CPT 77439: Ultrasound-Guided SRT Field Localization for Cutaneous Tumors

Medicare pays $17 on average nationally for this procedure.

CPT code 77439 describes ultrasound guidance used to localize and define surface radiation therapy (SRT) treatment fields for cutaneous tumors; the service type is image-guided localization for SRT and the typical site of service is a radiation oncology clinic or outpatient treatment facility, reported once per course of treatment in addition to the primary SRT delivery code.

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CPT 77439: Ultrasound-Guided SRT Field Localization for Cutaneous Tumors

Medicare pays $17 on average nationally for this procedure.

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Get alerted when payer policies referencing 77439 are released or updated.

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Clinical & Coding Specifications

Clinical Context

A typical patient is an adult with a biopsy-proven primary cutaneous malignancy such as basal cell carcinoma, squamous cell carcinoma, or early-stage cutaneous melanoma located on a cosmetically sensitive area (face, ear, scalp). The patient is referred to a dermatologic radiation oncology or surface radiation therapy (SRT) clinic for definitive superficial radiation therapy when surgery is contraindicated, declined, or would cause unacceptable functional/cosmetic outcomes.

The clinical workflow begins with consultation, review of the pathology report and lesion mapping, and determination of candidacy for SRT. Prior to the first SRT delivery session, the provider performs ultrasound imaging to identify tumor depth and lateral extent, mark field boundaries, and select applicator size and energy. Ultrasound-guided field placement is performed once per course of treatment and documented in the medical record, including images, measurements, and justification for field selection. The primary SRT delivery code(s) are billed separately for each treatment fraction; 77439 is reported a single time per course in addition to the primary delivery service code. Care coordination includes informed consent, simulation/planning notes, treatment delivery records, and follow-up visits to assess response and toxicity.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`77401`	Superficial radiation treatment delivery, small field, 1 fraction	One of the common SRT delivery codes billed per fraction for superficial lesions; billed separately from `77439`.
`77402`	Superficial radiation treatment delivery, intermediate field, 1 fraction	Alternative SRT delivery code for intermediate field size; each fraction billed in addition to the single `77439` per course.
`77403`	Superficial radiation treatment delivery, large field, 1 fraction	Used for larger treatment fields; delivered fractions billed alongside the once-per-course `77439`.
`76937`	Ultrasound guidance for placement of radiation therapy fields	Related ultrasound guidance code for some payers; `77439` specifically describes ultrasound guidance for SRT and is reported once per course in addition to the primary SRT delivery code.
`77295`	Radiation therapy plan, complex	May be used when more complex treatment planning is required prior to SRT; complements the field placement documentation though typically used for external beam planning.

Related Modifiers

6 rows

Modifier	Description	When to Use
25	CPT modifier 25 indicates that on the same day as another procedure or service, the same physician or other qualified health care professional provided a significant, separately identifiable…	- When to apply: Use modifier 25 only on an E/M code to indicate the same provider delivered a significant, separately identifiable E/M service on the same day as another procedure or service — i.e.,…
59	Modifier 59 indicates a distinct procedural service when two procedures that are not normally billed together are clinically and procedurally separate. The CPT definition (as reiterated by CMS)…	- Use modifier -59 to report a distinct procedural service when documentation supports that the procedure reported is not normally billed together with another service on the same day because of a…
76	Modifier -76, Repeat Procedure or Service by Same Physician or Other Qualified Health Care Professional, is appended when the same provider performs an identical, medically necessary procedure or…	- Use modifier -76 when the same physician or other qualified health care professional performs an identical procedure or service a second (or subsequent) time on the same date of service and the…
77	Modifier 77 indicates that a previously performed procedure or service was legitimately repeated by a different physician or other qualified health care professional. The AMA’s CPT definition…	- Use modifier 77 when a basic procedure or service already performed is repeated by a different physician or other qualified health care professional (for example, a second provider independently…
79	Modifier 79 indicates a surgical procedure performed during the postoperative global period of a prior surgery that is unrelated to the original procedure. Per AMA/CPT and CMS guidance, it is…	- Use modifier 79 when the same physician (or same‑specialty physician in the same group) performs a surgical procedure during the postoperative global period of a prior surgery and the new procedure…
26	Modifier 26 (Professional Component) identifies and bills only the professional portion of a split service — the physician’s interpretation, report, and medical judgment — when the technical…	- Use CPT Modifier -26 when you are billing only the professional component (PC) of a split‑bill eligible service—i.e., you performed the physician interpretation, medical judgment and prepared a…

