ModifiedUnitedHealthcarePolicy CS179ID.C

Radiation Therapy: Fractionation, Image-Guidance, and Special Services (for Idaho Only)

Clinical policy governing medically necessary fractionation limits, use of image-guided radiation therapy (IGRT), and special radiation services for members in Idaho, including Idaho Medicaid Plus plans; applies to radiation oncologists and billing staff.

Policy Summary

PayerUnitedHealthcare

PolicyRadiation Therapy: Fractionation, Image-Guidance, and Special Services (for Idaho Only)

Policy CodePolicy CS179ID.C

Change TypeMaterial revisions to APBI fractionation, connective tissue exception, and special dosimetry guidance

Effective DateJune 1, 2026

Next Review DateN/A

Key ActionWhen billing revised fractionation schedules or special dosimetry, obtain prior authorization and document clinical rationale, fractionation regimen, and IGRT frequency.

SourceLink

POLICY UPDATE CHANGES

Added criterion requiring delivery of up to 10 fractions for accelerated partial-breast irradiation with 3D technique.

Replaced criterion to require delivery of up to five fractions for accelerated partial breast irradiation with intensity-modulated radiation therapy.

Clarified connective tissue disorder examples to 'systemic lupus erythematosus or scleroderma' for allowing up to 33 fractions inclusive of boost.

Added detailed notation on CPT code 77331 special dosimetry use, typical measurement ranges (one to six), and documentation expectations for requests beyond the standard range.

Notated that CPT codes 77436–77439 are not on the State of Idaho Medicaid Fee Schedule and therefore may not be covered by Idaho Medicaid.

Updated guidance that megavoltage planning, imaging, and treatment delivery codes should not be reported during superficial, surface, or orthovoltage radiation therapy; CPT codes 77436–77439 should be reported for those therapies.

up to 10

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.

Coverage Criteria for Radiation Therapy

inv-01: Bone metastases — palliative EBRT — Medically necessary when ONE of the following is met

Medically necessary when ONE of the following is met

Bone metastases palliative EBRT: Delivery of up to 10 fractions of radiation therapy is medically necessary; delivery of greater than 10 fractions is medically necessary for treatment of a site that has previously received radiation therapy.<=10 fractions (initial); >10 allowed for previously irradiated site

Reirradiation exception per policy

inv-02: Breast adenocarcinoma — EBRT fractionation — Medically necessary when ONE of the following fractionation regimens applies

Medically necessary when ONE of the following fractionation regimens applies

Accelerated partial breast (IMRT): Delivery of up to five fractions for accelerated partial breast irradiation with intensity-modulated radiation therapy is medically necessary.<=5 fractions

Per policy revision: IMRT-specified APBI

Accelerated partial breast (3D): Delivery of up to 10 fractions for accelerated partial-breast irradiation with 3D technique is medically necessary.<=10 fractions

Added in 06/01/2026 policy revision

Whole-breast/chest (inclusive of boost): Delivery of up to 21 fractions (inclusive of a boost to the tumor bed) is medically necessary.<=21 fractions

Standard whole-breast/chest wall fractionation limit

Extended fractionation to 33 (conditional): Delivery of up to 33 fractions (inclusive of a boost to the tumor bed) is medically necessary when any of the following are present: treatment of supraclavicular and/or internal mammary lymph nodes; postmastectomy radiation; prior thoracic radiation; or connective tissue disorder such as systemic lupus erythematosus or scleroderma.<=33 fractions with listed conditions

Connective tissue disorder exception clarified in policy history

inv-03: Locally advanced non-small cell lung cancer — Medically necessary when ALL of the following are met

Medically necessary when ALL of the following are met

LA-NSCLC definitive/chemoradiation: Definitive radiotherapy for unresectable, locally advanced (stage III) non-small cell lung cancer delivered with concurrent platinum-based chemotherapy using standard-dose fractionation (minimum total dose >= 60 Gy) is medically necessary; delivery of up to 35 fractions is permitted.>=60 Gy; <=35 fractions

Escalation to 74 Gy with concurrent chemotherapy was not superior and may be harmful (RTOG trial)

inv-04: Prostate adenocarcinoma — EBRT fractionation — Medically necessary when ONE of the following applies

Medically necessary when ONE of the following applies

Definitive treatment — limited metastatic disease: Delivery of up to 20 fractions for definitive treatment in an individual with limited metastatic disease is medically necessary.<=20 fractions

For limited metastatic prostate disease per policy

Localized prostate cancer — standard: Delivery of up to 28 fractions for localized prostate cancer is medically necessary.<=28 fractions

