Radiation Oncology

Radiation Oncology is the medical use of ionizing radiation and part of a precise cancer treatment to control or kill malignant cells and certain non-malignant conditions. It involves a specially-trained team of professionals performing everything from Evaluation and Management (E/M) visits to weekly Radiation Treatments. Radiation therapy, radiotherapy or radiation oncology is often abbreviated RT, RTx, or XRT.

The treatment goal is to deliver the patient their prescribed amount of radiation to the cancerous tumor; while limiting the amount absorbed by the surrounding healthy and critical organs.

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A patient must have an E/M office visit or hospital consultation (CPTs 99201-99233) to prepare for treatment; clinical planning and simulation (CPTs 77261-77290). There are many treatment devices and special services (CPTs 77295-77370), along with placement guidance codes (HCPCS G6001, G6002) and radiation treatment delivery codes (HCPCS G6003-G6016). Then, the weekly radiation therapy management (CPTs 77427-77432) and any follow-up.

Covered in many place of service (POS) areas

  • Office, Freestanding Radiation Oncology Center, or Radiation Therapy Center (RTC) (POS 11)
  • Outpatient hospital - off campus (POS 19)
  • Inpatient hospital (POS 21)
  • Outpatient hospital - on campus (POS 22)
  • Ambulatory Surgical Center (ASC) (POS 24)

National Correct Coding Initiative (NCCI) is important to know and Noridian advises checking all codes billed on the same day, against the CCI edits. If the second column code is bundled into the first column with a zero (0) indicator, providers cannot bill Medicare or the patient. Watch Medically Unlikely Edits (MUEs) with MUE Adjustment Indicator (MAI); e.g., MAI-two (2) = Date of Service Edit: Policy Code Descriptor / CPT Instruction

Clinical Treatment Planning CPTs 77261 - 77263

CPT Code Description
77261 Simple planning requires a single treatment area of interest encompassed in a single port or simple parallel opposed ports with simple or no blocking
77262 Intermediate planning requires 3 or more converging ports, 2 separate treatment areas, multiple blocks, or special time dose constraints
77263 Complex planning requires highly complex blocking, custom shielding blocks, tangential ports, special wedges or compensators, 3 or more separate treatment areas, rotational or special beam considerations, combination of therapeutic modalities


Treatment Simulation CPTs 77280 - 77293

  • Typical course of radiation therapy will require between one and three simulations
    • No more than one simulation reported any given day
  • Treatment area(s) simulation-aided field settings following planning
    • Not for treatment field verification or billed as sole modality
  • Directs treatment beams with diagnostic imaging (e.g., MRI), radiation therapy (linear accelerator) or CT scanner
CPT Code Description
77280 Simple - single treatment with either a single port or parallel opposed ports
77285 Intermediate - 2 treatment areas, 3 or more converging ports, multiple blocks
77290 Complex - 3 or more treatment areas simulation of tangential portals, 3 or more treatment areas, rotation or arc therapy, complex blocking, custom shielding blocks, brachytherapy source verification, hyperthermia probe verification, any use of contrast materials
+77293 Add on code for respiratory motion management simulation-physician work


Dosimetry CPTs 77300 – 77301

  • As required during course of treatment; only when prescribed by treating physician
  • Unique/distinct/basic dosimetry calculations reported one (1) - six (6) times
  • 8 or more for head/neck, Hodgkin's, prostate, etc.
  • Separate claim for basic dosimetry (CPT 77300) when distinct service, prescribed by treating physician, over/above part of IMRT 77301 plan, and outside parameters
  • Separate step in process of care for IMRT

If anatomy changes (e.g., tumor shrinkage), another IMRT may be charged if advanced imaging (PET, MRI, CT) used

CPT Code Description
77300 Basic radiation dosimetry calculation
77301 IMRT plan, including dose-volume histograms for target and critical structure partial tolerance specifications


Isodose/Port Plan CPTs 77306, 77307, 77321

  • Dose calculations (77300) cannot be charged with these plans
CPT Code Description
77306 Simple plan; one or two unmodified ports; includes basic dosimetry calculations
77307 Complex plan; multiple treatment areas (including tangential ports, the use of wedges, blocking, rotational beams or special beam considerations) used and includes basic dosimetry calculations
77321 Special teletherapy port plan, particles, hemi- or total body with only one plan billed per treatment course


