HCPCS C2634: Iodine-125 High-Activity Brachytherapy Source

HCPCS Level II code C2634 designates a high-activity, non-stranded iodine-125 brachytherapy source (greater than 1.01 mCi, NIST) billed per source. Brachytherapy sources like these are central to targeted radiation oncology treatments for certain cancers, offering highly localized dosing that can reduce exposure to surrounding healthy tissue. Nationally, accurate coding for these devices affects facility billing, device reimbursement, and tracking of high-cost implantable oncology supplies.

Key payers addressed in this analysis include Aetna, Blue Cross Blue Shield, Cigna, UnitedHealthcare, and Medicare. Readers will find a concise overview of the clinical context for C2634, how the code is used in procedural billing lines, and typical sites of service where these sources are supplied and implanted. The publication summarizes benchmark considerations, common billing modifiers used with HCPCS Level II codes, and policy updates that commonly influence coverage and payment for radioactive brachytherapy sources.

This resource is aimed at billing professionals, radiation oncology administrators, and policy analysts seeking a national-level briefing on coding, clinical use, and payer considerations related to HCPCS Level II code C2634.

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Billing Code Overview

HCPCS Level II code C2634 describes a brachytherapy source, non-stranded, high activity, iodine-125, greater than 1.01 mCi (NIST), per source. This item represents an individual sealed radioactive source used in brachytherapy procedures where iodine-125 seeds are implanted temporarily or permanently to deliver localized radiation.

Service Type: Brachytherapy radioactive source supply and implant

Typical Site of Service: Hospital outpatient departments, ambulatory surgery centers, and radiation oncology clinics

Data not available in the input.

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HCPCS C2634: Iodine-125 High-Activity Brachytherapy Source

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Billing Code Overview

Service Type: Brachytherapy radioactive source supply and implant

Typical Site of Service: Hospital outpatient departments, ambulatory surgery centers, and radiation oncology clinics

Data not available in the input.

Clinical & Coding Specifications

Clinical Context

A 68-year-old male with clinically localized prostate cancer is evaluated for definitive brachytherapy. After multidisciplinary review, the radiation oncology team schedules an intraoperative permanent seed implantation using high-activity non-stranded iodine-125 sources (C2634) to achieve the prescribed dose to the prostate while minimizing dose to the urethra and rectum. On the day of service the patient presents to an outpatient radiation oncology procedural suite or an operating room within a hospital, undergoes general or spinal anesthesia, transrectal ultrasound (TRUS) planning to map gland volume and needle trajectories, and real-time seed placement using ultrasound and/or intraoperative fluoroscopy. The billing for each high-activity, non-stranded iodine-125 source is reported per source using C2634. Typical clinical workflow steps: pre-procedure consent and treatment planning, anesthesia and patient positioning, intraoperative imaging and real-time dosimetry, transperineal needle insertion and seed deposition, postimplant imaging (CT or MRI) for verification, and routine postprocedure follow-up for urinary and sexual function monitoring.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`C61`	Malignant neoplasm of prostate	Primary indication for permanent iodine-125 seed brachytherapy
`D07.5`	Carcinoma in situ of prostate	May be considered in localized prostatic neoplastic management discussions though less common indication for seed implantation
`N40.0`	Benign prostatic hyperplasia with lower urinary tract symptoms	Frequently a comorbidity affecting perioperative urinary management and counseling
`N41.9`	Prostatitis, unspecified	May be relevant as a preexisting condition influencing infection risk and perioperative antibiotics
`Z12.5`	Encounter for screening for malignant neoplasm of prostate	Associated with diagnostic workflows leading to definitive treatment such as brachytherapy