Conventional and moderate hypofractionation options described in guidelines

Localized prostate cancer — extended: Delivery of up to 45 fractions for localized prostate cancer is medically necessary when any of the following are present: treatment includes pelvic lymph nodes for high-risk disease, radiation delivered post-prostatectomy, history of inflammatory bowel disease (eg, ulcerative colitis or Crohn's disease), or prior pelvic radiation therapy.

inv-05: Image-guided radiation therapy (IGRT) coverage — IGRT is medically necessary when ANY of the following conditions are met

IGRT is medically necessary when ANY of the following conditions are met

With IMRT or PBRT: When image guidance is used with intensity-modulated radiation therapy (IMRT) or proton beam radiation therapy (PBRT).

Examples include prostate IMRT/PBRT

Target previously irradiated or adjacent to prior field: When the target has received prior radiation therapy or abuts a previously irradiated area, requiring precise abutment or sparing of adjacent tissues.

Supports safe reirradiation and narrow-margin treatments

Implanted fiducial markers: When implanted fiducial markers are being used for target localization.

Fiducial-based localization indications

3D-CRT definitive treatment for specified sites:

inv-06: Palliative bone metastases — recommended fractionation — Covered when one of the guideline-recommended palliative fractionation schemes is used and clinically indicated

Covered when one of the guideline-recommended palliative fractionation schemes is used and clinically indicated:

Accepted palliative bone RT fractionation: Accepted regimens include single-fraction 8 Gy; multifraction options such as 20 Gy in 5 fractions, 24 Gy in 6 fractions, and 30 Gy in 10 fractions; spine-compression regimens (8 Gy x1, 16 Gy in 2 fractions, 20 Gy in 5 fractions, or 30 Gy in 10 fractions); and reirradiation options including 8 Gy x1, 20 Gy/5, 24 Gy/6, or 20 Gy/8. Choice should consider prognosis, prior RT dose, normal tissue risks, quality of life, and patient goals per ASTRO/ACR/ESTRO/NCCN guidance.

Guideline-backed regimens summarized from ASTRO, ACR, ESTRO, NCCN

inv-07: Comparative effectiveness and harms — Clinical considerations and comparative outcomes to inform coverage decisions

Clinical considerations and comparative outcomes to inform coverage decisions:

Comparative outcomes: Single-fraction (8 Gy) and multifraction EBRT provide similar overall pain response for initial and reirradiation palliative treatment; single-fraction regimens have higher retreatment rates. SBRT may provide slightly higher pain response in some comparisons. Serious harms are rare across regimens. Evidence summarized from AHRQ review, multiple RCTs and meta-analyses.

Data include AHRQ review, Hartsell trial, and meta-analyses

inv-08: Early-stage breast cancer — hypofractionation and PBI — Covered when used in populations supported by trials demonstrating noninferiority or guideline endorsement

Covered when used in populations supported by trials demonstrating noninferiority or guideline endorsement:

Adjuvant whole-breast hypofractionation: Whole-breast hypofractionated schedules (eg, 40 Gy in 15 fractions or 42-42.56 Gy in 16 fractions) are supported for appropriate early-stage patients; five-fraction whole-breast schedules (eg, 26–27 Gy in 5 fractions) have trial support with required verification imaging per protocol.

Brunt et al. and guideline endorsement cited

APBI/PBI regimens: APBI regimens supported in selected early-stage patients include external-beam or brachytherapy schedules such as 30 Gy in 5 fractions (APBI-IMRT), 34 Gy brachytherapy, or 38.5 Gy in 10 fractions; trial results vary and some APBI trials did not meet strict equivalence to WBI, so indication is limited to selected populations and techniques.

NSABP B-39/RTOG 0413 and Meattini et al.; technique- and patient-selection dependent

inv-09: Breast RT dose-fractionation and PBI — Covered when consistent with evidence-based guideline regimens and technique documentation

Covered when consistent with evidence-based guideline regimens and technique documentation

Breast HF-WBI: Whole-breast hypofractionated RT for invasive cancer or DCIS is supported at doses approximately 40 Gy in 15 fractions or 42-42.56 Gy in 16 fractions; deliver boost doses per risk factors and document technique (eg, DIBH for left-sided tumors) and DVH constraints.

ASTRO and NCCN endorse these regimens

Partial-breast / APBI: External-beam or brachytherapy APBI/PBI regimens supported include 30 Gy in five fractions (nonconsecutive within 2 weeks), 4005 cGy in 15 fractions, or other trial-based schedules for selected patients; document technique, fractionation, and dose–volume constraints due to mixed trial results on equivalence and toxicity.

