Stereotactic Radiosurgery Using Gamma Rays
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Defines medical necessity and investigational uses of stereotactic radiosurgery using cobalt-60 gamma rays (e.g., Gamma Knife®) for intracranial and select extra‑cranial indications and governs CareFirst coverage for affected members and providers.
CareFirst has adopted the position of MCG Care Guidelines® and retired this policy, directing readers to the MCG site for medical necessity criteria.
The medically necessary indications were revised in 2023 to add epilepsy and to broaden the experimental/investigational statement to 'all other uses' rather than calling out chronic pain specifically.
Coverage and Medical Necessity Criteria
Medically necessary indications
Gamma-ray stereotactic radiosurgery (e.g., Gamma Knife®) is considered medically necessary for any one of the following indications:
- Vascular malformation: Angiographically visible arteriovenous malformations (AVM)
- Benign cranial tumors: Initial or recurrent benign cranial tumors including acoustic neuromas (smaller than 3 cm), non-resectable/residual/recurrent meningioma, and pituitary adenoma (e.g., Cushing's disease or acromegaly)
- Brain metastases: Solitary or multiple brain metastases in individuals with good performance status, defined by ALL of the following where applicable: absence of a large tumor (e.g., ~3.5 cm) on diagnostic imaging; ECOG ≤ 3 and expected to return to ≤ 2 with treatment; Karnofsky > 40 and expected to return to ≥ 70 with treatment
Performance status and tumor size criteria referenced in policy (see performance scales)
- Primary malignant brain neoplasms: Primary malignant neoplasms of the brain, initial or recurrent, without mass effect (e.g., no midline shift) on diagnostic imaging
- Epilepsy when ALL of the following are met: brain MRI findings concordant with EEG findings; EEG demonstrates a localized epileptogenic source (e.g., mesial temporal lobe); seizures refractory to at least two different anticonvulsant medications
- Essential tremor when ALL of the following are met: deep brain stimulation is not an option; disability of one or more limbs from resting, positional, or kinetic tremor that affects safety, functional status, or quality of life; tremor refractory to one year or more of standard medication
- Glomus jugulare tumor when ONE or more of the following apply: contraindication to microsurgical resection (e.g., unacceptable operative risk or tumor adjacent to critical structures); residual or recurrent tumor following microsurgical resection
- Trigeminal neuralgia refractory to medical management
- Non-operable spinal tumor (primary, recurrent, or metastatic) that is causing compression or intractable pain
- Uveal tract melanoma (melanoma of the iris, ciliary body, or choroid)
Experimental / Investigational
All other uses of gamma-ray stereotactic radiosurgery are considered experimental/investigational because the TEC/BCBSA evidentiary criteria are not met.
Rationale: available evidence does not permit conclusions about net health benefit for other indications (insufficient quantity/quality of studies, heterogeneous methods, small sample sizes, limited follow-up).
General clinical eligibility considerations
General clinical eligibility and administrative considerations to establish medical necessity and process requests:
Exact numeric cutoffs for specific indications are provided in individual indication nodes (e.g., brain metastases). Document expected post-treatment functional improvement when referenced.
Providers must check member contract and submit preauthorization requests as required (see provider guidelines).
Facility claims and applicability are subject to member contract provisions which supersede clinical criteria.
This policy specifically addresses stereotactic radiosurgery (SRS) delivered with cobalt-60 gamma rays (e.g., Gamma Knife®). It does not address SRS or SBRT delivered with photons or linear accelerators; those techniques are covered under the CareFirst policy “Stereotactic Radiosurgery and Stereotactic Body Radiotherapy with 3‑D Conformal Radiation Therapy (Policy #6.00.010).” In addition, neutron beam, proton beam, and helium ion therapies are governed by separate medical policies and are not covered by this gamma‑ray SRS policy (see Policy 6.01.018 and Policy 6.01.048).
Coverage for services described in this policy will vary by member contract, line of business, and place of service. Specific contract provisions, restrictions, and exclusions take precedence over the clinical criteria in this policy; always verify the member’s benefit plan before proceeding. Some services and places of service may require prior authorization per contract or facility rules.
