for radiation treatment delivery	Used for ongoing physics oversight during a course of radiation therapy that may include orthovoltage fractions
`77427`	Radiation treatment management, 5 treatments	Used to report radiation treatment management for a portion of a course of therapy; orthovoltage fractions such as `77438` are part of the overall management series
`17000`	Destruction of premalignant lesions (e.g., topical procedures) ; first lesion	May be performed for superficial lesions in the same patient but is an alternative local therapy rather than combined with `77438`
`11102`	Tangential biopsy of skin lesion including closure, when performed for diagnosis	May be performed prior to `77438` to obtain definitive histologic diagnosis supporting radiation therapy
`77499`	Unlisted radiation procedure	Used only when a specific orthovoltage-related service cannot be reported by an established code; not routine for standard `77438` delivery

CPT 77427: Radiation Therapy Management, External Beam

CPT-77431-RADIOTHERAPY-MANAGEMENT-ONE-TWO-FRACTION-COURSE

CPT 77431: Radiotherapy Management for One- or Two-Fraction Courses

CPT-77432-SINGLE-SESSION-STEREOTACTIC-RADIOSURGERY-PROFESSIONAL

CPT 77432: Single-Session Stereotactic Radiosurgery, Professional Component

CPT-77435-STEREOTACTIC-BODY-RADIOTHERAPY-TREATMENT-MANAGEMENT

CPT 77435: Stereotactic Body Radiotherapy Treatment Management

CPT-77437-SUPERFICIAL-RADIATION-THERAPY-PER-FRACTION

CPT 77437: Surface Radiation Therapy (Superficial) Per Fraction

CPT-77439-ULTRASOUND-GUIDED-SRT-FIELD-PLACEMENT

CPT 77439: Ultrasound Guidance for Surface Radiation Therapy Field Placement

CPT-77469-INTRAOPERATIVE-RADIATION-THERAPY-IORT-DURING-SURGERY

CPT 77469: Intraoperative Radiation Therapy during Surgery

CPT-77470-SPECIAL-RADIOTHERAPY-MANAGEMENT

CPT 77470: Special Radiotherapy Procedure Management

CPT-77499-UNLISTED-THERAPEUTIC-RADIOLOGY-TREATMENT-MANAGEMENT

CPT 77499: Unlisted Therapeutic Radiology Treatment Management

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.

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CPT 77438: Orthovoltage Surface Radiation Therapy, Single Fraction

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Billing Code Overview

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CPT 77438: Orthovoltage Surface Radiation Therapy, Single Fraction

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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