Technique- and schedule-specific documentation required

inv-10: Locally advanced (stage III) NSCLC definitive RT — Covered when delivered according to standard-dose concurrent chemoradiation practice

Covered when delivered according to standard-dose concurrent chemoradiation practice

Standard-dose concurrent chemoradiation for stage III NSCLC: Definitive RT for unresectable stage III NSCLC should be delivered with concurrent platinum-based chemotherapy using standard-dose fractionation with total dose at least 60 Gy (commonly 60 Gy in 2 Gy daily fractions); use of IGRT when indicated.>=60 Gy

RTOG trial found 74 Gy with concurrent chemo was not superior and may be harmful

inv-11: Prostate RT fractionation and pelvic nodal coverage — Covered regimens reflect trial-proven schedules and indications

Covered regimens reflect trial-proven schedules and indications

Moderate hypofractionation for localized prostate cancer: Moderate hypofractionation regimens (eg, 60 Gy in 20 fractions) are supported as noninferior to conventional fractionation for many patients; select regimens and patient counseling about toxicity are required.fraction sizes up to ~3.4 Gy

Cochrane review, Catton, Dearnaley trials support

Whole pelvic radiotherapy for high-risk prostate cancer: For men with estimated nodal risk >= 20%, prophylactic whole pelvic radiotherapy (eg, pelvic nodes to ~50 Gy with prostate dose) with IMRT/IGRT and long-term ADT is supported to improve biochemical/disease-free outcomes; consider WPRT before prostate-only RT in high-risk cases.nodal risk >=20%

Murthy et al. RCT supports improved BFFS and DFS

inv-12: Covered with criteria — Hypofractionation and IGRT — Relevant clinical trial outcomes and guideline recommendations supporting use of moderate hypofractionation and IGRT

Relevant clinical trial outcomes and guideline recommendations supporting use of moderate hypofractionation and IGRT:

Prostate hypofractionation evidence: Moderate hypofractionation (fraction sizes roughly 2.4–3.4 Gy) is supported by randomized trials and systematic reviews showing noninferior disease control and similar late GU/GI toxicity for many regimens (eg, 60 Gy in 20 fractions); daily IGRT is recommended to support margin reduction.fraction size 240-340 cGy

ASTRO, Cochrane, Catton, Dearnaley trials cited

Regimens with caution: Certain hypofractionated schedules (eg, HYPRO: 19 x 3.4 Gy) showed higher acute GU/GI toxicity signals and are not established as new standards; select regimens should be chosen considering toxicity evidence.

HYPRO trial concerns

Role of IGRT: Daily image guidance (eg, daily CBCT) is associated with reduced acute GU/GI toxicity and improved biochemical relapse-free survival in prostate RT compared with less frequent IGRT; IGRT enables margin reduction and improves targeting across tumor sites.

inv-13: Indications where IGRT is recommended — IGRT is recommended or strongly recommended in the following clinical scenarios per professional society and guideline statements

IGRT is recommended or strongly recommended in the following clinical scenarios per professional society and guideline statements:

IGRT indications summary: Any of the following: target near or within critical structures; target subject to inherent setup variation or daily internal motion; volume requiring narrow margins to protect adjacent structures; adjacent area previously irradiated requiring precise abutment; planned dose escalation beyond usual doses; use of stereotactic or highly conformal techniques (3D-CRT, IMRT, PBRT, SBRT/SABR).

Based on ACR-ASTRO, ASTRO, NCCN guidance

inv-14: Evidence-based benefits and motion-management considerations — Clinical evidence and studies report the following effects informing coverage decisions and clinical practice

Clinical evidence and studies report the following effects informing coverage decisions and clinical practice:

Margin reduction with respiratory IGRT: Respiratory management including 4D-CT planning and daily image guidance can reduce treatment field margins substantially (reported potential reduction ~37%–47%).

Korreman et al. 2012

Prostate intrafraction motion: Intrafraction prostate motion during 5–7 minute treatments is common: motion outside 2 mm observed in 66% of fractions and outside 3 mm in 28% of fractions, supporting minimum intrafraction margins (~2 mm) and use of image guidance/fiducials.

Kotte et al. 2007

BMI and setup error: Higher BMI correlates with larger systematic and random setup errors; an initial daily IGRT strategy for the first five fractions with subsequent mean-error correction reduces setup error and margin requirements.