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`55873`	Brachytherapy, insertion of radioactive source into prostate, interstitial (separate procedure)	Primary procedure code used for reporting the brachytherapy implantation service; `C2634` is billed per-source in addition to the professional/surgical CPT code
`77014`	Computed tomography guidance for localization and targeting during procedures (e.g., dosimetry verification)	Used when CT guidance or postimplant CT is performed for seed localization and dosimetric planning
`76937`	Ultrasound guidance for needle placement (e.g., prostate)	Used for intraoperative transrectal ultrasound guidance of needle placement and seed deposition
`77295`	Radiation physics consultation and treatment planning for brachytherapy (complex)	Used for detailed dosimetry, treatment planning, and physicist calculations associated with high-activity seed implants
`54300`	Implantation of radioactive material into prostate, interstitial (separate procedure—diagnostic or therapeutic)	Occasionally used in specific payer contexts for reporting prostate seed implant procedures alongside planning codes

Related Modifiers

12 rows

Modifier	Description	When to Use
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…
62	Modifier 62 indicates that two surgeons function as co‑surgeons, each performing distinct parts of the same primary surgical procedure. It is appended to the primary procedure code (and any…	- Use modifier -62 when two surgeons act as co‑surgeons (both primary surgeons) on a single definitive primary procedure, each performing distinct parts of the same surgical procedure (append -62 to…
80	CPT® Modifier 80 (Assistant Surgeon) is appended to a surgical CPT code when a physician (MD or DO) provides full, continuous assistance throughout the operative procedure. It is intended only for…	- Use CPT Modifier -80 when a physician (MD or DO) serves as an assistant surgeon and provides full, continuous assistance throughout the entire operative procedure; append -80 to the surgical CPT…
81	Modifier -81 indicates a physician served as a minimal assistant surgeon for part—not all—of an operative procedure. Use when a physician’s assisting role is limited and does not represent full…	- Use CPT modifier -81 when a physician acts as a minimum assistant surgeon who assists during only part (a limited portion) of an operative procedure; append -81 to the primary surgical CPT code to…
82	Modifier 82 is appended to a surgical CPT code to indicate that an attending physician acted as an assistant because a qualified resident surgeon was unavailable. In teaching hospitals it documents…	- When to use: Append modifier 82 in teaching-hospital settings to indicate a physician served as an assistant surgeon because a qualified resident surgeon was unavailable (includes situations where…
51	Modifier –51 (Multiple Procedures) is used when the same provider performs multiple procedures in the same session to identify secondary, non‑exempt procedures and indicate payment reduction logic…	- Use modifier -51 when the same provider performs multiple distinct procedures during the same patient encounter: report the highest‑valued procedure first (no modifier) and append -51 to…
52	Modifier ‑52 (Reduced Services) indicates that a service or procedure was partially reduced or omitted at the provider’s discretion, allowing reporting of the basic procedure number with a qualifier…	- Use modifier -52 when a physician or qualified health professional electively reduces or omits part of a procedure or service (for example, performing fewer required views or omitting a portion of…
53	Modifier 53 (Discontinued Procedure) signals that a surgical or diagnostic service was begun by the physician but terminated because of extenuating circumstances that threatened the patient’s…	- Use modifier -53 when a physician/qualified healthcare professional has started a surgical or diagnostic procedure (e.g., anesthesia administered, incision or scope insertion) and then discontinues…
22	Modifier –22 (Increased Procedural Services) is used when a reported procedure is substantially more extensive than normally required. The CPT Manual and CMS state it may be appended only when the…	- When to use: Append modifier -22 to a procedural CPT code when the service performed is substantially more extensive than the usual service described by that code — i.e., the procedure required…
23	Modifier -23 (Unusual Anesthesia) is used on anesthesia service CPT codes when a procedure that normally requires no anesthesia or only local anesthesia must be performed under general anesthesia…	- Use modifier -23 only on anesthesia CPT codes (00100–01999) when a procedure that normally requires no anesthesia or only local anesthesia must be performed under general anesthesia because of…