Radiation Physics CPTs 77300 - 77334

  • Includes both professional (-26) and technical (-TC) components
  • Radiation dosimetry calculations allowed if physician personally performs service or participated
    • E.g., review/validate physicist's calculation
  • 77261-77334 performed before treatment starts

Treatment Devices CPTs 77332 - 77334

  • May include metal or electronic inserts, wedges, or casts
  • Use of passive restraints such as straps, pillows, sandbags, etc., not billable
CPT Code Description
77332 Treatment devices, design and construction; simple (simple block, simple bolus) E.g., Pre-made electron block, Breast board, "Standard" bolus (simple beam modification device
77333 Treatment devices, design and construction; intermediate (multiple blocks, stents, bite blocks, special bolus) E.g., Bite block, Customized bolus
77334 Treatment devices, design and construction; complex (irregular blocks, special shields, compensators, etc.) E.g., Alpha cradles, Vac-Lok™, Aquaplast Mask or any of the MLCs or both custom shields or custom molds


Medical Physics Consults CPTs 77336 and 77370

  • Represents physician's (e.g., radiation oncologist, radiologist) care involvement
  • Specific to weekly radiation treatment plan review
  • Weekly physics before radiation treatment
CPT Code Description
77336 Continuing medical physics consult once per one (1) - five (5) fractions of external beam
77370 Special medical physics consult once per treatment course


Treatment Delivery HCPCS G6015, G6016, G6017

  • Determine treatment energy level in megavolt (MV)
  • CPT 77301 not billed same day as HCPCS G6015-G6016 (unless IMRT has additional modality in conjunction)
  • Both allowed same day as IMRT simulation/treatment  
  • Replaced CPTs 77385-77386 (status I codes)
  • HCPCS G6017 part of Image Guided Radiation Therapy (IGRT) - may not bill in facility or outpatient POS 22
HCPCS Code Description
G6015 Multi-leaf collimator (MLC) delivery
G6016 Solid compensator-based delivery
G6017 Intra-fraction localization, tracking of target and patient motion during delivery of radiation therapy (e.g., 3D positional tracking, gating, 3D surface tracking); each fraction of treatment


Image-Guided Radiation Therapy (IGRT) HCPCS G6001, G6002, CPT 77014

  • Modifies treatment delivery for intended target position changes - distinct service
  • Billed with IMRT or treatment delivery codes
CPT/HCPCS Code Description
G6001 Ultrasonic guidance for placement of radiation therapy fields
G6002 Stereoscopic X-ray guidance for localization of target volume-delivery of radiation therapy
77014 Computed tomography guidance for placement of radiation therapy fields (replaced 76370)


Radiation Treatment Management CPTs 77417 – 77431

  • CPT 77417 allowed weekly as technical-only code that ensures correct treatment setup
  • CPT 77427 weekly units of five (5) fractions or treatment sessions regardless of actual time furnished; don't need billing on consecutive days
    • Timeframe is usually five (5) - seven (7) days and reflected in comment or narrative field of claim
  • CPT 77431 covers entire treatment course, if only one (1) or two (2) fractions; physician reports fractions in narrative
CPT Code Description
77417 Therapeutic radiology port images or port films
77427 Treatment management, 1-5 treatments
77431 Treatment management, 1-2 fractions


Billing Tips

  • No modifiers between physician supervisory levels
  • If either radiation oncologist or neurosurgeon not fully participating in patient's care
    • One physician indicates 54 modifier (surgical care only) and another bills with 55 modifier (postoperative management only) for global days with NOS = 1 and date span in Item 19 narrative
    • Number of service (NOS) one (1) (up to 5 fractions)
  • Date of Service (DOS) or date range (Item 24A of CMS-1500 claim form)
  • Date range billed variety of ways and fractions reflected in narrative (Item 19 of CMS-1500 claim form or electronic NTE 02)
    • First or last treatment date
  • More than one set of treatments per day? NOS = 2 and narrative reflects one of the following:
    • AM/PM treatments
    • Eight (8), nine (9) or 10 fractions
    • BID or twice a day
  • Treatment course end? List final three (3) or final four (4) fractions in narrative
    • Six (6) or seven (7) fractions NOT common; however, allowed
  • CPTs 77401-77416 also for External Beam Therapy
  • If billing E/M visits or the weekly radiation codes the same day; never append modifier 59