Lin et al. 2012

inv-15: Quality assurance and operational requirements — Safe and effective IGRT requires institutional processes

Safe and effective IGRT requires institutional processes:

QA and operational requirements: Implement daily quality control procedures, geometric accuracy assessments, documented standard operating procedures, interdisciplinary staffing, and comprehensive QA programs to support IGRT when PTV margins are reduced and processes are more complex.

AAPM and ASTRO guidance cited

inv-16: Breast adenocarcinoma - accelerated partial breast irradiation (APBI) fractionation — Revised coverage criteria for fractionation in APBI

Revised coverage criteria for fractionation in APBI

APBI fractionation options: Coverage allows delivery of up to 10 fractions for APBI using 3D technique OR up to 5 fractions for APBI using intensity-modulated radiation therapy (IMRT); apply when billing APBI for breast adenocarcinoma and document technique.up to 10 (3D) OR up to 5 (IMRT)

Policy history 06/01/2026 revised APBI fractionation; note that some APBI trials did not meet equivalence to WBI and patient selection/technique matter

inv-17: Connective tissue disorder exception for fractionation — Exception permitting extended fractionation when connective tissue disorder present

Exception permitting extended fractionation when connective tissue disorder present

Connective tissue disorder: Delivery of up to 33 fractions (inclusive of a boost to the tumor bed) is allowed when the individual has a connective tissue disorder such as systemic lupus erythematosus or scleroderma.up to 33

Clarified connective tissue disorder examples in policy history

Image-guided radiation therapy (IGRT) is considered not medically necessary when the policy’s specified IGRT coverage criteria are not met. This includes use of IGRT solely to align bony landmarks without the presence of implanted fiducial markers (for example, during palliative radiation therapy) or when none of the listed clinical indications (such as use with IMRT/PBRT, prior/adjacent radiation, implanted fiducials, or documented motion/immobilization issues) are documented.

For breast cancer treatment, delivery of radiation exceeding 33 fractions (inclusive of any tumor‑bed boost) is not medically necessary except where the policy explicitly allows up to 33 fractions for the listed conditions (treatment of supraclavicular/internal mammary nodes, postmastectomy radiation, prior thoracic RT, or specified connective tissue disorders).

For locally advanced non‑small cell lung cancer treated with EBRT (with or without chemotherapy), delivery of radiation beyond 35 fractions is designated not medically necessary by this policy. The medically necessary limit is up to 35 fractions.

For localized prostate cancer, the policy limits EBRT to a maximum of 45 fractions only when one or more specific circumstances apply (e.g., pelvic nodal radiation for high‑risk disease, post‑prostatectomy treatment, history of inflammatory bowel disease, or prior pelvic RT). Delivery of greater than 45 fractions for localized prostate cancer is not medically necessary.

The large randomized NSABP B‑39/RTOG 0413 trial did not meet equivalence criteria for accelerated partial breast irradiation (APBI) compared with whole‑breast irradiation (WBI) for local tumor control, so APBI should not be assumed equivalent to WBI outside the specific patient populations, techniques, and schedules tested in trials. Coverage and indication for APBI are therefore limited to the populations and techniques supported by trial evidence and guideline endorsement.

APBI delivered with techniques or schedules that do not meet the dose‑volume requirements tested in randomized trials or professional guidelines—or delivered on twice‑daily schedules that have been associated with increased late toxicity and worse cosmetic outcomes—are discouraged unless the provider documents a clear rationale and that dose‑volume constraints and technique mitigate the known risks.

The HYPRO trial evaluated a hypofractionated prostate regimen of 19 fractions of 3.4 Gy and did not establish that schedule as superior; it showed higher acute GU/GI toxicity without clear superiority in efficacy. Therefore the HYPRO regimen cannot be regarded as the new standard of care for intermediate‑ or high‑risk prostate cancer and should not be adopted routinely without explicit justification and documentation.

IGRT is not indicated for superficial treatment of skin cancer, and is not medically necessary when used solely to align bony landmarks without implanted fiducials. The policy and ASTRO guidance specify that surface/superficial treatments generally do not require IGRT unless other specified clinical indications are present.

Megavoltage planning, imaging, and treatment delivery CPT codes should not be reported for superficial, surface, or orthovoltage radiation therapy. Instead, the policy clarifies that CPT codes for superficial/surface/orthovoltage therapy (CPT codes 77436–77439) should be reported for those treatments; billing of megavoltage codes in that context is inconsistent with the policy’s coding guidance.