Showing 1–10 of 12

Related Provider Taxonomies

8 rows

Taxonomy Code	Specialty	Notes
208000000X	Pediatrics Physician	A pediatrician is concerned with the physical, emotional and social health of children from birth to young adulthood. Care encompasses a broad spectru…
207P00000X	Emergency Medicine Physician	An emergency physician focuses on the immediate decision making and action necessary to prevent death or any further disability both in the pre-hospit…
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…
207PT0002X	Medical Toxicology (Emergency Medicine) Physician	Medical toxicologists are physicians who specialize in the prevention, evaluation, treatment and monitoring of injury and illness from exposures to dr…
163WA2000X	Administrator Registered Nurse	Nursing Service Providers · Registered Nurse
341800000X	Military/U.S. Coast Guard Transport	Transportation Services · Military/U.S. Coast Guard Transport
1223D0001X	Public Health Dentistry	The science and art of preventing and controlling dental diseases and promoting dental health through organized community efforts. It is that form of…
224Y00000X	Clinical Exercise Physiologist	A Clinical Exercise Physiologist is a health care professional who is trained to work with patients with chronic disease where exercise training has b…

HCPCS Level II C1713: Implantable Anchor/Screw for Bone or Soft Tissue

HCPCS-C1714-TRANSLUMINAL-DIRECTIONAL-ATHERECTOMY-CATHETER

HCPCS C1714: Catheter, Transluminal Directional Atherectomy

HCPCS-C1715-BRACHYTHERAPY-NEEDLE

HCPCS C1715: Brachytherapy Needle

HCPCS-C1716-BRACHYTHERAPY-GOLD-198-SOURCE

HCPCS Level II C1716: Brachytherapy Source, Gold-198

HCPCS-C1717-HDR-BRACHYTHERAPY-IRIDIUM-192-SOURCE

HCPCS C1717: HDR Brachytherapy Iridium-192 Source

HCPCS-C1719-BRACHYTHERAPY-IRIDIUM-192-SOURCE-NON-STRANDED

HCPCS C1719: Brachytherapy Source, Iridium-192, Non-Stranded

HCPCS-C1721-IMPLANTABLE-DUAL-CHAMBER-CARDIOVERTER-DEFIBRILLATOR

HCPCS C1721: Implantable Dual-Chamber Cardioverter-Defibrillator

HCPCS-C1724-ROTATIONAL-TRANSLUMINAL-ATHERECTOMY-CATHETER

HCPCS C1724: Catheter for Transluminal Rotational Atherectomy

HCPCS-C1725-TRANSLUMINAL-ANGIOPLASTY-CATHETER-NON-LASER

HCPCS C1725: Transluminal Angioplasty Catheter, Non-Laser

HCPCS-C1726-NON-VASCULAR-BALLOON-DILATATION-CATHETER

HCPCS C1726: Catheter, Balloon Dilatation, Non-Vascular

Showing 1–10 of 603

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 Diagnoses

ICD-10 Code	Description	Clinical Relevance
`C61`	Malignant neoplasm of prostate	Primary indication for permanent iodine-125 seed brachytherapy
`D07.5`	Carcinoma in situ of prostate	May be considered in localized prostatic neoplastic management discussions though less common indication for seed implantation
`N40.0`	Benign prostatic hyperplasia with lower urinary tract symptoms	Frequently a comorbidity affecting perioperative urinary management and counseling
`N41.9`	Prostatitis, unspecified	May be relevant as a preexisting condition influencing infection risk and perioperative antibiotics
`Z12.5`	Encounter for screening for malignant neoplasm of prostate	Associated with diagnostic workflows leading to definitive treatment such as brachytherapy

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`55873`	Brachytherapy, insertion of radioactive source into prostate, interstitial (separate procedure)	Primary procedure code used for reporting the brachytherapy implantation service; `C2634` is billed per-source in addition to the professional/surgical CPT code
`77014`	Computed tomography guidance for localization and targeting during procedures (e.g., dosimetry verification)	Used when CT guidance or postimplant CT is performed for seed localization and dosimetric planning
`76937`	Ultrasound guidance for needle placement (e.g., prostate)	Used for intraoperative transrectal ultrasound guidance of needle placement and seed deposition
`77295`	Radiation physics consultation and treatment planning for brachytherapy (complex)	Used for detailed dosimetry, treatment planning, and physicist calculations associated with high-activity seed implants
`54300`	Implantation of radioactive material into prostate, interstitial (separate procedure—diagnostic or therapeutic)	Occasionally used in specific payer contexts for reporting prostate seed implant procedures alongside planning codes