Related Provider Taxonomies

8 rows

Taxonomy Code	Specialty	Notes
207N00000X	Dermatology Physician	A dermatologist is trained to diagnose and treat pediatric and adult patients with benign and malignant disorders of the skin, mouth, external genital…
2080P0207X	Pediatric Hematology & Oncology Physician	A pediatrician trained in the combination of pediatrics, hematology and oncology to recognize and manage pediatric blood disorders and cancerous disea…
363L00000X	Nurse Practitioner	(1) A registered nurse provider with a graduate degree in nursing prepared for advanced practice involving independent and interdependent decision mak…
363A00000X	Physician Assistant	A physician assistant is a person who has successfully completed an accredited education program for physician assistant, is licensed by the state and…
111NN1001X	Nutrition Chiropractor	Chiropractic Nutrition is that specialty within the chiropractic profession that deals with the overall factors that affect the patient's ability to m…
363LA2200X	Adult Health Nurse Practitioner	Physician Assistants & Advanced Practice Nursing Providers · Nurse Practitioner
261QM1000X	Migrant Health Clinic/Center	Ambulatory Health Care Facilities · Clinic/Center
163WN0003X	Low-Risk Neonatal Registered Nurse	Nursing Service Providers · Registered Nurse

CPT 77427: Radiation Treatment Management

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

CPT 77431: Management of Short-Course Fractionated Radiotherapy

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

CPT 77432: Stereotactic Radiosurgery, Single Session (Professional Component)

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

CPT 77435: Stereotactic Body Radiotherapy Course (≤5 Fractions)

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

CPT 77437: Superficial Radiation Therapy, Per Fraction

CPT-77438-ORTHOVOLTAGE-SURFACE-RADIATION-THERAPY-SINGLE-FRACTION

CPT 77438: Orthovoltage Surface Radiation Therapy, Single Fraction

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

CPT 77469: Intraoperative Radiation Therapy Management

CPT-77470-SPECIAL-RADIOTHERAPY-MANAGEMENT

CPT 77470: Special Radiotherapy Procedures Requiring Additional Management

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

CPT 77499: Therapeutic Radiology Treatment Management, Unlisted

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.

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Clinical & Coding Specifications

Clinical Context

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`77401`	Superficial radiation treatment delivery, small field, 1 fraction	One of the common SRT delivery codes billed per fraction for superficial lesions; billed separately from `77439`.
`77402`	Superficial radiation treatment delivery, intermediate field, 1 fraction	Alternative SRT delivery code for intermediate field size; each fraction billed in addition to the single `77439` per course.
`77403`	Superficial radiation treatment delivery, large field, 1 fraction	Used for larger treatment fields; delivered fractions billed alongside the once-per-course `77439`.
`76937`	Ultrasound guidance for placement of radiation therapy fields	Related ultrasound guidance code for some payers; `77439` specifically describes ultrasound guidance for SRT and is reported once per course in addition to the primary SRT delivery code.
`77295`	Radiation therapy plan, complex	May be used when more complex treatment planning is required prior to SRT; complements the field placement documentation though typically used for external beam planning.

Related Modifiers

6 rows

Modifier	Description	When to Use
25	CPT modifier 25 indicates that on the same day as another procedure or service, the same physician or other qualified health care professional provided a significant, separately identifiable…	- When to apply: Use modifier 25 only on an E/M code to indicate the same provider delivered a significant, separately identifiable E/M service on the same day as another procedure or service — i.e.,…
59	Modifier 59 indicates a distinct procedural service when two procedures that are not normally billed together are clinically and procedurally separate. The CPT definition (as reiterated by CMS)…	- Use modifier -59 to report a distinct procedural service when documentation supports that the procedure reported is not normally billed together with another service on the same day because of a…
76	Modifier -76, Repeat Procedure or Service by Same Physician or Other Qualified Health Care Professional, is appended when the same provider performs an identical, medically necessary procedure or…	- Use modifier -76 when the same physician or other qualified health care professional performs an identical procedure or service a second (or subsequent) time on the same date of service and the…
77	Modifier 77 indicates that a previously performed procedure or service was legitimately repeated by a different physician or other qualified health care professional. The AMA’s CPT definition…	- Use modifier 77 when a basic procedure or service already performed is repeated by a different physician or other qualified health care professional (for example, a second provider independently…
79	Modifier 79 indicates a surgical procedure performed during the postoperative global period of a prior surgery that is unrelated to the original procedure. Per AMA/CPT and CMS guidance, it is…	- Use modifier 79 when the same physician (or same‑specialty physician in the same group) performs a surgical procedure during the postoperative global period of a prior surgery and the new procedure…
26	Modifier 26 (Professional Component) identifies and bills only the professional portion of a split service — the physician’s interpretation, report, and medical judgment — when the technical…	- Use CPT Modifier -26 when you are billing only the professional component (PC) of a split‑bill eligible service—i.e., you performed the physician interpretation, medical judgment and prepared a…