For breast cancer, delivery of radiation in excess of 33 fractions (inclusive of a boost) is identified as not medically necessary. The policy allows up to 33 fractions only under specified conditions (for example, nodal treatment, postmastectomy RT, prior thoracic RT, or defined connective tissue disorders).

For locally advanced (stage III) non‑small cell lung cancer, the policy states that delivery of more than 35 fractions is not medically necessary; the medically necessary regimen is limited to up to 35 fractions.

For localized prostate cancer, delivery of greater than 45 fractions is considered not medically necessary. Up to 45 fractions are permitted only when the documented clinical criteria described in the policy are met (eg, pelvic nodal irradiation, post‑prostatectomy, inflammatory bowel disease, prior pelvic RT).

Some palliative regimens present trade‑offs between efficacy and toxicity (for example, single‑fraction 8 Gy versus multifraction regimens such as 20 Gy/5); the evidence indicates similar overall pain response but differing retreatment rates and toxicity profiles. The policy does not convert these trade‑offs into blanket 'not medically necessary' statements—both approaches remain clinically acceptable options when chosen with appropriate documentation and clinical rationale.

Escalation of thoracic radiotherapy to 74 Gy with concurrent chemotherapy for stage III NSCLC was not superior and was associated with potential harm compared with standard‑dose chemoradiation (60 Gy), based on RTOG trial results; such dose escalation is therefore not supported by the trial evidence and is discouraged without compelling justification.

Hypofractionated prostate regimens that demonstrably increase acute genitourinary or gastrointestinal toxicity without established superiority in efficacy—such as the 19 × 3.4 Gy HYPRO schedule evaluated in trials—should be regarded as non‑preferred and require clear justification, counseling, and documentation if considered for individual patients.

Coding notes in the policy identify state‑specific coverage limitations: CPT codes 77436, 77437, 77438, and 77439 are noted as not appearing on the State of Idaho Medicaid Fee Schedule and therefore may not be covered for Idaho Medicaid members; providers should consult the Idaho Medicaid Provider Handbook for exclusions and fee‑schedule details.

Coding and Billing Guidance

Applicable CPT/HCPCS codes (reference)mixed

77331	Special dosimetry (e.g., TLD, microdosimetry) (specify)
77370	Special medical radiation physics consultation
77387	Guidance for localization of target volume for delivery of radiation treatment, includes intrafraction tracking, when performed
77399	Unlisted procedure, medical radiation physics, dosimetry and treatment devices, and special services
77402	Radiation treatment delivery; Level 1
77407	Radiation treatment delivery; Level 2, single-isocenter
77412	Radiation treatment delivery; Level 3, multiple isocenters or single-isocenter with active motion management
77436	Surface radiation therapy; superficial or orthovoltage, treatment planning and simulation-aided field setting
77437	Surface radiation therapy; superficial, delivery, 150 kV, per fraction
77438	Surface radiation therapy; orthovoltage, delivery, > 150-500 kV, per fraction

1–10 of 15

1/2

Special services and considerationsCPT

77331	Special dosimetry — considered for coverage only when primary radiation procedure is proven and medically necessary
77370	Special medical radiation physics consultation — report once under specified complex circumstances
77470	Special treatment procedure — report once under specified complex circumstances
77399	Unlisted procedure — only if no other code appropriately describes the procedure

No explicit CPT/HCPCS/ICD codes listedmixed

No codes listed

Referenced regimens and techniques (no explicit billing codes listed in this extract)mixed

No codes listed

Coding referencesmixed

CPT (referenced)

CPT codes are referenced through AMA CPT 2026 Professional Edition (document lists CPT as source but does not enumerate specific CPT codes in this section).

FDA device codes (informational)mixed

FDA product codes LHN, MUJ, IYE (informational)

Device product codes referenced for informational device approvals related to radiation therapy equipment.

Idaho Medicaid-noted CPT CodesCPT

77436	Megavoltage therapy delivery (not on Idaho Medicaid Fee Schedule)
77437	Megavoltage therapy delivery (not on Idaho Medicaid Fee Schedule)
77438	Megavoltage therapy delivery (not on Idaho Medicaid Fee Schedule)
77439	Megavoltage therapy delivery (not on Idaho Medicaid Fee Schedule)

Special dosimetryCPTCovered

77331

Special dosimetry

IMRT planningCPT

77301

IMRT planning

Hypofractionation fraction size

DefinitionHypofractionation = external beam RT with fraction size between 240 cGy and 340 cGy.

Typical thresholdFraction size >200 cGy qualifies as hypofractionated approach (policy defines specific range 240–340 cGy).