Radiation Therapy Treatment bundles the following services:

Anesthesia, infected skin care, checking treatment charts, dosage verification, final physical exam, nutritional counseling, pain management, review/revision of treatment plan, routine medical management unrelated, special ostomy care, written reports, progress note, follow-up exam/care for 90-days, etc. CPT codes include (not all inclusive):

  • 11920-11922, 16000-16030, 36425, 53670, 53675, 90780-90781, 90847, 99211-99285, 99050-99080, and 99371-99373

Miscellaneous bundling includes CPTs 77014, 77280, 77285, 77290, 77295, 77306 - 77321, 77331, and 77370 and should not be reported on the same date of service (DOS) as IMRT planning or in addition to CPT 77301 when provided prior to or as a part of the IMRT plan development.

  • CPTs 77306, 77307, and 77321 bills only when applying to another modality
    • E.g., accompanying boost with external beam

CPT 77338 multi-leaf collimator (MLC) device for IMRT design/construction/plan reported once per IMRT plan

  • Not in conjunction with HCPCS G6016 (compensator-based IMRT delivery)

Stereotactic Body Radiation Therapy (SBRT)

Stereotactic body radiation therapy (SBRT) is a treatment that couples a high degree of anatomic targeting accuracy with very high doses of extremely precise, externally generated, ionizing radiation; thereby, maximizing the cell-killing effect on the target(s), while minimizing radiation-related injury in adjacent normal tissues. It's also a method of delivering high doses of ionizing radiation to small intra-cranial targets when applied to "cranial lesions only."

All SBRT is performed with at least one form of image guidance to confirm proper patient positioning and tumor localization (CT/MR/PET imaging-based systems or advanced imaging). Since the goal of SBRT is to intensify the potency of the radiotherapy by completing an entire course of treatment within an extremely accelerated time frame, any course of radiation treatment extending beyond five fractions is not considered SBRT and is not to be billed.

When billing for SBRT delivery, it is not appropriate to bill more than one treatment delivery code on the same day of service, even though some types of delivery may have elements of several modalities (for example, an IMRT stereotactic approach. Only one delivery code is to be billed and this includes image guidance.

  • CPT 77373 paid only once per day of treatment regardless of number of sessions or lesions
  • CPT 77432 paid only once per course of treatment regardless of number of cranial (and spinal) lesions
  • CPT 77435 paid only once per course of treatment of SBRT

Both CPTs 77432 and 77435 cannot be billed during the same course of therapy.

Stereotactic Radiosurgery (SRS)

  • Distinct discipline as high-resolution imaging
    • Uses externally generated ionizing radiation
    • Inactivate or eradicate defined target(s)
      • Head or spine and without incision
    • Cranial lesions one treatment only
  • Computer-assisted, three-dimensional planning
    • E.g. Gamma Knife®, XKnife®, CyberKnife®, etc.
    • # of treatment sessions brief as 15 mins or few hours
      • Depends on individual treatment plan
  • Multidisciplinary team of Neurosurgeon-Radiation Oncologist-Medical Physicist
    • Radiation oncologists/neurosurgeons separately bill
  • CPTs 61796 - 61800, 63620 - 63621 for neurosurgeons
    • Physician present
    • Medically necessary
    • Fully participating
  • With Radiation Oncology CPTs 77432 or 77435
    • Medical records must clearly document need
  • If physician not fully participating, indicate by appended modifier 54/55 on global (date span in Item 19 of CMS-1500 claim form or electronic equivalent)
  • Surgical assistants not covered
    • Many individual components with different specialties

Robotic Radiosurgery

  • Image-guided robotic linear accelerator-based stereotactic radiosurgery
    • Allowed once/day regardless of # of lesions or sessions
    • Does not distinguish between "robotic or non-robotic"
HCPCS Code Description
G0339 Complete therapy course; first/only session fractionated treatment
G0340 Delivery including collimator changes and custom plugging, fractionated treatment; all lesions, per session, second (2nd) - fifth (5th) session, max five (5) sessions per treatment


Covered Providers and Enrollment

Specially-trained team of professionals; based on their state scope of license, include:

  • Radiation Oncologist or Neurosurgeon (specially-trained physician to treat cancer), who oversees care and writes course of treatment
    • Radiation oncologist must evaluate treatment clinical and technical aspects, document evaluation and resulting management decisions
    • If no radiation oncologist in area, radiation physicist charges not recognized under "incident to"
    • Physician supervision includes radiation oncologist evaluating clinical and technical treatment aspects; documenting results of management decisions
  • Medical physicist ensures accuracy of precise radiation dose and accurate computerized calculations
  • Dosimetrists work with medical physicist to calculate beam configurations and IMRT exposures
  • Radiation therapist operates machine and positioning patient on treatment table
  • Radiation therapy nurse collaborates with physician and assists with side effects and/or reactions from treatment
  • Non-physician practitioners (NPPs) not eligible to supervise radiation therapy services in office setting


All documentation must support the medical necessity and claims submitted without such evidence, will deny, or post pay monies recouped; as not medically necessary.

  • Treatment goal must be documented (curative, palliative or tumor control) in medical record
  • Record must contain patient's informed consent to treatment
  • Medical records are logical and clear (recommend flow charts, where helpful)
  • Prescription or treatment plan designed by radiation oncologist must be on file and signed
  • Treated illness/clinical management level
  • Treatment type, delivery, changes
  • Designation - treatment site and isotope
  • Designation - number of source positions
  • Planned dose to each point
  • Reports
  • Simulation, physicist, dosimetry, radiological, etc.
  • Any patient referrals/consultations
  • Records or pictures may use colored lines for film-based and black to show calculated dose distribution

Documentation for IMRT-specific in the patient's medical records must support:

  • Reasonable and necessary requirements as outlined under Indications and Limitations of Coverage and/or Medical Necessity section of this policy and must be available to Medicare for review upon request
  • Prescription must define goals and requirements of treatment plan, including specific dose constraints for target(s) and nearby critical structures
  • Statement by treating physician documenting special need for performing IMRT on patient in question, rather than performing conventional or 3-dimensional treatment planning and delivery
  • Signed and dated IMRT inverse plan that meets prescribed dose constraints for planning target volume (PTV) and surrounding normal tissue using either dynamic multi-leaf collimator (DMLC) or segmented multi-leaf collimator (SMLC) (average number of "steps" required to meet IMRT delivery is 5), or inverse planned IMRT solid compensators to achieve intensity modulation radiation delivery
  • Target verification methodology includes:
    • Both PTV or Planning treatment volume and Clinical treatment volume (CTV)
    • immobilization and patient positioning
    • Means of dose verification and secondary means of verification
  • Before patient's first treatment, monitor units (MUs), generated by IMRT treatment plan, must be independently checked
  • Documenting fluence distributions; meaning fluence map from treatment planning system (TPS) from electronic portal imaging device (EPID) images must be validated for 10 head and neck IMRT cases
  • Noridian must see that structures moving in and out of high and low dose regions created by respiration is documented. Voluntary breath holding is not considered appropriate and solution for movement can best be accomplished with gating technology

SBRT/SRS Documentation Requirements

  • Support medical necessity and frequency
  • Patient history/physical
  • Functional status
  • Karnofsky Status or Eastern Cooperative Oncology Group (ECOG) Performance
    • Measures patient's ability to survive chemotherapy, with performance scales of 100-0 and grades from 0-5. SBRT is not considered medical necessary for patients with poor performance status of Karnofsky (less than 40 or ECOG-3 or worse)
  • Date and current treatment dose
  • Radiation oncologist E/M decisions
  • Document and sign

CERT Errors and Compliance Risk Areas

When a specific, required documentation element is missing, such as a physician's order signature or a form required to be completed; Comprehensive Error Rate Testing (CERT) may recoup the monies previously paid. The medical record missing one or more of the following:

  • No radiation therapy plan submitted
  • Documentation submitted did not adequately describe service
  • Incorrect date of service
  • Physician's signature missing or signature log and/or attestation for illegible signature

CERT Special Study on CPT 77300 (Dosimetry) 

Signed radiation oncology consultation report received and missing:

  • IMRT order/prescription
  • Planning notes including treatment fields, physics, and dosimetry calculations signed by radiation oncologist/medical physicist
  • Documentation to support review of CT or MRI based images of target and all critical structures
  • Weekly physics consult review w/calculations for treatment



Last Updated Dec 09 , 2023

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