Related Modifiers

12 rows

Modifier	Description	When to Use
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…
62	Modifier 62 indicates that two surgeons function as co‑surgeons, each performing distinct parts of the same primary surgical procedure. It is appended to the primary procedure code (and any…	- Use modifier -62 when two surgeons act as co‑surgeons (both primary surgeons) on a single definitive primary procedure, each performing distinct parts of the same surgical procedure (append -62 to…
80	CPT® Modifier 80 (Assistant Surgeon) is appended to a surgical CPT code when a physician (MD or DO) provides full, continuous assistance throughout the operative procedure. It is intended only for…	- Use CPT Modifier -80 when a physician (MD or DO) serves as an assistant surgeon and provides full, continuous assistance throughout the entire operative procedure; append -80 to the surgical CPT…
81	Modifier -81 indicates a physician served as a minimal assistant surgeon for part—not all—of an operative procedure. Use when a physician’s assisting role is limited and does not represent full…	- Use CPT modifier -81 when a physician acts as a minimum assistant surgeon who assists during only part (a limited portion) of an operative procedure; append -81 to the primary surgical CPT code to…
82	Modifier 82 is appended to a surgical CPT code to indicate that an attending physician acted as an assistant because a qualified resident surgeon was unavailable. In teaching hospitals it documents…	- When to use: Append modifier 82 in teaching-hospital settings to indicate a physician served as an assistant surgeon because a qualified resident surgeon was unavailable (includes situations where…
51	Modifier –51 (Multiple Procedures) is used when the same provider performs multiple procedures in the same session to identify secondary, non‑exempt procedures and indicate payment reduction logic…	- Use modifier -51 when the same provider performs multiple distinct procedures during the same patient encounter: report the highest‑valued procedure first (no modifier) and append -51 to…
52	Modifier ‑52 (Reduced Services) indicates that a service or procedure was partially reduced or omitted at the provider’s discretion, allowing reporting of the basic procedure number with a qualifier…	- Use modifier -52 when a physician or qualified health professional electively reduces or omits part of a procedure or service (for example, performing fewer required views or omitting a portion of…
53	Modifier 53 (Discontinued Procedure) signals that a surgical or diagnostic service was begun by the physician but terminated because of extenuating circumstances that threatened the patient’s…	- Use modifier -53 when a physician/qualified healthcare professional has started a surgical or diagnostic procedure (e.g., anesthesia administered, incision or scope insertion) and then discontinues…
22	Modifier –22 (Increased Procedural Services) is used when a reported procedure is substantially more extensive than normally required. The CPT Manual and CMS state it may be appended only when the…	- When to use: Append modifier -22 to a procedural CPT code when the service performed is substantially more extensive than the usual service described by that code — i.e., the procedure required…
23	Modifier -23 (Unusual Anesthesia) is used on anesthesia service CPT codes when a procedure that normally requires no anesthesia or only local anesthesia must be performed under general anesthesia…	- Use modifier -23 only on anesthesia CPT codes (00100–01999) when a procedure that normally requires no anesthesia or only local anesthesia must be performed under general anesthesia because of…