Clinical contextApplied when delivering fewer fractions with larger per‑fraction dose compared with conventional fractionation.

Minimum definitive lung RT dose

Minimum definitive dose>= 60 Gy (recommended minimum for definitive RT in locally advanced stage III NSCLC).

Provider Actions, Authorization, and Documentation

Billing Rule

Applicable codes and coverage note

The following codes are provided for reference only; inclusion does not guarantee coverage or payment. Providers must bill the appropriate procedure code reflecting the documented level of complexity and clinical services rendered. Note that CPT codes 77436–77439 are not on the State of Idaho Medicaid Fee Schedule and therefore may not be covered by Idaho Medicaid.

Report radiation treatment delivery at the documented complexity level (77402 = Level 1, 77407 = Level 2, 77412 = Level 3) and include supporting documentation when 77412 is used.
IGRT technical components are typically included in 77402/77407/77412; report professional IGRT component with 77387-26 when appropriate.
Special dosimetry (77331), medical radiation physics consultation (77370), special treatment procedure (77470), and unlisted services (77399) are considered for coverage only when the primary radiation procedure is proven and medically necessary; document clinical justification for use.
CPT 77331: special dosimetry is intended for 1–6 measurements typically; requests beyond that range require justification and will be reviewed case-by-case.

Background and Evidence Summary

A radiation therapy course comprises several components including consultation, treatment planning, special services (eg, dosimetry, immobilization), treatment delivery across multiple fractions, and follow‑up. Fractionation strategies include conventional, hypofractionated (fraction sizes between 240–340 cGy defined here as hypofractionation), accelerated, and single‑fraction palliative approaches. Understanding these components and fractionation strategies is essential for applying the policy’s coverage criteria and documenting medical necessity.

Definitions and Terminology

Definitive Treatment

DefinitionDefinitive treatment = radiation treatments for cancer with curative intent.

ScopeIntended to eliminate disease or attain durable remission depending on cancer type and stage.

TeamDelivered by a multidisciplinary radiation oncology team including radiation oncologist, medical physicist, dosimetrist, therapists, and nursing support.

Limited Metastatic Disease (prostate)

DefinitionLimited metastatic disease (prostate) = absence of visceral metastasis or fewer than four bone metastases with no metastasis outside the vertebral bodies or pelvis.

Use caseDefinition applied when considering definitive or consolidative radiotherapy in oligometastatic prostate cancer.

Policy Summary

PayerUnitedHealthcare

PolicyRadiation Therapy: Fractionation, Image-Guidance, and Special Services (for Idaho Only)

Policy CodePolicy CS179ID.C

Change TypeMaterial revisions to APBI fractionation, connective tissue exception, and special dosimetry guidance

Effective DateJune 1, 2026

Next Review DateN/A

Key ActionWhen billing revised fractionation schedules or special dosimetry, obtain prior authorization and document clinical rationale, fractionation regimen, and IGRT frequency.

SourceLink

On This Page

Prior Authorization

Prior authorization: guideline‑backed regimens

Prior authorization is recommended for palliative bone RT regimens and for other guideline-backed altered-fractionation regimens where the requested schedule deviates from common standards or state-specific coverage rules. When seeking authorization, submit documentation of prognosis, prior RT doses, normal tissue constraints, and patient-centered goals to support the chosen regimen.

Accepted conventional palliative regimens include: 800 cGy ×1; 2000 cGy ×5; 2400 cGy ×6; 3000 cGy ×10. Spine compression regimens include 800 cGy ×1, 1600 cGy ×2, 2000 cGy ×5, or 3000 cGy ×10.
No mandated step therapy: multiple acceptable fractionation options exist and no single regimen is required prior to another.

Documentation Required

Document fractionation and IGRT frequency

Document the total fractionation schedule requested and the planned IGRT frequency (daily vs nondaily) in the medical record and in any prior‑authorization request. For altered or shortened fractionation, include clinical rationale and references to guideline support.

For prostate EBRT, state the specific fractionation (e.g., 60 Gy/20 fx) and whether daily localization (preferred) or nondaily IGRT is planned.
For hypofractionated breast and APBI regimens, specify verification-imaging frequency (trial evidence required verification each fraction for 5‑fraction schedules) and planned corrective thresholds.

Documentation Required

Clinical indications for IGRT

IGRT is commonly indicated when targets are adjacent to critical structures, when narrow PTV margins are used, or when targets are subject to daily internal motion. Indications also include previously irradiated adjacent areas, planned dose escalation, and situations requiring tight geometric accuracy (e.g., SBRT, IMRT, proton therapy).