Related Provider Taxonomies

8 rows

Taxonomy Code	Specialty	Notes
207N00000X	Dermatology Physician	A dermatologist is trained to diagnose and treat pediatric and adult patients with benign and malignant disorders of the skin, mouth, external genital…
2080P0207X	Pediatric Hematology & Oncology Physician	A pediatrician trained in the combination of pediatrics, hematology and oncology to recognize and manage pediatric blood disorders and cancerous disea…
363L00000X	Nurse Practitioner	(1) A registered nurse provider with a graduate degree in nursing prepared for advanced practice involving independent and interdependent decision mak…
363A00000X	Physician Assistant	A physician assistant is a person who has successfully completed an accredited education program for physician assistant, is licensed by the state and…
111NN1001X	Nutrition Chiropractor	Chiropractic Nutrition is that specialty within the chiropractic profession that deals with the overall factors that affect the patient's ability to m…
363LA2200X	Adult Health Nurse Practitioner	Physician Assistants & Advanced Practice Nursing Providers · Nurse Practitioner
261QM1000X	Migrant Health Clinic/Center	Ambulatory Health Care Facilities · Clinic/Center
163WN0003X	Low-Risk Neonatal Registered Nurse	Nursing Service Providers · Registered Nurse

CPT 77427: Radiation Treatment Management

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

CPT 77431: Management of Short-Course Fractionated Radiotherapy

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

CPT 77432: Stereotactic Radiosurgery, Single Session (Professional Component)

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

CPT 77435: Stereotactic Body Radiotherapy Course (≤5 Fractions)

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

CPT 77437: Superficial Radiation Therapy, Per Fraction

CPT-77438-ORTHOVOLTAGE-SURFACE-RADIATION-THERAPY-SINGLE-FRACTION

CPT 77438: Orthovoltage Surface Radiation Therapy, Single Fraction

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

CPT 77469: Intraoperative Radiation Therapy Management

CPT-77470-SPECIAL-RADIOTHERAPY-MANAGEMENT

CPT 77470: Special Radiotherapy Procedures Requiring Additional Management

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

CPT 77499: Therapeutic Radiology Treatment Management, Unlisted

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.

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 77439: Ultrasound-Guided SRT Field Localization for Cutaneous Tumors

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CPT 77439: Ultrasound-Guided SRT Field Localization for Cutaneous Tumors

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Clinical & Coding Specifications

Clinical Context

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related Codes

References

Clinical & Coding Specifications

Clinical Context

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related Codes

References

CPT 77439: Ultrasound-Guided SRT Field Localization for Cutaneous Tumors

Sign up for cpt 77439 policy alerts

CPT 77439: Ultrasound-Guided SRT Field Localization for Cutaneous Tumors

Sign up for cpt 77439 policy alerts

Clinical & Coding Specifications

Clinical Context

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related Codes

How often can I bill CPT 77439 during a course of SRT?

Which modifiers are commonly applicable to 77439 and when should they be used?

What documentation is expected when reporting 77439?

In what clinical scenarios is 77439 typically used?

Which specialties and settings commonly bill CPT 77439?

References

Clinical & Coding Specifications

Clinical Context

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related Codes

How often can I bill CPT 77439 during a course of SRT?

Which modifiers are commonly applicable to 77439 and when should they be used?

What documentation is expected when reporting 77439?

In what clinical scenarios is 77439 typically used?

Which specialties and settings commonly bill CPT 77439?

References