Showing 1–10 of 12

Related Provider Taxonomies

8 rows

Taxonomy Code	Specialty	Notes
208000000X	Pediatrics Physician	A pediatrician is concerned with the physical, emotional and social health of children from birth to young adulthood. Care encompasses a broad spectru…
207P00000X	Emergency Medicine Physician	An emergency physician focuses on the immediate decision making and action necessary to prevent death or any further disability both in the pre-hospit…
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…
207PT0002X	Medical Toxicology (Emergency Medicine) Physician	Medical toxicologists are physicians who specialize in the prevention, evaluation, treatment and monitoring of injury and illness from exposures to dr…
163WA2000X	Administrator Registered Nurse	Nursing Service Providers · Registered Nurse
341800000X	Military/U.S. Coast Guard Transport	Transportation Services · Military/U.S. Coast Guard Transport
1223D0001X	Public Health Dentistry	The science and art of preventing and controlling dental diseases and promoting dental health through organized community efforts. It is that form of…
224Y00000X	Clinical Exercise Physiologist	A Clinical Exercise Physiologist is a health care professional who is trained to work with patients with chronic disease where exercise training has b…

HCPCS Level II C1713: Implantable Anchor/Screw for Bone or Soft Tissue

HCPCS-C1714-TRANSLUMINAL-DIRECTIONAL-ATHERECTOMY-CATHETER

HCPCS C1714: Catheter, Transluminal Directional Atherectomy

HCPCS-C1715-BRACHYTHERAPY-NEEDLE

HCPCS C1715: Brachytherapy Needle

HCPCS-C1716-BRACHYTHERAPY-GOLD-198-SOURCE

HCPCS Level II C1716: Brachytherapy Source, Gold-198

HCPCS-C1717-HDR-BRACHYTHERAPY-IRIDIUM-192-SOURCE

HCPCS C1717: HDR Brachytherapy Iridium-192 Source

HCPCS-C1719-BRACHYTHERAPY-IRIDIUM-192-SOURCE-NON-STRANDED

HCPCS C1719: Brachytherapy Source, Iridium-192, Non-Stranded

HCPCS-C1721-IMPLANTABLE-DUAL-CHAMBER-CARDIOVERTER-DEFIBRILLATOR

HCPCS C1721: Implantable Dual-Chamber Cardioverter-Defibrillator

HCPCS-C1724-ROTATIONAL-TRANSLUMINAL-ATHERECTOMY-CATHETER

HCPCS C1724: Catheter for Transluminal Rotational Atherectomy

HCPCS-C1725-TRANSLUMINAL-ANGIOPLASTY-CATHETER-NON-LASER

HCPCS C1725: Transluminal Angioplasty Catheter, Non-Laser

HCPCS-C1726-NON-VASCULAR-BALLOON-DILATATION-CATHETER

HCPCS C1726: Catheter, Balloon Dilatation, Non-Vascular

Showing 1–10 of 603

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.

OpenPayer

HCPCS C2634: Iodine-125 High-Activity Brachytherapy Source

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Billing Code Overview

OpenPayer

HCPCS C2634: Iodine-125 High-Activity Brachytherapy Source

Sign up for hcpcs C2634 policy alerts

Billing Code Overview

Clinical & Coding Specifications

Clinical Context

Related Diagnoses

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related Codes

References

Clinical & Coding Specifications

Clinical Context

Related Diagnoses

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related Codes

References

HCPCS C2634: Iodine-125 High-Activity Brachytherapy Source

Sign up for hcpcs C2634 policy alerts

Billing Code Overview

HCPCS C2634: Iodine-125 High-Activity Brachytherapy Source

Sign up for hcpcs C2634 policy alerts

Billing Code Overview

Clinical & Coding Specifications

Clinical Context

Related Diagnoses

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related Codes

What does HCPCS C2634 describe and how is it reported?

How does C2634 relate to CPT procedure and ancillary codes?

Where and by which specialties is C2634 typically used?

Which modifiers are commonly used with C2634 billing?

What diagnoses and payers are referenced for C2634?

References

Clinical & Coding Specifications

Clinical Context

Related Diagnoses

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related Codes

What does HCPCS C2634 describe and how is it reported?

How does C2634 relate to CPT procedure and ancillary codes?

Where and by which specialties is C2634 typically used?

Which modifiers are commonly used with C2634 billing?

What diagnoses and payers are referenced for C2634?

References