Examples: head and neck, lung, pancreas, hepatobiliary, liver, prostate, pelvic sarcoma, and accelerated/ultra‑hypofractionated treatments.
IGRT is not medically necessary solely to align bony landmarks without implanted fiducials (for example, during palliative RT) unless other IGRT criteria are met.

Prior Authorization

Prior authorization recommended for revised fractionation and special dosimetry

Prior authorization is recommended when requesting revised fractionation schedules or special dosimetry (CPT 77331, 77370, 77470, 77399). Requests must include clinical justification, prior‑treatment history, and a clear description of why routine planning/dosimetry is insufficient.

If requesting CPT 77331, document the clinical scenario requiring point dose measurements and the anticipated number of measurements (typically 1–6).
Requests for CPT 77370 or 77470 should list the specific complexity (e.g., pediatric daily anesthesia, complex photon/electron interrelationships, specialized brachytherapy) and be supported by documentation.
Unlisted code 77399: provide detailed operative description and rationale that no other code applies.

Note

Not applicable / administrative notes

Not all provider actions in this policy create automatic authorization or denial triggers. Providers should follow payer-specific submission instructions; absence of a mandated step therapy for certain palliative regimens does not negate the need for documentation to support medical necessity.

No mandated step therapy is specified for palliative bone metastasis regimens — multiple acceptable options exist.
Providers must still meet usual prior‑authorization or medical‑necessity documentation requirements per payer.

Documentation Required

High‑dose thoracic RT may be disfavored

High‑dose thoracic chemoradiation (e.g., 74 Gy with concurrent chemotherapy for stage III NSCLC) may be disfavored based on trial data showing no survival benefit and higher toxicity compared with standard‑dose regimens (e.g., 60 Gy). Document rationale if higher thoracic doses are requested.

When requesting doses above commonly recommended ranges, provide clinical justification, prior treatment history, and toxicity mitigation strategies (e.g., IGRT, motion management).

Documentation Required

Daily prostate localization using IGRT is essential

Daily prostate localization using IGRT is considered essential for margin reduction and treatment accuracy per guidelines. When daily IGRT is planned, document modality, verification method, and how image guidance will inform setup corrections.

State whether daily volumetric imaging (CBCT/MVCT) or other daily localization (fiducials, kV imaging) will be used.
If nondaily IGRT is chosen, include evidence-based rationale; daily IGRT has been associated with improved biochemical control compared with nondaily schedules.

Documentation Required

Patient medical record must contain documentation supporting medical necessity

The patient's medical record must contain documentation that fully supports medical necessity for the requested services. Required items include relevant history, physical exam findings, prior radiation doses, imaging and diagnostic test results, and a clear treatment plan describing fractionation, dose constraints, IGRT modality/frequency, and motion‑management techniques.

Make all documentation legible, available upon request, and submitted with prior‑authorization materials as applicable.
Include dose‑volume histograms and comparative plans when claiming differences in normal tissue sparing or when justifying IGRT/use of special dosimetry.

Documentation Required

Verification imaging for hypofractionated breast RT

Verification imaging is required for certain hypofractionated breast regimens and APBI; trial evidence for 5‑fraction whole‑breast schedules mandated verification imaging for each fraction with correction of measured displacements. At minimum, document the planned verification frequency and corrective action thresholds.

For external‑beam PBI (e.g., 30 Gy in 5 fx) and 5‑fraction whole‑breast regimens, indicate whether imaging will be performed each fraction and the planned action for measured shifts.
Use DVHs to evaluate normal tissue constraints (heart, lung) and document use of techniques such as DIBH when applicable.

Documentation Required

Imaging and dosimetric documentation

Use dose‑volume histograms and imaging records to document dosimetric reproducibility and to justify reductions in margins or dose escalation. Maintain records of image verification, IGRT modality, and any adaptive/replanning actions taken during the course of treatment.

When requesting special dosimetry or advanced physics consultation, include DVHs, plan comparisons, and a description of measurements to be performed.
Document the frequency and type of verification imaging (daily, weekly, on‑line vs off‑line) and the method used to determine and apply setup corrections.

Documentation Required

Providers should document IGRT modality, frequency, and image verification method

Providers should explicitly document the IGRT modality (CBCT, MVCT, kV imaging, fiducials), the image verification method (online vs offline), and the planned imaging frequency in the medical record and in prior‑authorization submissions.

Specify whether volumetric imaging will be used and the proposed schedule (e.g., daily CBCT for first 5 fractions then mean‑error correction vs daily for entire course).
If trainees will be involved in verification processes, document supervision and QA procedures.