The evidence does not support the use of gamma‑ray SRS for a number of indications. Reported literature limitations (small sample sizes, heterogeneous methods, short follow‑up) mean SRS is considered experimental/investigational for conditions such as chronic pain syndromes (other than trigeminal neuralgia), cluster headaches, facial nerve schwannomas, and psychiatric disorders (e.g., obsessive‑compulsive disorder). Published reviews and series report inconsistent benefit and methodologic concerns; additional well‑designed studies are needed to demonstrate net health benefit.
Member contract terms may impose additional restrictions that render a service noncovered even if clinical criteria are met. Providers must check the member’s contract and applicable benefit limitations; contract provisions supersede the clinical criteria in this policy and may result in denial or noncoverage.
Coding and Performance Thresholds
| No codes listed |
| CPT | Referenced: Current Procedural Terminology (CPT) (4th edition) cited as a resource (2010). |
Provider Actions, Prior Authorization, and Documentation
Prior Authorization Required
Some services, devices, drugs, and places of service require prior authorization. Providers must obtain prior authorization when indicated and follow MCG criteria adopted by CareFirst for stereotactic radiosurgery. Check the member contract for benefit specifics, as contract provisions, restrictions, and exclusions take precedence over the clinical criteria.
- Submit preauthorization requests online at www.provider.carefirst.com
- Or call 1-866-773-2884 (1-866-PRE-AUTH)
Denial Risk for Non‑listed Indications
Requests for indications not listed in the policy (including uses that do not meet the adopted MCG criteria) are considered experimental/investigational and are at high risk for denial.
Required Documentation and Benefit Note
Specific documentation must be provided to support medical necessity, including relevant imaging (CT, MRI, angiography), clinical history, ECOG or Karnofsky performance status, prior treatment records, and operative or pathology reports when applicable. When services are performed in a facility setting, include the required Benefit Applications statement and verify benefits per the member contract.
- Include imaging reports demonstrating target size and location
- Document ECOG or Karnofsky performance status and rationale for expected functional change with treatment
- Include evidence of prior surgery or contraindication to surgery when applicable
- Attach EEG/MRI concordance and anticonvulsant trial history for epilepsy indications
Prior Treatment Expectations
For certain indications, evidence of prior treatment or trials is required (examples: epilepsy — seizures refractory to at least two anticonvulsant medications with EEG/MRI concordance; trigeminal neuralgia — refractory to medical management; essential tremor — refractory to ≥1 year of standard medication and when deep brain stimulation is not an option). Provide documentation of prior therapies, contraindications, or reasons therapies are not appropriate.
- Epilepsy: documentation of at least 2 failed anticonvulsant medications and concordant EEG/MRI
- Trigeminal neuralgia: documentation of failed medical management
- Essential tremor: documentation of ≥1 year of medication failure and that deep brain stimulation is not an option
Contract Precedence and Benefit Verification
Member contract provisions, restrictions, and exclusions supersede the clinical criteria adopted in this policy. Always verify member benefits and any applicable preauthorization or site-of-service requirements prior to scheduling or performing SRS.
- If the member contract limits coverage, that limitation prevails even if clinical criteria are met
- Confirm site-of-service coverage (inpatient vs outpatient vs ASC) as some places require authorization
Background and Scope
Stereotactic radiosurgery (SRS) is a nonsurgical, highly focused radiation technique that delivers a high dose of radiation to a small, well‑defined target using multiple convergent beams. Gamma‑ray SRS (example: Gamma Knife®) is typically delivered in a single session using stereotactic immobilization, imaging (CT, MRI, or angiography) for target localization, and computerized treatment planning to shape dose and spare adjacent critical structures. An immobilizing frame is often used during treatment to ensure accuracy; once positioned, the patient is monitored from an adjacent control room while beams converge on the treatment target. Functional status scales such as the Karnofsky and ECOG scores are used to assess candidacy and expected outcomes.
Definitions and Performance Scales
Policy Revision History
Policy retired and CareFirst adopted the position of MCG Care Guidelines® for medical necessity and clinical appropriateness of stereotactic radiosurgery; readers directed to the MCG site.
Annual update and review documented; policy status updated in association with adoption of MCG Care Guidelines® and retirement of the policy.
Medically necessary indications revised to add epilepsy and wording of experimental/investigational statement broadened to 'All other uses' (removing the prior specific reference to chronic pain).
Original Medical Policy Committee approval of the stereotactic radiosurgery using gamma rays policy (MPC approval).
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