Documentation Required

Quality and safety documentation

Implement and document quality and safety processes for IGRT programs, including standard operating procedures, interdisciplinary team roles, routine QA checks, and documented decision‑making pathways for adaptive replanning or corrective actions.

Maintain SOPs that address geometric accuracy, daily quality control, and personnel responsibilities.
Document QA logs, equipment calibration, and incident investigation procedures as part of the medical record and program quality files.

Prior Authorization

Special dosimetry documentation

When CPT 77331 (special dosimetry) is requested, document the clinical need, the specific measurement technique, and the anticipated number of measurements (typically 1–6). Requests exceeding the typical range require explicit justification and will be reviewed on a case‑by‑case basis.

Note that IMRT planning (77301) includes special dosimetry; when separate 77331 is billed, clarify why the measurement is not encompassed by routine planning.
Provide device details (e.g., TLDs, diode probes, film) and measurement locations relative to PTV/OARs.

Step Therapy

No mandated step therapy specified

No mandated step therapy is specified for palliative bone metastases; multiple guideline‑endorsed fractionation options are acceptable. Choose the regimen that best matches the clinical situation and patient goals, and document the rationale.

Acceptable regimens include single‑fraction 8 Gy and multifraction options (2000 cGy/5 fx, 2400 cGy/6 fx, 3000 cGy/10 fx).
If selecting single‑fraction therapy, note higher retreatment rates may occur and document the discussion with the patient.

Documentation Required

Consider WPRT before prostate‑only RT in high‑risk cases

For high‑nodal‑risk prostate cancer (estimated nodal risk ≥20%), consider whole pelvic radiotherapy (WPRT) prior to prostate‑only RT; when WPRT is selected, document nodal risk estimate, planned nodal dose, use of IMRT/IGRT, and duration of ADT.

Typical WPRT approach example: 68 Gy/25 fx to prostate plus 50 Gy/25 fx to pelvic nodes with IMRT/IGRT and at least 2 years of ADT in high‑risk cases.
Include rationale and expected benefit (improved biochemical failure‑free survival and disease‑free survival) in authorization materials.

Documentation Required

Evidence supports using moderate hypofractionation for localized prostate cancer

Evidence supports moderate hypofractionation (e.g., 60 Gy in 20 fractions) as an appropriate alternative to conventional fractionation for localized prostate cancer; document trial basis and chosen schedule when requesting authorization.

Preferred moderate hypofractionation examples: 3 Gy ×20 (60 Gy total), 2.7 Gy ×26, 2.5 Gy ×28; conventional regimens typically 1.8–2 Gy ×37–45.
When using hypofractionation, document IGRT plans and any motion‑management strategies to support margin reduction.

Documentation Required

Imaging frequency and verification

Initial verification imaging strategies (for example, imaging during the first 3–5 fractions with mean‑error correction thereafter) can reduce setup error and should be documented. Specify whether verification will be online (immediate correction) or offline (delayed review) and the thresholds that will prompt immediate corrective action or replanning.

Document planned verification schedule (e.g., daily for first 5 fractions then weekly or mean‑error correction) and the numeric shift thresholds that will trigger correction or repeat imaging.
For patients with high BMI or known setup variability, consider daily imaging for margin reduction and document this clinical plan.

Partial-breast irradiation (PBI)/APBI

DefinitionPartial‑breast irradiation (PBI)/accelerated partial breast irradiation (APBI) = radiation limited to the lumpectomy cavity/partial breast using techniques such as brachytherapy, 3D‑CRT, IMRT, or EBRT given in fewer fractions than whole‑breast irradiation.

TechniquesIncludes multicatheter/interstitial brachytherapy, intracavitary devices, 3D‑CRT, and IMRT-based external beam approaches.

Patient selectionUsed in selected early‑stage patients meeting trial and guideline criteria due to variable trial outcomes and technique‑dependent toxicity/cosmesis results.

Intrafraction motion

DefinitionIntrafraction motion = target movement that occurs during a single treatment fraction (example: prostate motion observed during 5–7 minute treatments causing motion outside 2–3 mm in many fractions).

ImpactIntrafraction motion can produce position uncertainty even with perfect start‑of‑treatment corrections, supporting minimum intrafraction margins (e.g., ~2 mm for prostate) and the use of motion management techniques.

Clinical implicationFrequent intrafraction motion supports use of fiducials, intrafraction imaging or tracking, and appropriate PTV margins for accurate delivery.